[PATCH v2 1/3] pwm: sun4i: improve hardware read out

[Alexandre Belloni]

Implement .get_state instead of only reading the polarity at probe time.
This allows to get the proper state, period and duty cycle.

Signed-off-by: Alexandre Belloni <alexandre.bell...@free-electrons.com>
---
 drivers/pwm/pwm-sun4i.c | 65 ++++++++++++++++++++++++++++++++++---------------
 1 file changed, 46 insertions(+), 19 deletions(-)

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index 1284ffa05921..175a69245a8a 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -44,6 +44,10 @@
 
 #define PWM_DTY_MASK           GENMASK(15, 0)
 
+#define PWM_REG_PRD(reg)       ((((reg) >> 16) & PWM_PRD_MASK) + 1)
+#define PWM_REG_DTY(reg)       ((reg) & PWM_DTY_MASK)
+#define PWM_REG_PRESCAL(reg, chan)     (((reg) >> ((chan) * PWMCH_OFFSET)) & 
PWM_PRESCAL_MASK)
+
 #define BIT_CH(bit, chan)      ((bit) << ((chan) * PWMCH_OFFSET))
 
 static const u32 prescaler_table[] = {
@@ -96,6 +100,46 @@ static inline void sun4i_pwm_writel(struct sun4i_pwm_chip 
*chip,
        writel(val, chip->base + offset);
 }
 
+static void sun4i_pwm_get_state(struct pwm_chip *chip,
+                               struct pwm_device *pwm,
+                               struct pwm_state *state)
+{
+       struct sun4i_pwm_chip *sun4i_pwm = to_sun4i_pwm_chip(chip);
+       u64 clk_rate, tmp;
+       u32 val;
+       unsigned int prescaler;
+
+       clk_rate = clk_get_rate(sun4i_pwm->clk);
+
+       val = sun4i_pwm_readl(sun4i_pwm, PWM_CTRL_REG);
+
+       if ((val == PWM_PRESCAL_MASK) && sun4i_pwm->data->has_prescaler_bypass)
+               prescaler = 1;
+       else
+               prescaler = prescaler_table[PWM_REG_PRESCAL(val, pwm->hwpwm)];
+
+       if (prescaler == 0)
+               return;
+
+       if (val & BIT_CH(PWM_ACT_STATE, pwm->hwpwm))
+               state->polarity = PWM_POLARITY_NORMAL;
+       else
+               state->polarity = PWM_POLARITY_INVERSED;
+
+       if (val & BIT_CH(PWM_CLK_GATING | PWM_EN, pwm->hwpwm))
+               state->enabled = true;
+       else
+               state->enabled = false;
+
+       val = sun4i_pwm_readl(sun4i_pwm, PWM_CH_PRD(pwm->hwpwm));
+
+       tmp = prescaler * NSEC_PER_SEC * PWM_REG_DTY(val);
+       state->duty_cycle = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
+
+       tmp = prescaler * NSEC_PER_SEC * PWM_REG_PRD(val);
+       state->period = DIV_ROUND_CLOSEST_ULL(tmp, clk_rate);
+}
+
 static int sun4i_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
                            int duty_ns, int period_ns)
 {
@@ -257,6 +301,7 @@ static const struct pwm_ops sun4i_pwm_ops = {
        .set_polarity = sun4i_pwm_set_polarity,
        .enable = sun4i_pwm_enable,
        .disable = sun4i_pwm_disable,
+       .get_state = sun4i_pwm_get_state,
        .owner = THIS_MODULE,
 };
 
@@ -316,8 +361,7 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
 {
        struct sun4i_pwm_chip *pwm;
        struct resource *res;
-       u32 val;
-       int i, ret;
+       int ret;
        const struct of_device_id *match;
 
        match = of_match_device(sun4i_pwm_dt_ids, &pdev->dev);
@@ -353,24 +397,7 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
 
        platform_set_drvdata(pdev, pwm);
 
-       ret = clk_prepare_enable(pwm->clk);
-       if (ret) {
-               dev_err(&pdev->dev, "failed to enable PWM clock\n");
-               goto clk_error;
-       }
-
-       val = sun4i_pwm_readl(pwm, PWM_CTRL_REG);
-       for (i = 0; i < pwm->chip.npwm; i++)
-               if (!(val & BIT_CH(PWM_ACT_STATE, i)))
-                       pwm_set_polarity(&pwm->chip.pwms[i],
-                                        PWM_POLARITY_INVERSED);
-       clk_disable_unprepare(pwm->clk);
-
        return 0;
-
-clk_error:
-       pwmchip_remove(&pwm->chip);
-       return ret;
 }
 
 static int sun4i_pwm_remove(struct platform_device *pdev)
-- 
2.11.0