diff options
| author | Boris Brezillon <boris.brezillon@free-electrons.com> | 2016-06-14 11:13:13 +0200 |
|---|---|---|
| committer | Thierry Reding <thierry.reding@gmail.com> | 2016-07-11 12:49:27 +0200 |
| commit | 48cf973cae33488f84d7ab79a0f613383cff4de4 (patch) | |
| tree | 9a990cee1a27949b156050525318553adf63c807 /drivers/pwm | |
| parent | pwm: rockchip: Add support for hardware readout (diff) | |
| download | linux-48cf973cae33488f84d7ab79a0f613383cff4de4.tar.xz linux-48cf973cae33488f84d7ab79a0f613383cff4de4.zip | |
pwm: rockchip: Avoid glitches on already running PWMs
The current logic will disable the PWM clk even if the PWM was left
enabled by the bootloader (because it's controlling a critical device
like a regulator for example).
Keep the PWM clk enabled if the PWM is enabled to avoid any glitches.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm')
| -rw-r--r-- | drivers/pwm/pwm-rockchip.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c index c72b4192c7bf..dd8ca8663c24 100644 --- a/drivers/pwm/pwm-rockchip.c +++ b/drivers/pwm/pwm-rockchip.c @@ -319,7 +319,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev) if (IS_ERR(pc->clk)) return PTR_ERR(pc->clk); - ret = clk_prepare(pc->clk); + ret = clk_prepare_enable(pc->clk); if (ret) return ret; @@ -342,6 +342,10 @@ static int rockchip_pwm_probe(struct platform_device *pdev) dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); } + /* Keep the PWM clk enabled if the PWM appears to be up and running. */ + if (!pwm_is_enabled(pc->chip.pwms)) + clk_disable(pc->clk); + return ret; } @@ -349,6 +353,20 @@ static int rockchip_pwm_remove(struct platform_device *pdev) { struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev); + /* + * Disable the PWM clk before unpreparing it if the PWM device is still + * running. This should only happen when the last PWM user left it + * enabled, or when nobody requested a PWM that was previously enabled + * by the bootloader. + * + * FIXME: Maybe the core should disable all PWM devices in + * pwmchip_remove(). In this case we'd only have to call + * clk_unprepare() after pwmchip_remove(). + * + */ + if (pwm_is_enabled(pc->chip.pwms)) + clk_disable(pc->clk); + clk_unprepare(pc->clk); return pwmchip_remove(&pc->chip); |