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authorDavid Wu <david.wu@rock-chips.com>2017-03-01 19:10:55 +0800
committerThierry Reding <thierry.reding@gmail.com>2017-04-06 15:08:52 +0200
commita900152b5c29aea8134cc7a4c5db25552b3cd8f7 (patch)
treeb2c1710e98c98cf6cfb2db2bcdf8c2778e9422c8 /drivers/pwm/pwm-rockchip.c
parentb997e3edca4fb4ab7732ab7240c545da0c360a44 (diff)
pwm: rockchip: State of PWM clock should synchronize with PWM enabled state
If the PWM was not enabled at U-Boot 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 U-Boot 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 and 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> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm/pwm-rockchip.c')
-rw-r--r--drivers/pwm/pwm-rockchip.c40
1 files changed, 33 insertions, 7 deletions
diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
index ef89df1f7336..744d56197286 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 rockchip_pwm_enable(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ bool enable,
+ enum pwm_polarity polarity)
+{
+ 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 = rockchip_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);
-
+ rockchip_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 = rockchip_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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