From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiko Stuebner Subject: Re: [PATCH v8 8/8] i2c: rk3x: support fast-mode plus for rk3399 Date: Wed, 11 May 2016 23:09:43 +0200 Message-ID: <5153288.jNhUuzGC3g@phil> References: <1462908252-27016-1-git-send-email-david.wu@rock-chips.com> <1462908794-27333-1-git-send-email-david.wu@rock-chips.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <1462908794-27333-1-git-send-email-david.wu@rock-chips.com> Sender: linux-kernel-owner@vger.kernel.org To: David Wu Cc: wsa@the-dreams.de, robh+dt@kernel.org, dianders@chromium.org, andy.shevchenko@gmail.com, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, briannorris@google.com, davidriley@google.com, huangtao@rock-chips.com, hl@rock-chips.com, xjq@rock-chips.com, zyw@rock-chips.com, cf@rock-chips.com, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-rockchip.vger.kernel.org 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 > Signed-off-by: David Wu > Reviewed-by: Douglas Anderson > --- > 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))