The i.MX pwm unit on i.MX27 and newer SoCs provides a configurable
output polarity. This patch adds support to utilize this feature where
available.
Signed-off-by: Lothar Waßmann <l...@karo-electronics.de>
---
drivers/pwm/pwm-imx.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
index 52aac5e..a43410a 100644
--- a/drivers/pwm/pwm-imx.c
+++ b/drivers/pwm/pwm-imx.c
@@ -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_dbg(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 +292,11 @@ static int imx_pwm_probe(struct platform_device *pdev)
return PTR_ERR(imx->mmio_base);
data = of_id->data;
+ if (data->output_polarity) {
+ dev_dbg(&pdev->dev, "PWM supports output inversion\n");
+ imx_pwm_ops.set_polarity = imx_pwm_set_polarity;
+ }
+
imx->config = data->config;
imx->set_enable = data->set_enable;
--
1.7.10.4
--
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