[RFT][PATCH 1/2] pwm: lpc32xx: Properly set PWM_ENABLE bit in lpc32xx_pwm_[enable|disable]

[RFT][PATCH 1/2] pwm: lpc32xx: Properly set PWM_ENABLE bit in lpc32xx_pwm_[enable|disable]

[Axel Lin]

According to the LPC32x0 User Manual [1]:

PWMx Control Registers:
BIT 31 (PWMx_EN):
0 = PWM disabled. (Default)
1 = PWM enabled

In lpc32xx_pwm_enable(), we should set PWM_ENABLE bit.
In lpc32xx_pwm_disable(), we should just clear PWM_ENABLE bit rather than
write 0 to the register which will also clear PWMx_RELOADV and PWMx_DUTY bits.

[1] http://www.nxp.com/documents/user_manual/UM10326.pdf

Signed-off-by: Axel Lin <axel.lin@ingics.com>
---
Hi,
I don't have this hardware handy so I'd appreciate if someone can test this
patch serial.

Thanks,
Axel

 drivers/pwm/pwm-lpc32xx.c |   18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/pwm-lpc32xx.c b/drivers/pwm/pwm-lpc32xx.c
index b3f0d0d..1a5075e 100644
--- a/drivers/pwm/pwm-lpc32xx.c
+++ b/drivers/pwm/pwm-lpc32xx.c
@@ -77,15 +77,29 @@ static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 static int lpc32xx_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
+	u32 val;
+	int ret;
+
+	ret = clk_enable(lpc32xx->clk);
+	if (ret)
+		return ret;
 
-	return clk_enable(lpc32xx->clk);
+	val = readl(lpc32xx->base + (pwm->hwpwm << 2));
+	val |= PWM_ENABLE;
+	writel(val, lpc32xx->base + (pwm->hwpwm << 2));
+
+	return 0;
 }
 
 static void lpc32xx_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
+	u32 val;
+
+	val = readl(lpc32xx->base + (pwm->hwpwm << 2));
+	val &= ~PWM_ENABLE;
+	writel(val, lpc32xx->base + (pwm->hwpwm << 2));
 
-	writel(0, lpc32xx->base + (pwm->hwpwm << 2));
 	clk_disable(lpc32xx->clk);
 }
 
-- 
1.7.10.4

[RFT][PATCH 2/2] pwm: lpc32xx: Don't change PWM_ENABLE bit in lpc32xx_pwm_config

[Axel Lin]

lpc32xx_pwm_config() is supposed to set duty_ns and period_ns,
it should not change PWM_ENABLE bit.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
---
 drivers/pwm/pwm-lpc32xx.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-lpc32xx.c b/drivers/pwm/pwm-lpc32xx.c
index 1a5075e..ac4d28d 100644
--- a/drivers/pwm/pwm-lpc32xx.c
+++ b/drivers/pwm/pwm-lpc32xx.c
@@ -68,7 +68,7 @@ static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 		c = 255;
 	duty_cycles = 256 - c;
 
-	writel(PWM_ENABLE | PWM_RELOADV(period_cycles) | PWM_DUTY(duty_cycles),
+	writel(PWM_RELOADV(period_cycles) | PWM_DUTY(duty_cycles),
 		lpc32xx->base + (pwm->hwpwm << 2));
 
 	return 0;
-- 
1.7.10.4

[RFT][PATCH v2 2/2] pwm: lpc32xx: Don't change PWM_ENABLE bit in lpc32xx_pwm_config

[Axel Lin]

lpc32xx_pwm_config() is supposed to set duty_ns and period_ns,
it should not change PWM_ENABLE and other bits.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
---
 drivers/pwm/pwm-lpc32xx.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/pwm-lpc32xx.c b/drivers/pwm/pwm-lpc32xx.c
index 1a5075e..e936202 100644
--- a/drivers/pwm/pwm-lpc32xx.c
+++ b/drivers/pwm/pwm-lpc32xx.c
@@ -37,6 +37,7 @@ static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	struct lpc32xx_pwm_chip *lpc32xx = to_lpc32xx_pwm_chip(chip);
 	unsigned long long c;
 	int period_cycles, duty_cycles;
+	u32 val;
 
 	c = clk_get_rate(lpc32xx->clk) / 256;
 	c = c * period_ns;
@@ -68,8 +69,10 @@ static int lpc32xx_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 		c = 255;
 	duty_cycles = 256 - c;
 
-	writel(PWM_ENABLE | PWM_RELOADV(period_cycles) | PWM_DUTY(duty_cycles),
-		lpc32xx->base + (pwm->hwpwm << 2));
+	val = readl(lpc32xx->base + (pwm->hwpwm << 2));
+	val &= ~0xFFFF;
+	val |= PWM_RELOADV(period_cycles) | PWM_DUTY(duty_cycles);
+	writel(val, lpc32xx->base + (pwm->hwpwm << 2));
 
 	return 0;
 }
-- 
1.7.10.4