ath79: add Mikrotik rb4xx series drivers

[openwrt/openwrt.git] / target / linux / ath79 / files / drivers / gpio / gpio-rb4xx.c

diff --git a/target/linux/ath79/files/drivers/gpio/gpio-rb4xx.c b/target/linux/ath79/files/drivers/gpio/gpio-rb4xx.c
new file mode 100644 (file)
index 0000000..f802243
--- /dev/null
+++ b/target/linux/ath79/files/drivers/gpio/gpio-rb4xx.c
@@ -0,0 +1,172 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * GPIO driver for the MikroTik RouterBoard 4xx series
+ *
+ * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
+ * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
+ * Copyright (C) 2015 Bert Vermeulen <bert@biot.com>
+ * Copyright (C) 2020 Christopher Hill <ch6574@gmail.com>
+ *
+ * This file was based on the driver for Linux 2.6.22 published by
+ * MikroTik for their RouterBoard 4xx series devices.
+ *
+ * N.B. driver probe reports "DMA mask not set" warnings which are
+ * an artifact of using a platform_driver as an MFD device child.
+ * See conversation here https://lkml.org/lkml/2020/4/28/675
+ */
+#include <linux/platform_device.h>
+#include <linux/gpio/driver.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+
+#include <mfd/rb4xx-cpld.h>
+
+struct rb4xx_gpio {
+       struct rb4xx_cpld *cpld;
+       struct device *dev;
+
+       struct gpio_chip chip;
+       struct mutex lock;
+       u16 values;             /* bitfield of GPIO 0-8 current values */
+};
+
+static int rb4xx_gpio_cpld_set(struct rb4xx_gpio *gpio, unsigned int offset,
+                              int value)
+{
+       struct rb4xx_cpld *cpld = gpio->cpld;
+       u16 values;
+       int ret;
+
+       mutex_lock(&gpio->lock);
+       values = gpio->values;
+
+       if (value)
+               values |= BIT(offset);
+       else
+               values &= ~(BIT(offset));
+
+       if (values == gpio->values) {
+               ret = 0;
+               goto unlock;
+       }
+
+       if (offset < 8) {
+               ret = cpld->gpio_set_0_7(cpld, values & 0xff);
+       } else if (offset == 8) {
+               ret = cpld->gpio_set_8(cpld, values >> 8);
+       }
+
+       if(likely(!ret))
+               gpio->values = values;
+
+unlock:
+       mutex_unlock(&gpio->lock);
+       return ret;
+}
+
+static int rb4xx_gpio_get_direction(struct gpio_chip *chip, unsigned int offset)
+{
+       return 0; /* All 9 GPIOs are out */
+}
+
+static int rb4xx_gpio_direction_input(struct gpio_chip *chip,
+                                     unsigned int offset)
+{
+       return -EOPNOTSUPP;
+}
+
+static int rb4xx_gpio_direction_output(struct gpio_chip *chip,
+                                      unsigned int offset, int value)
+{
+       return rb4xx_gpio_cpld_set(gpiochip_get_data(chip), offset, value);
+}
+
+static int rb4xx_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+       struct rb4xx_gpio *gpio = gpiochip_get_data(chip);
+       int ret;
+
+       mutex_lock(&gpio->lock);
+       ret = (gpio->values >> offset) & 0x1;
+       mutex_unlock(&gpio->lock);
+
+       return ret;
+}
+
+static void rb4xx_gpio_set(struct gpio_chip *chip, unsigned int offset,
+                          int value)
+{
+       rb4xx_gpio_cpld_set(gpiochip_get_data(chip), offset, value);
+}
+
+static int rb4xx_gpio_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct device *parent = dev->parent;
+       struct rb4xx_gpio *gpio;
+       u32 val;
+
+       if (!parent)
+               return -ENODEV;
+
+       gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
+       if (!gpio)
+               return -ENOMEM;
+
+       platform_set_drvdata(pdev, gpio);
+       gpio->cpld      = dev_get_drvdata(parent);
+       gpio->dev       = dev;
+       gpio->values    = 0;
+       mutex_init(&gpio->lock);
+
+       gpio->chip.label                = "rb4xx-gpio";
+       gpio->chip.parent               = dev;
+       gpio->chip.owner                = THIS_MODULE;
+       gpio->chip.get_direction        = rb4xx_gpio_get_direction;
+       gpio->chip.direction_input      = rb4xx_gpio_direction_input;
+       gpio->chip.direction_output     = rb4xx_gpio_direction_output;
+       gpio->chip.get                  = rb4xx_gpio_get;
+       gpio->chip.set                  = rb4xx_gpio_set;
+       gpio->chip.ngpio                = 9;
+       gpio->chip.base                 = -1;
+       gpio->chip.can_sleep            = 1;
+
+       if (!of_property_read_u32(dev->of_node, "base", &val))
+               gpio->chip.base = val;
+
+       return gpiochip_add_data(&gpio->chip, gpio);
+}
+
+static int rb4xx_gpio_remove(struct platform_device *pdev)
+{
+       struct rb4xx_gpio *gpio = platform_get_drvdata(pdev);
+
+       gpiochip_remove(&gpio->chip);
+       mutex_destroy(&gpio->lock);
+
+       return 0;
+}
+
+static const struct platform_device_id rb4xx_gpio_id_table[] = {
+       { "mikrotik,rb4xx-gpio", },
+       { },
+};
+MODULE_DEVICE_TABLE(platform, rb4xx_gpio_id_table);
+
+static struct platform_driver rb4xx_gpio_driver = {
+       .probe = rb4xx_gpio_probe,
+       .remove = rb4xx_gpio_remove,
+       .id_table = rb4xx_gpio_id_table,
+       .driver = {
+               .name = "rb4xx-gpio",
+       },
+};
+
+module_platform_driver(rb4xx_gpio_driver);
+
+MODULE_DESCRIPTION("Mikrotik RB4xx GPIO driver");
+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
+MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org>");
+MODULE_AUTHOR("Bert Vermeulen <bert@biot.com>");
+MODULE_AUTHOR("Christopher Hill <ch6574@gmail.com");
+MODULE_LICENSE("GPL v2");