pwm: imx: support output polarity inversion
authorLothar Waßmann <LW@KARO-electronics.de>
Fri, 7 Mar 2014 08:36:23 +0000 (09:36 +0100)
committerLothar Waßmann <LW@KARO-electronics.de>
Fri, 7 Mar 2014 08:36:23 +0000 (09:36 +0100)
drivers/pwm/pwm-imx.c

index 52aac5e..a072053 100644 (file)
@@ -138,6 +138,8 @@ static int imx_pwm_config_v2(struct pwm_chip *chip,
 
        if (test_bit(PWMF_ENABLED, &pwm->flags))
                cr |= MX3_PWMCR_EN;
+       if (pwm->polarity == PWM_POLARITY_INVERSED)
+               cr |= MX3_PWMCR_POUTC;
 
        writel(cr, imx->mmio_base + MX3_PWMCR);
 
@@ -156,6 +158,11 @@ static void imx_pwm_set_enable_v2(struct pwm_chip *chip, bool enable)
        else
                val &= ~MX3_PWMCR_EN;
 
+       if (chip->pwms[0].polarity == PWM_POLARITY_INVERSED)
+               val |= MX3_PWMCR_POUTC;
+       else
+               val &= ~MX3_PWMCR_POUTC;
+
        writel(val, imx->mmio_base + MX3_PWMCR);
 }
 
@@ -199,6 +206,17 @@ static void imx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
        clk_disable_unprepare(imx->clk_per);
 }
 
+static int imx_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
+                               enum pwm_polarity polarity)
+{
+       struct imx_chip *imx = to_imx_chip(chip);
+
+       dev_info(imx->chip.dev, "%s: polarity set to %s\n", __func__,
+               polarity == PWM_POLARITY_INVERSED ? "inverted" : "normal");
+
+       return 0;
+}
+
 static struct pwm_ops imx_pwm_ops = {
        .enable = imx_pwm_enable,
        .disable = imx_pwm_disable,
@@ -210,6 +228,7 @@ struct imx_pwm_data {
        int (*config)(struct pwm_chip *chip,
                struct pwm_device *pwm, int duty_ns, int period_ns);
        void (*set_enable)(struct pwm_chip *chip, bool enable);
+       unsigned output_polarity:1;
 };
 
 static struct imx_pwm_data imx_pwm_data_v1 = {
@@ -220,6 +239,7 @@ static struct imx_pwm_data imx_pwm_data_v1 = {
 static struct imx_pwm_data imx_pwm_data_v2 = {
        .config = imx_pwm_config_v2,
        .set_enable = imx_pwm_set_enable_v2,
+       .output_polarity = 1,
 };
 
 static const struct of_device_id imx_pwm_dt_ids[] = {
@@ -272,6 +292,13 @@ static int imx_pwm_probe(struct platform_device *pdev)
                return PTR_ERR(imx->mmio_base);
 
        data = of_id->data;
+       if (data->output_polarity) {
+               dev_info(&pdev->dev, "PWM supports output inversion\n");
+               imx_pwm_ops.set_polarity = imx_pwm_set_polarity;
+               imx->chip.of_xlate = of_pwm_xlate_with_flags;
+               imx->chip.of_pwm_n_cells = 3;
+       }
+
        imx->config = data->config;
        imx->set_enable = data->set_enable;