Re: [PATCH v3 2/4] gpio/xilinx: Convert the driver to platform device interface
From: Michal Simek
Date: Wed Dec 10 2014 - 10:29:29 EST
On 12/10/2014 04:24 PM, Ricardo Ribalda Delgado wrote:
> This way we do not need to transverse the device tree manually and we
> support hot plugged devices.
>
> Also Implement remove callback so the driver can be unloaded
>
> Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@xxxxxxxxx>
> ---
>
> v3:
> Add inited to kernel-doc
> Keep the driver in susbys_initcall
>
>
> drivers/gpio/gpio-xilinx.c | 77 ++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 60 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
> index e668ec4..9a81c82 100644
> --- a/drivers/gpio/gpio-xilinx.c
> +++ b/drivers/gpio/gpio-xilinx.c
> @@ -44,12 +44,18 @@
> * gpio_state: GPIO state shadow register
> * gpio_dir: GPIO direction shadow register
> * gpio_lock: Lock used for synchronization
> + * inited: True if the port has been inited
> */
> struct xgpio_instance {
> struct of_mm_gpio_chip mmchip;
> u32 gpio_state;
> u32 gpio_dir;
> spinlock_t gpio_lock;
> + bool inited;
> +};
> +
> +struct xgpio {
> + struct xgpio_instance port[2];
> };
>
> /**
> @@ -172,24 +178,56 @@ static void xgpio_save_regs(struct of_mm_gpio_chip *mm_gc)
> }
>
> /**
> + * xgpio_remove - Remove method for the GPIO device.
> + * @pdev: pointer to the platform device
> + *
> + * This function remove gpiochips and frees all the allocated resources.
> + */
> +static int xgpio_remove(struct platform_device *pdev)
> +{
> + struct xgpio *xgpio = platform_get_drvdata(pdev);
> + int i;
> +
> + for (i = 0; i < 2; i++) {
> + if (!xgpio->port[i].inited)
> + continue;
> + gpiochip_remove(&xgpio->port[i].mmchip.gc);
> +
> + if (i == 1)
> + xgpio->port[i].mmchip.regs -= XGPIO_CHANNEL_OFFSET;
> +
> + iounmap(xgpio->port[i].mmchip.regs);
> + kfree(xgpio->port[i].mmchip.gc.label);
> + }
> +
> + return 0;
> +}
> +
> +/**
> * xgpio_of_probe - Probe method for the GPIO device.
> - * @np: pointer to device tree node
> + * @pdev: pointer to the platform device
> *
> * This function probes the GPIO device in the device tree. It initializes the
> * driver data structure. It returns 0, if the driver is bound to the GPIO
> * device, or a negative value if there is an error.
> */
> -static int xgpio_of_probe(struct device_node *np)
> +static int xgpio_probe(struct platform_device *pdev)
> {
> + struct xgpio *xgpio;
> struct xgpio_instance *chip;
> int status = 0;
> + struct device_node *np = pdev->dev.of_node;
> const u32 *tree_info;
> u32 ngpio;
>
> - chip = kzalloc(sizeof(*chip), GFP_KERNEL);
> - if (!chip)
> + xgpio = devm_kzalloc(&pdev->dev, sizeof(*xgpio), GFP_KERNEL);
> + if (!xgpio)
> return -ENOMEM;
>
> + platform_set_drvdata(pdev, xgpio);
> +
> + chip = &xgpio->port[0];
> +
> /* Update GPIO state shadow register with default value */
> of_property_read_u32(np, "xlnx,dout-default", &chip->gpio_state);
>
> @@ -209,6 +247,7 @@ static int xgpio_of_probe(struct device_node *np)
>
> spin_lock_init(&chip->gpio_lock);
>
> + chip->mmchip.gc.dev = &pdev->dev;
> chip->mmchip.gc.direction_input = xgpio_dir_in;
> chip->mmchip.gc.direction_output = xgpio_dir_out;
> chip->mmchip.gc.get = xgpio_get;
> @@ -219,20 +258,18 @@ static int xgpio_of_probe(struct device_node *np)
> /* Call the OF gpio helper to setup and register the GPIO device */
> status = of_mm_gpiochip_add(np, &chip->mmchip);
> if (status) {
> - kfree(chip);
> pr_err("%s: error in probe function with status %d\n",
> np->full_name, status);
> return status;
> }
> + chip->inited = true;
>
> pr_info("XGpio: %s: registered, base is %d\n", np->full_name,
> chip->mmchip.gc.base);
>
> tree_info = of_get_property(np, "xlnx,is-dual", NULL);
> if (tree_info && be32_to_cpup(tree_info)) {
> - chip = kzalloc(sizeof(*chip), GFP_KERNEL);
> - if (!chip)
> - return -ENOMEM;
> + chip = &xgpio->port[1];
>
> /* Update GPIO state shadow register with default value */
> of_property_read_u32(np, "xlnx,dout-default-2",
> @@ -254,6 +291,7 @@ static int xgpio_of_probe(struct device_node *np)
>
> spin_lock_init(&chip->gpio_lock);
>
> + chip->mmchip.gc.dev = &pdev->dev;
> chip->mmchip.gc.direction_input = xgpio_dir_in;
> chip->mmchip.gc.direction_output = xgpio_dir_out;
> chip->mmchip.gc.get = xgpio_get;
> @@ -264,7 +302,7 @@ static int xgpio_of_probe(struct device_node *np)
> /* Call the OF gpio helper to setup and register the GPIO dev */
> status = of_mm_gpiochip_add(np, &chip->mmchip);
> if (status) {
> - kfree(chip);
> + xgpio_remove(pdev);
> pr_err("%s: error in probe function with status %d\n",
> np->full_name, status);
> return status;
> @@ -272,6 +310,7 @@ static int xgpio_of_probe(struct device_node *np)
>
> /* Add dual channel offset */
> chip->mmchip.regs += XGPIO_CHANNEL_OFFSET;
> + chip->inited = true;
>
> pr_info("XGpio: %s: dual channel registered, base is %d\n",
> np->full_name, chip->mmchip.gc.base);
> @@ -285,19 +324,23 @@ static const struct of_device_id xgpio_of_match[] = {
> { /* end of list */ },
> };
>
> -static int __init xgpio_init(void)
> -{
> - struct device_node *np;
> +MODULE_DEVICE_TABLE(of, xgpio_of_match);
>
> - for_each_matching_node(np, xgpio_of_match)
> - xgpio_of_probe(np);
> +static struct platform_driver xgpio_plat_driver = {
> + .probe = xgpio_probe,
> + .remove = xgpio_remove,
> + .driver = {
> + .name = "gpio-xilinx",
> + .of_match_table = xgpio_of_match,
> + },
> +};
>
> - return 0;
> +static int __init xgpio_init(void)
> +{
> + return platform_driver_register(&xgpio_plat_driver);
> }
>
> -/* Make sure we get initialized before anyone else tries to use us */
> subsys_initcall(xgpio_init);
> -/* No exit call at the moment as we cannot unregister of GPIO chips */
>
Still not correct.
Here should be module_exit if you want to use as module.
I expect that you haven't tested it.
Thanks,
Michal
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