package/w1-gpio-custom/src/w1-gpio-custom.c

   1 /*
   2  *  Custom GPIO-based W1 driver
   3  *
   4  *  Copyright (C) 2007 Gabor Juhos <juhosg at openwrt.org>
   5  *  Copyright (C) 2008 Bifferos <bifferos at yahoo.co.uk>
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  10  *
  11  * ---------------------------------------------------------------------------
  12  *
  13  *  The behaviour of this driver can be altered by setting some parameters
  14  *  from the insmod command line.
  15  *
  16  *  The following parameters are adjustable:
  17  *
  18  *      bus0    These four arguments must be arrays of
  19  *      bus1    3 unsigned integers as follows:
  20  *      bus2
  21  *      bus3    <id>,<pin>,<od>
  22  *
  23  *  where:
  24  *
  25  *  <id>        ID to used as device_id for the corresponding bus (required)
  26  *  <sda>       GPIO pin ID of data pin (required)
  27  *  <od>        Pin is configured as open drain.
  28  *
  29  *  See include/w1-gpio.h for more information about the parameters.
  30  *
  31  *  If this driver is built into the kernel, you can use the following kernel
  32  *  command line parameters, with the same values as the corresponding module
  33  *  parameters listed above:
  34  *
  35  *      w1-gpio-custom.bus0
  36  *      w1-gpio-custom.bus1
  37  *      w1-gpio-custom.bus2
  38  *      w1-gpio-custom.bus3
  39  */
  40
  41 #include <linux/kernel.h>
  42 #include <linux/module.h>
  43 #include <linux/init.h>
  44 #include <linux/platform_device.h>
  45
  46 #include <linux/w1-gpio.h>
  47
  48 #define DRV_NAME        "w1-gpio-custom"
  49 #define DRV_DESC        "Custom GPIO-based W1 driver"
  50 #define DRV_VERSION     "0.1.0"
  51
  52 #define PFX             DRV_NAME ": "
  53
  54 #define BUS_PARAM_ID            0
  55 #define BUS_PARAM_PIN           1
  56 #define BUS_PARAM_OD            2
  57
  58 #define BUS_PARAM_REQUIRED      3
  59 #define BUS_PARAM_COUNT         3
  60 #define BUS_COUNT_MAX           4
  61
  62 static unsigned int bus0[BUS_PARAM_COUNT] __initdata;
  63 static unsigned int bus1[BUS_PARAM_COUNT] __initdata;
  64 static unsigned int bus2[BUS_PARAM_COUNT] __initdata;
  65 static unsigned int bus3[BUS_PARAM_COUNT] __initdata;
  66
  67 static unsigned int bus_nump[BUS_COUNT_MAX] __initdata;
  68
  69 #define BUS_PARM_DESC " config -> id,pin,od"
  70
  71 module_param_array(bus0, uint, &bus_nump[0], 0);
  72 MODULE_PARM_DESC(bus0, "bus0" BUS_PARM_DESC);
  73 module_param_array(bus1, uint, &bus_nump[1], 0);
  74 MODULE_PARM_DESC(bus1, "bus1" BUS_PARM_DESC);
  75 module_param_array(bus2, uint, &bus_nump[2], 0);
  76 MODULE_PARM_DESC(bus2, "bus2" BUS_PARM_DESC);
  77 module_param_array(bus3, uint, &bus_nump[3], 0);
  78 MODULE_PARM_DESC(bus3, "bus3" BUS_PARM_DESC);
  79
  80 static struct platform_device *devices[BUS_COUNT_MAX];
  81 static unsigned int nr_devices;
  82
  83 static void w1_gpio_custom_cleanup(void)
  84 {
  85         int i;
  86
  87         for (i = 0; i < nr_devices; i++)
  88                 if (devices[i])
  89                         platform_device_unregister(devices[i]);
  90 }
  91
  92 static int __init w1_gpio_custom_add_one(unsigned int id, unsigned int *params)
  93 {
  94         struct platform_device *pdev;
  95         struct w1_gpio_platform_data pdata;
  96         int err;
  97
  98         if (!bus_nump[id])
  99                 return 0;
 100
 101         if (bus_nump[id] < BUS_PARAM_REQUIRED) {
 102                 printk(KERN_ERR PFX "not enough parameters for bus%d\n", id);
 103                 err = -EINVAL;
 104                 goto err;
 105         }
 106
 107         pdev = platform_device_alloc("w1-gpio", params[BUS_PARAM_ID]);
 108         if (!pdev) {
 109                 err = -ENOMEM;
 110                 goto err;
 111         }
 112
 113         devices[nr_devices++] = pdev;
 114
 115         pdata.pin = params[BUS_PARAM_PIN];
 116         pdata.is_open_drain = params[BUS_PARAM_OD] ? 1:0;
 117
 118         err = platform_device_add_data(pdev, &pdata, sizeof(pdata));
 119         if (err)
 120                 goto err;
 121
 122         err = platform_device_register(pdev);
 123         if (err)
 124                 goto err;
 125
 126         return 0;
 127
 128 err:
 129         return err;
 130 }
 131
 132 static int __init w1_gpio_custom_probe(void)
 133 {
 134         int err;
 135
 136         nr_devices = 0;
 137         printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
 138
 139         err = w1_gpio_custom_add_one(0, bus0);
 140         if (err) goto err;
 141
 142         err = w1_gpio_custom_add_one(1, bus1);
 143         if (err) goto err;
 144
 145         err = w1_gpio_custom_add_one(2, bus2);
 146         if (err) goto err;
 147
 148         err = w1_gpio_custom_add_one(3, bus3);
 149         if (err) goto err;
 150
 151         if (!nr_devices) {
 152                 printk(KERN_ERR PFX "no bus parameter(s) specified\n");
 153                 err = -ENODEV;
 154                 goto err;
 155         }
 156
 157         return 0;
 158
 159 err:
 160         w1_gpio_custom_cleanup();
 161         return err;
 162 }
 163
 164 #ifdef MODULE
 165 static int __init w1_gpio_custom_init(void)
 166 {
 167         return w1_gpio_custom_probe();
 168 }
 169 module_init(w1_gpio_custom_init);
 170
 171 static void __exit w1_gpio_custom_exit(void)
 172 {
 173         w1_gpio_custom_cleanup();
 174 }
 175 module_exit(w1_gpio_custom_exit);
 176 #else
 177 subsys_initcall(w1_gpio_custom_probe);
 178 #endif /* MODULE*/
 179
 180 MODULE_LICENSE("GPL v2");
 181 MODULE_AUTHOR("Bifferos <bifferos at yahoo.co.uk >");
 182 MODULE_DESCRIPTION(DRV_DESC);
 183 MODULE_VERSION(DRV_VERSION);