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




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