[PATCH v2 1/3] pwm: sun4i: improve hardware read out
Alexandre Belloni
alexandre.belloni at free-electrons.com
Tue May 30 12:32:07 PDT 2017
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.belloni at 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
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