1 /* 2 * w1-gpio - GPIO w1 bus master driver 3 * 4 * Copyright (C) 2007 Ville Syrjala <syrjala@sci.fi> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 8 * as published by the Free Software Foundation. 9 */ 10 11 #include <linux/init.h> 12 #include <linux/module.h> 13 #include <linux/platform_device.h> 14 #include <linux/slab.h> 15 #include <linux/w1-gpio.h> 16 #include <linux/gpio.h> 17 #include <linux/of_platform.h> 18 #include <linux/of_gpio.h> 19 #include <linux/err.h> 20 #include <linux/of.h> 21 #include <linux/delay.h> 22 23 #include <linux/w1.h> 24 25 static u8 w1_gpio_set_pullup(void *data, int delay) 26 { 27 struct w1_gpio_platform_data *pdata = data; 28 29 if (delay) { 30 pdata->pullup_duration = delay; 31 } else { 32 if (pdata->pullup_duration) { 33 gpio_direction_output(pdata->pin, 1); 34 35 msleep(pdata->pullup_duration); 36 37 gpio_direction_input(pdata->pin); 38 } 39 pdata->pullup_duration = 0; 40 } 41 42 return 0; 43 } 44 45 static void w1_gpio_write_bit_dir(void *data, u8 bit) 46 { 47 struct w1_gpio_platform_data *pdata = data; 48 49 if (bit) 50 gpio_direction_input(pdata->pin); 51 else 52 gpio_direction_output(pdata->pin, 0); 53 } 54 55 static void w1_gpio_write_bit_val(void *data, u8 bit) 56 { 57 struct w1_gpio_platform_data *pdata = data; 58 59 gpio_set_value(pdata->pin, bit); 60 } 61 62 static u8 w1_gpio_read_bit(void *data) 63 { 64 struct w1_gpio_platform_data *pdata = data; 65 66 return gpio_get_value(pdata->pin) ? 1 : 0; 67 } 68 69 #if defined(CONFIG_OF) 70 static const struct of_device_id w1_gpio_dt_ids[] = { 71 { .compatible = "w1-gpio" }, 72 {} 73 }; 74 MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids); 75 #endif 76 77 static int w1_gpio_probe_dt(struct platform_device *pdev) 78 { 79 struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev); 80 struct device_node *np = pdev->dev.of_node; 81 int gpio; 82 83 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 84 if (!pdata) 85 return -ENOMEM; 86 87 if (of_get_property(np, "linux,open-drain", NULL)) 88 pdata->is_open_drain = 1; 89 90 gpio = of_get_gpio(np, 0); 91 if (gpio < 0) { 92 if (gpio != -EPROBE_DEFER) 93 dev_err(&pdev->dev, 94 "Failed to parse gpio property for data pin (%d)\n", 95 gpio); 96 97 return gpio; 98 } 99 pdata->pin = gpio; 100 101 gpio = of_get_gpio(np, 1); 102 if (gpio == -EPROBE_DEFER) 103 return gpio; 104 /* ignore other errors as the pullup gpio is optional */ 105 pdata->ext_pullup_enable_pin = gpio; 106 107 pdev->dev.platform_data = pdata; 108 109 return 0; 110 } 111 112 static int w1_gpio_probe(struct platform_device *pdev) 113 { 114 struct w1_bus_master *master; 115 struct w1_gpio_platform_data *pdata; 116 int err; 117 118 if (of_have_populated_dt()) { 119 err = w1_gpio_probe_dt(pdev); 120 if (err < 0) 121 return err; 122 } 123 124 pdata = dev_get_platdata(&pdev->dev); 125 126 if (!pdata) { 127 dev_err(&pdev->dev, "No configuration data\n"); 128 return -ENXIO; 129 } 130 131 master = devm_kzalloc(&pdev->dev, sizeof(struct w1_bus_master), 132 GFP_KERNEL); 133 if (!master) { 134 dev_err(&pdev->dev, "Out of memory\n"); 135 return -ENOMEM; 136 } 137 138 err = devm_gpio_request(&pdev->dev, pdata->pin, "w1"); 139 if (err) { 140 dev_err(&pdev->dev, "gpio_request (pin) failed\n"); 141 return err; 142 } 143 144 if (gpio_is_valid(pdata->ext_pullup_enable_pin)) { 145 err = devm_gpio_request_one(&pdev->dev, 146 pdata->ext_pullup_enable_pin, GPIOF_INIT_LOW, 147 "w1 pullup"); 148 if (err < 0) { 149 dev_err(&pdev->dev, "gpio_request_one " 150 "(ext_pullup_enable_pin) failed\n"); 151 return err; 152 } 153 } 154 155 master->data = pdata; 156 master->read_bit = w1_gpio_read_bit; 157 158 if (pdata->is_open_drain) { 159 gpio_direction_output(pdata->pin, 1); 160 master->write_bit = w1_gpio_write_bit_val; 161 } else { 162 gpio_direction_input(pdata->pin); 163 master->write_bit = w1_gpio_write_bit_dir; 164 master->set_pullup = w1_gpio_set_pullup; 165 } 166 167 err = w1_add_master_device(master); 168 if (err) { 169 dev_err(&pdev->dev, "w1_add_master device failed\n"); 170 return err; 171 } 172 173 if (pdata->enable_external_pullup) 174 pdata->enable_external_pullup(1); 175 176 if (gpio_is_valid(pdata->ext_pullup_enable_pin)) 177 gpio_set_value(pdata->ext_pullup_enable_pin, 1); 178 179 platform_set_drvdata(pdev, master); 180 181 return 0; 182 } 183 184 static int w1_gpio_remove(struct platform_device *pdev) 185 { 186 struct w1_bus_master *master = platform_get_drvdata(pdev); 187 struct w1_gpio_platform_data *pdata = dev_get_platdata(&pdev->dev); 188 189 if (pdata->enable_external_pullup) 190 pdata->enable_external_pullup(0); 191 192 if (gpio_is_valid(pdata->ext_pullup_enable_pin)) 193 gpio_set_value(pdata->ext_pullup_enable_pin, 0); 194 195 w1_remove_master_device(master); 196 197 return 0; 198 } 199 200 static int __maybe_unused w1_gpio_suspend(struct device *dev) 201 { 202 struct w1_gpio_platform_data *pdata = dev_get_platdata(dev); 203 204 if (pdata->enable_external_pullup) 205 pdata->enable_external_pullup(0); 206 207 return 0; 208 } 209 210 static int __maybe_unused w1_gpio_resume(struct device *dev) 211 { 212 struct w1_gpio_platform_data *pdata = dev_get_platdata(dev); 213 214 if (pdata->enable_external_pullup) 215 pdata->enable_external_pullup(1); 216 217 return 0; 218 } 219 220 static SIMPLE_DEV_PM_OPS(w1_gpio_pm_ops, w1_gpio_suspend, w1_gpio_resume); 221 222 static struct platform_driver w1_gpio_driver = { 223 .driver = { 224 .name = "w1-gpio", 225 .pm = &w1_gpio_pm_ops, 226 .of_match_table = of_match_ptr(w1_gpio_dt_ids), 227 }, 228 .probe = w1_gpio_probe, 229 .remove = w1_gpio_remove, 230 }; 231 232 module_platform_driver(w1_gpio_driver); 233 234 MODULE_DESCRIPTION("GPIO w1 bus master driver"); 235 MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>"); 236 MODULE_LICENSE("GPL"); 237