On Tue, May 08, 2012 at 06:55:29PM +0530, Jayachandran C wrote:
> From: Ganesan Ramalingam <ganesanr@xxxxxxxxxxxx>
>
> Some architectures supports only 16-bit or 32-bit read/write access
> to their iospace. Add a 'regwidth' platform and OF parameter which
> specifies the IO width to support these platforms.
>
> regwidth can be specified as 1, 2 or 4, and has a default value
> of 1 if it is unspecified.
>
> Signed-off-by: Ganesan Ramalingam <ganesanr@xxxxxxxxxxxx>
> Signed-off-by: Jayachandran C <jayachandranc@xxxxxxxxxxxxxxxxx>
Hmm, this is a generic issue and should not be handled with a driver
specific property. CCing devicetree-discuss, maybe there is already a
way to handle this? The already existing 'regstep' looks suspicious, too?
Can't find any documentation for it.
Thanks,
Wolfram
> ---
> drivers/i2c/busses/i2c-ocores.c | 32 ++++++++++++++++++++++++++++++--
> include/linux/i2c-ocores.h | 1 +
> 2 files changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
> index ebd2700..1313145 100644
> --- a/drivers/i2c/busses/i2c-ocores.c
> +++ b/drivers/i2c/busses/i2c-ocores.c
> @@ -19,6 +19,9 @@
> * - regstep : size of device registers in bytes
> * - clock-frequency : frequency of bus clock in Hz
> *
> + * Optional properties:
> + * - regwidth : io register width in bytes (1, 2 or 4)
> +
> * Example:
> *
> * i2c0: ocores@a0000000 {
> @@ -27,6 +30,7 @@
> * interrupts = <10>;
> *
> * regstep = <1>;
> + * regwidth = <1>;
> * clock-frequency = <20000000>;
> *
> * -- Devices connected on this I2C bus get
> @@ -60,6 +64,7 @@
> struct ocores_i2c {
> void __iomem *base;
> int regstep;
> + int regwidth;
> wait_queue_head_t wait;
> struct i2c_adapter adap;
> struct i2c_msg *msg;
> @@ -102,12 +107,22 @@ struct ocores_i2c {
>
> static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
> {
> - iowrite8(value, i2c->base + reg * i2c->regstep);
> + if (i2c->regwidth == 4)
> + iowrite32(value, i2c->base + reg * i2c->regstep);
> + else if (i2c->regwidth == 2)
> + iowrite16(value, i2c->base + reg * i2c->regstep);
> + else
> + iowrite8(value, i2c->base + reg * i2c->regstep);
> }
>
> static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
> {
> - return ioread8(i2c->base + reg * i2c->regstep);
> + if (i2c->regwidth == 4)
> + return ioread32(i2c->base + reg * i2c->regstep);
> + else if (i2c->regwidth == 2)
> + return ioread16(i2c->base + reg * i2c->regstep);
> + else
> + return ioread8(i2c->base + reg * i2c->regstep);
> }
>
> static void ocores_process(struct ocores_i2c *i2c)
> @@ -267,6 +282,10 @@ static int ocores_i2c_of_probe(struct platform_device* pdev,
> }
> i2c->clock_khz = be32_to_cpup(val) / 1000;
>
> + val = of_get_property(pdev->dev.of_node, "regwidth", NULL);
> + if (val)
> + i2c->regwidth = be32_to_cpup(val);
> +
> return 0;
> }
> #else
> @@ -309,12 +328,21 @@ static int __devinit ocores_i2c_probe(struct platform_device *pdev)
> pdata = pdev->dev.platform_data;
> if (pdata) {
> i2c->regstep = pdata->regstep;
> + i2c->regwidth = pdata->regwidth;
> i2c->clock_khz = pdata->clock_khz;
> } else {
> ret = ocores_i2c_of_probe(pdev, i2c);
> if (ret)
> return ret;
> }
> + if (i2c->regwidth == 0)
> + i2c->regwidth = 1; /* not configured, use default */
> + else if (i2c->regwidth != 1 && i2c->regwidth != 2 &&
> + i2c->regwidth != 4) {
> + dev_err(&pdev->dev, "Invalid register width %d\n",
> + i2c->regwidth);
> + return -EINVAL;
> + }
>
> ocores_init(i2c);
>
> diff --git a/include/linux/i2c-ocores.h b/include/linux/i2c-ocores.h
> index 4d5e57f..d1258ad 100644
> --- a/include/linux/i2c-ocores.h
> +++ b/include/linux/i2c-ocores.h
> @@ -13,6 +13,7 @@
>
> struct ocores_i2c_platform_data {
> u32 regstep; /* distance between registers */
> + u32 regwidth; /* io read/write register witdth */
> u32 clock_khz; /* input clock in kHz */
> u8 num_devices; /* number of devices in the devices list */
> struct i2c_board_info const *devices; /* devices connected to the bus */
> --
> 1.7.9.5
>
>
> --
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--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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