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Date: Tue, 18 Feb 2020 17:02:37 +0100
From: Bartosz Golaszewski <bgolaszewski@...libre.com>
To: Srinivas Neeli <srinivas.neeli@...inx.com>
Cc: Michal Simek <michal.simek@...inx.com>,
shubhrajyoti.datta@...inx.com, sgoud@...inx.com,
Linus Walleij <linus.walleij@...aro.org>,
LKML <linux-kernel@...r.kernel.org>,
arm-soc <linux-arm-kernel@...ts.infradead.org>,
linux-gpio <linux-gpio@...r.kernel.org>, git@...inx.com
Subject: Re: [PATCH 1/2] gpio: xilinx: Add clock adaptation support
pon., 17 lut 2020 o 11:57 Srinivas Neeli <srinivas.neeli@...inx.com> napisał(a):
>
> Add support of clock adaptation for AXI GPIO driver.
>
> Signed-off-by: Srinivas Neeli <srinivas.neeli@...inx.com>
> ---
> drivers/gpio/gpio-xilinx.c | 105 ++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 103 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
> index a9748b5198e6..26753ae58295 100644
> --- a/drivers/gpio/gpio-xilinx.c
> +++ b/drivers/gpio/gpio-xilinx.c
> @@ -14,6 +14,8 @@
> #include <linux/io.h>
> #include <linux/gpio/driver.h>
> #include <linux/slab.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/clk.h>
>
> /* Register Offset Definitions */
> #define XGPIO_DATA_OFFSET (0x0) /* Data register */
> @@ -38,6 +40,7 @@
> * @gpio_state: GPIO state shadow register
> * @gpio_dir: GPIO direction shadow register
> * @gpio_lock: Lock used for synchronization
> + * @clk: clock resource for this driver
> */
> struct xgpio_instance {
> struct gpio_chip gc;
> @@ -45,7 +48,8 @@ struct xgpio_instance {
> unsigned int gpio_width[2];
> u32 gpio_state[2];
> u32 gpio_dir[2];
> - spinlock_t gpio_lock[2];
> + spinlock_t gpio_lock[2]; /* For serializing operations */
> + struct clk *clk;
> };
>
> static inline int xgpio_index(struct xgpio_instance *chip, int gpio)
> @@ -255,6 +259,70 @@ 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 = 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 platform_device *pdev = to_platform_device(dev);
> + int irq = platform_get_irq(pdev, 0);
> + struct irq_data *data = irq_get_irq_data(irq);
> +
> + if (!irqd_is_wakeup_set(data))
> + return pm_runtime_force_suspend(dev);
> +
> + return 0;
> +}
> +
> +static int __maybe_unused xgpio_resume(struct device *dev)
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> + int irq = platform_get_irq(pdev, 0);
> + struct irq_data *data = irq_get_irq_data(irq);
> +
> + 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_of_probe - Probe method for the GPIO device.
> * @pdev: pointer to the platform device
> @@ -323,6 +391,8 @@ static int xgpio_probe(struct platform_device *pdev)
> chip->gc.direction_output = xgpio_dir_out;
> 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);
> @@ -333,15 +403,45 @@ static int xgpio_probe(struct platform_device *pdev)
> return PTR_ERR(chip->regs);
> }
>
> + chip->clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
> + if (IS_ERR(chip->clk)) {
> + if (PTR_ERR(chip->clk) != -ENOENT) {
> + if (PTR_ERR(chip->clk) != -EPROBE_DEFER)
> + dev_err(&pdev->dev, "Input clock not found\n");
> + return PTR_ERR(chip->clk);
> + }
> + /*
> + * Clock framework support is optional, continue on
> + * anyways if we don't find a matching clock.
> + */
Why not use devm_clk_get_optional() then?
> + chip->clk = NULL;
> + }
> + status = clk_prepare_enable(chip->clk);
> + if (status < 0) {
> + dev_err(&pdev->dev, "Failed to prepare clk\n");
> + return status;
> + }
> + pm_runtime_enable(&pdev->dev);
> + status = pm_runtime_get_sync(&pdev->dev);
> + if (status < 0)
> + goto err_unprepare_clk;
> +
> xgpio_save_regs(chip);
>
> status = devm_gpiochip_add_data(&pdev->dev, &chip->gc, chip);
> if (status) {
> dev_err(&pdev->dev, "failed to add GPIO chip\n");
> - return status;
> + goto err_pm_put;
> }
>
> + pm_runtime_put(&pdev->dev);
> return 0;
> +err_pm_put:
> + pm_runtime_put(&pdev->dev);
> +err_unprepare_clk:
> + pm_runtime_disable(&pdev->dev);
> + clk_unprepare(chip->clk);
> + return status;
> }
>
> static const struct of_device_id xgpio_of_match[] = {
> @@ -356,6 +456,7 @@ static struct platform_driver xgpio_plat_driver = {
> .driver = {
> .name = "gpio-xilinx",
> .of_match_table = xgpio_of_match,
> + .pm = &xgpio_dev_pm_ops,
> },
> };
>
> --
> 2.7.4
>
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