| Message ID | 1353310254-21581-3-git-send-email-linux@prisktech.co.nz (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Nov 19, 2012 at 08:30:54PM +1300, Tony Prisk wrote: > 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 <linux@prisktech.co.nz> > Tested-by: Peter Vasil <petervasil@gmail.com> > --- > 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; > + }; I'm not entirely happy about this error message. What bugs me about it is that the clock doesn't fail to enable in pwm_config() but rather in vt8500_pwm_config(), so it might be slightly misleading. I'm not sure if the failure location is needed at all. "failed to enable clock" sounds useful enough. Furthermore I think that if it fails here it will likely also fail elsewhere. If you really absolutely want to specify where clk_enable() failed, then I'd be slightly happier with "%s(): failed to enable clock", __func__. Thierry
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; }