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| author | Tony Prisk <linux@prisktech.co.nz> | 2012-11-20 06:44:46 +1300 |
|---|---|---|
| committer | Thierry Reding <thierry.reding@avionic-design.de> | 2012-11-22 22:47:12 +0100 |
| commit | 422470a8265fbb1d182c00ab2421f4b416ab2dba (patch) | |
| tree | aacef5cee631f3a0a15b0f927cc06151a3ce4eca /drivers/pwm | |
| parent | 2f9569f7ceab31242b306d040861737580e1876f (diff) | |
| download | linux-rpi-422470a8265fbb1d182c00ab2421f4b416ab2dba.tar.gz linux-rpi-422470a8265fbb1d182c00ab2421f4b416ab2dba.tar.bz2 linux-rpi-422470a8265fbb1d182c00ab2421f4b416ab2dba.zip | |
pwm: vt8500: Ensure PWM clock is enabled during pwm_config
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>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Diffstat (limited to 'drivers/pwm')
| -rw-r--r-- | drivers/pwm/pwm-vt8500.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/drivers/pwm/pwm-vt8500.c b/drivers/pwm/pwm-vt8500.c index 806f72c2421f..b0ba2d403439 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\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; } @@ -103,7 +113,7 @@ static int vt8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) if (err < 0) { dev_err(chip->dev, "failed to enable clock\n"); return err; - }; + } pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 0)); writel(5, vt8500->base + (pwm->hwpwm << 4)); |