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206 lines
4.8 KiB
206 lines
4.8 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* w1-gpio - GPIO w1 bus master driver |
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* |
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* Copyright (C) 2007 Ville Syrjala <[email protected]> |
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*/ |
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#include <linux/init.h> |
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#include <linux/module.h> |
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#include <linux/platform_device.h> |
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#include <linux/slab.h> |
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#include <linux/w1-gpio.h> |
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#include <linux/gpio/consumer.h> |
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#include <linux/of_platform.h> |
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#include <linux/err.h> |
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#include <linux/of.h> |
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#include <linux/delay.h> |
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#include <linux/w1.h> |
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static u8 w1_gpio_set_pullup(void *data, int delay) |
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{ |
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struct w1_gpio_platform_data *pdata = data; |
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if (delay) { |
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pdata->pullup_duration = delay; |
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} else { |
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if (pdata->pullup_duration) { |
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/* |
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* This will OVERRIDE open drain emulation and force-pull |
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* the line high for some time. |
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*/ |
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gpiod_direction_output_raw(pdata->gpiod, 1); |
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msleep(pdata->pullup_duration); |
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/* |
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* This will simply set the line as input since we are doing |
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* open drain emulation in the GPIO library. |
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*/ |
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gpiod_set_value(pdata->gpiod, 1); |
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} |
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pdata->pullup_duration = 0; |
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} |
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return 0; |
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} |
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static void w1_gpio_write_bit(void *data, u8 bit) |
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{ |
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struct w1_gpio_platform_data *pdata = data; |
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gpiod_set_value(pdata->gpiod, bit); |
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} |
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static u8 w1_gpio_read_bit(void *data) |
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{ |
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struct w1_gpio_platform_data *pdata = data; |
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return gpiod_get_value(pdata->gpiod) ? 1 : 0; |
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} |
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#if defined(CONFIG_OF) |
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static const struct of_device_id w1_gpio_dt_ids[] = { |
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{ .compatible = "w1-gpio" }, |
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{} |
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}; |
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MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids); |
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#endif |
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static int w1_gpio_probe(struct platform_device *pdev) |
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{ |
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struct w1_bus_master *master; |
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struct w1_gpio_platform_data *pdata; |
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struct device *dev = &pdev->dev; |
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struct device_node *np = dev->of_node; |
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/* Enforce open drain mode by default */ |
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enum gpiod_flags gflags = GPIOD_OUT_LOW_OPEN_DRAIN; |
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int err; |
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if (of_have_populated_dt()) { |
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pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); |
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if (!pdata) |
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return -ENOMEM; |
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/* |
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* This parameter means that something else than the gpiolib has |
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* already set the line into open drain mode, so we should just |
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* driver it high/low like we are in full control of the line and |
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* open drain will happen transparently. |
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*/ |
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if (of_get_property(np, "linux,open-drain", NULL)) |
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gflags = GPIOD_OUT_LOW; |
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pdev->dev.platform_data = pdata; |
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} |
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pdata = dev_get_platdata(dev); |
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if (!pdata) { |
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dev_err(dev, "No configuration data\n"); |
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return -ENXIO; |
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} |
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master = devm_kzalloc(dev, sizeof(struct w1_bus_master), |
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GFP_KERNEL); |
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if (!master) { |
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dev_err(dev, "Out of memory\n"); |
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return -ENOMEM; |
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} |
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pdata->gpiod = devm_gpiod_get_index(dev, NULL, 0, gflags); |
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if (IS_ERR(pdata->gpiod)) { |
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dev_err(dev, "gpio_request (pin) failed\n"); |
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return PTR_ERR(pdata->gpiod); |
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} |
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pdata->pullup_gpiod = |
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devm_gpiod_get_index_optional(dev, NULL, 1, GPIOD_OUT_LOW); |
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if (IS_ERR(pdata->pullup_gpiod)) { |
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dev_err(dev, "gpio_request_one " |
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"(ext_pullup_enable_pin) failed\n"); |
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return PTR_ERR(pdata->pullup_gpiod); |
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} |
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master->data = pdata; |
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master->read_bit = w1_gpio_read_bit; |
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gpiod_direction_output(pdata->gpiod, 1); |
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master->write_bit = w1_gpio_write_bit; |
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/* |
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* If we are using open drain emulation from the GPIO library, |
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* we need to use this pullup function that hammers the line |
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* high using a raw accessor to provide pull-up for the w1 |
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* line. |
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*/ |
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if (gflags == GPIOD_OUT_LOW_OPEN_DRAIN) |
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master->set_pullup = w1_gpio_set_pullup; |
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err = w1_add_master_device(master); |
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if (err) { |
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dev_err(dev, "w1_add_master device failed\n"); |
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return err; |
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} |
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if (pdata->enable_external_pullup) |
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pdata->enable_external_pullup(1); |
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if (pdata->pullup_gpiod) |
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gpiod_set_value(pdata->pullup_gpiod, 1); |
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platform_set_drvdata(pdev, master); |
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return 0; |
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} |
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static int w1_gpio_remove(struct platform_device *pdev) |
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{ |
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struct w1_bus_master *master = platform_get_drvdata(pdev); |
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struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev); |
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if (pdata->enable_external_pullup) |
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pdata->enable_external_pullup(0); |
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if (pdata->pullup_gpiod) |
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gpiod_set_value(pdata->pullup_gpiod, 0); |
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w1_remove_master_device(master); |
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return 0; |
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} |
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static int __maybe_unused w1_gpio_suspend(struct device *dev) |
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{ |
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struct w1_gpio_platform_data *pdata = dev_get_platdata(dev); |
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if (pdata->enable_external_pullup) |
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pdata->enable_external_pullup(0); |
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return 0; |
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} |
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static int __maybe_unused w1_gpio_resume(struct device *dev) |
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{ |
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struct w1_gpio_platform_data *pdata = dev_get_platdata(dev); |
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if (pdata->enable_external_pullup) |
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pdata->enable_external_pullup(1); |
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return 0; |
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} |
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static SIMPLE_DEV_PM_OPS(w1_gpio_pm_ops, w1_gpio_suspend, w1_gpio_resume); |
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static struct platform_driver w1_gpio_driver = { |
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.driver = { |
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.name = "w1-gpio", |
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.pm = &w1_gpio_pm_ops, |
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.of_match_table = of_match_ptr(w1_gpio_dt_ids), |
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}, |
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.probe = w1_gpio_probe, |
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.remove = w1_gpio_remove, |
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}; |
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module_platform_driver(w1_gpio_driver); |
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MODULE_DESCRIPTION("GPIO w1 bus master driver"); |
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MODULE_AUTHOR("Ville Syrjala <[email protected]>"); |
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MODULE_LICENSE("GPL");
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