linux-kernel - [PATCH 2/2 v3] pwm: axi-pwmgen: add duty offset support

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Date: Tue, 21 May 2024 15:49:16 -0400
From: Trevor Gamblin <tgamblin@...libre.com>
To: linux-pwm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org,
	u.kleine-koenig@...gutronix.de,
	michael.hennerich@...log.com,
	nuno.sa@...log.com,
	tgamblin@...libre.com,
	dlechner@...libre.com
Subject: [PATCH 2/2 v3] pwm: axi-pwmgen: add duty offset support

Enable duty_offset feature now that it is supported in the pwm
subsystem. Related macros and struct fields related to duty_offset are
renamed to be consistent.

Signed-off-by: Trevor Gamblin <tgamblin@...libre.com>
---
v3 changes:
* rebased on top of latest pwm/for-next

v2 changes:
* Address feedback for driver in v1:
  * Remove line setting supports_offset flag in pwm_chip, since that has
    been removed from the struct in core.c.
---
 drivers/pwm/pwm-axi-pwmgen.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-axi-pwmgen.c b/drivers/pwm/pwm-axi-pwmgen.c
index e0bf90cc2ba3..9ae06b105d07 100644
--- a/drivers/pwm/pwm-axi-pwmgen.c
+++ b/drivers/pwm/pwm-axi-pwmgen.c
@@ -56,7 +56,7 @@ static int axi_pwmgen_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	struct axi_pwmgen_ddata *ddata = pwmchip_get_drvdata(chip);
 	unsigned int ch = pwm->hwpwm;
 	struct regmap *regmap = ddata->regmap;
-	u64 period_cnt, duty_cnt;
+	u64 period_cnt, duty_cnt, duty_offset_cnt;
 	int ret;
 
 	if (state->polarity != PWM_POLARITY_NORMAL)
@@ -81,6 +81,14 @@ static int axi_pwmgen_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 		ret = regmap_write(regmap, AXI_PWMGEN_CHX_DUTY(ch), duty_cnt);
 		if (ret)
 			return ret;
+
+		duty_offset_cnt = mul_u64_u64_div_u64(state->duty_offset, ddata->clk_rate_hz, NSEC_PER_SEC);
+		if (duty_offset_cnt > UINT_MAX)
+			duty_offset_cnt = UINT_MAX;
+
+		ret = regmap_write(regmap, AXI_PWMGEN_CHX_OFFSET(ch), duty_offset_cnt);
+		if (ret)
+			return ret;
 	} else {
 		ret = regmap_write(regmap, AXI_PWMGEN_CHX_PERIOD(ch), 0);
 		if (ret)
@@ -89,6 +97,10 @@ static int axi_pwmgen_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 		ret = regmap_write(regmap, AXI_PWMGEN_CHX_DUTY(ch), 0);
 		if (ret)
 			return ret;
+
+		ret = regmap_write(regmap, AXI_PWMGEN_CHX_OFFSET(ch), 0);
+		if (ret)
+			return ret;
 	}
 
 	return regmap_write(regmap, AXI_PWMGEN_REG_CONFIG, AXI_PWMGEN_LOAD_CONFIG);
@@ -117,6 +129,12 @@ static int axi_pwmgen_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 
 	state->duty_cycle = DIV_ROUND_UP_ULL((u64)cnt * NSEC_PER_SEC, ddata->clk_rate_hz);
 
+	ret = regmap_read(regmap, AXI_PWMGEN_CHX_OFFSET(ch), &cnt);
+	if (ret)
+		return ret;
+
+	state->duty_offset = DIV_ROUND_UP_ULL((u64)cnt * NSEC_PER_SEC, ddata->clk_rate_hz);
+
 	state->polarity = PWM_POLARITY_NORMAL;
 
 	return 0;
-- 
2.45.1