[PATCH v9 13/17] pwm: crc: Implement get_state() method

[Hans de Goede]

Implement the pwm_ops.get_state() method to complete the support for the
new atomic PWM API.

Reviewed-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
Acked-by: Thierry Reding <thierry.reding at gmail.com>
Signed-off-by: Hans de Goede <hdegoede at redhat.com>
---
Changes in v6:
- Rebase on 5.9-rc1
- Use DIV_ROUND_UP_ULL because pwm_state.period and .duty_cycle are now u64

Changes in v5:
- Fix an indentation issue

Changes in v4:
- Use DIV_ROUND_UP when calculating the period and duty_cycle from the
  controller's register values

Changes in v3:
- Add Andy's Reviewed-by tag
- Remove extra whitespace to align some code after assignments (requested by
  Uwe Kleine-König)
---
 drivers/pwm/pwm-crc.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/drivers/pwm/pwm-crc.c b/drivers/pwm/pwm-crc.c
index 27dc30882424..ecfdfac0c2d9 100644
--- a/drivers/pwm/pwm-crc.c
+++ b/drivers/pwm/pwm-crc.c
@@ -121,8 +121,39 @@ static int crc_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	return 0;
 }
 
+static void crc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+			      struct pwm_state *state)
+{
+	struct crystalcove_pwm *crc_pwm = to_crc_pwm(chip);
+	struct device *dev = crc_pwm->chip.dev;
+	unsigned int clk_div, clk_div_reg, duty_cycle_reg;
+	int error;
+
+	error = regmap_read(crc_pwm->regmap, PWM0_CLK_DIV, &clk_div_reg);
+	if (error) {
+		dev_err(dev, "Error reading PWM0_CLK_DIV %d\n", error);
+		return;
+	}
+
+	error = regmap_read(crc_pwm->regmap, PWM0_DUTY_CYCLE, &duty_cycle_reg);
+	if (error) {
+		dev_err(dev, "Error reading PWM0_DUTY_CYCLE %d\n", error);
+		return;
+	}
+
+	clk_div = (clk_div_reg & ~PWM_OUTPUT_ENABLE) + 1;
+
+	state->period =
+		DIV_ROUND_UP(clk_div * NSEC_PER_USEC * 256, PWM_BASE_CLK_MHZ);
+	state->duty_cycle =
+		DIV_ROUND_UP_ULL(duty_cycle_reg * state->period, PWM_MAX_LEVEL);
+	state->polarity = PWM_POLARITY_NORMAL;
+	state->enabled = !!(clk_div_reg & PWM_OUTPUT_ENABLE);
+}
+
 static const struct pwm_ops crc_pwm_ops = {
 	.apply = crc_pwm_apply,
+	.get_state = crc_pwm_get_state,
 };
 
 static int crystalcove_pwm_probe(struct platform_device *pdev)
-- 
2.28.0