Hi,
I agree ,will address comments in V2.

-----Original Message-----
From: Bartosz Golaszewski <redacted>
Sent: Tuesday, February 18, 2020 9:33 PM
To: Srinivas Neeli <redacted>
Cc: Michal Simek <redacted>; Shubhrajyoti Datta
[off-list ref]; Srinivas Goud [off-list ref]; Linus Walleij
[off-list ref]; LKML [off-list ref]; arm-soc
[off-list ref]; linux-gpio <linux-
gpio@vger.kernel.org>; git [off-list ref]
Subject: Re: [PATCH 1/2] gpio: xilinx: Add clock adaptation support

pon., 17 lut 2020 o 11:57 Srinivas Neeli [off-list ref] napisał(a):

quoted

Add support of clock adaptation for AXI GPIO driver.

Signed-off-by: Srinivas Neeli <redacted>
---
 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)

quoted

                       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?

quoted

+               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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