[PATCH v2 3/3] pwm: sophgo: add driver for SG2044

[Longbin Li <looong.bin@gmail.com>]

Add PWM controller for SG2044 on base of SG2042.

Signed-off-by: Longbin Li <looong.bin@gmail.com>
---
 drivers/pwm/pwm-sophgo-sg2042.c | 89 ++++++++++++++++++++++++++++++++-
 1 file changed, 87 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/pwm-sophgo-sg2042.c b/drivers/pwm/pwm-sophgo-sg2042.c
index 23a83843ba53..26147ec596c9 100644
--- a/drivers/pwm/pwm-sophgo-sg2042.c
+++ b/drivers/pwm/pwm-sophgo-sg2042.c
@@ -13,6 +13,9 @@
  *   the running period.
  * - When PERIOD and HLPERIOD is set to 0, the PWM wave output will
  *   be stopped and the output is pulled to high.
+ * - SG2044 support polarity while SG2042 does not. When PWMSTART is
+ *   false, POLARITY being NORMAL will make output being low,
+ *   POLARITY being INVERSED will make output being high.
  * See the datasheet [1] for more details.
  * [1]:https://github.com/sophgo/sophgo-doc/tree/main/SG2042/TRM
  */
@@ -26,6 +29,10 @@
 #include <linux/pwm.h>
 #include <linux/reset.h>

+#define SG2044_REG_POLARITY		0x40
+#define SG2044_REG_PWMSTART		0x44
+#define SG2044_REG_PWM_OE		0xD0
+
 #define SG2042_PWM_HLPERIOD(chan) ((chan) * 8 + 0)
 #define SG2042_PWM_PERIOD(chan) ((chan) * 8 + 4)

@@ -72,8 +79,8 @@ static void pwm_set_dutycycle(struct pwm_chip *chip, struct pwm_device *pwm,
 	period_ticks = min(mul_u64_u64_div_u64(ddata->clk_rate_hz, state->period, NSEC_PER_SEC), U32_MAX);
 	hlperiod_ticks = min(mul_u64_u64_div_u64(ddata->clk_rate_hz, state->duty_cycle, NSEC_PER_SEC), U32_MAX);

-	dev_dbg(pwmchip_parent(chip), "chan[%u]: PERIOD=%u, HLPERIOD=%u\n",
-		pwm->hwpwm, period_ticks, hlperiod_ticks);
+	dev_dbg(pwmchip_parent(chip), "chan[%u]: ENABLE=%u, PERIOD=%u, HLPERIOD=%u, POLARITY=%u\n",
+		pwm->hwpwm, state->enabled, period_ticks, hlperiod_ticks, state->polarity);

 	pwm_sg2042_config(ddata, pwm->hwpwm, period_ticks, hlperiod_ticks);
 }
@@ -123,6 +130,74 @@ static int pwm_sg2042_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
 	return 0;
 }

+static void pwm_sg2044_set_start(struct sg2042_pwm_ddata *ddata, struct pwm_device *pwm,
+				 bool enabled)
+{
+	u32 pwm_value;
+
+	pwm_value = readl(ddata->base + SG2044_REG_PWMSTART);
+
+	if (enabled)
+		pwm_value |= BIT(pwm->hwpwm);
+	else
+		pwm_value &= ~BIT(pwm->hwpwm);
+
+	writel(pwm_value, ddata->base + SG2044_REG_PWMSTART);
+}
+
+static void pwm_sg2044_set_outputdir(struct sg2042_pwm_ddata *ddata, struct pwm_device *pwm,
+				     bool enabled)
+{
+	u32 pwm_value;
+
+	pwm_value = readl(ddata->base + SG2044_REG_PWM_OE);
+
+	if (enabled)
+		pwm_value |= BIT(pwm->hwpwm);
+	else
+		pwm_value &= ~BIT(pwm->hwpwm);
+
+	writel(pwm_value, ddata->base + SG2044_REG_PWM_OE);
+}
+
+static void pwm_sg2044_set_polarity(struct sg2042_pwm_ddata *ddata, struct pwm_device *pwm,
+				    const struct pwm_state *state)
+{
+	u32 pwm_value;
+
+	pwm_value = readl(ddata->base + SG2044_REG_POLARITY);
+
+	if (state->polarity == PWM_POLARITY_NORMAL)
+		pwm_value &= ~BIT(pwm->hwpwm);
+	else
+		pwm_value |= BIT(pwm->hwpwm);
+
+	writel(pwm_value, ddata->base + SG2044_REG_POLARITY);
+}
+
+static int pwm_sg2044_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+			    const struct pwm_state *state)
+{
+	struct sg2042_pwm_ddata *ddata = pwmchip_get_drvdata(chip);
+
+	pwm_sg2044_set_polarity(ddata, pwm, state);
+
+	pwm_set_dutycycle(chip, pwm, state);
+
+	/*
+	 * re-enable PWMSTART to refresh the register period
+	 */
+	pwm_sg2044_set_start(ddata, pwm, false);
+
+	if (!state->enabled)
+		return 0;
+
+	pwm_sg2044_set_outputdir(ddata, pwm, true);
+	pwm_sg2044_set_start(ddata, pwm, true);
+
+	return 0;
+}
+
 static const struct sg2042_chip_data sg2042_chip_data = {
 	.ops = {
 		.apply = pwm_sg2042_apply,
@@ -130,9 +205,18 @@ static const struct sg2042_chip_data sg2042_chip_data = {
 	}
 };

+static const struct sg2042_chip_data sg2044_chip_data = {
+	.ops = {
+		.apply = pwm_sg2044_apply,
+		.get_state = pwm_sg2042_get_state,
+	}
+};
+
 static const struct of_device_id sg2042_pwm_ids[] = {
 	{ .compatible = "sophgo,sg2042-pwm",
 	  .data = &sg2042_chip_data },
+	{ .compatible = "sophgo,sg2044-pwm",
+	  .data = &sg2044_chip_data },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, sg2042_pwm_ids);
@@ -198,5 +282,6 @@ static struct platform_driver pwm_sg2042_driver = {
 module_platform_driver(pwm_sg2042_driver);

 MODULE_AUTHOR("Chen Wang");
+MODULE_AUTHOR("Longbin Li <looong.bin@gmail.com>");
 MODULE_DESCRIPTION("Sophgo SG2042 PWM driver");
 MODULE_LICENSE("GPL");
--
2.49.0