diff options
Diffstat (limited to 'target/linux/ath79/files/drivers/gpio/gpio-rb4xx.c')
| -rw-r--r-- | target/linux/ath79/files/drivers/gpio/gpio-rb4xx.c | 172 |
1 files changed, 172 insertions, 0 deletions
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 index 0000000000..f8022436e0 --- /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"); |