From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@prisktech.co.nz (Tony Prisk) Date: Mon, 19 Nov 2012 20:30:54 +1300 Subject: [PATCH v2 2/2] pwm: vt8500: Ensure pwm clock is enabled during pwm_config In-Reply-To: <1353310254-21581-1-git-send-email-linux@prisktech.co.nz> References: <1353310254-21581-1-git-send-email-linux@prisktech.co.nz> Message-ID: <1353310254-21581-3-git-send-email-linux@prisktech.co.nz> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org This patch corrects a bug reported by Peter Vasil. When all PWMs are disabled, PWM module may be disabled during calls to pwm_config. This patch enables/disables the clock in pwm_config to ensure the module is active before register read/ writes. Signed-off-by: Tony Prisk Tested-by: Peter Vasil --- drivers/pwm/pwm-vt8500.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/pwm/pwm-vt8500.c b/drivers/pwm/pwm-vt8500.c index 806f72c..9fdb70d 100644 --- a/drivers/pwm/pwm-vt8500.c +++ b/drivers/pwm/pwm-vt8500.c @@ -62,6 +62,13 @@ static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, struct vt8500_chip *vt8500 = to_vt8500_chip(chip); unsigned long long c; unsigned long period_cycles, prescale, pv, dc; + int err; + + err = clk_enable(vt8500->clk); + if (err < 0) { + dev_err(chip->dev, "failed to enable clock in pwm_config()\n"); + return err; + }; c = clk_get_rate(vt8500->clk); c = c * period_ns; @@ -75,8 +82,10 @@ static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, if (pv > 4095) pv = 4095; - if (prescale > 1023) + if (prescale > 1023) { + clk_disable(vt8500->clk); return -EINVAL; + } c = (unsigned long long)pv * duty_ns; do_div(c, period_ns); @@ -91,6 +100,7 @@ static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 3)); writel(dc, vt8500->base + 0xc + (pwm->hwpwm << 4)); + clk_disable(vt8500->clk); return 0; } -- 1.7.9.5