On Thursday 18 June 2015 02:23 PM, Alexander Sverdlin wrote:
> According to KeyStone Architecture I2C User Guide,
>
> module clock frequency
> master clock frequency = ----------------------
> (ICCL + 6) + (ICCH + 6)
>
> i.e. "d" in i2c_davinci_calc_clk_dividers() should be fixed and
> not dependent from module clock prescaler PSC on these SoCs.
>
> Signed-off-by: Alexander Sverdlin <[email protected]>
> ---
>
> RFC: If someone from TI has an idea how to improve the coverage of future
> Keystone
> revisions -- hints/patches are welcome. The current ID check is based on
> Davinci/Keystone datasheets and is at least working on real Keystone II.
+ Murali who works on Keystone devices in TI.
>
> drivers/i2c/busses/i2c-davinci.c | 10 ++++++++++
> 1 files changed, 10 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-davinci.c
> b/drivers/i2c/busses/i2c-davinci.c
> index 4a110af..3d78f6a 100644
> --- a/drivers/i2c/busses/i2c-davinci.c
> +++ b/drivers/i2c/busses/i2c-davinci.c
> @@ -60,6 +60,8 @@
> #define DAVINCI_I2C_IVR_REG 0x28
> #define DAVINCI_I2C_EMDR_REG 0x2c
> #define DAVINCI_I2C_PSC_REG 0x30
> +#define DAVINCI_I2C_ICPID1_REG 0x34
> +#define DAVINCI_I2C_ICPID2_REG 0x38
> #define DAVINCI_I2C_FUNC_REG 0x48
> #define DAVINCI_I2C_DIR_REG 0x4c
> #define DAVINCI_I2C_DIN_REG 0x50
> @@ -203,6 +205,9 @@ static void i2c_davinci_calc_clk_dividers(struct
> davinci_i2c_dev *dev)
> * where if PSC == 0, d = 7,
> * if PSC == 1, d = 6
> * if PSC > 1 , d = 5
> + *
> + * Note:
> + * d is always 6 on Keystone I2C controller
> */
>
> /* get minimum of 7 MHz clock, but max of 12 MHz */
> @@ -211,6 +216,11 @@ static void i2c_davinci_calc_clk_dividers(struct
> davinci_i2c_dev *dev)
> psc++; /* better to run under spec than over */
> d = (psc >= 2) ? 5 : 7 - psc;
>
> + if (davinci_i2c_read_reg(dev, DAVINCI_I2C_ICPID2_REG) == 0x2206) {
> + dev_dbg(dev->dev, "Keystone SoC detected\n");
> + d = 6;
> + }
I think its better to use a different compatible string for i2c on
keystone devices rather than using a fixed hardcoded IP version.
Thanks,
Sekhar
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