Re: [PATCH v1 1/1] nvmem: Change return type of reg read/write to ssize_t

[Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>]

Hi Joy,



On 19/02/2024 11:31, Joy Chakraborty wrote:
> Change return type of reg_read() and reg_write() callback to ssize_t for
> nvmem suppliers to return number of bytes read/written to the nvmem core.
>
> Currently nvmem core assumes the amount of data read/written is equal
> to what it has requested from the supplier, this return code facilitates
> better error handling in the nvmem core.
>
> Signed-off-by: Joy Chakraborty <joychakr@xxxxxxxxxx>

This does not apply cleanly on 
https://git.kernel.org/pub/scm/linux/kernel/git/srini/nvmem.git/log/?h=for-next

can you rebase and send?

thanks,
srini

> ---
>   drivers/nvmem/apple-efuses.c        |  5 +-
>   drivers/nvmem/bcm-ocotp.c           |  8 ++--
>   drivers/nvmem/brcm_nvram.c          |  8 +++-
>   drivers/nvmem/core.c                | 73 +++++++++++++----------------
>   drivers/nvmem/imx-iim.c             |  4 +-
>   drivers/nvmem/imx-ocotp-ele.c       |  4 +-
>   drivers/nvmem/imx-ocotp-scu.c       |  8 ++--
>   drivers/nvmem/imx-ocotp.c           |  6 +--
>   drivers/nvmem/jz4780-efuse.c        |  5 +-
>   drivers/nvmem/lan9662-otpc.c        |  8 ++--
>   drivers/nvmem/layerscape-sfp.c      |  7 ++-
>   drivers/nvmem/lpc18xx_eeprom.c      | 10 ++--
>   drivers/nvmem/lpc18xx_otp.c         |  4 +-
>   drivers/nvmem/meson-efuse.c         | 10 +++-
>   drivers/nvmem/meson-mx-efuse.c      |  4 +-
>   drivers/nvmem/microchip-otpc.c      |  4 +-
>   drivers/nvmem/mtk-efuse.c           |  4 +-
>   drivers/nvmem/mxs-ocotp.c           |  5 +-
>   drivers/nvmem/nintendo-otp.c        |  4 +-
>   drivers/nvmem/qcom-spmi-sdam.c      |  8 ++--
>   drivers/nvmem/qfprom.c              | 10 ++--
>   drivers/nvmem/qoriq-efuse.c         |  4 +-
>   drivers/nvmem/rave-sp-eeprom.c      | 12 ++---
>   drivers/nvmem/rmem.c                |  2 +-
>   drivers/nvmem/rockchip-efuse.c      | 11 +++--
>   drivers/nvmem/rockchip-otp.c        | 13 ++---
>   drivers/nvmem/sc27xx-efuse.c        |  3 +-
>   drivers/nvmem/sec-qfprom.c          |  4 +-
>   drivers/nvmem/snvs_lpgpr.c          | 13 +++--
>   drivers/nvmem/sprd-efuse.c          |  8 ++--
>   drivers/nvmem/stm32-bsec-optee-ta.c |  8 ++--
>   drivers/nvmem/stm32-bsec-optee-ta.h | 12 ++---
>   drivers/nvmem/stm32-romem.c         | 16 +++----
>   drivers/nvmem/sunplus-ocotp.c       |  4 +-
>   drivers/nvmem/sunxi_sid.c           | 11 +++--
>   drivers/nvmem/u-boot-env.c          |  4 +-
>   drivers/nvmem/uniphier-efuse.c      |  4 +-
>   drivers/nvmem/vf610-ocotp.c         |  5 +-
>   drivers/nvmem/zynqmp_nvmem.c        |  2 +-
>   include/linux/nvmem-provider.h      |  4 +-
>   40 files changed, 180 insertions(+), 159 deletions(-)
>
> diff --git a/drivers/nvmem/apple-efuses.c b/drivers/nvmem/apple-efuses.c
> index d3d49d22338b..9a564cb0f26d 100644
> --- a/drivers/nvmem/apple-efuses.c
> +++ b/drivers/nvmem/apple-efuses.c
> @@ -15,10 +15,11 @@ struct apple_efuses_priv {
>   	void __iomem *fuses;
>   };
>   
> -static int apple_efuses_read(void *context, unsigned int offset, void *val,
> +static ssize_t apple_efuses_read(void *context, unsigned int offset, void *val,
>   			     size_t bytes)
>   {
>   	struct apple_efuses_priv *priv = context;
> +	size_t bytes_read = bytes;
>   	u32 *dst = val;
>   
>   	while (bytes >= sizeof(u32)) {
> @@ -27,7 +28,7 @@ static int apple_efuses_read(void *context, unsigned int offset, void *val,
>   		offset += sizeof(u32);
>   	}
>   
> -	return 0;
> +	return bytes_read;
>   }
>   
>   static int apple_efuses_probe(struct platform_device *pdev)
> diff --git a/drivers/nvmem/bcm-ocotp.c b/drivers/nvmem/bcm-ocotp.c
> index 2490f44caa40..803354574fe0 100644
> --- a/drivers/nvmem/bcm-ocotp.c
> +++ b/drivers/nvmem/bcm-ocotp.c
> @@ -148,7 +148,7 @@ static int disable_ocotp_program(void __iomem *base)
>   	return ret;
>   }
>   
> -static int bcm_otpc_read(void *context, unsigned int offset, void *val,
> +static ssize_t bcm_otpc_read(void *context, unsigned int offset, void *val,
>   	size_t bytes)
>   {
>   	struct otpc_priv *priv = context;
> @@ -176,10 +176,10 @@ static int bcm_otpc_read(void *context, unsigned int offset, void *val,
>   		reset_start_bit(priv->base);
>   	}
>   
> -	return 0;
> +	return bytes_read;
>   }
>   
> -static int bcm_otpc_write(void *context, unsigned int offset, void *val,
> +static ssize_t bcm_otpc_write(void *context, unsigned int offset, void *val,
>   	size_t bytes)
>   {
>   	struct otpc_priv *priv = context;
> @@ -214,7 +214,7 @@ static int bcm_otpc_write(void *context, unsigned int offset, void *val,
>   
>   	disable_ocotp_program(priv->base);
>   
> -	return 0;
> +	return bytes_written;
>   }
>   
>   static struct nvmem_config bcm_otpc_nvmem_config = {
> diff --git a/drivers/nvmem/brcm_nvram.c b/drivers/nvmem/brcm_nvram.c
> index 5cdf339cfbec..d8700b7e2642 100644
> --- a/drivers/nvmem/brcm_nvram.c
> +++ b/drivers/nvmem/brcm_nvram.c
> @@ -46,7 +46,7 @@ struct brcm_nvram_header {
>   	__le32 config_ncdl;	/* ncdl values for memc */
>   };
>   
> -static int brcm_nvram_read(void *context, unsigned int offset, void *val,
> +static ssize_t brcm_nvram_read(void *context, unsigned int offset, void *val,
>   			   size_t bytes)
>   {
>   	struct brcm_nvram *priv = context;
> @@ -61,7 +61,11 @@ static int brcm_nvram_read(void *context, unsigned int offset, void *val,
>   
>   	memset((uint8_t *)val + to_copy, priv->padding_byte, bytes - to_copy);
>   
> -	return 0;
> +	/*
> +	 * Returning bytes requested as the whole buffer is padded even if the
> +	 * requested bytes to be read is out of bounds of resource size.
> +	 */
> +	return bytes;
>   }
>   
>   static int brcm_nvram_copy_data(struct brcm_nvram *priv, struct platform_device *pdev)
> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> index eb357ac2e54a..c3ee526d9396 100644
> --- a/drivers/nvmem/core.c
> +++ b/drivers/nvmem/core.c
> @@ -55,7 +55,7 @@ static LIST_HEAD(nvmem_lookup_list);
>   
>   static BLOCKING_NOTIFIER_HEAD(nvmem_notifier);
>   
> -static int __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
> +static ssize_t __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
>   			    void *val, size_t bytes)
>   {
>   	if (nvmem->reg_read)
> @@ -64,10 +64,10 @@ static int __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
>   	return -EINVAL;
>   }
>   
> -static int __nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
> +static ssize_t __nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
>   			     void *val, size_t bytes)
>   {
> -	int ret;
> +	ssize_t ret;
>   
>   	if (nvmem->reg_write) {
>   		gpiod_set_value_cansleep(nvmem->wp_gpio, 0);
> @@ -79,7 +79,7 @@ static int __nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
>   	return -EINVAL;
>   }
>   
> -static int nvmem_access_with_keepouts(struct nvmem_device *nvmem,
> +static ssize_t nvmem_access_with_keepouts(struct nvmem_device *nvmem,
>   				      unsigned int offset, void *val,
>   				      size_t bytes, int write)
>   {
> @@ -88,7 +88,7 @@ static int nvmem_access_with_keepouts(struct nvmem_device *nvmem,
>   	unsigned int kend, ksize;
>   	const struct nvmem_keepout *keepout = nvmem->keepout;
>   	const struct nvmem_keepout *keepoutend = keepout + nvmem->nkeepout;
> -	int rc;
> +	ssize_t rc, count = 0;
>   
>   	/*
>   	 * Skip all keepouts before the range being accessed.
> @@ -107,11 +107,12 @@ static int nvmem_access_with_keepouts(struct nvmem_device *nvmem,
>   			else
>   				rc = __nvmem_reg_read(nvmem, offset, val, ksize);
>   
> -			if (rc)
> +			if (rc < 0)
>   				return rc;
>   
>   			offset += ksize;
>   			val += ksize;
> +			count += rc;
>   		}
>   
>   		/*
> @@ -135,15 +136,20 @@ static int nvmem_access_with_keepouts(struct nvmem_device *nvmem,
>   	if (offset < end) {
>   		ksize = end - offset;
>   		if (write)
> -			return __nvmem_reg_write(nvmem, offset, val, ksize);
> +			rc = __nvmem_reg_write(nvmem, offset, val, ksize);
>   		else
> -			return __nvmem_reg_read(nvmem, offset, val, ksize);
> +			rc = __nvmem_reg_read(nvmem, offset, val, ksize);
> +
> +		if (rc < 0)
> +			return rc;
> +
> +		count += rc;
>   	}
>   
> -	return 0;
> +	return count;
>   }
>   
> -static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
> +static ssize_t nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
>   			  void *val, size_t bytes)
>   {
>   	if (!nvmem->nkeepout)
> @@ -152,7 +158,7 @@ static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset,
>   	return nvmem_access_with_keepouts(nvmem, offset, val, bytes, false);
>   }
>   
> -static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
> +static ssize_t nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset,
>   			   void *val, size_t bytes)
>   {
>   	if (!nvmem->nkeepout)
> @@ -195,7 +201,6 @@ static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
>   {
>   	struct device *dev;
>   	struct nvmem_device *nvmem;
> -	int rc;
>   
>   	if (attr->private)
>   		dev = attr->private;
> @@ -221,12 +226,7 @@ static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj,
>   	if (!nvmem->reg_read)
>   		return -EPERM;
>   
> -	rc = nvmem_reg_read(nvmem, pos, buf, count);
> -
> -	if (rc)
> -		return rc;
> -
> -	return count;
> +	return nvmem_reg_read(nvmem, pos, buf, count);
>   }
>   
>   static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
> @@ -235,7 +235,6 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
>   {
>   	struct device *dev;
>   	struct nvmem_device *nvmem;
> -	int rc;
>   
>   	if (attr->private)
>   		dev = attr->private;
> @@ -261,12 +260,7 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
>   	if (!nvmem->reg_write)
>   		return -EPERM;
>   
> -	rc = nvmem_reg_write(nvmem, pos, buf, count);
> -
> -	if (rc)
> -		return rc;
> -
> -	return count;
> +	return nvmem_reg_write(nvmem, pos, buf, count);
>   }
>   
>   static umode_t nvmem_bin_attr_get_umode(struct nvmem_device *nvmem)
> @@ -1633,9 +1627,12 @@ static int __nvmem_cell_read(struct nvmem_device *nvmem,
>   
>   	rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->raw_len);
>   
> -	if (rc)
> +	if (rc < 0)
>   		return rc;
>   
> +	if (rc != cell->raw_len)
> +		return -EIO;
> +
>   	/* shift bits in-place */
>   	if (cell->bit_offset || cell->nbits)
>   		nvmem_shift_read_buffer_in_place(cell, buf);
> @@ -1708,8 +1705,11 @@ static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell_entry *cell,
>   
>   		/* setup the first byte with lsb bits from nvmem */
>   		rc = nvmem_reg_read(nvmem, cell->offset, &v, 1);
> -		if (rc)
> +		if (rc < 1) {
> +			if (rc == 0)
> +				rc = -EIO;
>   			goto err;
> +		}
>   		*b++ |= GENMASK(bit_offset - 1, 0) & v;
>   
>   		/* setup rest of the byte if any */
> @@ -1728,8 +1728,11 @@ static void *nvmem_cell_prepare_write_buffer(struct nvmem_cell_entry *cell,
>   		/* setup the last byte with msb bits from nvmem */
>   		rc = nvmem_reg_read(nvmem,
>   				    cell->offset + cell->bytes - 1, &v, 1);
> -		if (rc)
> +		if (rc < 1) {
> +			if (rc == 0)
> +				rc = -EIO;
>   			goto err;
> +		}
>   		*p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v;
>   
>   	}
> @@ -1769,10 +1772,7 @@ static int __nvmem_cell_entry_write(struct nvmem_cell_entry *cell, void *buf, si
>   	if (cell->bit_offset || cell->nbits)
>   		kfree(buf);
>   
> -	if (rc)
> -		return rc;
> -
> -	return len;
> +	return rc;
>   }
>   
>   /**
> @@ -2047,17 +2047,10 @@ int nvmem_device_read(struct nvmem_device *nvmem,
>   		      unsigned int offset,
>   		      size_t bytes, void *buf)
>   {
> -	int rc;
> -
>   	if (!nvmem)
>   		return -EINVAL;
>   
> -	rc = nvmem_reg_read(nvmem, offset, buf, bytes);
> -
> -	if (rc)
> -		return rc;
> -
> -	return bytes;
> +	return nvmem_reg_read(nvmem, offset, buf, bytes);
>   }
>   EXPORT_SYMBOL_GPL(nvmem_device_read);
>   
> diff --git a/drivers/nvmem/imx-iim.c b/drivers/nvmem/imx-iim.c
> index f13bbd164086..af46c5490416 100644
> --- a/drivers/nvmem/imx-iim.c
> +++ b/drivers/nvmem/imx-iim.c
> @@ -29,7 +29,7 @@ struct iim_priv {
>   	struct clk *clk;
>   };
>   
> -static int imx_iim_read(void *context, unsigned int offset,
> +static ssize_t imx_iim_read(void *context, unsigned int offset,
>   			  void *buf, size_t bytes)
>   {
>   	struct iim_priv *iim = context;
> @@ -49,7 +49,7 @@ static int imx_iim_read(void *context, unsigned int offset,
>   
>   	clk_disable_unprepare(iim->clk);
>   
> -	return 0;
> +	return bytes;
>   }
>   
>   static struct imx_iim_drvdata imx27_drvdata = {
> diff --git a/drivers/nvmem/imx-ocotp-ele.c b/drivers/nvmem/imx-ocotp-ele.c
> index cf920542f939..3025fe8aa991 100644
> --- a/drivers/nvmem/imx-ocotp-ele.c
> +++ b/drivers/nvmem/imx-ocotp-ele.c
> @@ -61,7 +61,7 @@ static enum fuse_type imx_ocotp_fuse_type(void *context, u32 index)
>   	return FUSE_INVALID;
>   }
>   
> -static int imx_ocotp_reg_read(void *context, unsigned int offset, void *val, size_t bytes)
> +static ssize_t imx_ocotp_reg_read(void *context, unsigned int offset, void *val, size_t bytes)
>   {
>   	struct imx_ocotp_priv *priv = context;
>   	void __iomem *reg = priv->base + priv->data->reg_off;
> @@ -102,7 +102,7 @@ static int imx_ocotp_reg_read(void *context, unsigned int offset, void *val, siz
>   
>   	kfree(p);
>   
> -	return 0;
> +	return bytes;
>   };
>   
>   static int imx_ele_ocotp_probe(struct platform_device *pdev)
> diff --git a/drivers/nvmem/imx-ocotp-scu.c b/drivers/nvmem/imx-ocotp-scu.c
> index 517d83e11af2..2f9b9f035c49 100644
> --- a/drivers/nvmem/imx-ocotp-scu.c
> +++ b/drivers/nvmem/imx-ocotp-scu.c
> @@ -129,7 +129,7 @@ static int imx_sc_misc_otp_fuse_read(struct imx_sc_ipc *ipc, u32 word,
>   	return 0;
>   }
>   
> -static int imx_scu_ocotp_read(void *context, unsigned int offset,
> +static ssize_t imx_scu_ocotp_read(void *context, unsigned int offset,
>   			      void *val, size_t bytes)
>   {
>   	struct ocotp_priv *priv = context;
> @@ -174,10 +174,10 @@ static int imx_scu_ocotp_read(void *context, unsigned int offset,
>   
>   	kfree(p);
>   
> -	return 0;
> +	return bytes;
>   }
>   
> -static int imx_scu_ocotp_write(void *context, unsigned int offset,
> +static ssize_t imx_scu_ocotp_write(void *context, unsigned int offset,
>   			       void *val, size_t bytes)
>   {
>   	struct ocotp_priv *priv = context;
> @@ -215,7 +215,7 @@ static int imx_scu_ocotp_write(void *context, unsigned int offset,
>   
>   	mutex_unlock(&scu_ocotp_mutex);
>   
> -	return res.a0;
> +	return res.a0 < 0 ? res.a0 : bytes;
>   }
>   
>   static struct nvmem_config imx_scu_ocotp_nvmem_config = {
> diff --git a/drivers/nvmem/imx-ocotp.c b/drivers/nvmem/imx-ocotp.c
> index 79dd4fda0329..2b04d49c7bf0 100644
> --- a/drivers/nvmem/imx-ocotp.c
> +++ b/drivers/nvmem/imx-ocotp.c
> @@ -154,7 +154,7 @@ static void imx_ocotp_clr_err_if_set(struct ocotp_priv *priv)
>   	writel(bm_ctrl_error, base + IMX_OCOTP_ADDR_CTRL_CLR);
>   }
>   
> -static int imx_ocotp_read(void *context, unsigned int offset,
> +static ssize_t imx_ocotp_read(void *context, unsigned int offset,
>   			  void *val, size_t bytes)
>   {
>   	struct ocotp_priv *priv = context;
> @@ -217,7 +217,7 @@ static int imx_ocotp_read(void *context, unsigned int offset,
>   
>   	kfree(p);
>   
> -	return ret;
> +	return ret < 0 ? ret : bytes;
>   }
>   
>   static int imx_ocotp_cell_pp(void *context, const char *id, int index,
> @@ -307,7 +307,7 @@ static void imx_ocotp_set_imx7_timing(struct ocotp_priv *priv)
>   	writel(timing, priv->base + IMX_OCOTP_ADDR_TIMING);
>   }
>   
> -static int imx_ocotp_write(void *context, unsigned int offset, void *val,
> +static ssize_t imx_ocotp_write(void *context, unsigned int offset, void *val,
>   			   size_t bytes)
>   {
>   	struct ocotp_priv *priv = context;
> diff --git a/drivers/nvmem/jz4780-efuse.c b/drivers/nvmem/jz4780-efuse.c
> index 0b01b840edd9..3c3f57dd1ffc 100644
> --- a/drivers/nvmem/jz4780-efuse.c
> +++ b/drivers/nvmem/jz4780-efuse.c
> @@ -66,10 +66,11 @@ struct jz4780_efuse {
>   };
>   
>   /* main entry point */
> -static int jz4780_efuse_read(void *context, unsigned int offset,
> +static ssize_t jz4780_efuse_read(void *context, unsigned int offset,
>   			     void *val, size_t bytes)
>   {
>   	struct jz4780_efuse *efuse = context;
> +	size_t bytes_read = bytes;
>   
>   	while (bytes > 0) {
>   		size_t start = offset & ~(JZ_EFU_READ_SIZE - 1);
> @@ -112,7 +113,7 @@ static int jz4780_efuse_read(void *context, unsigned int offset,
>   		bytes -= chunk;
>   	}
>   
> -	return 0;
> +	return bytes_read;
>   }
>   
>   static struct nvmem_config jz4780_efuse_nvmem_config = {
> diff --git a/drivers/nvmem/lan9662-otpc.c b/drivers/nvmem/lan9662-otpc.c
> index 56fc19f092a7..a6bdc79867c7 100644
> --- a/drivers/nvmem/lan9662-otpc.c
> +++ b/drivers/nvmem/lan9662-otpc.c
> @@ -119,7 +119,7 @@ static int lan9662_otp_write_byte(struct lan9662_otp *otp, u32 offset, u8 data)
>   	return rc;
>   }
>   
> -static int lan9662_otp_read(void *context, unsigned int offset,
> +static ssize_t lan9662_otp_read(void *context, unsigned int offset,
>   			    void *_val, size_t bytes)
>   {
>   	struct lan9662_otp *otp = context;
> @@ -136,10 +136,10 @@ static int lan9662_otp_read(void *context, unsigned int offset,
>   	}
>   	lan9662_otp_power(otp, false);
>   
> -	return rc;
> +	return rc < 0 ? rc : bytes;
>   }
>   
> -static int lan9662_otp_write(void *context, unsigned int offset,
> +static ssize_t lan9662_otp_write(void *context, unsigned int offset,
>   			     void *_val, size_t bytes)
>   {
>   	struct lan9662_otp *otp = context;
> @@ -167,7 +167,7 @@ static int lan9662_otp_write(void *context, unsigned int offset,
>   	}
>   	lan9662_otp_power(otp, false);
>   
> -	return rc;
> +	return rc < 0 ? rc : bytes;
>   }
>   
>   static struct nvmem_config otp_config = {
> diff --git a/drivers/nvmem/layerscape-sfp.c b/drivers/nvmem/layerscape-sfp.c
> index e2b424561949..0aab245abd6e 100644
> --- a/drivers/nvmem/layerscape-sfp.c
> +++ b/drivers/nvmem/layerscape-sfp.c
> @@ -26,14 +26,17 @@ struct layerscape_sfp_data {
>   	enum regmap_endian endian;
>   };
>   
> -static int layerscape_sfp_read(void *context, unsigned int offset, void *val,
> +static ssize_t layerscape_sfp_read(void *context, unsigned int offset, void *val,
>   			       size_t bytes)
>   {
>   	struct layerscape_sfp_priv *priv = context;
> +	int ret;
>   
> -	return regmap_bulk_read(priv->regmap,
> +	ret = regmap_bulk_read(priv->regmap,
>   				LAYERSCAPE_SFP_OTP_OFFSET + offset, val,
>   				bytes / 4);
> +
> +	return ret < 0 ? ret : bytes;
>   }
>   
>   static struct nvmem_config layerscape_sfp_nvmem_config = {
> diff --git a/drivers/nvmem/lpc18xx_eeprom.c b/drivers/nvmem/lpc18xx_eeprom.c
> index a0275b29afd5..cc8f59c2cd63 100644
> --- a/drivers/nvmem/lpc18xx_eeprom.c
> +++ b/drivers/nvmem/lpc18xx_eeprom.c
> @@ -87,10 +87,11 @@ static int lpc18xx_eeprom_busywait_until_prog(struct lpc18xx_eeprom_dev *eeprom)
>   	return -ETIMEDOUT;
>   }
>   
> -static int lpc18xx_eeprom_gather_write(void *context, unsigned int reg,
> +static ssize_t lpc18xx_eeprom_gather_write(void *context, unsigned int reg,
>   				       void *val, size_t bytes)
>   {
>   	struct lpc18xx_eeprom_dev *eeprom = context;
> +	size_t bytes_written = bytes;
>   	unsigned int offset = reg;
>   	int ret;
>   
> @@ -123,13 +124,14 @@ static int lpc18xx_eeprom_gather_write(void *context, unsigned int reg,
>   	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
>   			      LPC18XX_EEPROM_PWRDWN_YES);
>   
> -	return 0;
> +	return bytes_written;
>   }
>   
> -static int lpc18xx_eeprom_read(void *context, unsigned int offset,
> +static ssize_t lpc18xx_eeprom_read(void *context, unsigned int offset,
>   			       void *val, size_t bytes)
>   {
>   	struct lpc18xx_eeprom_dev *eeprom = context;
> +	size_t bytes_read = bytes;
>   
>   	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
>   			      LPC18XX_EEPROM_PWRDWN_NO);
> @@ -147,7 +149,7 @@ static int lpc18xx_eeprom_read(void *context, unsigned int offset,
>   	lpc18xx_eeprom_writel(eeprom, LPC18XX_EEPROM_PWRDWN,
>   			      LPC18XX_EEPROM_PWRDWN_YES);
>   
> -	return 0;
> +	return bytes_read;
>   }
>   
>   
> diff --git a/drivers/nvmem/lpc18xx_otp.c b/drivers/nvmem/lpc18xx_otp.c
> index adc9948e7b2e..da7d7667e10c 100644
> --- a/drivers/nvmem/lpc18xx_otp.c
> +++ b/drivers/nvmem/lpc18xx_otp.c
> @@ -37,7 +37,7 @@ struct lpc18xx_otp {
>   	void __iomem *base;
>   };
>   
> -static int lpc18xx_otp_read(void *context, unsigned int offset,
> +static ssize_t lpc18xx_otp_read(void *context, unsigned int offset,
>   			    void *val, size_t bytes)
>   {
>   	struct lpc18xx_otp *otp = context;
> @@ -52,7 +52,7 @@ static int lpc18xx_otp_read(void *context, unsigned int offset,
>   	for (i = index; i < (index + count); i++)
>   		*buf++ = readl(otp->base + i * LPC18XX_OTP_WORD_SIZE);
>   
> -	return 0;
> +	return bytes;
>   }
>   
>   static struct nvmem_config lpc18xx_otp_nvmem_config = {
> diff --git a/drivers/nvmem/meson-efuse.c b/drivers/nvmem/meson-efuse.c
> index b922df99f9bc..da2e856b16a1 100644
> --- a/drivers/nvmem/meson-efuse.c
> +++ b/drivers/nvmem/meson-efuse.c
> @@ -18,18 +18,24 @@ static int meson_efuse_read(void *context, unsigned int offset,
>   			    void *val, size_t bytes)
>   {
>   	struct meson_sm_firmware *fw = context;
> +	int ret;
>   
> -	return meson_sm_call_read(fw, (u8 *)val, bytes, SM_EFUSE_READ, offset,
> +	ret = meson_sm_call_read(fw, (u8 *)val, bytes, SM_EFUSE_READ, offset,
>   				  bytes, 0, 0, 0);
> +
> +	return ret < 0 ? ret : bytes;
>   }
>   
>   static int meson_efuse_write(void *context, unsigned int offset,
>   			     void *val, size_t bytes)
>   {
>   	struct meson_sm_firmware *fw = context;
> +	int ret;
>   
> -	return meson_sm_call_write(fw, (u8 *)val, bytes, SM_EFUSE_WRITE, offset,
> +	ret = meson_sm_call_write(fw, (u8 *)val, bytes, SM_EFUSE_WRITE, offset,
>   				   bytes, 0, 0, 0);
> +
> +	return ret < 0 ? ret : bytes;
>   }
>   
>   static const struct of_device_id meson_efuse_match[] = {
> diff --git a/drivers/nvmem/meson-mx-efuse.c b/drivers/nvmem/meson-mx-efuse.c
> index 3ff04d5ca8f8..fdc598adfe9e 100644
> --- a/drivers/nvmem/meson-mx-efuse.c
> +++ b/drivers/nvmem/meson-mx-efuse.c
> @@ -132,7 +132,7 @@ static int meson_mx_efuse_read_addr(struct meson_mx_efuse *efuse,
>   	return 0;
>   }
>   
> -static int meson_mx_efuse_read(void *context, unsigned int offset,
> +static ssize_t meson_mx_efuse_read(void *context, unsigned int offset,
>   			       void *buf, size_t bytes)
>   {
>   	struct meson_mx_efuse *efuse = context;
> @@ -163,7 +163,7 @@ static int meson_mx_efuse_read(void *context, unsigned int offset,
>   
>   	meson_mx_efuse_hw_disable(efuse);
>   
> -	return err;
> +	return err < 0 ? err : bytes;
>   }
>   
>   static const struct meson_mx_efuse_platform_data meson6_efuse_data = {
> diff --git a/drivers/nvmem/microchip-otpc.c b/drivers/nvmem/microchip-otpc.c
> index 7cf81738a3e0..9b53fcb75e98 100644
> --- a/drivers/nvmem/microchip-otpc.c
> +++ b/drivers/nvmem/microchip-otpc.c
> @@ -143,7 +143,7 @@ static int mchp_otpc_prepare_read(struct mchp_otpc *otpc,
>    * packet. The user will have to be aware of the memory footprint before doing
>    * the read request.
>    */
> -static int mchp_otpc_read(void *priv, unsigned int off, void *val,
> +static ssize_t mchp_otpc_read(void *priv, unsigned int off, void *val,
>   			  size_t bytes)
>   {
>   	struct mchp_otpc *otpc = priv;
> @@ -187,7 +187,7 @@ static int mchp_otpc_read(void *priv, unsigned int off, void *val,
>   		} while (payload_size >= 0 && len < bytes);
>   	}
>   
> -	return 0;
> +	return len;
>   }
>   
>   static int mchp_otpc_init_packets_list(struct mchp_otpc *otpc, u32 *size)
> diff --git a/drivers/nvmem/mtk-efuse.c b/drivers/nvmem/mtk-efuse.c
> index 84f05b40a411..3819d416b505 100644
> --- a/drivers/nvmem/mtk-efuse.c
> +++ b/drivers/nvmem/mtk-efuse.c
> @@ -20,7 +20,7 @@ struct mtk_efuse_priv {
>   	void __iomem *base;
>   };
>   
> -static int mtk_reg_read(void *context,
> +static ssize_t mtk_reg_read(void *context,
>   			unsigned int reg, void *_val, size_t bytes)
>   {
>   	struct mtk_efuse_priv *priv = context;
> @@ -31,7 +31,7 @@ static int mtk_reg_read(void *context,
>   	for (i = 0; i < bytes; i++, val++)
>   		*val = readb(addr + i);
>   
> -	return 0;
> +	return bytes;
>   }
>   
>   static int mtk_efuse_gpu_speedbin_pp(void *context, const char *id, int index,
> diff --git a/drivers/nvmem/mxs-ocotp.c b/drivers/nvmem/mxs-ocotp.c
> index 7b78f18f9545..ddf7394de71b 100644
> --- a/drivers/nvmem/mxs-ocotp.c
> +++ b/drivers/nvmem/mxs-ocotp.c
> @@ -56,10 +56,11 @@ static int mxs_ocotp_wait(struct mxs_ocotp *otp)
>   	return 0;
>   }
>   
> -static int mxs_ocotp_read(void *context, unsigned int offset,
> +static ssize_t mxs_ocotp_read(void *context, unsigned int offset,
>   			  void *val, size_t bytes)
>   {
>   	struct mxs_ocotp *otp = context;
> +	size_t bytes_read = bytes;
>   	u32 *buf = val;
>   	int ret;
>   
> @@ -102,7 +103,7 @@ static int mxs_ocotp_read(void *context, unsigned int offset,
>   disable_clk:
>   	clk_disable(otp->clk);
>   
> -	return ret;
> +	return ret < 0 ? ret : bytes_read;
>   }
>   
>   static struct nvmem_config ocotp_config = {
> diff --git a/drivers/nvmem/nintendo-otp.c b/drivers/nvmem/nintendo-otp.c
> index 355e7f1fc6d5..880f2915c030 100644
> --- a/drivers/nvmem/nintendo-otp.c
> +++ b/drivers/nvmem/nintendo-otp.c
> @@ -45,7 +45,7 @@ static const struct nintendo_otp_devtype_data latte_otp_data = {
>   	.num_banks = 8,
>   };
>   
> -static int nintendo_otp_reg_read(void *context,
> +static ssize_t nintendo_otp_reg_read(void *context,
>   				 unsigned int reg, void *_val, size_t bytes)
>   {
>   	struct nintendo_otp_priv *priv = context;
> @@ -61,7 +61,7 @@ static int nintendo_otp_reg_read(void *context,
>   		reg += WORD_SIZE;
>   	}
>   
> -	return 0;
> +	return bytes;
>   }
>   
>   static const struct of_device_id nintendo_otp_of_table[] = {
> diff --git a/drivers/nvmem/qcom-spmi-sdam.c b/drivers/nvmem/qcom-spmi-sdam.c
> index 9aa8f42faa4c..c4dfde372794 100644
> --- a/drivers/nvmem/qcom-spmi-sdam.c
> +++ b/drivers/nvmem/qcom-spmi-sdam.c
> @@ -60,7 +60,7 @@ static bool sdam_is_ro(unsigned int offset, size_t len)
>   	return false;
>   }
>   
> -static int sdam_read(void *priv, unsigned int offset, void *val,
> +static ssize_t sdam_read(void *priv, unsigned int offset, void *val,
>   				size_t bytes)
>   {
>   	struct sdam_chip *sdam = priv;
> @@ -78,10 +78,10 @@ static int sdam_read(void *priv, unsigned int offset, void *val,
>   		dev_err(dev, "Failed to read SDAM offset %#x len=%zd, rc=%d\n",
>   						offset, bytes, rc);
>   
> -	return rc;
> +	return rc < 0 ? rc : bytes;
>   }
>   
> -static int sdam_write(void *priv, unsigned int offset, void *val,
> +static ssize_t sdam_write(void *priv, unsigned int offset, void *val,
>   				size_t bytes)
>   {
>   	struct sdam_chip *sdam = priv;
> @@ -105,7 +105,7 @@ static int sdam_write(void *priv, unsigned int offset, void *val,
>   		dev_err(dev, "Failed to write SDAM offset %#x len=%zd, rc=%d\n",
>   						offset, bytes, rc);
>   
> -	return rc;
> +	return rc < 0 ? rc : bytes;
>   }
>   
>   static int sdam_probe(struct platform_device *pdev)
> diff --git a/drivers/nvmem/qfprom.c b/drivers/nvmem/qfprom.c
> index 116a39e804c7..4d571ae6ba3e 100644
> --- a/drivers/nvmem/qfprom.c
> +++ b/drivers/nvmem/qfprom.c
> @@ -251,9 +251,9 @@ static int qfprom_enable_fuse_blowing(const struct qfprom_priv *priv,
>    *
>    * Writes to fuses.  WARNING: THIS IS PERMANENT.
>    *
> - * Return: 0 or -err.
> + * Return: bytes written or -err.
>    */
> -static int qfprom_reg_write(void *context, unsigned int reg, void *_val,
> +static ssize_t qfprom_reg_write(void *context, unsigned int reg, void *_val,
>   			    size_t bytes)
>   {
>   	struct qfprom_priv *priv = context;
> @@ -314,10 +314,10 @@ static int qfprom_reg_write(void *context, unsigned int reg, void *_val,
>   exit_enabled_fuse_blowing:
>   	qfprom_disable_fuse_blowing(priv, &old);
>   
> -	return ret;
> +	return ret < 0 ? ret : bytes;
>   }
>   
> -static int qfprom_reg_read(void *context,
> +static ssize_t qfprom_reg_read(void *context,
>   			unsigned int reg, void *_val, size_t bytes)
>   {
>   	struct qfprom_priv *priv = context;
> @@ -331,7 +331,7 @@ static int qfprom_reg_read(void *context,
>   	while (words--)
>   		*val++ = readb(base + reg + i++);
>   
> -	return 0;
> +	return bytes;
>   }
>   
>   static void qfprom_runtime_disable(void *data)
> diff --git a/drivers/nvmem/qoriq-efuse.c b/drivers/nvmem/qoriq-efuse.c
> index e7fd04d6dd94..1e7315953e44 100644
> --- a/drivers/nvmem/qoriq-efuse.c
> +++ b/drivers/nvmem/qoriq-efuse.c
> @@ -14,7 +14,7 @@ struct qoriq_efuse_priv {
>   	void __iomem *base;
>   };
>   
> -static int qoriq_efuse_read(void *context, unsigned int offset, void *val,
> +static ssize_t qoriq_efuse_read(void *context, unsigned int offset, void *val,
>   			    size_t bytes)
>   {
>   	struct qoriq_efuse_priv *priv = context;
> @@ -24,7 +24,7 @@ static int qoriq_efuse_read(void *context, unsigned int offset, void *val,
>   
>   	/* Ignore trailing bytes (there shouldn't be any) */
>   
> -	return 0;
> +	return bytes;
>   }
>   
>   static int qoriq_efuse_probe(struct platform_device *pdev)
> diff --git a/drivers/nvmem/rave-sp-eeprom.c b/drivers/nvmem/rave-sp-eeprom.c
> index 9ecf3873cbb7..6c8aecde8311 100644
> --- a/drivers/nvmem/rave-sp-eeprom.c
> +++ b/drivers/nvmem/rave-sp-eeprom.c
> @@ -214,10 +214,10 @@ rave_sp_eeprom_page_access(struct rave_sp_eeprom *eeprom,
>    * arbitrary offset (not necessary page aligned) of arbitrary length
>    * (is not constrained by EEPROM page size).
>    *
> - * Returns zero in case of success or negative error code in case of
> - * failure.
> + * Returns number of bytes in case of success or negative error code
> + * in case of failure.
>    */
> -static int rave_sp_eeprom_access(struct rave_sp_eeprom *eeprom,
> +static ssize_t rave_sp_eeprom_access(struct rave_sp_eeprom *eeprom,
>   				 enum rave_sp_eeprom_access_type type,
>   				 unsigned int offset, u8 *data,
>   				 unsigned int data_len)
> @@ -267,17 +267,17 @@ static int rave_sp_eeprom_access(struct rave_sp_eeprom *eeprom,
>   	} while (residue);
>   out:
>   	mutex_unlock(&eeprom->mutex);
> -	return ret;
> +	return ret < 0 ? ret : data_len;
>   }
>   
> -static int rave_sp_eeprom_reg_read(void *eeprom, unsigned int offset,
> +static ssize_t rave_sp_eeprom_reg_read(void *eeprom, unsigned int offset,
>   				   void *val, size_t bytes)
>   {
>   	return rave_sp_eeprom_access(eeprom, RAVE_SP_EEPROM_READ,
>   				     offset, val, bytes);
>   }
>   
> -static int rave_sp_eeprom_reg_write(void *eeprom, unsigned int offset,
> +static ssize_t rave_sp_eeprom_reg_write(void *eeprom, unsigned int offset,
>   				    void *val, size_t bytes)
>   {
>   	return rave_sp_eeprom_access(eeprom, RAVE_SP_EEPROM_WRITE,
> diff --git a/drivers/nvmem/rmem.c b/drivers/nvmem/rmem.c
> index 752d0bf4445e..1ddb832cd178 100644
> --- a/drivers/nvmem/rmem.c
> +++ b/drivers/nvmem/rmem.c
> @@ -17,7 +17,7 @@ struct rmem {
>   	phys_addr_t size;
>   };
>   
> -static int rmem_read(void *context, unsigned int offset,
> +static ssize_t rmem_read(void *context, unsigned int offset,
>   		     void *val, size_t bytes)
>   {
>   	struct rmem *priv = context;
> diff --git a/drivers/nvmem/rockchip-efuse.c b/drivers/nvmem/rockchip-efuse.c
> index 2b40978ddb18..fe05d7afd281 100644
> --- a/drivers/nvmem/rockchip-efuse.c
> +++ b/drivers/nvmem/rockchip-efuse.c
> @@ -52,7 +52,7 @@ struct rockchip_efuse_chip {
>   	struct clk *clk;
>   };
>   
> -static int rockchip_rk3288_efuse_read(void *context, unsigned int offset,
> +static ssize_t rockchip_rk3288_efuse_read(void *context, unsigned int offset,
>   				      void *val, size_t bytes)
>   {
>   	struct rockchip_efuse_chip *efuse = context;
> @@ -65,6 +65,7 @@ static int rockchip_rk3288_efuse_read(void *context, unsigned int offset,
>   		return ret;
>   	}
>   
> +	ret = bytes;
>   	writel(RK3288_LOAD | RK3288_PGENB, efuse->base + REG_EFUSE_CTRL);
>   	udelay(1);
>   	while (bytes--) {
> @@ -89,7 +90,7 @@ static int rockchip_rk3288_efuse_read(void *context, unsigned int offset,
>   
>   	clk_disable_unprepare(efuse->clk);
>   
> -	return 0;
> +	return ret;
>   }
>   
>   static int rockchip_rk3328_efuse_read(void *context, unsigned int offset,
> @@ -144,10 +145,10 @@ static int rockchip_rk3328_efuse_read(void *context, unsigned int offset,
>   nomem:
>   	clk_disable_unprepare(efuse->clk);
>   
> -	return ret;
> +	return ret < 0 ? ret : bytes;
>   }
>   
> -static int rockchip_rk3399_efuse_read(void *context, unsigned int offset,
> +static ssize_t rockchip_rk3399_efuse_read(void *context, unsigned int offset,
>   				      void *val, size_t bytes)
>   {
>   	struct rockchip_efuse_chip *efuse = context;
> @@ -200,7 +201,7 @@ static int rockchip_rk3399_efuse_read(void *context, unsigned int offset,
>   
>   	clk_disable_unprepare(efuse->clk);
>   
> -	return 0;
> +	return bytes;
>   }
>   
>   static struct nvmem_config econfig = {
> diff --git a/drivers/nvmem/rockchip-otp.c b/drivers/nvmem/rockchip-otp.c
> index cb9aa5428350..f7eb1feea978 100644
> --- a/drivers/nvmem/rockchip-otp.c
> +++ b/drivers/nvmem/rockchip-otp.c
> @@ -144,10 +144,11 @@ static int rockchip_otp_ecc_enable(struct rockchip_otp *otp, bool enable)
>   	return ret;
>   }
>   
> -static int px30_otp_read(void *context, unsigned int offset,
> +static ssize_t px30_otp_read(void *context, unsigned int offset,
>   			 void *val, size_t bytes)
>   {
>   	struct rockchip_otp *otp = context;
> +	size_t bytes_read = bytes;
>   	u8 *buf = val;
>   	int ret;
>   
> @@ -181,10 +182,10 @@ static int px30_otp_read(void *context, unsigned int offset,
>   read_end:
>   	writel(0x0 | OTPC_USE_USER_MASK, otp->base + OTPC_USER_CTRL);
>   
> -	return ret;
> +	return ret < 0 ? ret : bytes_read;
>   }
>   
> -static int rk3588_otp_read(void *context, unsigned int offset,
> +static ssize_t rk3588_otp_read(void *context, unsigned int offset,
>   			   void *val, size_t bytes)
>   {
>   	struct rockchip_otp *otp = context;
> @@ -227,10 +228,10 @@ static int rk3588_otp_read(void *context, unsigned int offset,
>   read_end:
>   	kfree(buf);
>   
> -	return ret;
> +	return ret < 0 ? ret : bytes;
>   }
>   
> -static int rockchip_otp_read(void *context, unsigned int offset,
> +static ssize_t rockchip_otp_read(void *context, unsigned int offset,
>   			     void *val, size_t bytes)
>   {
>   	struct rockchip_otp *otp = context;
> @@ -249,7 +250,7 @@ static int rockchip_otp_read(void *context, unsigned int offset,
>   
>   	clk_bulk_disable_unprepare(otp->data->num_clks, otp->clks);
>   
> -	return ret;
> +	return ret < 0 ? ret : bytes;
>   }
>   
>   static struct nvmem_config otp_config = {
> diff --git a/drivers/nvmem/sc27xx-efuse.c b/drivers/nvmem/sc27xx-efuse.c
> index bff27011f4ff..309ba1306939 100644
> --- a/drivers/nvmem/sc27xx-efuse.c
> +++ b/drivers/nvmem/sc27xx-efuse.c
> @@ -121,7 +121,7 @@ static int sc27xx_efuse_poll_status(struct sc27xx_efuse *efuse, u32 bits)
>   	return 0;
>   }
>   
> -static int sc27xx_efuse_read(void *context, u32 offset, void *val, size_t bytes)
> +static ssize_t sc27xx_efuse_read(void *context, u32 offset, void *val, size_t bytes)
>   {
>   	struct sc27xx_efuse *efuse = context;
>   	u32 buf, blk_index = offset / SC27XX_EFUSE_BLOCK_WIDTH;
> @@ -194,6 +194,7 @@ static int sc27xx_efuse_read(void *context, u32 offset, void *val, size_t bytes)
>   	if (!ret) {
>   		buf >>= blk_offset;
>   		memcpy(val, &buf, bytes);
> +		ret = bytes;
>   	}
>   
>   	return ret;
> diff --git a/drivers/nvmem/sec-qfprom.c b/drivers/nvmem/sec-qfprom.c
> index 19799b3fe00a..dbacaab519e7 100644
> --- a/drivers/nvmem/sec-qfprom.c
> +++ b/drivers/nvmem/sec-qfprom.c
> @@ -20,7 +20,7 @@ struct sec_qfprom {
>   	struct device *dev;
>   };
>   
> -static int sec_qfprom_reg_read(void *context, unsigned int reg, void *_val, size_t bytes)
> +static ssize_t sec_qfprom_reg_read(void *context, unsigned int reg, void *_val, size_t bytes)
>   {
>   	struct sec_qfprom *priv = context;
>   	unsigned int i;
> @@ -40,7 +40,7 @@ static int sec_qfprom_reg_read(void *context, unsigned int reg, void *_val, size
>   		val[i] = tmp[reg & 3];
>   	}
>   
> -	return 0;
> +	return bytes;
>   }
>   
>   static int sec_qfprom_probe(struct platform_device *pdev)
> diff --git a/drivers/nvmem/snvs_lpgpr.c b/drivers/nvmem/snvs_lpgpr.c
> index 89c27112320f..3019bf0c6271 100644
> --- a/drivers/nvmem/snvs_lpgpr.c
> +++ b/drivers/nvmem/snvs_lpgpr.c
> @@ -50,7 +50,7 @@ static const struct snvs_lpgpr_cfg snvs_lpgpr_cfg_imx7d = {
>   	.size		= 16,
>   };
>   
> -static int snvs_lpgpr_write(void *context, unsigned int offset, void *val,
> +static ssize_t snvs_lpgpr_write(void *context, unsigned int offset, void *val,
>   			    size_t bytes)
>   {
>   	struct snvs_lpgpr_priv *priv = context;
> @@ -72,18 +72,23 @@ static int snvs_lpgpr_write(void *context, unsigned int offset, void *val,
>   	if (lock_reg & IMX_GPR_HL)
>   		return -EPERM;
>   
> -	return regmap_bulk_write(priv->regmap, dcfg->offset + offset, val,
> +	ret = regmap_bulk_write(priv->regmap, dcfg->offset + offset, val,
>   				bytes / 4);
> +
> +	return ret < 0 ? ret : bytes;
>   }
>   
> -static int snvs_lpgpr_read(void *context, unsigned int offset, void *val,
> +static ssize_t snvs_lpgpr_read(void *context, unsigned int offset, void *val,
>   			   size_t bytes)
>   {
>   	struct snvs_lpgpr_priv *priv = context;
>   	const struct snvs_lpgpr_cfg *dcfg = priv->dcfg;
> +	int ret;
>   
> -	return regmap_bulk_read(priv->regmap, dcfg->offset + offset,
> +	ret = regmap_bulk_read(priv->regmap, dcfg->offset + offset,
>   			       val, bytes / 4);
> +
> +	return ret < 0 ? ret : bytes;
>   }
>   
>   static int snvs_lpgpr_probe(struct platform_device *pdev)
> diff --git a/drivers/nvmem/sprd-efuse.c b/drivers/nvmem/sprd-efuse.c
> index bb3105f3291f..5a1581df7555 100644
> --- a/drivers/nvmem/sprd-efuse.c
> +++ b/drivers/nvmem/sprd-efuse.c
> @@ -291,7 +291,7 @@ static int sprd_efuse_raw_read(struct sprd_efuse *efuse, int blk, u32 *val,
>   	return 0;
>   }
>   
> -static int sprd_efuse_read(void *context, u32 offset, void *val, size_t bytes)
> +static ssize_t sprd_efuse_read(void *context, u32 offset, void *val, size_t bytes)
>   {
>   	struct sprd_efuse *efuse = context;
>   	bool blk_double = efuse->data->blk_double;
> @@ -318,10 +318,10 @@ static int sprd_efuse_read(void *context, u32 offset, void *val, size_t bytes)
>   
>   unlock:
>   	sprd_efuse_unlock(efuse);
> -	return ret;
> +	return ret < 0 ? ret : bytes;
>   }
>   
> -static int sprd_efuse_write(void *context, u32 offset, void *val, size_t bytes)
> +static ssize_t sprd_efuse_write(void *context, u32 offset, void *val, size_t bytes)
>   {
>   	struct sprd_efuse *efuse = context;
>   	bool blk_double = efuse->data->blk_double;
> @@ -355,7 +355,7 @@ static int sprd_efuse_write(void *context, u32 offset, void *val, size_t bytes)
>   
>   unlock:
>   	sprd_efuse_unlock(efuse);
> -	return ret;
> +	return ret < 0 ? ret : bytes;
>   }
>   
>   static int sprd_efuse_probe(struct platform_device *pdev)
> diff --git a/drivers/nvmem/stm32-bsec-optee-ta.c b/drivers/nvmem/stm32-bsec-optee-ta.c
> index f89ce791dd12..059f13af0886 100644
> --- a/drivers/nvmem/stm32-bsec-optee-ta.c
> +++ b/drivers/nvmem/stm32-bsec-optee-ta.c
> @@ -136,7 +136,7 @@ void stm32_bsec_optee_ta_close(void *ctx)
>   }
>   
>   /* stm32_bsec_optee_ta_read() - nvmem read access using PTA client driver */
> -int stm32_bsec_optee_ta_read(struct tee_context *ctx, unsigned int offset,
> +ssize_t stm32_bsec_optee_ta_read(struct tee_context *ctx, unsigned int offset,
>   			     void *buf, size_t bytes)
>   {
>   	struct tee_shm *shm;
> @@ -198,11 +198,11 @@ int stm32_bsec_optee_ta_read(struct tee_context *ctx, unsigned int offset,
>   out_tee_session:
>   	stm32_bsec_ta_close_session(ctx, session_id);
>   
> -	return ret;
> +	return ret < 0 ? ret : bytes;
>   }
>   
>   /* stm32_bsec_optee_ta_write() - nvmem write access using PTA client driver */
> -int stm32_bsec_optee_ta_write(struct tee_context *ctx, unsigned int lower,
> +ssize_t stm32_bsec_optee_ta_write(struct tee_context *ctx, unsigned int lower,
>   			      unsigned int offset, void *buf, size_t bytes)
>   {	struct tee_shm *shm;
>   	struct tee_ioctl_invoke_arg arg;
> @@ -294,5 +294,5 @@ int stm32_bsec_optee_ta_write(struct tee_context *ctx, unsigned int lower,
>   out_tee_session:
>   	stm32_bsec_ta_close_session(ctx, session_id);
>   
> -	return ret;
> +	return ret < 0 ? ret : bytes;
>   }
> diff --git a/drivers/nvmem/stm32-bsec-optee-ta.h b/drivers/nvmem/stm32-bsec-optee-ta.h
> index 3966a0535179..799f9f915150 100644
> --- a/drivers/nvmem/stm32-bsec-optee-ta.h
> +++ b/drivers/nvmem/stm32-bsec-optee-ta.h
> @@ -33,9 +33,9 @@ void stm32_bsec_optee_ta_close(void *ctx);
>    * @bytes: number of bytes to read
>    *
>    * Return:
> - *	On success, 0. On failure, -errno.
> + *	On success, bytes read. On failure, -errno.
>    */
> -int stm32_bsec_optee_ta_read(struct tee_context *ctx, unsigned int offset,
> +ssize_t stm32_bsec_optee_ta_read(struct tee_context *ctx, unsigned int offset,
>   			     void *buf, size_t bytes);
>   
>   /**
> @@ -47,9 +47,9 @@ int stm32_bsec_optee_ta_read(struct tee_context *ctx, unsigned int offset,
>    * @bytes: number of bytes to write
>    *
>    * Return:
> - *	On success, 0. On failure, -errno.
> + *	On success, bytes written. On failure, -errno.
>    */
> -int stm32_bsec_optee_ta_write(struct tee_context *ctx, unsigned int lower,
> +ssize_t stm32_bsec_optee_ta_write(struct tee_context *ctx, unsigned int lower,
>   			      unsigned int offset, void *buf, size_t bytes);
>   
>   #else
> @@ -63,14 +63,14 @@ static inline void stm32_bsec_optee_ta_close(void *ctx)
>   {
>   }
>   
> -static inline int stm32_bsec_optee_ta_read(struct tee_context *ctx,
> +static inline ssize_t stm32_bsec_optee_ta_read(struct tee_context *ctx,
>   					   unsigned int offset, void *buf,
>   					   size_t bytes)
>   {
>   	return -EOPNOTSUPP;
>   }
>   
> -static inline int stm32_bsec_optee_ta_write(struct tee_context *ctx,
> +static inline ssize_t stm32_bsec_optee_ta_write(struct tee_context *ctx,
>   					    unsigned int lower,
>   					    unsigned int offset, void *buf,
>   					    size_t bytes)
> diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c
> index 82879b1c9eb9..a8c6983f9139 100644
> --- a/drivers/nvmem/stm32-romem.c
> +++ b/drivers/nvmem/stm32-romem.c
> @@ -40,7 +40,7 @@ struct stm32_romem_priv {
>   	struct tee_context *ctx;
>   };
>   
> -static int stm32_romem_read(void *context, unsigned int offset, void *buf,
> +static ssize_t stm32_romem_read(void *context, unsigned int offset, void *buf,
>   			    size_t bytes)
>   {
>   	struct stm32_romem_priv *priv = context;
> @@ -50,7 +50,7 @@ static int stm32_romem_read(void *context, unsigned int offset, void *buf,
>   	for (i = offset; i < offset + bytes; i++)
>   		*buf8++ = readb_relaxed(priv->base + i);
>   
> -	return 0;
> +	return bytes;
>   }
>   
>   static int stm32_bsec_smc(u8 op, u32 otp, u32 data, u32 *result)
> @@ -71,7 +71,7 @@ static int stm32_bsec_smc(u8 op, u32 otp, u32 data, u32 *result)
>   #endif
>   }
>   
> -static int stm32_bsec_read(void *context, unsigned int offset, void *buf,
> +static ssize_t stm32_bsec_read(void *context, unsigned int offset, void *buf,
>   			   size_t bytes)
>   {
>   	struct stm32_romem_priv *priv = context;
> @@ -115,10 +115,10 @@ static int stm32_bsec_read(void *context, unsigned int offset, void *buf,
>   		skip_bytes = 0;
>   	}
>   
> -	return 0;
> +	return bytes;
>   }
>   
> -static int stm32_bsec_write(void *context, unsigned int offset, void *buf,
> +static ssize_t stm32_bsec_write(void *context, unsigned int offset, void *buf,
>   			    size_t bytes)
>   {
>   	struct stm32_romem_priv *priv = context;
> @@ -142,10 +142,10 @@ static int stm32_bsec_write(void *context, unsigned int offset, void *buf,
>   	if (offset + bytes >= priv->lower * 4)
>   		dev_warn(dev, "Update of upper OTPs with ECC protection (word programming, only once)\n");
>   
> -	return 0;
> +	return bytes;
>   }
>   
> -static int stm32_bsec_pta_read(void *context, unsigned int offset, void *buf,
> +static ssize_t stm32_bsec_pta_read(void *context, unsigned int offset, void *buf,
>   			       size_t bytes)
>   {
>   	struct stm32_romem_priv *priv = context;
> @@ -153,7 +153,7 @@ static int stm32_bsec_pta_read(void *context, unsigned int offset, void *buf,
>   	return stm32_bsec_optee_ta_read(priv->ctx, offset, buf, bytes);
>   }
>   
> -static int stm32_bsec_pta_write(void *context, unsigned int offset, void *buf,
> +static ssize_t stm32_bsec_pta_write(void *context, unsigned int offset, void *buf,
>   				size_t bytes)
>   {
>   	struct stm32_romem_priv *priv = context;
> diff --git a/drivers/nvmem/sunplus-ocotp.c b/drivers/nvmem/sunplus-ocotp.c
> index 38f5d9df39cd..7bda128bb93e 100644
> --- a/drivers/nvmem/sunplus-ocotp.c
> +++ b/drivers/nvmem/sunplus-ocotp.c
> @@ -114,7 +114,7 @@ static int sp_otp_read_real(struct sp_ocotp_priv *otp, int addr, char *value)
>   	return ret;
>   }
>   
> -static int sp_ocotp_read(void *priv, unsigned int offset, void *value, size_t bytes)
> +static ssize_t sp_ocotp_read(void *priv, unsigned int offset, void *value, size_t bytes)
>   {
>   	struct sp_ocotp_priv *otp = priv;
>   	unsigned int addr;
> @@ -140,7 +140,7 @@ static int sp_ocotp_read(void *priv, unsigned int offset, void *value, size_t by
>   disable_clk:
>   	clk_disable(otp->clk);
>   
> -	return ret;
> +	return ret < 0 ? ret : bytes;
>   }
>   
>   static struct nvmem_config sp_ocotp_nvmem_config = {
> diff --git a/drivers/nvmem/sunxi_sid.c b/drivers/nvmem/sunxi_sid.c
> index ba14a76208ab..26580c7a3c6d 100644
> --- a/drivers/nvmem/sunxi_sid.c
> +++ b/drivers/nvmem/sunxi_sid.c
> @@ -36,7 +36,7 @@ struct sunxi_sid {
>   	u32			value_offset;
>   };
>   
> -static int sunxi_sid_read(void *context, unsigned int offset,
> +static ssize_t sunxi_sid_read(void *context, unsigned int offset,
>   			  void *val, size_t bytes)
>   {
>   	struct sunxi_sid *sid = context;
> @@ -56,7 +56,7 @@ static int sunxi_sid_read(void *context, unsigned int offset,
>   	word = readl_relaxed(sid->base + sid->value_offset + offset);
>   	memcpy(val, &word, bytes);
>   
> -	return 0;
> +	return bytes;
>   }
>   
>   static int sun8i_sid_register_readout(const struct sunxi_sid *sid,
> @@ -90,10 +90,11 @@ static int sun8i_sid_register_readout(const struct sunxi_sid *sid,
>    * to be not reliable at all.
>    * Read by the registers instead.
>    */
> -static int sun8i_sid_read_by_reg(void *context, unsigned int offset,
> +static ssize_t sun8i_sid_read_by_reg(void *context, unsigned int offset,
>   				 void *val, size_t bytes)
>   {
>   	struct sunxi_sid *sid = context;
> +	size_t bytes_read = bytes;
>   	u32 word;
>   	int ret;
>   
> @@ -109,7 +110,7 @@ static int sun8i_sid_read_by_reg(void *context, unsigned int offset,
>   	}
>   
>   	if (!bytes)
> -		return 0;
> +		return bytes_read;
>   
>   	/* Handle any trailing bytes */
>   	ret = sun8i_sid_register_readout(sid, offset, &word);
> @@ -118,7 +119,7 @@ static int sun8i_sid_read_by_reg(void *context, unsigned int offset,
>   
>   	memcpy(val, &word, bytes);
>   
> -	return 0;
> +	return bytes_read;
>   }
>   
>   static int sunxi_sid_probe(struct platform_device *pdev)
> diff --git a/drivers/nvmem/u-boot-env.c b/drivers/nvmem/u-boot-env.c
> index befbab156cda..a3cf63dfac2a 100644
> --- a/drivers/nvmem/u-boot-env.c
> +++ b/drivers/nvmem/u-boot-env.c
> @@ -47,7 +47,7 @@ struct u_boot_env_image_broadcom {
>   	DECLARE_FLEX_ARRAY(uint8_t, data);
>   } __packed;
>   
> -static int u_boot_env_read(void *context, unsigned int offset, void *val,
> +static ssize_t u_boot_env_read(void *context, unsigned int offset, void *val,
>   			   size_t bytes)
>   {
>   	struct u_boot_env *priv = context;
> @@ -66,7 +66,7 @@ static int u_boot_env_read(void *context, unsigned int offset, void *val,
>   		return -EIO;
>   	}
>   
> -	return 0;
> +	return bytes_read;
>   }
>   
>   static int u_boot_env_read_post_process_ethaddr(void *context, const char *id, int index,
> diff --git a/drivers/nvmem/uniphier-efuse.c b/drivers/nvmem/uniphier-efuse.c
> index 6ad3295d3195..728c9af9fbe4 100644
> --- a/drivers/nvmem/uniphier-efuse.c
> +++ b/drivers/nvmem/uniphier-efuse.c
> @@ -16,7 +16,7 @@ struct uniphier_efuse_priv {
>   	void __iomem *base;
>   };
>   
> -static int uniphier_reg_read(void *context,
> +static ssize_t uniphier_reg_read(void *context,
>   			     unsigned int reg, void *_val, size_t bytes)
>   {
>   	struct uniphier_efuse_priv *priv = context;
> @@ -26,7 +26,7 @@ static int uniphier_reg_read(void *context,
>   	for (offs = 0; offs < bytes; offs += sizeof(u8))
>   		*val++ = readb(priv->base + reg + offs);
>   
> -	return 0;
> +	return bytes;
>   }
>   
>   static int uniphier_efuse_probe(struct platform_device *pdev)
> diff --git a/drivers/nvmem/vf610-ocotp.c b/drivers/nvmem/vf610-ocotp.c
> index ee9c61ae727d..0ed91de61950 100644
> --- a/drivers/nvmem/vf610-ocotp.c
> +++ b/drivers/nvmem/vf610-ocotp.c
> @@ -143,11 +143,12 @@ static int vf610_get_fuse_address(int base_addr_offset)
>   	return -EINVAL;
>   }
>   
> -static int vf610_ocotp_read(void *context, unsigned int offset,
> +static ssize_t vf610_ocotp_read(void *context, unsigned int offset,
>   			void *val, size_t bytes)
>   {
>   	struct vf610_ocotp *ocotp = context;
>   	void __iomem *base = ocotp->base;
> +	size_t bytes_read = bytes;
>   	u32 reg, *buf = val;
>   	int fuse_addr;
>   	int ret;
> @@ -193,7 +194,7 @@ static int vf610_ocotp_read(void *context, unsigned int offset,
>   		offset += 4;
>   	}
>   
> -	return 0;
> +	return bytes_read;
>   }
>   
>   static struct nvmem_config ocotp_config = {
> diff --git a/drivers/nvmem/zynqmp_nvmem.c b/drivers/nvmem/zynqmp_nvmem.c
> index 7f15aa89a9d0..50f8497cc17a 100644
> --- a/drivers/nvmem/zynqmp_nvmem.c
> +++ b/drivers/nvmem/zynqmp_nvmem.c
> @@ -30,7 +30,7 @@ static int zynqmp_nvmem_read(void *context, unsigned int offset,
>   	dev_dbg(priv->dev, "Read chipid val %x %x\n", idcode, version);
>   	*(int *)val = version & SILICON_REVISION_MASK;
>   
> -	return 0;
> +	return bytes;
>   }
>   
>   static struct nvmem_config econfig = {
> diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
> index f0ba0e03218f..2cdab3fec2be 100644
> --- a/include/linux/nvmem-provider.h
> +++ b/include/linux/nvmem-provider.h
> @@ -16,9 +16,9 @@
>   #include <linux/gpio/consumer.h>
>   
>   struct nvmem_device;
> -typedef int (*nvmem_reg_read_t)(void *priv, unsigned int offset,
> +typedef ssize_t (*nvmem_reg_read_t)(void *priv, unsigned int offset,
>   				void *val, size_t bytes);
> -typedef int (*nvmem_reg_write_t)(void *priv, unsigned int offset,
> +typedef ssize_t (*nvmem_reg_write_t)(void *priv, unsigned int offset,
>   				 void *val, size_t bytes);
>   /* used for vendor specific post processing of cell data */
>   typedef int (*nvmem_cell_post_process_t)(void *priv, const char *id, int index,