On Mon, Apr 06, 2015 at 07:40:28PM -0700, Kuppuswamy Sathyanarayanan wrote:
> If the device configuration is updated by firmware and
> the information is not passed to driver via firmware
> interfaces like ACPI or DT parameters, then that information
> will be lost once the device either resets or suspends. This
> patch checks the boot value of hold and setup time during
> device probe and updates the driver hold and setup time params.
> This fix will ensure that the updates to hold and setup time
> values are not lost after device suspend or resets.
>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
Adding Mika to CC.
> ---
> drivers/i2c/busses/i2c-designware-core.c | 37 +++++++++++++++++++++++++++++
> drivers/i2c/busses/i2c-designware-core.h | 2 ++
> drivers/i2c/busses/i2c-designware-platdrv.c | 4 ++++
> 3 files changed, 43 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
> index 6e25c01..2598207 100644
> --- a/drivers/i2c/busses/i2c-designware-core.c
> +++ b/drivers/i2c/busses/i2c-designware-core.c
> @@ -64,6 +64,7 @@
> #define DW_IC_RXFLR 0x78
> #define DW_IC_SDA_HOLD 0x7c
> #define DW_IC_TX_ABRT_SOURCE 0x80
> +#define DW_IC_SDA_SETUP 0x94
> #define DW_IC_ENABLE_STATUS 0x9c
> #define DW_IC_COMP_PARAM_1 0xf4
> #define DW_IC_COMP_VERSION 0xf8
> @@ -89,6 +90,9 @@
> DW_IC_INTR_TX_ABRT | \
> DW_IC_INTR_STOP_DET)
>
> +#define DW_IC_DEFAULT_SDA_SETUP 0x64
> +#define DW_IC_DEFAULT_SDA_HOLD 0x1
> +
> #define DW_IC_STATUS_ACTIVITY 0x1
>
> #define DW_IC_ERR_TX_ABRT 0x1
> @@ -271,6 +275,35 @@ static void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable)
> enable ? "en" : "dis");
> }
>
> +/*
> + * Update device default param values if its changed by
> + * firmware
> + */
> +void dw_i2c_update_defaults(struct dw_i2c_dev *dev)
> +{
> + int ret;
> +
> + /*
> + * make sure default is not updated by firmware
> + * interfaces like OF or ACPI
> + */
> +
> + /* SDA hold time update */
> + if (!dev->sda_hold_time) {
> + ret = dw_readl(dev, DW_IC_SDA_HOLD);
> + if ((ret > 0) && (ret != DW_IC_DEFAULT_SDA_HOLD))
> + dev->sda_hold_time = ret;
> + }
> +
> + /* SDA setup time update */
> + if (!dev->sda_setup_time) {
> + ret = dw_readl(dev, DW_IC_SDA_SETUP);
> + if ((ret > 0) && (ret != DW_IC_DEFAULT_SDA_SETUP))
> + dev->sda_setup_time = ret;
> + }
> +}
> +EXPORT_SYMBOL_GPL(dw_i2c_update_defaults);
> +
> /**
> * i2c_dw_init() - initialize the designware i2c master hardware
> * @dev: device private data
> @@ -368,6 +401,10 @@ int i2c_dw_init(struct dw_i2c_dev *dev)
> "Hardware too old to adjust SDA hold time.");
> }
>
> + /* Configure SDA setup time if required */
> + if (dev->sda_setup_time)
> + dw_writel(dev, dev->sda_setup_time, DW_IC_SDA_SETUP);
> +
> /* Configure Tx/Rx FIFO threshold levels */
> dw_writel(dev, dev->tx_fifo_depth / 2, DW_IC_TX_TL);
> dw_writel(dev, 0, DW_IC_RX_TL);
> diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
> index 9630222..23ae2e8 100644
> --- a/drivers/i2c/busses/i2c-designware-core.h
> +++ b/drivers/i2c/busses/i2c-designware-core.h
> @@ -98,6 +98,7 @@ struct dw_i2c_dev {
> unsigned int rx_fifo_depth;
> int rx_outstanding;
> u32 sda_hold_time;
> + u32 sda_setup_time;
> u32 sda_falling_time;
> u32 scl_falling_time;
> u16 ss_hcnt;
> @@ -131,3 +132,4 @@ extern int i2c_dw_eval_lock_support(struct dw_i2c_dev *dev);
> #else
> static inline int i2c_dw_eval_lock_support(struct dw_i2c_dev *dev) { return 0; }
> #endif
> +extern void dw_i2c_update_defaults(struct dw_i2c_dev *dev);
> diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
> index c270f5f..d8995d8 100644
> --- a/drivers/i2c/busses/i2c-designware-platdrv.c
> +++ b/drivers/i2c/busses/i2c-designware-platdrv.c
> @@ -233,6 +233,10 @@ static int dw_i2c_probe(struct platform_device *pdev)
> dev->rx_fifo_depth = ((param1 >> 8) & 0xff) + 1;
> dev->adapter.nr = pdev->id;
> }
> +
> + /* call after firmware param update */
> + dw_i2c_update_defaults(dev);
What about calling this from the pci driver?
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