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1// SPDX-License-Identifier: GPL-2.02/*3 * Turris Mox Moxtet GPIO expander4 *5 * Copyright (C) 2018 Marek Behún <kabel@kernel.org>6 */7 8#include <linux/bitops.h>9#include <linux/gpio/driver.h>10#include <linux/moxtet.h>11#include <linux/module.h>12 13#define MOXTET_GPIO_NGPIOS 1214#define MOXTET_GPIO_INPUTS 415 16struct moxtet_gpio_desc {17 u16 in_mask;18 u16 out_mask;19};20 21static const struct moxtet_gpio_desc descs[] = {22 [TURRIS_MOX_MODULE_SFP] = {23 .in_mask = GENMASK(2, 0),24 .out_mask = GENMASK(5, 4),25 },26};27 28struct moxtet_gpio_chip {29 struct device *dev;30 struct gpio_chip gpio_chip;31 const struct moxtet_gpio_desc *desc;32};33 34static int moxtet_gpio_get_value(struct gpio_chip *gc, unsigned int offset)35{36 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);37 int ret;38 39 if (chip->desc->in_mask & BIT(offset)) {40 ret = moxtet_device_read(chip->dev);41 } else if (chip->desc->out_mask & BIT(offset)) {42 ret = moxtet_device_written(chip->dev);43 if (ret >= 0)44 ret <<= MOXTET_GPIO_INPUTS;45 } else {46 return -EINVAL;47 }48 49 if (ret < 0)50 return ret;51 52 return !!(ret & BIT(offset));53}54 55static void moxtet_gpio_set_value(struct gpio_chip *gc, unsigned int offset,56 int val)57{58 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);59 int state;60 61 state = moxtet_device_written(chip->dev);62 if (state < 0)63 return;64 65 offset -= MOXTET_GPIO_INPUTS;66 67 if (val)68 state |= BIT(offset);69 else70 state &= ~BIT(offset);71 72 moxtet_device_write(chip->dev, state);73}74 75static int moxtet_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)76{77 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);78 79 /* All lines are hard wired to be either input or output, not both. */80 if (chip->desc->in_mask & BIT(offset))81 return GPIO_LINE_DIRECTION_IN;82 else if (chip->desc->out_mask & BIT(offset))83 return GPIO_LINE_DIRECTION_OUT;84 else85 return -EINVAL;86}87 88static int moxtet_gpio_direction_input(struct gpio_chip *gc,89 unsigned int offset)90{91 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);92 93 if (chip->desc->in_mask & BIT(offset))94 return 0;95 else if (chip->desc->out_mask & BIT(offset))96 return -ENOTSUPP;97 else98 return -EINVAL;99}100 101static int moxtet_gpio_direction_output(struct gpio_chip *gc,102 unsigned int offset, int val)103{104 struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);105 106 if (chip->desc->out_mask & BIT(offset))107 moxtet_gpio_set_value(gc, offset, val);108 else if (chip->desc->in_mask & BIT(offset))109 return -ENOTSUPP;110 else111 return -EINVAL;112 113 return 0;114}115 116static int moxtet_gpio_probe(struct device *dev)117{118 struct moxtet_gpio_chip *chip;119 struct device_node *nc = dev->of_node;120 int id;121 122 id = to_moxtet_device(dev)->id;123 124 if (id >= ARRAY_SIZE(descs)) {125 dev_err(dev, "%pOF Moxtet device id 0x%x is not supported by gpio-moxtet driver\n",126 nc, id);127 return -ENOTSUPP;128 }129 130 chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);131 if (!chip)132 return -ENOMEM;133 134 chip->dev = dev;135 chip->gpio_chip.parent = dev;136 chip->desc = &descs[id];137 138 dev_set_drvdata(dev, chip);139 140 chip->gpio_chip.label = dev_name(dev);141 chip->gpio_chip.get_direction = moxtet_gpio_get_direction;142 chip->gpio_chip.direction_input = moxtet_gpio_direction_input;143 chip->gpio_chip.direction_output = moxtet_gpio_direction_output;144 chip->gpio_chip.get = moxtet_gpio_get_value;145 chip->gpio_chip.set = moxtet_gpio_set_value;146 chip->gpio_chip.base = -1;147 148 chip->gpio_chip.ngpio = MOXTET_GPIO_NGPIOS;149 150 chip->gpio_chip.can_sleep = true;151 chip->gpio_chip.owner = THIS_MODULE;152 153 return devm_gpiochip_add_data(dev, &chip->gpio_chip, chip);154}155 156static const struct of_device_id moxtet_gpio_dt_ids[] = {157 { .compatible = "cznic,moxtet-gpio", },158 {},159};160MODULE_DEVICE_TABLE(of, moxtet_gpio_dt_ids);161 162static const enum turris_mox_module_id moxtet_gpio_module_table[] = {163 TURRIS_MOX_MODULE_SFP,164 0,165};166 167static struct moxtet_driver moxtet_gpio_driver = {168 .driver = {169 .name = "moxtet-gpio",170 .of_match_table = moxtet_gpio_dt_ids,171 .probe = moxtet_gpio_probe,172 },173 .id_table = moxtet_gpio_module_table,174};175module_moxtet_driver(moxtet_gpio_driver);176 177MODULE_AUTHOR("Marek Behun <kabel@kernel.org>");178MODULE_DESCRIPTION("Turris Mox Moxtet GPIO expander");179MODULE_LICENSE("GPL v2");180