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// 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", },
{ }
};
MODULE_DEVICE_TABLE(of, modepin_platform_id);
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");
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