diff options
Diffstat (limited to 'drivers/gpio/gpio-zynqmp-modepin.c')
| -rw-r--r-- | drivers/gpio/gpio-zynqmp-modepin.c | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-zynqmp-modepin.c b/drivers/gpio/gpio-zynqmp-modepin.c new file mode 100644 index 0000000000..a0d69387c1 --- /dev/null +++ b/drivers/gpio/gpio-zynqmp-modepin.c @@ -0,0 +1,162 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Driver for the ps-mode pin configuration. + * + * Copyright (c) 2021 Xilinx, Inc. + */ + +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/gpio/driver.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/firmware/xlnx-zynqmp.h> + +/* 4-bit boot mode pins */ +#define MODE_PINS 4 + +/** + * modepin_gpio_get_value - Get the state of the specified pin of GPIO device + * @chip: gpio_chip instance to be worked on + * @pin: gpio pin number within the device + * + * This function reads the state of the specified pin of the GPIO device. + * + * Return: 0 if the pin is low, 1 if pin is high, -EINVAL wrong pin configured + * or error value. + */ +static int modepin_gpio_get_value(struct gpio_chip *chip, unsigned int pin) +{ + u32 regval = 0; + int ret; + + ret = zynqmp_pm_bootmode_read(®val); + if (ret) + return ret; + + /* When [0:3] corresponding bit is set, then read output bit [8:11], + * if the bit is clear then read input bit [4:7] for status or value. + */ + if (regval & BIT(pin)) + return !!(regval & BIT(pin + 8)); + else + return !!(regval & BIT(pin + 4)); +} + +/** + * modepin_gpio_set_value - Modify the state of the pin with specified value + * @chip: gpio_chip instance to be worked on + * @pin: gpio pin number within the device + * @state: value used to modify the state of the specified pin + * + * This function reads the state of the specified pin of the GPIO device, mask + * with the capture state of GPIO pin, and update pin of GPIO device. + * + * Return: None. + */ +static void modepin_gpio_set_value(struct gpio_chip *chip, unsigned int pin, + int state) +{ + u32 bootpin_val = 0; + int ret; + + zynqmp_pm_bootmode_read(&bootpin_val); + + /* Configure pin as an output by set bit [0:3] */ + bootpin_val |= BIT(pin); + + if (state) + bootpin_val |= BIT(pin + 8); + else + bootpin_val &= ~BIT(pin + 8); + + /* Configure bootpin value */ + ret = zynqmp_pm_bootmode_write(bootpin_val); + if (ret) + pr_err("modepin: set value error %d for pin %d\n", ret, pin); +} + +/** + * modepin_gpio_dir_in - Set the direction of the specified GPIO pin as input + * @chip: gpio_chip instance to be worked on + * @pin: gpio pin number within the device + * + * Return: 0 always + */ +static int modepin_gpio_dir_in(struct gpio_chip *chip, unsigned int pin) +{ + return 0; +} + +/** + * modepin_gpio_dir_out - Set the direction of the specified GPIO pin as output + * @chip: gpio_chip instance to be worked on + * @pin: gpio pin number within the device + * @state: value to be written to specified pin + * + * Return: 0 always + */ +static int modepin_gpio_dir_out(struct gpio_chip *chip, unsigned int pin, + int state) +{ + return 0; +} + +/** + * modepin_gpio_probe - Initialization method for modepin_gpio + * @pdev: platform device instance + * + * Return: 0 on success, negative error otherwise. + */ +static int modepin_gpio_probe(struct platform_device *pdev) +{ + struct gpio_chip *chip; + int status; + + chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + platform_set_drvdata(pdev, chip); + + /* configure the gpio chip */ + chip->base = -1; + chip->ngpio = MODE_PINS; + chip->owner = THIS_MODULE; + chip->parent = &pdev->dev; + chip->get = modepin_gpio_get_value; + chip->set = modepin_gpio_set_value; + chip->direction_input = modepin_gpio_dir_in; + chip->direction_output = modepin_gpio_dir_out; + chip->label = dev_name(&pdev->dev); + + /* modepin gpio registration */ + status = devm_gpiochip_add_data(&pdev->dev, chip, chip); + if (status) + return dev_err_probe(&pdev->dev, status, + "Failed to add GPIO chip\n"); + + return status; +} + +static const struct of_device_id modepin_platform_id[] = { + { .compatible = "xlnx,zynqmp-gpio-modepin", }, + { } +}; + +static struct platform_driver modepin_platform_driver = { + .driver = { + .name = "modepin-gpio", + .of_match_table = modepin_platform_id, + }, + .probe = modepin_gpio_probe, +}; + +module_platform_driver(modepin_platform_driver); + +MODULE_AUTHOR("Piyush Mehta <piyush.mehta@xilinx.com>"); +MODULE_DESCRIPTION("ZynqMP Boot PS_MODE Configuration"); +MODULE_LICENSE("GPL v2"); |