180 lines
4.0 KiB
C
180 lines
4.0 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Turris Mox Moxtet GPIO expander
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*
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* Copyright (C) 2018 Marek Behun <marek.behun@nic.cz>
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*/
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#include <linux/bitops.h>
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#include <linux/gpio/driver.h>
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#include <linux/moxtet.h>
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#include <linux/module.h>
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#define MOXTET_GPIO_NGPIOS 12
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#define MOXTET_GPIO_INPUTS 4
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struct moxtet_gpio_desc {
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u16 in_mask;
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u16 out_mask;
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};
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static const struct moxtet_gpio_desc descs[] = {
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[TURRIS_MOX_MODULE_SFP] = {
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.in_mask = GENMASK(2, 0),
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.out_mask = GENMASK(5, 4),
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},
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};
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struct moxtet_gpio_chip {
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struct device *dev;
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struct gpio_chip gpio_chip;
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const struct moxtet_gpio_desc *desc;
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};
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static int moxtet_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
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{
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struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
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int ret;
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if (chip->desc->in_mask & BIT(offset)) {
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ret = moxtet_device_read(chip->dev);
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} else if (chip->desc->out_mask & BIT(offset)) {
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ret = moxtet_device_written(chip->dev);
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if (ret >= 0)
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ret <<= MOXTET_GPIO_INPUTS;
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} else {
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return -EINVAL;
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}
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if (ret < 0)
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return ret;
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return !!(ret & BIT(offset));
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}
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static void moxtet_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
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int val)
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{
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struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
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int state;
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state = moxtet_device_written(chip->dev);
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if (state < 0)
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return;
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offset -= MOXTET_GPIO_INPUTS;
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if (val)
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state |= BIT(offset);
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else
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state &= ~BIT(offset);
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moxtet_device_write(chip->dev, state);
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}
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static int moxtet_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
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{
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struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
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/* All lines are hard wired to be either input or output, not both. */
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if (chip->desc->in_mask & BIT(offset))
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return 1;
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else if (chip->desc->out_mask & BIT(offset))
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return 0;
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else
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return -EINVAL;
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}
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static int moxtet_gpio_direction_input(struct gpio_chip *gc,
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unsigned int offset)
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{
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struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
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if (chip->desc->in_mask & BIT(offset))
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return 0;
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else if (chip->desc->out_mask & BIT(offset))
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return -ENOTSUPP;
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else
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return -EINVAL;
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}
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static int moxtet_gpio_direction_output(struct gpio_chip *gc,
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unsigned int offset, int val)
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{
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struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
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if (chip->desc->out_mask & BIT(offset))
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moxtet_gpio_set_value(gc, offset, val);
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else if (chip->desc->in_mask & BIT(offset))
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return -ENOTSUPP;
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else
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return -EINVAL;
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return 0;
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}
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static int moxtet_gpio_probe(struct device *dev)
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{
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struct moxtet_gpio_chip *chip;
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struct device_node *nc = dev->of_node;
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int id;
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id = to_moxtet_device(dev)->id;
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if (id >= ARRAY_SIZE(descs)) {
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dev_err(dev, "%pOF Moxtet device id 0x%x is not supported by gpio-moxtet driver\n",
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nc, id);
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return -ENOTSUPP;
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}
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chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
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if (!chip)
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return -ENOMEM;
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chip->dev = dev;
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chip->gpio_chip.parent = dev;
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chip->desc = &descs[id];
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dev_set_drvdata(dev, chip);
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chip->gpio_chip.label = dev_name(dev);
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chip->gpio_chip.get_direction = moxtet_gpio_get_direction;
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chip->gpio_chip.direction_input = moxtet_gpio_direction_input;
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chip->gpio_chip.direction_output = moxtet_gpio_direction_output;
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chip->gpio_chip.get = moxtet_gpio_get_value;
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chip->gpio_chip.set = moxtet_gpio_set_value;
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chip->gpio_chip.base = -1;
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chip->gpio_chip.ngpio = MOXTET_GPIO_NGPIOS;
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chip->gpio_chip.can_sleep = true;
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chip->gpio_chip.owner = THIS_MODULE;
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return devm_gpiochip_add_data(dev, &chip->gpio_chip, chip);
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}
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static const struct of_device_id moxtet_gpio_dt_ids[] = {
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{ .compatible = "cznic,moxtet-gpio", },
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{},
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};
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MODULE_DEVICE_TABLE(of, moxtet_gpio_dt_ids);
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static const enum turris_mox_module_id moxtet_gpio_module_table[] = {
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TURRIS_MOX_MODULE_SFP,
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0,
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};
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static struct moxtet_driver moxtet_gpio_driver = {
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.driver = {
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.name = "moxtet-gpio",
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.of_match_table = moxtet_gpio_dt_ids,
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.probe = moxtet_gpio_probe,
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},
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.id_table = moxtet_gpio_module_table,
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};
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module_moxtet_driver(moxtet_gpio_driver);
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MODULE_AUTHOR("Marek Behun <marek.behun@nic.cz>");
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MODULE_DESCRIPTION("Turris Mox Moxtet GPIO expander");
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MODULE_LICENSE("GPL v2");
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