| Message ID | 1464942192-25967-6-git-send-email-boris.brezillon@free-electrons.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi, Just noticed a few things: On Fri, Jun 03, 2016 at 10:23:03AM +0200, Boris Brezillon wrote: > 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> > --- > drivers/pwm/pwm-rockchip.c | 24 +++++++++++++++++++++++- > 1 file changed, 23 insertions(+), 1 deletion(-) > > diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c > index dfacf7d..798a787 100644 > --- a/drivers/pwm/pwm-rockchip.c > +++ b/drivers/pwm/pwm-rockchip.c > @@ -299,6 +299,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev) > { > const struct of_device_id *id; > struct rockchip_pwm_chip *pc; > + struct pwm_state state; > struct resource *r; > int ret; > > @@ -319,7 +320,7 @@ 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; > > @@ -342,12 +343,33 @@ 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. */ > + pwm_get_state(pc->chip.pwms, &state); > + if (!state.enabled) Why not just if (!pwm_is_enabled())? > + clk_disable(pc->clk); > + > return ret; > } > > static int rockchip_pwm_remove(struct platform_device *pdev) > { > struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev); > + struct pwm_state state; > + > + /* > + * 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(). > + * > + */ > + pwm_get_state(pc->chip.pwms, &state); > + if (state.enabled) Same here. With that: Reviewed-by: Brian Norris <briannorris@chromium.org> And it tests out fine: Tested-by: Brian Norris <briannorris@chromium.org> > + clk_disable(pc->clk); > > clk_unprepare(pc->clk); > > -- > 2.7.4 >
On Fri, 3 Jun 2016 13:28:59 -0700 Brian Norris <briannorris@chromium.org> wrote: > Hi, > > Just noticed a few things: > > On Fri, Jun 03, 2016 at 10:23:03AM +0200, Boris Brezillon wrote: > > 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> > > --- > > drivers/pwm/pwm-rockchip.c | 24 +++++++++++++++++++++++- > > 1 file changed, 23 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c > > index dfacf7d..798a787 100644 > > --- a/drivers/pwm/pwm-rockchip.c > > +++ b/drivers/pwm/pwm-rockchip.c > > @@ -299,6 +299,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev) > > { > > const struct of_device_id *id; > > struct rockchip_pwm_chip *pc; > > + struct pwm_state state; > > struct resource *r; > > int ret; > > > > @@ -319,7 +320,7 @@ 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; > > > > @@ -342,12 +343,33 @@ 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. */ > > + pwm_get_state(pc->chip.pwms, &state); > > + if (!state.enabled) > > Why not just if (!pwm_is_enabled())? It's a leftover from a previous version where I was deprecating pwm_enable(). I'll switch back to pwm_enable(). Thanks, Boris
diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c index dfacf7d..798a787 100644 --- a/drivers/pwm/pwm-rockchip.c +++ b/drivers/pwm/pwm-rockchip.c @@ -299,6 +299,7 @@ static int rockchip_pwm_probe(struct platform_device *pdev) { const struct of_device_id *id; struct rockchip_pwm_chip *pc; + struct pwm_state state; struct resource *r; int ret; @@ -319,7 +320,7 @@ 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; @@ -342,12 +343,33 @@ 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. */ + pwm_get_state(pc->chip.pwms, &state); + if (!state.enabled) + clk_disable(pc->clk); + return ret; } static int rockchip_pwm_remove(struct platform_device *pdev) { struct rockchip_pwm_chip *pc = platform_get_drvdata(pdev); + struct pwm_state state; + + /* + * 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(). + * + */ + pwm_get_state(pc->chip.pwms, &state); + if (state.enabled) + clk_disable(pc->clk); clk_unprepare(pc->clk);
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> --- drivers/pwm/pwm-rockchip.c | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-)