[PATCH] pwm: rockchip: State of pwm clock should synchronize with pwm enabled state

[David Wu]

From: "david.wu" <david...@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.

Signed-off-by: David Wu <david...@rock-chips.com>
---
 drivers/pwm/pwm-rockchip.c | 38 +++++++++++++++++++++++++++++++-------
 1 file changed, 31 insertions(+), 7 deletions(-)

diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
index ef89df1..14a0445 100644
--- a/drivers/pwm/pwm-rockchip.c
+++ b/drivers/pwm/pwm-rockchip.c
@@ -191,6 +191,26 @@ 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)
+{
+       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 +227,26 @@ 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
-- 
1.9.1