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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * TI/National Semiconductor LP3943 GPIO driver4 *5 * Copyright 2013 Texas Instruments6 *7 * Author: Milo Kim <milo.kim@ti.com>8 */9 10#include <linux/bitops.h>11#include <linux/err.h>12#include <linux/gpio/driver.h>13#include <linux/i2c.h>14#include <linux/mfd/lp3943.h>15#include <linux/module.h>16#include <linux/platform_device.h>17#include <linux/slab.h>18 19enum lp3943_gpios {20 LP3943_GPIO1,21 LP3943_GPIO2,22 LP3943_GPIO3,23 LP3943_GPIO4,24 LP3943_GPIO5,25 LP3943_GPIO6,26 LP3943_GPIO7,27 LP3943_GPIO8,28 LP3943_GPIO9,29 LP3943_GPIO10,30 LP3943_GPIO11,31 LP3943_GPIO12,32 LP3943_GPIO13,33 LP3943_GPIO14,34 LP3943_GPIO15,35 LP3943_GPIO16,36 LP3943_MAX_GPIO,37};38 39struct lp3943_gpio {40 struct gpio_chip chip;41 struct lp3943 *lp3943;42 u16 input_mask; /* 1 = GPIO is input direction, 0 = output */43};44 45static int lp3943_gpio_request(struct gpio_chip *chip, unsigned int offset)46{47 struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);48 struct lp3943 *lp3943 = lp3943_gpio->lp3943;49 50 /* Return an error if the pin is already assigned */51 if (test_and_set_bit(offset, &lp3943->pin_used))52 return -EBUSY;53 54 return 0;55}56 57static void lp3943_gpio_free(struct gpio_chip *chip, unsigned int offset)58{59 struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);60 struct lp3943 *lp3943 = lp3943_gpio->lp3943;61 62 clear_bit(offset, &lp3943->pin_used);63}64 65static int lp3943_gpio_set_mode(struct lp3943_gpio *lp3943_gpio, u8 offset,66 u8 val)67{68 struct lp3943 *lp3943 = lp3943_gpio->lp3943;69 const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;70 71 return lp3943_update_bits(lp3943, mux[offset].reg, mux[offset].mask,72 val << mux[offset].shift);73}74 75static int lp3943_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)76{77 struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);78 79 lp3943_gpio->input_mask |= BIT(offset);80 81 return lp3943_gpio_set_mode(lp3943_gpio, offset, LP3943_GPIO_IN);82}83 84static int lp3943_get_gpio_in_status(struct lp3943_gpio *lp3943_gpio,85 struct gpio_chip *chip, unsigned int offset)86{87 u8 addr, read;88 int err;89 90 switch (offset) {91 case LP3943_GPIO1 ... LP3943_GPIO8:92 addr = LP3943_REG_GPIO_A;93 break;94 case LP3943_GPIO9 ... LP3943_GPIO16:95 addr = LP3943_REG_GPIO_B;96 offset = offset - 8;97 break;98 default:99 return -EINVAL;100 }101 102 err = lp3943_read_byte(lp3943_gpio->lp3943, addr, &read);103 if (err)104 return err;105 106 return !!(read & BIT(offset));107}108 109static int lp3943_get_gpio_out_status(struct lp3943_gpio *lp3943_gpio,110 struct gpio_chip *chip, unsigned int offset)111{112 struct lp3943 *lp3943 = lp3943_gpio->lp3943;113 const struct lp3943_reg_cfg *mux = lp3943->mux_cfg;114 u8 read;115 int err;116 117 err = lp3943_read_byte(lp3943, mux[offset].reg, &read);118 if (err)119 return err;120 121 read = (read & mux[offset].mask) >> mux[offset].shift;122 123 if (read == LP3943_GPIO_OUT_HIGH)124 return 1;125 else if (read == LP3943_GPIO_OUT_LOW)126 return 0;127 else128 return -EINVAL;129}130 131static int lp3943_gpio_get(struct gpio_chip *chip, unsigned int offset)132{133 struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);134 135 /*136 * Limitation:137 * LP3943 doesn't have the GPIO direction register. It provides138 * only input and output status registers.139 * So, direction info is required to handle the 'get' operation.140 * This variable is updated whenever the direction is changed and141 * it is used here.142 */143 144 if (lp3943_gpio->input_mask & BIT(offset))145 return lp3943_get_gpio_in_status(lp3943_gpio, chip, offset);146 else147 return lp3943_get_gpio_out_status(lp3943_gpio, chip, offset);148}149 150static void lp3943_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)151{152 struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);153 u8 data;154 155 if (value)156 data = LP3943_GPIO_OUT_HIGH;157 else158 data = LP3943_GPIO_OUT_LOW;159 160 lp3943_gpio_set_mode(lp3943_gpio, offset, data);161}162 163static int lp3943_gpio_direction_output(struct gpio_chip *chip, unsigned int offset,164 int value)165{166 struct lp3943_gpio *lp3943_gpio = gpiochip_get_data(chip);167 168 lp3943_gpio_set(chip, offset, value);169 lp3943_gpio->input_mask &= ~BIT(offset);170 171 return 0;172}173 174static const struct gpio_chip lp3943_gpio_chip = {175 .label = "lp3943",176 .owner = THIS_MODULE,177 .request = lp3943_gpio_request,178 .free = lp3943_gpio_free,179 .direction_input = lp3943_gpio_direction_input,180 .get = lp3943_gpio_get,181 .direction_output = lp3943_gpio_direction_output,182 .set = lp3943_gpio_set,183 .base = -1,184 .ngpio = LP3943_MAX_GPIO,185 .can_sleep = 1,186};187 188static int lp3943_gpio_probe(struct platform_device *pdev)189{190 struct lp3943 *lp3943 = dev_get_drvdata(pdev->dev.parent);191 struct lp3943_gpio *lp3943_gpio;192 193 lp3943_gpio = devm_kzalloc(&pdev->dev, sizeof(*lp3943_gpio),194 GFP_KERNEL);195 if (!lp3943_gpio)196 return -ENOMEM;197 198 lp3943_gpio->lp3943 = lp3943;199 lp3943_gpio->chip = lp3943_gpio_chip;200 lp3943_gpio->chip.parent = &pdev->dev;201 202 return devm_gpiochip_add_data(&pdev->dev, &lp3943_gpio->chip,203 lp3943_gpio);204}205 206static const struct of_device_id lp3943_gpio_of_match[] = {207 { .compatible = "ti,lp3943-gpio", },208 { }209};210MODULE_DEVICE_TABLE(of, lp3943_gpio_of_match);211 212static struct platform_driver lp3943_gpio_driver = {213 .probe = lp3943_gpio_probe,214 .driver = {215 .name = "lp3943-gpio",216 .of_match_table = lp3943_gpio_of_match,217 },218};219module_platform_driver(lp3943_gpio_driver);220 221MODULE_DESCRIPTION("LP3943 GPIO driver");222MODULE_ALIAS("platform:lp3943-gpio");223MODULE_AUTHOR("Milo Kim");224MODULE_LICENSE("GPL");225