Hi all,
it looks good to me.
Le 30/09/2015 10:47, Ludovic Desroches a écrit :
> From: Wenyou Yang <wenyou.yang@xxxxxxxxx>
>
> Add the HOLD field setting in order to support I2C slave devices which need
> a longer hold time of the data.
> Since it depends on the slave devices connected to the bus, add a DT
> property "atmel,twd-hold-cycles" to specify this HOLD field.
>
> Signed-off-by: Wenyou Yang <wenyou.yang@xxxxxxxxx>
> Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
Acked-by: Cyrille Pitchen <cyrille.pitchen@xxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-at91.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
> index 1c758cd..06e66ef 100644
> --- a/drivers/i2c/busses/i2c-at91.c
> +++ b/drivers/i2c/busses/i2c-at91.c
> @@ -64,6 +64,7 @@
> #define AT91_TWI_IADR 0x000c /* Internal Address Register */
>
> #define AT91_TWI_CWGR 0x0010 /* Clock Waveform Generator Reg */
> +#define AT91_TWI_CWGR_HOLD(x) (((x) & 0x1f) << 24)
>
> #define AT91_TWI_SR 0x0020 /* Status Register */
> #define AT91_TWI_TXCOMP BIT(0) /* Transmission Complete */
> @@ -185,7 +186,8 @@ static void at91_init_twi_bus(struct at91_twi_dev *dev)
> * Calculate symmetric clock as stated in datasheet:
> * twi_clk = F_MAIN / (2 * (cdiv * (1 << ckdiv) + offset))
> */
> -static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
> +static void at91_calc_twi_clock(struct at91_twi_dev *dev,
> + int twi_clk, u32 twd_hold)
> {
> int ckdiv, cdiv, div;
> struct at91_twi_pdata *pdata = dev->pdata;
> @@ -204,7 +206,9 @@ static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
> cdiv = 255;
> }
>
> - dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv;
> + dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv
> + | AT91_TWI_CWGR_HOLD(twd_hold);
> +
> dev_dbg(dev->dev, "cdiv %d ckdiv %d\n", cdiv, ckdiv);
> }
>
> @@ -936,6 +940,7 @@ static int at91_twi_probe(struct platform_device *pdev)
> int rc;
> u32 phy_addr;
> u32 bus_clk_rate;
> + u32 twd_hold_cycles;
>
> dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
> if (!dev)
> @@ -992,7 +997,12 @@ static int at91_twi_probe(struct platform_device *pdev)
> if (rc)
> bus_clk_rate = DEFAULT_TWI_CLK_HZ;
>
> - at91_calc_twi_clock(dev, bus_clk_rate);
> + rc = of_property_read_u32(dev->dev->of_node,
> + "atmel,twd-hold-cycles", &twd_hold_cycles);
> + if (rc)
> + twd_hold_cycles = 0;
> +
> + at91_calc_twi_clock(dev, bus_clk_rate, twd_hold_cycles);
> at91_init_twi_bus(dev);
>
> snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
>
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