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SubjectRe: [PATCH v2] pwm: rockchip: State of pwm clock should synchronize with pwm enabled state
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Hi Boris,

在 2017/3/1 18:19, Boris Brezillon 写道:
> On Wed, 1 Mar 2017 18:16:02 +0800
> David Wu <david.wu@rock-chips.com> wrote:
>
>> From: "david.wu" <david.wu@rock-chips.com>
>>
>> If the pwm was not enabled at uboot loader, pwm could not work for clock
>> always disabled at pwm driver. The pwm clock is enabled at beginning of
>> pwm_apply(), but disabled at end of pwm_apply().
>>
>> If the pwm was enabled at uboot loader, pwm clock is always enabled unless
>> closed by ATF. The pwm-backlight might turn off the power at early suspend,
>> should disable pwm clock for saving power consume.
>>
>> It is important to provide opportunity to enable/disable clock at pwm driver,
>> the pwm consumer should ensure correct order to call pwm enable/disable, and
>> pwm driver ensure state of pwm clock synchronized with pwm enabled state.
>>
>> Fixes: 2bf1c98aa5a4 ("pwm: rockchip: Add support for atomic update")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: David Wu <david.wu@rock-chips.com>
>> Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
>> ---
>> drivers/pwm/pwm-rockchip.c | 40 +++++++++++++++++++++++++++++++++-------
>> 1 file changed, 33 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
>> index ef89df1..dbee3c3 100644
>> --- a/drivers/pwm/pwm-rockchip.c
>> +++ b/drivers/pwm/pwm-rockchip.c
>> @@ -191,6 +191,28 @@ static int rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
>> return 0;
>> }
>>
>> +static int rk_pwm_enable(struct pwm_chip *chip,
>> + struct pwm_device *pwm,
>> + bool enable,
>> + enum pwm_polarity polarity)
>
> You didn't change the function name:
>
> s/rk_pwm_enable/rockchip_pwm_enable/

Sorry, it is a pity not to fix in in v2.

>
>> +{
>> + struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
>> + int ret;
>> +
>> + if (enable) {
>> + ret = clk_enable(pc->clk);
>> + if (ret)
>> + return ret;
>> + }
>> +
>> + pc->data->set_enable(chip, pwm, enable, polarity);
>> +
>> + if (!enable)
>> + clk_disable(pc->clk);
>> +
>> + return 0;
>> +}
>> +
>> static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>> struct pwm_state *state)
>> {
>> @@ -207,22 +229,26 @@ static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>> return ret;
>>
>> if (state->polarity != curstate.polarity && enabled) {
>> - pc->data->set_enable(chip, pwm, false, state->polarity);
>> + ret = rk_pwm_enable(chip, pwm, false, state->polarity);
>> + if (ret)
>> + goto out;
>> enabled = false;
>> }
>>
>> ret = rockchip_pwm_config(chip, pwm, state->duty_cycle, state->period);
>> if (ret) {
>> if (enabled != curstate.enabled)
>> - pc->data->set_enable(chip, pwm, !enabled,
>> - state->polarity);
>> -
>> + rk_pwm_enable(chip, pwm, !enabled,
>> + state->polarity);
>> goto out;
>> }
>>
>> - if (state->enabled != enabled)
>> - pc->data->set_enable(chip, pwm, state->enabled,
>> - state->polarity);
>> + if (state->enabled != enabled) {
>> + ret = rk_pwm_enable(chip, pwm, state->enabled,
>> + state->polarity);
>> + if (ret)
>> + goto out;
>> + }
>>
>> /*
>> * Update the state with the real hardware, which can differ a bit
>
>
>
>

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