[PATCH 3/8] pwm i.MX: add functions to enable/disable pwm.

From: Sascha Hauer
Date: Wed Sep 05 2012 - 09:35:46 EST


We used to enable/disable the pwm only by switching the
clock on or off. Instead, use the dedicated register bits.
These differ on different SoCs, so introduce a SoC specific
function for this.

Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
drivers/pwm/pwm-imx.c | 48 ++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 44 insertions(+), 4 deletions(-)

diff --git a/drivers/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
index 0f244e6..3fc4ae8 100644
--- a/drivers/pwm/pwm-imx.c
+++ b/drivers/pwm/pwm-imx.c
@@ -25,6 +25,7 @@
#define MX1_PWMS 0x04 /* PWM Sample Register */
#define MX1_PWMP 0x08 /* PWM Period Register */

+#define MX1_PWMC_EN (1 << 4)

/* i.MX27, i.MX31, i.MX35 share the same PWM function block: */

@@ -49,6 +50,7 @@ struct imx_chip {

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);
};

#define to_imx_chip(chip) container_of(chip, struct imx_chip, chip)
@@ -81,6 +83,21 @@ static int imx_pwm_config_v1(struct pwm_chip *chip,
return 0;
}

+static void imx_pwm_set_enable_v1(struct pwm_chip *chip, bool enable)
+{
+ struct imx_chip *imx = to_imx_chip(chip);
+ u32 val;
+
+ val = readl(imx->mmio_base + MX1_PWMC);
+
+ if (enable)
+ val |= MX1_PWMC_EN;
+ else
+ val &= ~MX1_PWMC_EN;
+
+ writel(val, imx->mmio_base + MX1_PWMC);
+}
+
static int imx_pwm_config_v2(struct pwm_chip *chip,
struct pwm_device *pwm, int duty_ns, int period_ns)
{
@@ -115,7 +132,10 @@ static int imx_pwm_config_v2(struct pwm_chip *chip,

cr = MX3_PWMCR_PRESCALER(prescale) |
MX3_PWMCR_DOZEEN | MX3_PWMCR_WAITEN |
- MX3_PWMCR_DBGEN | MX3_PWMCR_EN;
+ MX3_PWMCR_DBGEN;
+
+ if (imx->enabled)
+ cr |= MX3_PWMCR_EN;

if (cpu_is_mx25())
cr |= MX3_PWMCR_CLKSRC_IPG;
@@ -127,6 +147,21 @@ static int imx_pwm_config_v2(struct pwm_chip *chip,
return 0;
}

+static void imx_pwm_set_enable_v2(struct pwm_chip *chip, bool enable)
+{
+ struct imx_chip *imx = to_imx_chip(chip);
+ u32 val;
+
+ val = readl(imx->mmio_base + MX3_PWMCR);
+
+ if (enable)
+ val |= MX3_PWMCR_EN;
+ else
+ val &= ~MX3_PWMCR_EN;
+
+ writel(val, imx->mmio_base + MX3_PWMCR);
+}
+
static int imx_pwm_config(struct pwm_chip *chip,
struct pwm_device *pwm, int duty_ns, int period_ns)
{
@@ -144,6 +179,8 @@ static int imx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
if (rc)
return rc;

+ imx->set_enable(chip, true);
+
imx->enabled = 1;

return 0;
@@ -153,7 +190,7 @@ static void imx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct imx_chip *imx = to_imx_chip(chip);

- writel(0, imx->mmio_base + MX3_PWMCR);
+ imx->set_enable(chip, false);

clk_disable_unprepare(imx->clk);
imx->enabled = 0;
@@ -198,10 +235,13 @@ static int __devinit imx_pwm_probe(struct platform_device *pdev)
if (imx->mmio_base == NULL)
return -EADDRNOTAVAIL;

- if (cpu_is_mx1() || cpu_is_mx21())
+ if (cpu_is_mx1() || cpu_is_mx21()) {
imx->config = imx_pwm_config_v1;
- else
+ imx->set_enable = imx_pwm_set_enable_v1;
+ } else {
imx->config = imx_pwm_config_v2;
+ imx->set_enable = imx_pwm_set_enable_v2;
+ }

ret = pwmchip_add(&imx->chip);
if (ret < 0)
--
1.7.10.4

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