107 lines
2.5 KiB
C
107 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* GPIO-controlled multiplexer driver
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*
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* Copyright (C) 2017 Axentia Technologies AB
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*
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* Author: Peter Rosin <peda@axentia.se>
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*/
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#include <linux/bitmap.h>
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#include <linux/err.h>
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#include <linux/gpio/consumer.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/mux/driver.h>
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#include <linux/platform_device.h>
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#include <linux/property.h>
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struct mux_gpio {
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struct gpio_descs *gpios;
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};
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static int mux_gpio_set(struct mux_control *mux, int state)
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{
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struct mux_gpio *mux_gpio = mux_chip_priv(mux->chip);
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DECLARE_BITMAP(values, BITS_PER_TYPE(state));
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u32 value = state;
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bitmap_from_arr32(values, &value, BITS_PER_TYPE(value));
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gpiod_set_array_value_cansleep(mux_gpio->gpios->ndescs,
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mux_gpio->gpios->desc,
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mux_gpio->gpios->info, values);
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return 0;
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}
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static const struct mux_control_ops mux_gpio_ops = {
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.set = mux_gpio_set,
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};
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static const struct of_device_id mux_gpio_dt_ids[] = {
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{ .compatible = "gpio-mux", },
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, mux_gpio_dt_ids);
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static int mux_gpio_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct mux_chip *mux_chip;
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struct mux_gpio *mux_gpio;
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int pins;
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s32 idle_state;
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int ret;
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pins = gpiod_count(dev, "mux");
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if (pins < 0)
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return pins;
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mux_chip = devm_mux_chip_alloc(dev, 1, sizeof(*mux_gpio));
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if (IS_ERR(mux_chip))
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return PTR_ERR(mux_chip);
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mux_gpio = mux_chip_priv(mux_chip);
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mux_chip->ops = &mux_gpio_ops;
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mux_gpio->gpios = devm_gpiod_get_array(dev, "mux", GPIOD_OUT_LOW);
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if (IS_ERR(mux_gpio->gpios))
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return dev_err_probe(dev, PTR_ERR(mux_gpio->gpios),
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"failed to get gpios\n");
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WARN_ON(pins != mux_gpio->gpios->ndescs);
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mux_chip->mux->states = BIT(pins);
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ret = device_property_read_u32(dev, "idle-state", (u32 *)&idle_state);
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if (ret >= 0 && idle_state != MUX_IDLE_AS_IS) {
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if (idle_state < 0 || idle_state >= mux_chip->mux->states) {
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dev_err(dev, "invalid idle-state %u\n", idle_state);
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return -EINVAL;
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}
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mux_chip->mux->idle_state = idle_state;
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}
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ret = devm_mux_chip_register(dev, mux_chip);
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if (ret < 0)
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return ret;
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dev_info(dev, "%u-way mux-controller registered\n",
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mux_chip->mux->states);
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return 0;
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}
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static struct platform_driver mux_gpio_driver = {
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.driver = {
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.name = "gpio-mux",
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.of_match_table = mux_gpio_dt_ids,
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},
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.probe = mux_gpio_probe,
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};
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module_platform_driver(mux_gpio_driver);
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MODULE_DESCRIPTION("GPIO-controlled multiplexer driver");
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MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
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MODULE_LICENSE("GPL v2");
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