diff options
Diffstat (limited to 'drivers/gpio/gpio-lp3943.c')
| -rw-r--r-- | drivers/gpio/gpio-lp3943.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-lp3943.c b/drivers/gpio/gpio-lp3943.c new file mode 100644 index 000000000..cfc5b12b4 --- /dev/null +++ b/drivers/gpio/gpio-lp3943.c @@ -0,0 +1,242 @@ +/* + * TI/National Semiconductor LP3943 GPIO driver + * + * Copyright 2013 Texas Instruments + * + * Author: Milo Kim <milo.kim@ti.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2. + */ + +#include <linux/bitops.h> +#include <linux/err.h> +#include <linux/gpio.h> +#include <linux/i2c.h> +#include <linux/mfd/lp3943.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/slab.h> + +enum lp3943_gpios { + LP3943_GPIO1, + LP3943_GPIO2, + LP3943_GPIO3, + LP3943_GPIO4, + LP3943_GPIO5, + LP3943_GPIO6, + LP3943_GPIO7, + LP3943_GPIO8, + LP3943_GPIO9, + LP3943_GPIO10, + LP3943_GPIO11, + LP3943_GPIO12, + LP3943_GPIO13, + LP3943_GPIO14, + LP3943_GPIO15, + LP3943_GPIO16, + LP3943_MAX_GPIO, +}; + +struct lp3943_gpio { + struct gpio_chip chip; + struct lp3943 *lp3943; + u16 input_mask; /* 1 = GPIO is input direction, 0 = output */ +}; + +static inline struct lp3943_gpio *to_lp3943_gpio(struct gpio_chip *_chip) +{ + return container_of(_chip, struct lp3943_gpio, chip); +} + +static int lp3943_gpio_request(struct gpio_chip *chip, unsigned offset) +{ + struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip); + struct lp3943 *lp3943 = lp3943_gpio->lp3943; + + /* Return an error if the pin is already assigned */ + if (test_and_set_bit(offset, &lp3943->pin_used)) + return -EBUSY; + + return 0; +} + +static void lp3943_gpio_free(struct gpio_chip *chip, unsigned offset) +{ + struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip); + struct lp3943 *lp3943 = lp3943_gpio->lp3943; + + clear_bit(offset, &lp3943->pin_used); +} + +static int lp3943_gpio_set_mode(struct lp3943_gpio *lp3943_gpio, u8 offset, + u8 val) +{ + struct lp3943 *lp3943 = lp3943_gpio->lp3943; + const struct lp3943_reg_cfg *mux = lp3943->mux_cfg; + + return lp3943_update_bits(lp3943, mux[offset].reg, mux[offset].mask, + val << mux[offset].shift); +} + +static int lp3943_gpio_direction_input(struct gpio_chip *chip, unsigned offset) +{ + struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip); + + lp3943_gpio->input_mask |= BIT(offset); + + return lp3943_gpio_set_mode(lp3943_gpio, offset, LP3943_GPIO_IN); +} + +static int lp3943_get_gpio_in_status(struct lp3943_gpio *lp3943_gpio, + struct gpio_chip *chip, unsigned offset) +{ + u8 addr, read; + int err; + + switch (offset) { + case LP3943_GPIO1 ... LP3943_GPIO8: + addr = LP3943_REG_GPIO_A; + break; + case LP3943_GPIO9 ... LP3943_GPIO16: + addr = LP3943_REG_GPIO_B; + offset = offset - 8; + break; + default: + return -EINVAL; + } + + err = lp3943_read_byte(lp3943_gpio->lp3943, addr, &read); + if (err) + return err; + + return !!(read & BIT(offset)); +} + +static int lp3943_get_gpio_out_status(struct lp3943_gpio *lp3943_gpio, + struct gpio_chip *chip, unsigned offset) +{ + struct lp3943 *lp3943 = lp3943_gpio->lp3943; + const struct lp3943_reg_cfg *mux = lp3943->mux_cfg; + u8 read; + int err; + + err = lp3943_read_byte(lp3943, mux[offset].reg, &read); + if (err) + return err; + + read = (read & mux[offset].mask) >> mux[offset].shift; + + if (read == LP3943_GPIO_OUT_HIGH) + return 1; + else if (read == LP3943_GPIO_OUT_LOW) + return 0; + else + return -EINVAL; +} + +static int lp3943_gpio_get(struct gpio_chip *chip, unsigned offset) +{ + struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip); + + /* + * Limitation: + * LP3943 doesn't have the GPIO direction register. It provides + * only input and output status registers. + * So, direction info is required to handle the 'get' operation. + * This variable is updated whenever the direction is changed and + * it is used here. + */ + + if (lp3943_gpio->input_mask & BIT(offset)) + return lp3943_get_gpio_in_status(lp3943_gpio, chip, offset); + else + return lp3943_get_gpio_out_status(lp3943_gpio, chip, offset); +} + +static void lp3943_gpio_set(struct gpio_chip *chip, unsigned offset, int value) +{ + struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip); + u8 data; + + if (value) + data = LP3943_GPIO_OUT_HIGH; + else + data = LP3943_GPIO_OUT_LOW; + + lp3943_gpio_set_mode(lp3943_gpio, offset, data); +} + +static int lp3943_gpio_direction_output(struct gpio_chip *chip, unsigned offset, + int value) +{ + struct lp3943_gpio *lp3943_gpio = to_lp3943_gpio(chip); + + lp3943_gpio_set(chip, offset, value); + lp3943_gpio->input_mask &= ~BIT(offset); + + return 0; +} + +static const struct gpio_chip lp3943_gpio_chip = { + .label = "lp3943", + .owner = THIS_MODULE, + .request = lp3943_gpio_request, + .free = lp3943_gpio_free, + .direction_input = lp3943_gpio_direction_input, + .get = lp3943_gpio_get, + .direction_output = lp3943_gpio_direction_output, + .set = lp3943_gpio_set, + .base = -1, + .ngpio = LP3943_MAX_GPIO, + .can_sleep = 1, +}; + +static int lp3943_gpio_probe(struct platform_device *pdev) +{ + struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent); + struct lp3943_gpio *lp3943_gpio; + + lp3943_gpio = devm_kzalloc(&pdev->dev, sizeof(*lp3943_gpio), + GFP_KERNEL); + if (!lp3943_gpio) + return -ENOMEM; + + lp3943_gpio->lp3943 = lp3943; + lp3943_gpio->chip = lp3943_gpio_chip; + lp3943_gpio->chip.dev = &pdev->dev; + + platform_set_drvdata(pdev, lp3943_gpio); + + return gpiochip_add(&lp3943_gpio->chip); +} + +static int lp3943_gpio_remove(struct platform_device *pdev) +{ + struct lp3943_gpio *lp3943_gpio = platform_get_drvdata(pdev); + + gpiochip_remove(&lp3943_gpio->chip); + return 0; +} + +static const struct of_device_id lp3943_gpio_of_match[] = { + { .compatible = "ti,lp3943-gpio", }, + { } +}; +MODULE_DEVICE_TABLE(of, lp3943_gpio_of_match); + +static struct platform_driver lp3943_gpio_driver = { + .probe = lp3943_gpio_probe, + .remove = lp3943_gpio_remove, + .driver = { + .name = "lp3943-gpio", + .of_match_table = lp3943_gpio_of_match, + }, +}; +module_platform_driver(lp3943_gpio_driver); + +MODULE_DESCRIPTION("LP3943 GPIO driver"); +MODULE_ALIAS("platform:lp3943-gpio"); +MODULE_AUTHOR("Milo Kim"); +MODULE_LICENSE("GPL"); |