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/w1-gpio.h> 15 16 #include "../w1.h" 17 #include "../w1_int.h" 18 19 #include <asm/gpio.h> 20 21 static void w1_gpio_write_bit_dir(void *data, u8 bit) 22 { 23 struct w1_gpio_platform_data *pdata = data; 24 25 if (bit) 26 gpio_direction_input(pdata->pin); 27 else 28 gpio_direction_output(pdata->pin, 0); 29 } 30 31 static void w1_gpio_write_bit_val(void *data, u8 bit) 32 { 33 struct w1_gpio_platform_data *pdata = data; 34 35 gpio_set_value(pdata->pin, bit); 36 } 37 38 static u8 w1_gpio_read_bit(void *data) 39 { 40 struct w1_gpio_platform_data *pdata = data; 41 42 return gpio_get_value(pdata->pin); 43 } 44 45 static int __init w1_gpio_probe(struct platform_device *pdev) 46 { 47 struct w1_bus_master *master; 48 struct w1_gpio_platform_data *pdata = pdev->dev.platform_data; 49 int err; 50 51 if (!pdata) 52 return -ENXIO; 53 54 master = kzalloc(sizeof(struct w1_bus_master), GFP_KERNEL); 55 if (!master) 56 return -ENOMEM; 57 58 err = gpio_request(pdata->pin, "w1"); 59 if (err) 60 goto free_master; 61 62 master->data = pdata; 63 master->read_bit = w1_gpio_read_bit; 64 65 if (pdata->is_open_drain) { 66 gpio_direction_output(pdata->pin, 1); 67 master->write_bit = w1_gpio_write_bit_val; 68 } else { 69 gpio_direction_input(pdata->pin); 70 master->write_bit = w1_gpio_write_bit_dir; 71 } 72 73 err = w1_add_master_device(master); 74 if (err) 75 goto free_gpio; 76 77 platform_set_drvdata(pdev, master); 78 79 return 0; 80 81 free_gpio: 82 gpio_free(pdata->pin); 83 free_master: 84 kfree(master); 85 86 return err; 87 } 88 89 static int __exit w1_gpio_remove(struct platform_device *pdev) 90 { 91 struct w1_bus_master *master = platform_get_drvdata(pdev); 92 struct w1_gpio_platform_data *pdata = pdev->dev.platform_data; 93 94 w1_remove_master_device(master); 95 gpio_free(pdata->pin); 96 kfree(master); 97 98 return 0; 99 } 100 101 static struct platform_driver w1_gpio_driver = { 102 .driver = { 103 .name = "w1-gpio", 104 .owner = THIS_MODULE, 105 }, 106 .remove = __exit_p(w1_gpio_remove), 107 }; 108 109 static int __init w1_gpio_init(void) 110 { 111 return platform_driver_probe(&w1_gpio_driver, w1_gpio_probe); 112 } 113 114 static void __exit w1_gpio_exit(void) 115 { 116 platform_driver_unregister(&w1_gpio_driver); 117 } 118 119 module_init(w1_gpio_init); 120 module_exit(w1_gpio_exit); 121 122 MODULE_DESCRIPTION("GPIO w1 bus master driver"); 123 MODULE_AUTHOR("Ville Syrjala <syrjala@sci.fi>"); 124 MODULE_LICENSE("GPL"); 125