pwm: imx: Add polarity inversion support to i.MX's PWMv2

With this patch the polarity settings for i.MX's PWMv2 is now supported
on top of atomic PWM setting

Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Signed-off-by: Lukasz Majewski <l.majewski@majess.pl>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-imx.c

@@ -38,6 +38,7 @@
 #define MX3_PWMCR_DOZEEN		(1 << 24)
 #define MX3_PWMCR_WAITEN		(1 << 23)
 #define MX3_PWMCR_DBGEN			(1 << 22)
+#define MX3_PWMCR_POUTC			(1 << 18)
 #define MX3_PWMCR_CLKSRC_IPG_HIGH	(2 << 16)
 #define MX3_PWMCR_CLKSRC_IPG		(1 << 16)
 #define MX3_PWMCR_SWR			(1 << 3)
@@ -163,6 +164,7 @@ static int imx_pwm_apply_v2(struct pwm_chip *chip, struct pwm_device *pwm,
 	struct pwm_state cstate;
 	unsigned long long c;
 	int ret;
+	u32 cr;
 
 	pwm_get_state(pwm, &cstate);
 
@@ -207,11 +209,15 @@ static int imx_pwm_apply_v2(struct pwm_chip *chip, struct pwm_device *pwm,
 		writel(duty_cycles, imx->mmio_base + MX3_PWMSAR);
 		writel(period_cycles, imx->mmio_base + MX3_PWMPR);
 
-		writel(MX3_PWMCR_PRESCALER(prescale) |
-		       MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN |
-		       MX3_PWMCR_DBGEN | MX3_PWMCR_CLKSRC_IPG_HIGH |
-		       MX3_PWMCR_EN,
-		       imx->mmio_base + MX3_PWMCR);
+		cr = MX3_PWMCR_PRESCALER(prescale) |
+		     MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN |
+		     MX3_PWMCR_DBGEN | MX3_PWMCR_CLKSRC_IPG_HIGH |
+		     MX3_PWMCR_EN;
+
+		if (state->polarity == PWM_POLARITY_INVERSED)
+			cr |= MX3_PWMCR_POUTC;
+
+		writel(cr, imx->mmio_base + MX3_PWMCR);
 	} else if (cstate.enabled) {
 		writel(0, imx->mmio_base + MX3_PWMCR);
 
@@ -234,6 +240,7 @@ static const struct pwm_ops imx_pwm_ops_v2 = {
 };
 
 struct imx_pwm_data {
+	bool polarity_supported;
 	const struct pwm_ops *ops;
 };
 
@@ -242,6 +249,7 @@ static struct imx_pwm_data imx_pwm_data_v1 = {
 };
 
 static struct imx_pwm_data imx_pwm_data_v2 = {
+	.polarity_supported = true,
 	.ops = &imx_pwm_ops_v2,
 };
 
@@ -283,6 +291,12 @@ static int imx_pwm_probe(struct platform_device *pdev)
 	imx->chip.npwm = 1;
 	imx->chip.can_sleep = true;
 
+	if (data->polarity_supported) {
+		dev_dbg(&pdev->dev, "PWM supports output inversion\n");
+		imx->chip.of_xlate = of_pwm_xlate_with_flags;
+		imx->chip.of_pwm_n_cells = 3;
+	}
+
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	imx->mmio_base = devm_ioremap_resource(&pdev->dev, r);
 	if (IS_ERR(imx->mmio_base))