gpio: cadence: Add quirk for Axiado AX3000 platform

On the Axiado AX3000 platform, pinmux and pin configuration (such as
direction and output enable) are configured by the hardware/firmware
at boot time before Linux boots.

To prevent conflicts, introduce a platform-specific quirk triggered by
the "axiado,ax3000-gpio" compatible string.

When this quirk is active, the driver will skip its default
initialization of pinmux configuration and direction settings during
probe.

Co-developed-by: Tzu-Hao Wei <twei@axiado.com>
Signed-off-by: Tzu-Hao Wei <twei@axiado.com>
Signed-off-by: Swark Yang <syang@axiado.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Link: https://lore.kernel.org/r/20260109-axiado-ax3000-cadence-gpio-support-v2-1-fc1e28edf68a@axiado.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

diff --git a/drivers/gpio/gpio-cadence.c b/drivers/gpio/gpio-cadence.c
index b75734ca22dd7381e2007efd3e7f5d7aa593de0c..85aef54d0aec2a0972b7da2a56704121f0015f62 100644 (file)
--- a/drivers/gpio/gpio-cadence.c
+++ b/drivers/gpio/gpio-cadence.c
@@ -2,6 +2,7 @@
 
 /*
  * Copyright 2017-2018 Cadence
+ * Copyright (C) 2025 Axiado Corporation.
  *
  * Authors:
  *  Jan Kotas <jank@cadence.com>
@@ -31,10 +32,23 @@
 #define CDNS_GPIO_IRQ_VALUE            0x28
 #define CDNS_GPIO_IRQ_ANY_EDGE         0x2c
 
+struct cdns_gpio_quirks {
+       bool skip_init;
+};
+
 struct cdns_gpio_chip {
        struct gpio_generic_chip gen_gc;
        void __iomem *regs;
        u32 bypass_orig;
+       const struct cdns_gpio_quirks *quirks;
+};
+
+static const struct cdns_gpio_quirks cdns_default_quirks = {
+       .skip_init = false,
+};
+
+static const struct cdns_gpio_quirks ax3000_gpio_quirks = {
+       .skip_init = true,
 };
 
 static int cdns_gpio_request(struct gpio_chip *chip, unsigned int offset)
@@ -141,6 +155,19 @@ static const struct irq_chip cdns_gpio_irqchip = {
        GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
+static const struct of_device_id cdns_of_ids[] = {
+       {
+               .compatible = "axiado,ax3000-gpio",
+               .data = &ax3000_gpio_quirks
+       },
+       {
+               .compatible = "cdns,gpio-r1p02",
+               .data = &cdns_default_quirks
+       },
+       { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, cdns_of_ids);
+
 static int cdns_gpio_probe(struct platform_device *pdev)
 {
        struct gpio_generic_chip_config config = { };
@@ -165,6 +192,10 @@ static int cdns_gpio_probe(struct platform_device *pdev)
                return -EINVAL;
        }
 
+       cgpio->quirks = device_get_match_data(&pdev->dev);
+       if (!cgpio->quirks)
+               cgpio->quirks = &cdns_default_quirks;
+
        /*
         * Set all pins as inputs by default, otherwise:
         * gpiochip_lock_as_irq:
@@ -173,8 +204,15 @@ static int cdns_gpio_probe(struct platform_device *pdev)
         * so it needs to be changed before gpio_generic_chip_init() is called.
         */
        dir_prev = ioread32(cgpio->regs + CDNS_GPIO_DIRECTION_MODE);
-       iowrite32(GENMASK(num_gpios - 1, 0),
-                 cgpio->regs + CDNS_GPIO_DIRECTION_MODE);
+
+       /*
+        * The AX3000 platform performs the required configuration at boot time
+        * before Linux boots, so this quirk disables pinmux initialization.
+        */
+       if (!cgpio->quirks->skip_init) {
+               iowrite32(GENMASK(num_gpios - 1, 0),
+                       cgpio->regs + CDNS_GPIO_DIRECTION_MODE);
+       }
 
        config.dev = &pdev->dev;
        config.sz = 4;
@@ -240,9 +278,11 @@ static int cdns_gpio_probe(struct platform_device *pdev)
        /*
         * Enable gpio outputs, ignored for input direction
         */
-       iowrite32(GENMASK(num_gpios - 1, 0),
-                 cgpio->regs + CDNS_GPIO_OUTPUT_EN);
-       iowrite32(0, cgpio->regs + CDNS_GPIO_BYPASS_MODE);
+       if (!cgpio->quirks->skip_init) {
+               iowrite32(GENMASK(num_gpios - 1, 0),
+                       cgpio->regs + CDNS_GPIO_OUTPUT_EN);
+               iowrite32(0, cgpio->regs + CDNS_GPIO_BYPASS_MODE);
+       }
 
        platform_set_drvdata(pdev, cgpio);
        return 0;
@@ -260,12 +300,6 @@ static void cdns_gpio_remove(struct platform_device *pdev)
        iowrite32(cgpio->bypass_orig, cgpio->regs + CDNS_GPIO_BYPASS_MODE);
 }
 
-static const struct of_device_id cdns_of_ids[] = {
-       { .compatible = "cdns,gpio-r1p02" },
-       { /* sentinel */ },
-};
-MODULE_DEVICE_TABLE(of, cdns_of_ids);
-
 static struct platform_driver cdns_gpio_driver = {
        .driver = {
                .name = "cdns-gpio",