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Diffstat (limited to '')
| -rw-r--r-- | drivers/gpio/gpio-sama5d2-piobu.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-sama5d2-piobu.c b/drivers/gpio/gpio-sama5d2-piobu.c new file mode 100644 index 000000000..3e95da717 --- /dev/null +++ b/drivers/gpio/gpio-sama5d2-piobu.c @@ -0,0 +1,248 @@ +// 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>"); |