/* * 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 int lp3943_gpio_request(struct gpio_chip *chip, unsigned offset) { struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(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 = gpiochip_get_data(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 = gpiochip_get_data(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 = gpiochip_get_data(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 = gpiochip_get_data(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 = gpiochip_get_data(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.parent = &pdev->dev; platform_set_drvdata(pdev, lp3943_gpio); return devm_gpiochip_add_data(&pdev->dev, &lp3943_gpio->chip, lp3943_gpio); } 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, .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");