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106 lines
2.5 KiB
106 lines
2.5 KiB
// 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 <[email protected]> |
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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 <[email protected]>"); |
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MODULE_LICENSE("GPL v2");
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