On 02/27/2014 07:56 AM, Peter Ujfalusi wrote:
> All boards using twl6040 configures the i2c bus to 400KHz. While twl6040's
> defaults to normal mode (100KHz). So far twl6040 has no problem with i2c
> communication in this configuration it is safer to select fast i2c mode.
>
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> ---
> drivers/mfd/twl6040.c | 9 +++++++--
> include/linux/mfd/twl6040.h | 1 +
> 2 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mfd/twl6040.c b/drivers/mfd/twl6040.c
> index 6e88f25832fb..2c308750f40f 100644
> --- a/drivers/mfd/twl6040.c
> +++ b/drivers/mfd/twl6040.c
> @@ -87,8 +87,13 @@ static struct reg_default twl6040_defaults[] = {
> };
>
> static struct reg_default twl6040_patch[] = {
> - /* Select I2C bus access to dual access registers */
> - { TWL6040_REG_ACCCTL, 0x09 },
> + /*
> + * Select I2C bus access to dual access registers
> + * Interrupt register is cleared on read
> + * Select fast mode for i2c (400KHz)
> + */
> + { TWL6040_REG_ACCCTL,
> + TWL6040_I2CSEL | TWL6040_INTCLRMODE | TWL6040_I2CMODE(1) },
> };
>
>
> diff --git a/include/linux/mfd/twl6040.h b/include/linux/mfd/twl6040.h
> index 81f639bc1ae6..a69d16b30c18 100644
> --- a/include/linux/mfd/twl6040.h
> +++ b/include/linux/mfd/twl6040.h
> @@ -157,6 +157,7 @@
> #define TWL6040_I2CSEL 0x01
> #define TWL6040_RESETSPLIT 0x04
> #define TWL6040_INTCLRMODE 0x08
> +#define TWL6040_I2CMODE(x) ((x & 0x3) << 4)
>
> /* STATUS (0x2E) fields */
>
>
we should ideally have been using highspeed for i2c bus.
is'nt it better if i2c_check_functionality (and adding required flags
for func) be used to check the adapter speed and decide this in the
driver instead of hardcoding the bus speed within TWL6040 -
considering that 6040 can infact do max high speed as well?
--
Regards,
Nishanth Menon
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