pwm: imx: support output polarity inversion

[karo-tx-linux.git] / drivers / pwm / pwm-imx.c

diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
index 2b7c4f88b461b788c1d683a141d6a402d958af12..a07205333b884f637eed68545ed81e22240279a8 100644 (file)
--- a/drivers/pwm/pwm-imx.c
+++ b/drivers/pwm/pwm-imx.c
@@ -16,6 +16,7 @@
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/pwm.h>
+#include <linux/of.h>
 #include <linux/of_device.h>
 
 /* i.MX1 and i.MX21 share the same PWM function block: */
@@ -24,20 +25,21 @@
 #define MX1_PWMS    0x04   /* PWM Sample Register */
 #define MX1_PWMP    0x08   /* PWM Period Register */
 
-#define MX1_PWMC_EN            (1 << 4)
+#define MX1_PWMC_EN                    (1 << 4)
 
 /* i.MX27, i.MX31, i.MX35 share the same PWM function block: */
 
-#define MX3_PWMCR                 0x00    /* PWM Control Register */
-#define MX3_PWMSAR                0x0C    /* PWM Sample Register */
-#define MX3_PWMPR                 0x10    /* PWM Period Register */
-#define MX3_PWMCR_PRESCALER(x)    (((x - 1) & 0xFFF) << 4)
-#define MX3_PWMCR_DOZEEN                (1 << 24)
-#define MX3_PWMCR_WAITEN                (1 << 23)
+#define MX3_PWMCR                      0x00      /* PWM Control Register */
+#define MX3_PWMSAR                     0x0C      /* PWM Sample Register */
+#define MX3_PWMPR                      0x10      /* PWM Period Register */
+#define MX3_PWMCR_PRESCALER(x)         ((((x) - 1) & 0xFFF) << 4)
+#define MX3_PWMCR_DOZEEN               (1 << 24)
+#define MX3_PWMCR_WAITEN               (1 << 23)
 #define MX3_PWMCR_DBGEN                        (1 << 22)
-#define MX3_PWMCR_CLKSRC_IPG_HIGH (2 << 16)
-#define MX3_PWMCR_CLKSRC_IPG      (1 << 16)
-#define MX3_PWMCR_EN              (1 << 0)
+#define MX3_PWMCR_POUTC                        (1 << 18)
+#define MX3_PWMCR_CLKSRC_IPG_HIGH      (2 << 16)
+#define MX3_PWMCR_CLKSRC_IPG           (1 << 16)
+#define MX3_PWMCR_EN                   (1 << 0)
 
 struct imx_chip {
        struct clk      *clk_per;
@@ -136,6 +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);
 
@@ -154,6 +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);
 }
 
@@ -197,6 +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,
@@ -208,6 +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 = {
@@ -218,6 +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[] = {
@@ -270,6 +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;
 
@@ -296,7 +325,7 @@ static struct platform_driver imx_pwm_driver = {
        .driver         = {
                .name   = "imx-pwm",
                .owner = THIS_MODULE,
-               .of_match_table = of_match_ptr(imx_pwm_dt_ids),
+               .of_match_table = imx_pwm_dt_ids,
        },
        .probe          = imx_pwm_probe,
        .remove         = imx_pwm_remove,