/* * w1-gpio - GPIO w1 bus master driver * * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation. */ #include <linux/init.h> #include <linux/module.h> #include <linux/platform_device.h> #include <linux/slab.h> #include <linux/w1-gpio.h> #include <linux/gpio.h> #include <linux/of_platform.h> #include <linux/of_gpio.h> #include <linux/err.h> #include <linux/of.h> #include <linux/delay.h> #include "../w1.h" #include "../w1_int.h" static u8 w1_gpio_set_pullup(void *data, int delay) { struct w1_gpio_platform_data *pdata = data; if (delay) { pdata->pullup_duration = delay; } else { if (pdata->pullup_duration) { gpio_direction_output(pdata->pin, 1); msleep(pdata->pullup_duration); gpio_direction_input(pdata->pin); } pdata->pullup_duration = 0; } return 0; } static void w1_gpio_write_bit_dir(void *data, u8 bit) { struct w1_gpio_platform_data *pdata = data; if (bit) gpio_direction_input(pdata->pin); else gpio_direction_output(pdata->pin, 0); } static void w1_gpio_write_bit_val(void *data, u8 bit) { struct w1_gpio_platform_data *pdata = data; gpio_set_value(pdata->pin, bit); } static u8 w1_gpio_read_bit(void *data) { struct w1_gpio_platform_data *pdata = data; return gpio_get_value(pdata->pin) ? 1 : 0; } #if defined(CONFIG_OF) static const struct of_device_id w1_gpio_dt_ids[] = { { .compatible = "w1-gpio" }, {} }; MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids); #endif static int w1_gpio_probe_dt(struct platform_device *pdev) { struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev); struct device_node *np = pdev->dev.of_node; int gpio; pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); if (!pdata) return -ENOMEM; if (of_get_property(np, "linux,open-drain", NULL)) pdata->is_open_drain = 1; gpio = of_get_gpio(np, 0); if (gpio < 0) { if (gpio != -EPROBE_DEFER) dev_err(&pdev->dev, "Failed to parse gpio property for data pin (%d)\n", gpio); return gpio; } pdata->pin = gpio; gpio = of_get_gpio(np, 1); if (gpio == -EPROBE_DEFER) return gpio; /* ignore other errors as the pullup gpio is optional */ pdata->ext_pullup_enable_pin = gpio; pdev->dev.platform_data = pdata; return 0; } static int w1_gpio_probe(struct platform_device *pdev) { struct w1_bus_master *master; struct w1_gpio_platform_data *pdata; int err; if (of_have_populated_dt()) { err = w1_gpio_probe_dt(pdev); if (err < 0) return err; } pdata = dev_get_platdata(&pdev->dev); if (!pdata) { dev_err(&pdev->dev, "No configuration data\n"); return -ENXIO; } master = devm_kzalloc(&pdev->dev, sizeof(struct w1_bus_master), GFP_KERNEL); if (!master) { dev_err(&pdev->dev, "Out of memory\n"); return -ENOMEM; } err = devm_gpio_request(&pdev->dev, pdata->pin, "w1"); if (err) { dev_err(&pdev->dev, "gpio_request (pin) failed\n"); return err; } if (gpio_is_valid(pdata->ext_pullup_enable_pin)) { err = devm_gpio_request_one(&pdev->dev, pdata->ext_pullup_enable_pin, GPIOF_INIT_LOW, "w1 pullup"); if (err < 0) { dev_err(&pdev->dev, "gpio_request_one " "(ext_pullup_enable_pin) failed\n"); return err; } } master->data = pdata; master->read_bit = w1_gpio_read_bit; if (pdata->is_open_drain) { gpio_direction_output(pdata->pin, 1); master->write_bit = w1_gpio_write_bit_val; } else { gpio_direction_input(pdata->pin); master->write_bit = w1_gpio_write_bit_dir; master->set_pullup = w1_gpio_set_pullup; } err = w1_add_master_device(master); if (err) { dev_err(&pdev->dev, "w1_add_master device failed\n"); return err; } if (pdata->enable_external_pullup) pdata->enable_external_pullup(1); if (gpio_is_valid(pdata->ext_pullup_enable_pin)) gpio_set_value(pdata->ext_pullup_enable_pin, 1); platform_set_drvdata(pdev, master); return 0; } static int w1_gpio_remove(struct platform_device *pdev) { struct w1_bus_master *master = platform_get_drvdata(pdev); struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev); if (pdata->enable_external_pullup) pdata->enable_external_pullup(0); if (gpio_is_valid(pdata->ext_pullup_enable_pin)) gpio_set_value(pdata->ext_pullup_enable_pin, 0); w1_remove_master_device(master); return 0; } static int __maybe_unused w1_gpio_suspend(struct device *dev) { struct w1_gpio_platform_data *pdata = dev_get_platdata(dev); if (pdata->enable_external_pullup) pdata->enable_external_pullup(0); return 0; } static int __maybe_unused w1_gpio_resume(struct device *dev) { struct w1_gpio_platform_data *pdata = dev_get_platdata(dev); if (pdata->enable_external_pullup) pdata->enable_external_pullup(1); return 0; } static SIMPLE_DEV_PM_OPS(w1_gpio_pm_ops, w1_gpio_suspend, w1_gpio_resume); static struct platform_driver w1_gpio_driver = { .driver = { .name = "w1-gpio", .pm = &w1_gpio_pm_ops, .of_match_table = of_match_ptr(w1_gpio_dt_ids), }, .probe = w1_gpio_probe, .remove = w1_gpio_remove, }; module_platform_driver(w1_gpio_driver); MODULE_DESCRIPTION("GPIO w1 bus master driver"); MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>"); MODULE_LICENSE("GPL");