| Message ID | 1609936000-28378-5-git-send-email-srinivas.neeli@xilinx.com |
|---|---|
| State | New |
| Headers | show |
| Series | gpio-xilinx: Update on xilinx gpio driver | expand |
On Wed, Jan 6, 2021 at 1:27 PM Srinivas Neeli <srinivas.neeli@xilinx.com> wrote: > Add support for suspend and resume, pm runtime suspend and resume. > Added free and request calls. > > Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com> (...) > +static int xgpio_request(struct gpio_chip *chip, unsigned int offset) > +{ > + int ret; > + > + ret = pm_runtime_get_sync(chip->parent); > + /* > + * If the device is already active pm_runtime_get() will return 1 on > + * success, but gpio_request still needs to return 0. > + */ > + return ret < 0 ? ret : 0; > +} That's clever. I think more GPIO drivers should be doing it like this, today I think most just ignore the return code. > +static int __maybe_unused xgpio_suspend(struct device *dev) > +static int __maybe_unused xgpio_resume(struct device *dev) Those look good. > /** > * xgpio_remove - Remove method for the GPIO device. > * @pdev: pointer to the platform device > @@ -289,7 +323,10 @@ static int xgpio_remove(struct platform_device *pdev) > { > struct xgpio_instance *gpio = platform_get_drvdata(pdev); > > - clk_disable_unprepare(gpio->clk); > + if (!pm_runtime_suspended(&pdev->dev)) > + clk_disable_unprepare(gpio->clk); > + > + pm_runtime_disable(&pdev->dev); This looks complex and racy. What if the device is resumed after you executed the first part of the statement. The normal sequence is: pm_runtime_get_sync(dev); pm_runtime_put_noidle(dev); pm_runtime_disable(dev); This will make sure the clock is enabled and pm runtime is disabled. After this you can unconditionally call clk_disable_unprepare(gpio->clk); It is what you are doing on the errorpath of probe(). Yours, Linus Walleij
Hi Linus, > -----Original Message----- > From: Linus Walleij <linus.walleij@linaro.org> > Sent: Thursday, January 7, 2021 3:17 PM > To: Srinivas Neeli <sneeli@xilinx.com> > Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>; Michal Simek > <michals@xilinx.com>; Shubhrajyoti Datta <shubhraj@xilinx.com>; Srinivas > Goud <sgoud@xilinx.com>; Robert Hancock <hancock@sedsystems.ca>; > William Breathitt Gray <vilhelm.gray@gmail.com>; Syed Nayyar Waris > <syednwaris@gmail.com>; open list:GPIO SUBSYSTEM <linux- > gpio@vger.kernel.org>; Linux ARM <linux-arm-kernel@lists.infradead.org>; > linux-kernel@vger.kernel.org; git <git@xilinx.com> > Subject: Re: [PATCH V4 4/5] gpio: gpio-xilinx: Add support for suspend and > resume > > On Wed, Jan 6, 2021 at 1:27 PM Srinivas Neeli <srinivas.neeli@xilinx.com> > wrote: > > > Add support for suspend and resume, pm runtime suspend and resume. > > Added free and request calls. > > > > Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com> > (...) > > > +static int xgpio_request(struct gpio_chip *chip, unsigned int offset) > > +{ > > + int ret; > > + > > + ret = pm_runtime_get_sync(chip->parent); > > + /* > > + * If the device is already active pm_runtime_get() will return 1 on > > + * success, but gpio_request still needs to return 0. > > + */ > > + return ret < 0 ? ret : 0; > > +} > > That's clever. I think more GPIO drivers should be doing it like this, today I > think most just ignore the return code. > > > +static int __maybe_unused xgpio_suspend(struct device *dev) static > > +int __maybe_unused xgpio_resume(struct device *dev) > > Those look good. > > > > /** > > * xgpio_remove - Remove method for the GPIO device. > > * @pdev: pointer to the platform device @@ -289,7 +323,10 @@ static > > int xgpio_remove(struct platform_device *pdev) { > > struct xgpio_instance *gpio = platform_get_drvdata(pdev); > > > > - clk_disable_unprepare(gpio->clk); > > + if (!pm_runtime_suspended(&pdev->dev)) > > + clk_disable_unprepare(gpio->clk); > > + > > + pm_runtime_disable(&pdev->dev); > > This looks complex and racy. What if the device is resumed after you > executed the first part of the statement. Could you please explain more on this. What is the need to call pm_runtime_get_sync(); in remove API ? > > The normal sequence is: > > pm_runtime_get_sync(dev); > pm_runtime_put_noidle(dev); > pm_runtime_disable(dev); > > This will make sure the clock is enabled and pm runtime is disabled. > After this you can unconditionally call clk_disable_unprepare(gpio->clk); > > It is what you are doing on the errorpath of probe(). > > Yours, > Linus Walleij
On Fri, Jan 8, 2021 at 12:41 PM Srinivas Neeli <sneeli@xilinx.com> wrote: > > On Wed, Jan 6, 2021 at 1:27 PM Srinivas Neeli <srinivas.neeli@xilinx.com> > > wrote: > > > /** > > > * xgpio_remove - Remove method for the GPIO device. > > > * @pdev: pointer to the platform device @@ -289,7 +323,10 @@ static > > > int xgpio_remove(struct platform_device *pdev) { > > > struct xgpio_instance *gpio = platform_get_drvdata(pdev); > > > > > > - clk_disable_unprepare(gpio->clk); > > > + if (!pm_runtime_suspended(&pdev->dev)) > > > + clk_disable_unprepare(gpio->clk); > > > + > > > + pm_runtime_disable(&pdev->dev); > > > > This looks complex and racy. What if the device is resumed after you > > executed the first part of the statement. > > Could you please explain more on this. > What is the need to call pm_runtime_get_sync(); in remove API ? I explain that on the lines right below your comment ;D > > The normal sequence is: > > > > pm_runtime_get_sync(dev); > > pm_runtime_put_noidle(dev); > > pm_runtime_disable(dev); > > > > This will make sure the clock is enabled and pm runtime is disabled. > > After this you can unconditionally call clk_disable_unprepare(gpio->clk); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Yours, Linus Walleij
diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c index 437c50e72aa1..e47ae08167f8 100644 --- a/drivers/gpio/gpio-xilinx.c +++ b/drivers/gpio/gpio-xilinx.c @@ -17,6 +17,7 @@ #include <linux/of_device.h> #include <linux/of_gpio.h> #include <linux/of_platform.h> +#include <linux/pm_runtime.h> #include <linux/slab.h> /* Register Offset Definitions */ @@ -277,6 +278,39 @@ static void xgpio_save_regs(struct xgpio_instance *chip) chip->gpio_dir[1]); } +static int xgpio_request(struct gpio_chip *chip, unsigned int offset) +{ + int ret; + + ret = pm_runtime_get_sync(chip->parent); + /* + * If the device is already active pm_runtime_get() will return 1 on + * success, but gpio_request still needs to return 0. + */ + return ret < 0 ? ret : 0; +} + +static void xgpio_free(struct gpio_chip *chip, unsigned int offset) +{ + pm_runtime_put(chip->parent); +} + +static int __maybe_unused xgpio_suspend(struct device *dev) +{ + struct xgpio_instance *gpio = dev_get_drvdata(dev); + struct irq_data *data = irq_get_irq_data(gpio->irq); + + if (!data) { + dev_err(dev, "irq_get_irq_data() failed\n"); + return -EINVAL; + } + + if (!irqd_is_wakeup_set(data)) + return pm_runtime_force_suspend(dev); + + return 0; +} + /** * xgpio_remove - Remove method for the GPIO device. * @pdev: pointer to the platform device @@ -289,7 +323,10 @@ static int xgpio_remove(struct platform_device *pdev) { struct xgpio_instance *gpio = platform_get_drvdata(pdev); - clk_disable_unprepare(gpio->clk); + if (!pm_runtime_suspended(&pdev->dev)) + clk_disable_unprepare(gpio->clk); + + pm_runtime_disable(&pdev->dev); return 0; } @@ -304,6 +341,46 @@ static void xgpio_irq_ack(struct irq_data *irq_data) { } +static int __maybe_unused xgpio_resume(struct device *dev) +{ + struct xgpio_instance *gpio = dev_get_drvdata(dev); + struct irq_data *data = irq_get_irq_data(gpio->irq); + + if (!data) { + dev_err(dev, "irq_get_irq_data() failed\n"); + return -EINVAL; + } + + if (!irqd_is_wakeup_set(data)) + return pm_runtime_force_resume(dev); + + return 0; +} + +static int __maybe_unused xgpio_runtime_suspend(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct xgpio_instance *gpio = platform_get_drvdata(pdev); + + clk_disable(gpio->clk); + + return 0; +} + +static int __maybe_unused xgpio_runtime_resume(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct xgpio_instance *gpio = platform_get_drvdata(pdev); + + return clk_enable(gpio->clk); +} + +static const struct dev_pm_ops xgpio_dev_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(xgpio_suspend, xgpio_resume) + SET_RUNTIME_PM_OPS(xgpio_runtime_suspend, + xgpio_runtime_resume, NULL) +}; + /** * xgpio_irq_mask - Write the specified signal of the GPIO device. * @irq_data: per IRQ and chip data passed down to chip functions @@ -548,6 +625,8 @@ static int xgpio_probe(struct platform_device *pdev) chip->gc.of_gpio_n_cells = cells; chip->gc.get = xgpio_get; chip->gc.set = xgpio_set; + chip->gc.request = xgpio_request; + chip->gc.free = xgpio_free; chip->gc.set_multiple = xgpio_set_multiple; chip->gc.label = dev_name(&pdev->dev); @@ -567,6 +646,9 @@ static int xgpio_probe(struct platform_device *pdev) dev_err(&pdev->dev, "Failed to prepare clk\n"); return status; } + pm_runtime_get_noresume(&pdev->dev); + pm_runtime_set_active(&pdev->dev); + pm_runtime_enable(&pdev->dev); xgpio_save_regs(chip); @@ -591,7 +673,7 @@ static int xgpio_probe(struct platform_device *pdev) GFP_KERNEL); if (!girq->parents) { status = -ENOMEM; - goto err_unprepare_clk; + goto err_pm_put; } girq->parents[0] = chip->irq; girq->default_type = IRQ_TYPE_NONE; @@ -601,12 +683,15 @@ static int xgpio_probe(struct platform_device *pdev) status = devm_gpiochip_add_data(&pdev->dev, &chip->gc, chip); if (status) { dev_err(&pdev->dev, "failed to add GPIO chip\n"); - goto err_unprepare_clk; + goto err_pm_put; } + pm_runtime_put(&pdev->dev); return 0; -err_unprepare_clk: +err_pm_put: + pm_runtime_disable(&pdev->dev); + pm_runtime_put_noidle(&pdev->dev); clk_disable_unprepare(chip->clk); return status; } @@ -624,6 +709,7 @@ static struct platform_driver xgpio_plat_driver = { .driver = { .name = "gpio-xilinx", .of_match_table = xgpio_of_match, + .pm = &xgpio_dev_pm_ops, }, };
Add support for suspend and resume, pm runtime suspend and resume. Added free and request calls. Signed-off-by: Srinivas Neeli <srinivas.neeli@xilinx.com> --- Changes in V4: -Adjust code to remove conflicts. Changes in V3: -Created new patch for suspend and resume. --- drivers/gpio/gpio-xilinx.c | 94 ++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 90 insertions(+), 4 deletions(-)