Am Mittwoch, 11. Mai 2016, 03:33:14 schrieb David Wu:
please always try to also provide some sort of commit message.
---
Implement fast mode plus that allows bus speeds of up to 1MHz.
.....
---
Additionally, the i2c-noob in me would wish for a short sentence on where
the timing values come from (measured, somewhere in the TRM I didn't find or
something completely different).
Patch content itself looks good, so with a suitable commit message,
Reviewed-by: Heiko Stuebner <heiko@xxxxxxxxx>
> Signed-off-by: David Wu <david.wu@xxxxxxxxxxxxxx>
> Reviewed-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> ---
> Change in v8:
> - None
>
> drivers/i2c/busses/i2c-rk3x.c | 21 +++++++++++++++++----
> 1 file changed, 17 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
> index 25ed1ad..0ba25ee 100644
> --- a/drivers/i2c/busses/i2c-rk3x.c
> +++ b/drivers/i2c/busses/i2c-rk3x.c
> @@ -126,6 +126,17 @@ static const struct i2c_spec_values fast_mode_spec =
> { .min_hold_buffer_ns = 1300,
> };
>
> +static const struct i2c_spec_values fast_mode_plus_spec = {
> + .min_hold_start_ns = 260,
> + .min_low_ns = 500,
> + .min_high_ns = 260,
> + .min_setup_start_ns = 260,
> + .max_data_hold_ns = 400,
> + .min_data_setup_ns = 50,
> + .min_setup_stop_ns = 260,
> + .min_hold_buffer_ns = 500,
> +};
> +
> /**
> * struct rk3x_i2c_calced_timings:
> * @div_low: Divider output for low
> @@ -531,8 +542,10 @@ static const struct i2c_spec_values
> *rk3x_i2c_get_spec(unsigned int speed) {
> if (speed <= 100000)
> return &standard_mode_spec;
> - else
> + else if (speed <= 400000)
> return &fast_mode_spec;
> + else
> + return &fast_mode_plus_spec;
> }
>
> /**
> @@ -743,9 +756,9 @@ static int rk3x_i2c_v1_calc_timings(unsigned long
> clk_rate, const struct i2c_spec_values *spec;
> int ret = 0;
>
> - /* Support standard-mode and fast-mode */
> - if (WARN_ON(t->bus_freq_hz > 400000))
> - t->bus_freq_hz = 400000;
> + /* Support standard-mode, fast-mode and fast-mode plus */
> + if (WARN_ON(t->bus_freq_hz > 1000000))
> + t->bus_freq_hz = 1000000;
>
> /* prevent scl_rate_khz from becoming 0 */
> if (WARN_ON(t->bus_freq_hz < 1000))
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