// SPDX-License-Identifier: GPL-2.0
/*
* SAMA5D2 PIOBU GPIO controller
*
* Copyright (C) 2018 Microchip Technology Inc. and its subsidiaries
*
* Author: Andrei Stefanescu <andrei.stefanescu@microchip.com>
*
*/
#include <linux/bits.h>
#include <linux/gpio/driver.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#define PIOBU_NUM 8
#define PIOBU_REG_SIZE 4
/*
* backup mode protection register for tamper detection
* normal mode protection register for tamper detection
* wakeup signal generation
*/
#define PIOBU_BMPR 0x7C
#define PIOBU_NMPR 0x80
#define PIOBU_WKPR 0x90
#define PIOBU_BASE 0x18 /* PIOBU offset from SECUMOD base register address. */
#define PIOBU_DET_OFFSET 16
/* In the datasheet this bit is called OUTPUT */
#define PIOBU_DIRECTION BIT(8)
#define PIOBU_OUT BIT(8)
#define PIOBU_IN 0
#define PIOBU_SOD BIT(9)
#define PIOBU_PDS BIT(10)
#define PIOBU_HIGH BIT(9)
#define PIOBU_LOW 0
struct sama5d2_piobu {
struct gpio_chip chip;
struct regmap *regmap;
};
/*
* sama5d2_piobu_setup_pin() - prepares a pin for set_direction call
*
* Do not consider pin for tamper detection (normal and backup modes)
* Do not consider pin as tamper wakeup interrupt source
*/
static int sama5d2_piobu_setup_pin(struct gpio_chip *chip, unsigned int pin)
{
int ret;
struct sama5d2_piobu *piobu = container_of(chip, struct sama5d2_piobu,
chip);
unsigned int mask = BIT(PIOBU_DET_OFFSET + pin);
ret = regmap_update_bits(piobu->regmap, PIOBU_BMPR, mask, 0);
if (ret)
return ret;
ret = regmap_update_bits(piobu->regmap, PIOBU_NMPR, mask, 0);
if (ret)
return ret;
return regmap_update_bits(piobu->regmap, PIOBU_WKPR, mask, 0);
}
/*
* sama5d2_piobu_write_value() - writes value & mask at the pin's PIOBU register
*/
static int sama5d2_piobu_write_value(struct gpio_chip *chip, unsigned int pin,
unsigned int mask, unsigned int value)
{
int reg;
struct sama5d2_piobu *piobu = container_of(chip, struct sama5d2_piobu,
chip);
reg = PIOBU_BASE + pin * PIOBU_REG_SIZE;
return regmap_update_bits(piobu->regmap, reg, mask, value);
}
/*
* sama5d2_piobu_read_value() - read the value with masking from the pin's PIOBU
* register
*/
static int sama5d2_piobu_read_value(struct gpio_chip *chip, unsigned int pin,
unsigned int mask)
{
struct sama5d2_piobu *piobu = container_of(chip, struct sama5d2_piobu,
chip);
unsigned int val, reg;
int ret;
reg = PIOBU_BASE + pin * PIOBU_REG_SIZE;
ret = regmap_read(piobu->regmap, reg, &val);
if (ret < 0)
return ret;
return val & mask;
}
/*
* sama5d2_piobu_get_direction() - gpiochip get_direction
*/
static int sama5d2_piobu_get_direction(struct gpio_chip *chip,
unsigned int pin)
{
int ret = sama5d2_piobu_read_value(chip, pin, PIOBU_DIRECTION);
if (ret < 0)
return ret;
return (ret == PIOBU_IN) ? GPIO_LINE_DIRECTION_IN :
GPIO_LINE_DIRECTION_OUT;
}
/*
* sama5d2_piobu_direction_input() - gpiochip direction_input
*/
static int sama5d2_piobu_direction_input(struct gpio_chip *chip,
unsigned int pin)
{
return sama5d2_piobu_write_value(chip, pin, PIOBU_DIRECTION, PIOBU_IN);
}
/*
* sama5d2_piobu_direction_output() - gpiochip direction_output
*/
static int sama5d2_piobu_direction_output(struct gpio_chip *chip,
unsigned int pin, int value)
{
unsigned int val = PIOBU_OUT;
if (value)
val |= PIOBU_HIGH;
return sama5d2_piobu_write_value(chip, pin, PIOBU_DIRECTION | PIOBU_SOD,
val);
}
/*
* sama5d2_piobu_get() - gpiochip get
*/
static int sama5d2_piobu_get(struct gpio_chip *chip, unsigned int pin)
{
/* if pin is input, read value from PDS else read from SOD */
int ret = sama5d2_piobu_get_direction(chip, pin);
if (ret == GPIO_LINE_DIRECTION_IN)
ret = sama5d2_piobu_read_value(chip, pin, PIOBU_PDS);
else if (ret == GPIO_LINE_DIRECTION_OUT)
ret = sama5d2_piobu_read_value(chip, pin, PIOBU_SOD);
if (ret < 0)
return ret;
return !!ret;
}
/*
* sama5d2_piobu_set() - gpiochip set
*/
static void sama5d2_piobu_set(struct gpio_chip *chip, unsigned int pin,
int value)
{
if (!value)
value = PIOBU_LOW;
else
value = PIOBU_HIGH;
sama5d2_piobu_write_value(chip, pin, PIOBU_SOD, value);
}
static int sama5d2_piobu_probe(struct platform_device *pdev)
{
struct sama5d2_piobu *piobu;
int ret, i;
piobu = devm_kzalloc(&pdev->dev, sizeof(*piobu), GFP_KERNEL);
if (!piobu)
return -ENOMEM;
platform_set_drvdata(pdev, piobu);
piobu->chip.label = pdev->name;
piobu->chip.parent = &pdev->dev;
piobu->chip.owner = THIS_MODULE,
piobu->chip.get_direction = sama5d2_piobu_get_direction,
piobu->chip.direction_input = sama5d2_piobu_direction_input,
piobu->chip.direction_output = sama5d2_piobu_direction_output,
piobu->chip.get = sama5d2_piobu_get,
piobu->chip.set = sama5d2_piobu_set,
piobu->chip.base = -1,
piobu->chip.ngpio = PIOBU_NUM,
piobu->chip.can_sleep = 0,
piobu->regmap = syscon_node_to_regmap(pdev->dev.of_node);
if (IS_ERR(piobu->regmap)) {
dev_err(&pdev->dev, "Failed to get syscon regmap %ld\n",
PTR_ERR(piobu->regmap));
return PTR_ERR(piobu->regmap);
}
ret = devm_gpiochip_add_data(&pdev->dev, &piobu->chip, piobu);
if (ret) {
dev_err(&pdev->dev, "Failed to add gpiochip %d\n", ret);
return ret;
}
for (i = 0; i < PIOBU_NUM; ++i) {
ret = sama5d2_piobu_setup_pin(&piobu->chip, i);
if (ret) {
dev_err(&pdev->dev, "Failed to setup pin: %d %d\n",
i, ret);
return ret;
}
}
return 0;
}
static const struct of_device_id sama5d2_piobu_ids[] = {
{ .compatible = "atmel,sama5d2-secumod" },
{},
};
MODULE_DEVICE_TABLE(of, sama5d2_piobu_ids);
static struct platform_driver sama5d2_piobu_driver = {
.driver = {
.name = "sama5d2-piobu",
.of_match_table = of_match_ptr(sama5d2_piobu_ids)
},
.probe = sama5d2_piobu_probe,
};
module_platform_driver(sama5d2_piobu_driver);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("SAMA5D2 PIOBU controller driver");
MODULE_AUTHOR("Andrei Stefanescu <andrei.stefanescu@microchip.com>");
