[PATCH v5 24/46] pwm: sti: add support for initial state retrieval

Boris Brezillon
2016-03-30T20:13:36Z

Implement ->get_state() to provide support for initial state retrieval.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---
drivers/pwm/pwm-sti.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)

diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c
index 92abbd5..0fbca94 100644
--- a/drivers/pwm/pwm-sti.c
+++ b/drivers/pwm/pwm-sti.c
@@ -238,6 +238,46 @@ static void sti_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
mutex_unlock(&pc->sti_pwm_lock);
}

+static void sti_pwm_get_state(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ struct pwm_state *pstate)
+{
+ struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
+ unsigned int regval, prescaler;
+ u64 timens;
+ int ret;
+
+ /* The clock has to be enabled to access PWM registers */
+ ret = clk_enable(pc->clk);
+ if (ret) {
+ dev_err(chip->dev, "Failed to enable PWM clk");
+ return;
+ }
+
+ regmap_field_read(pc->prescale_high, &regval);
+ prescaler = regval << 4;
+ regmap_field_read(pc->prescale_low, &regval);
+ prescaler |= regval;
+
+ timens = (u64)(prescaler + 1) * NSEC_PER_SEC *
+ (pc->cdata->max_pwm_cnt + 1);
+ do_div(timens, pc->clk_rate);
+
+ pstate->period = timens;
+
+ regmap_read(pc->regmap, STI_DS_REG(pwm->hwpwm), &regval);
+ timens = (u64)(regval + 1) * pstate->period;
+ do_div(timens, pc->cdata->max_pwm_cnt + 1);
+ pstate->duty_cycle = timens;
+
+ regmap_field_read(pc->pwm_en, &regval);
+ pstate->enabled = regval;
+
+ pstate->polarity = PWM_POLARITY_NORMAL;
+
+ clk_disable(pc->clk);
+}
+
static void sti_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
@@ -249,6 +289,7 @@ static const struct pwm_ops sti_pwm_ops = {
.config = sti_pwm_config,
.enable = sti_pwm_enable,
.disable = sti_pwm_disable,
+ .get_state = sti_pwm_get_state,
.free = sti_pwm_free,
.owner = THIS_MODULE,
};
--
2.5.0