![Andrei.Stefanescu@microchip.com](/assets/img/avatar_default.png)
PIOBU pins do not lose their voltage during Backup/Self-refresh. This patch adds a simple GPIO controller for them and a maintainer for the driver. This driver adds support for using the pins as GPIO offering the possibility to read/set the voltage. Signed-off-by: Andrei Stefanescu <andrei.stefanescu@microchip.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
254 lines
6.1 KiB
C
254 lines
6.1 KiB
C
// 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_set_direction() - mark pin as input or output
|
|
*/
|
|
static int sama5d2_piobu_set_direction(struct gpio_chip *chip,
|
|
unsigned int direction,
|
|
unsigned int pin)
|
|
{
|
|
return sama5d2_piobu_write_value(chip, pin, PIOBU_DIRECTION, direction);
|
|
}
|
|
|
|
/**
|
|
* 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) ? 1 : 0;
|
|
}
|
|
|
|
/**
|
|
* sama5d2_piobu_direction_input() - gpiochip direction_input
|
|
*/
|
|
static int sama5d2_piobu_direction_input(struct gpio_chip *chip,
|
|
unsigned int pin)
|
|
{
|
|
return sama5d2_piobu_set_direction(chip, PIOBU_IN, pin);
|
|
}
|
|
|
|
/**
|
|
* sama5d2_piobu_direction_output() - gpiochip direction_output
|
|
*/
|
|
static int sama5d2_piobu_direction_output(struct gpio_chip *chip,
|
|
unsigned int pin, int value)
|
|
{
|
|
return sama5d2_piobu_set_direction(chip, PIOBU_OUT, pin);
|
|
}
|
|
|
|
/**
|
|
* 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 == 1)
|
|
ret = sama5d2_piobu_read_value(chip, pin, PIOBU_PDS);
|
|
else if (!ret)
|
|
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.of_node = pdev->dev.of_node;
|
|
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_VERSION("1.0");
|
|
MODULE_LICENSE("GPL v2");
|
|
MODULE_DESCRIPTION("SAMA5D2 PIOBU controller driver");
|
|
MODULE_AUTHOR("Andrei Stefanescu <andrei.stefanescu@microchip.com>");
|