From 08ee77b5a5de27ad63c92262ebcb4efe0da93b58 Mon Sep 17 00:00:00 2001 From: Axel Lin Date: Tue, 23 Apr 2013 14:01:31 +0800 Subject: [PATCH] pwm: lpc32xx: Properly set PWM_ENABLE bit in lpc32xx_pwm_[enable|disable] According to the LPC32x0 User Manual [1]: For both PWM1 and PWM2 Control Registers: BIT 31: This bit gates the PWM_CLK signal and enables the external output pin to the PWM_PIN_STATE logical level. 0 = PWM disabled. (Default) 1 = PWM enabled So 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 Tested-by: Roland Stigge Signed-off-by: Thierry Reding --- 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 b55cc5c1d614ad..6b6272f61da5a6 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); }