Re: [PATCH v2] gpio: xilinx: convert from OF GPIO to standard devm APIs

[Michal Simek <michal.simek@xxxxxxxxxx>]

+Shubhrajyoti

On 06. 06. 19 18:28, Robert Hancock wrote:
> This driver was using the OF GPIO helper API, but barely used any of its
> features and it cost more code than it saved. Also, the OF GPIO code is
> now deprecated. Convert it to use a more standard setup and use devm
> APIs for initialization to avoid the need for a remove function.
> 
> Our rationale for this change is that we are using the Xilinx GPIO with
> resources injected using the MFD core rather than on the device tree
> itself. Using platform rather than OF-specific resources allows this to
> work for free.
> 
> Signed-off-by: Robert Hancock <hancock@xxxxxxxxxxxxx>
> ---
> 
> Changes from v1:
> -use dev_name() to set GPIO chip label
> -use specific dev_err() for each probe error location rather than
>  a generic pr_err() message
> 
>  drivers/gpio/Kconfig       |  1 -
>  drivers/gpio/gpio-xilinx.c | 92 +++++++++++++++++++---------------------------
>  2 files changed, 38 insertions(+), 55 deletions(-)
> 
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index acd40eb..66f1f13 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -602,7 +602,6 @@ config GPIO_XGENE_SB
>  
>  config GPIO_XILINX
>  	tristate "Xilinx GPIO support"
> -	depends on OF_GPIO
>  	help
>  	  Say yes here to support the Xilinx FPGA GPIO device
>  
> diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
> index 32944eb..1c0ed1d 100644
> --- a/drivers/gpio/gpio-xilinx.c
> +++ b/drivers/gpio/gpio-xilinx.c
> @@ -11,7 +11,6 @@
>  #include <linux/module.h>
>  #include <linux/of_device.h>
>  #include <linux/of_platform.h>
> -#include <linux/of_gpio.h>
>  #include <linux/io.h>
>  #include <linux/gpio/driver.h>
>  #include <linux/slab.h>
> @@ -33,14 +32,16 @@
>  
>  /**
>   * struct xgpio_instance - Stores information about GPIO device
> - * @mmchip: OF GPIO chip for memory mapped banks
> + * @gc: GPIO chip
> + * @regs: register block
>   * @gpio_width: GPIO width for every channel
>   * @gpio_state: GPIO state shadow register
>   * @gpio_dir: GPIO direction shadow register
>   * @gpio_lock: Lock used for synchronization
>   */
>  struct xgpio_instance {
> -	struct of_mm_gpio_chip mmchip;
> +	struct gpio_chip gc;
> +	void __iomem *regs;
>  	unsigned int gpio_width[2];
>  	u32 gpio_state[2];
>  	u32 gpio_dir[2];
> @@ -84,11 +85,10 @@ static inline int xgpio_offset(struct xgpio_instance *chip, int gpio)
>   */
>  static int xgpio_get(struct gpio_chip *gc, unsigned int gpio)
>  {
> -	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
>  	struct xgpio_instance *chip = gpiochip_get_data(gc);
>  	u32 val;
>  
> -	val = xgpio_readreg(mm_gc->regs + XGPIO_DATA_OFFSET +
> +	val = xgpio_readreg(chip->regs + XGPIO_DATA_OFFSET +
>  			    xgpio_regoffset(chip, gpio));
>  
>  	return !!(val & BIT(xgpio_offset(chip, gpio)));
> @@ -106,7 +106,6 @@ static int xgpio_get(struct gpio_chip *gc, unsigned int gpio)
>  static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
>  {
>  	unsigned long flags;
> -	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
>  	struct xgpio_instance *chip = gpiochip_get_data(gc);
>  	int index =  xgpio_index(chip, gpio);
>  	int offset =  xgpio_offset(chip, gpio);
> @@ -119,7 +118,7 @@ static void xgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
>  	else
>  		chip->gpio_state[index] &= ~BIT(offset);
>  
> -	xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET +
> +	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
>  		       xgpio_regoffset(chip, gpio), chip->gpio_state[index]);
>  
>  	spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
> @@ -138,7 +137,6 @@ static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
>  			       unsigned long *bits)
>  {
>  	unsigned long flags;
> -	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
>  	struct xgpio_instance *chip = gpiochip_get_data(gc);
>  	int index = xgpio_index(chip, 0);
>  	int offset, i;
> @@ -150,7 +148,7 @@ static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
>  		if (*mask == 0)
>  			break;
>  		if (index !=  xgpio_index(chip, i)) {
> -			xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET +
> +			xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
>  				       xgpio_regoffset(chip, i),
>  				       chip->gpio_state[index]);
>  			spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
> @@ -166,7 +164,7 @@ static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
>  		}
>  	}
>  
> -	xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET +
> +	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
>  		       xgpio_regoffset(chip, i), chip->gpio_state[index]);
>  
>  	spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
> @@ -184,7 +182,6 @@ static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
>  static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
>  {
>  	unsigned long flags;
> -	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
>  	struct xgpio_instance *chip = gpiochip_get_data(gc);
>  	int index =  xgpio_index(chip, gpio);
>  	int offset =  xgpio_offset(chip, gpio);
> @@ -193,7 +190,7 @@ static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
>  
>  	/* Set the GPIO bit in shadow register and set direction as input */
>  	chip->gpio_dir[index] |= BIT(offset);
> -	xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET +
> +	xgpio_writereg(chip->regs + XGPIO_TRI_OFFSET +
>  		       xgpio_regoffset(chip, gpio), chip->gpio_dir[index]);
>  
>  	spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
> @@ -216,7 +213,6 @@ static int xgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
>  static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
>  {
>  	unsigned long flags;
> -	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
>  	struct xgpio_instance *chip = gpiochip_get_data(gc);
>  	int index =  xgpio_index(chip, gpio);
>  	int offset =  xgpio_offset(chip, gpio);
> @@ -228,12 +224,12 @@ static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
>  		chip->gpio_state[index] |= BIT(offset);
>  	else
>  		chip->gpio_state[index] &= ~BIT(offset);
> -	xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET +
> +	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
>  			xgpio_regoffset(chip, gpio), chip->gpio_state[index]);
>  
>  	/* Clear the GPIO bit in shadow register and set direction as output */
>  	chip->gpio_dir[index] &= ~BIT(offset);
> -	xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET +
> +	xgpio_writereg(chip->regs + XGPIO_TRI_OFFSET +
>  			xgpio_regoffset(chip, gpio), chip->gpio_dir[index]);
>  
>  	spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
> @@ -243,43 +239,23 @@ static int xgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
>  
>  /**
>   * xgpio_save_regs - Set initial values of GPIO pins
> - * @mm_gc: Pointer to memory mapped GPIO chip structure
> + * @chip: Pointer to GPIO instance
>   */
> -static void xgpio_save_regs(struct of_mm_gpio_chip *mm_gc)
> +static void xgpio_save_regs(struct xgpio_instance *chip)
>  {
> -	struct xgpio_instance *chip =
> -		container_of(mm_gc, struct xgpio_instance, mmchip);
> -
> -	xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET,	chip->gpio_state[0]);
> -	xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET, chip->gpio_dir[0]);
> +	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET,	chip->gpio_state[0]);
> +	xgpio_writereg(chip->regs + XGPIO_TRI_OFFSET, chip->gpio_dir[0]);
>  
>  	if (!chip->gpio_width[1])
>  		return;
>  
> -	xgpio_writereg(mm_gc->regs + XGPIO_DATA_OFFSET + XGPIO_CHANNEL_OFFSET,
> +	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET + XGPIO_CHANNEL_OFFSET,
>  		       chip->gpio_state[1]);
> -	xgpio_writereg(mm_gc->regs + XGPIO_TRI_OFFSET + XGPIO_CHANNEL_OFFSET,
> +	xgpio_writereg(chip->regs + XGPIO_TRI_OFFSET + XGPIO_CHANNEL_OFFSET,
>  		       chip->gpio_dir[1]);
>  }
>  
>  /**
> - * xgpio_remove - Remove method for the GPIO device.
> - * @pdev: pointer to the platform device
> - *
> - * This function remove gpiochips and frees all the allocated resources.
> - *
> - * Return: 0 always
> - */
> -static int xgpio_remove(struct platform_device *pdev)
> -{
> -	struct xgpio_instance *chip = platform_get_drvdata(pdev);
> -
> -	of_mm_gpiochip_remove(&chip->mmchip);
> -
> -	return 0;
> -}
> -
> -/**
>   * xgpio_of_probe - Probe method for the GPIO device.
>   * @pdev: pointer to the platform device
>   *
> @@ -340,21 +316,30 @@ static int xgpio_probe(struct platform_device *pdev)
>  		spin_lock_init(&chip->gpio_lock[1]);
>  	}
>  
> -	chip->mmchip.gc.ngpio = chip->gpio_width[0] + chip->gpio_width[1];
> -	chip->mmchip.gc.parent = &pdev->dev;
> -	chip->mmchip.gc.direction_input = xgpio_dir_in;
> -	chip->mmchip.gc.direction_output = xgpio_dir_out;
> -	chip->mmchip.gc.get = xgpio_get;
> -	chip->mmchip.gc.set = xgpio_set;
> -	chip->mmchip.gc.set_multiple = xgpio_set_multiple;
> +	chip->gc.base = -1;
> +	chip->gc.ngpio = chip->gpio_width[0] + chip->gpio_width[1];
> +	chip->gc.parent = &pdev->dev;
> +	chip->gc.direction_input = xgpio_dir_in;
> +	chip->gc.direction_output = xgpio_dir_out;
> +	chip->gc.get = xgpio_get;
> +	chip->gc.set = xgpio_set;
> +	chip->gc.set_multiple = xgpio_set_multiple;
> +
> +	chip->gc.label = dev_name(&pdev->dev);
> +
> +	chip->regs = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(chip->regs)) {
> +		status = PTR_ERR(chip->regs);
> +		dev_err(&pdev->dev, "failed to ioremap memory resource: %d\n",
> +			status);
> +		return status;
> +	}
>  
> -	chip->mmchip.save_regs = xgpio_save_regs;
> +	xgpio_save_regs(chip);
>  
> -	/* Call the OF gpio helper to setup and register the GPIO device */
> -	status = of_mm_gpiochip_add_data(np, &chip->mmchip, chip);
> +	status = devm_gpiochip_add_data(&pdev->dev, &chip->gc, chip);
>  	if (status) {
> -		pr_err("%pOF: error in probe function with status %d\n",
> -		       np, status);
> +		dev_err(&pdev->dev, "failed to add GPIO chip: %d\n", status);
>  		return status;
>  	}
>  
> @@ -370,7 +355,6 @@ static int xgpio_probe(struct platform_device *pdev)
>  
>  static struct platform_driver xgpio_plat_driver = {
>  	.probe		= xgpio_probe,
> -	.remove		= xgpio_remove,
>  	.driver		= {
>  			.name = "gpio-xilinx",
>  			.of_match_table	= xgpio_of_match,
> 


Please take a look at it.
M