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

   1 /*
   2  *  Custom GPIO-based rotary driver
   3  *
   4  *  Copyright (C) 2010 Claudio Mignanti <c.mignanti@gmail.com>
   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 as
   8  *  published by the Free Software Foundation.
   9  *
  10  *  Strongly based on Custom GPIO-based I2C driver by:
  11  *  Copyright (C) 2007-2008 Gabor Juhos <juhosg@openwrt.org>
  12  *
  13  * ---------------------------------------------------------------------------
  14  *
  15  *  The behaviour of this driver can be altered by setting some parameters
  16  *  from the insmod command line.
  17  *
  18  *  The following parameters are adjustable:
  19  *
  20  *      bus0    These four arguments can be arrays of
  21  *      bus1    1-8 unsigned integers as follows:
  22  *      bus2
  23  *      bus3    <id>,<steps>,<axis>,<gpioa>,<gpiob>,<inverted>
  24  *
  25  *
  26  *  If this driver is built into the kernel, you can use the following kernel
  27  *  command line parameters, with the same values as the corresponding module
  28  *  parameters listed above:
  29  *
  30  *      rotary-gpio-custom.bus0
  31  *      rotary-gpio-custom.bus1
  32  *      rotary-gpio-custom.bus2
  33  *      rotary-gpio-custom.bus3
  34  */
  35
  36 #include <linux/kernel.h>
  37 #include <linux/module.h>
  38 #include <linux/init.h>
  39 #include <linux/input.h>
  40 #include <linux/platform_device.h>
  41 #include <linux/rotary_encoder.h>
  42
  43 #define DRV_NAME        "rotary-gpio-custom"
  44 #define DRV_DESC        "Custom GPIO-based rotary driver"
  45 #define DRV_VERSION     "0.1.0"
  46
  47 #define PFX             DRV_NAME ": "
  48
  49 #define BUS_PARAM_REQUIRED      5
  50 #define BUS_PARAM_COUNT         6
  51 #define BUS_COUNT_MAX           4
  52
  53 static unsigned int bus0[BUS_PARAM_COUNT] __initdata;
  54 static unsigned int bus1[BUS_PARAM_COUNT] __initdata;
  55 static unsigned int bus2[BUS_PARAM_COUNT] __initdata;
  56 static unsigned int bus3[BUS_PARAM_COUNT] __initdata;
  57
  58 static unsigned int bus_nump[BUS_COUNT_MAX] __initdata;
  59
  60 #define BUS_PARM_DESC \
  61         " config -> id,steps,axis,gpioa,gpiob[,inverted]"
  62
  63 module_param_array(bus0, uint, &bus_nump[0], 0);
  64 MODULE_PARM_DESC(bus0, "bus0" BUS_PARM_DESC);
  65 module_param_array(bus1, uint, &bus_nump[1], 0);
  66 MODULE_PARM_DESC(bus1, "bus1" BUS_PARM_DESC);
  67 module_param_array(bus2, uint, &bus_nump[2], 0);
  68 MODULE_PARM_DESC(bus2, "bus2" BUS_PARM_DESC);
  69 module_param_array(bus3, uint, &bus_nump[3], 0);
  70 MODULE_PARM_DESC(bus3, "bus3" BUS_PARM_DESC);
  71
  72 static struct platform_device *devices[BUS_COUNT_MAX];
  73 static unsigned int nr_devices;
  74
  75 static void rotary_gpio_custom_cleanup(void)
  76 {
  77         int i;
  78
  79         for (i = 0; i < nr_devices; i++)
  80                 if (devices[i])
  81                         platform_device_put(devices[i]);
  82 }
  83
  84 static int __init rotary_gpio_custom_add_one(unsigned int id, unsigned int *params)
  85 {
  86         struct platform_device *pdev;
  87         struct rotary_encoder_platform_data pdata;
  88         int err;
  89
  90         if (!bus_nump[id])
  91                 return 0;
  92
  93         if (bus_nump[id] < BUS_PARAM_REQUIRED) {
  94                 printk(KERN_ERR PFX "not enough parameters for bus%d\n", id);
  95                 err = -EINVAL;
  96                 goto err;
  97         }
  98
  99         pdev = platform_device_alloc("rotary-gpio", params[0]);
 100         if (!pdev) {
 101                 err = -ENOMEM;
 102                 goto err;
 103         }
 104
 105         pdata.steps = params[1];
 106         pdata.axis = params[2];
 107         pdata.relative_axis = false;
 108         pdata.rollover = false;
 109         pdata.gpio_a = params[3];
 110         pdata.gpio_b = params[4];
 111
 112         if (params[5] == 1) {
 113                 pdata.inverted_a = 1;
 114                 pdata.inverted_b = 1;
 115         } else {
 116                 pdata.inverted_a = 0;
 117                 pdata.inverted_b = 0;
 118         }
 119
 120         err = platform_device_add_data(pdev, &pdata, sizeof(pdata));
 121         if (err)
 122                 goto err_put;
 123
 124         err = platform_device_add(pdev);
 125         if (err)
 126                 goto err_put;
 127
 128         devices[nr_devices++] = pdev;
 129         return 0;
 130
 131 err_put:
 132         platform_device_put(pdev);
 133 err:
 134         return err;
 135 }
 136
 137 static int __init rotary_gpio_custom_probe(void)
 138 {
 139         int err;
 140
 141         printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
 142
 143         err = rotary_gpio_custom_add_one(0, bus0);
 144         if (err) goto err;
 145
 146         err = rotary_gpio_custom_add_one(1, bus1);
 147         if (err) goto err;
 148
 149         err = rotary_gpio_custom_add_one(2, bus2);
 150         if (err) goto err;
 151
 152         err = rotary_gpio_custom_add_one(3, bus3);
 153         if (err) goto err;
 154
 155         if (!nr_devices) {
 156                 printk(KERN_ERR PFX "no bus parameter(s) specified\n");
 157                 err = -ENODEV;
 158                 goto err;
 159         }
 160
 161         return 0;
 162
 163 err:
 164         rotary_gpio_custom_cleanup();
 165         return err;
 166 }
 167
 168 #ifdef MODULE
 169 static int __init rotary_gpio_custom_init(void)
 170 {
 171         return rotary_gpio_custom_probe();
 172 }
 173 module_init(rotary_gpio_custom_init);
 174
 175 static void __exit rotary_gpio_custom_exit(void)
 176 {
 177         rotary_gpio_custom_cleanup();
 178 }
 179 module_exit(rotary_gpio_custom_exit);
 180 #else
 181 subsys_initcall(rotary_gpio_custom_probe);
 182 #endif /* MODULE*/
 183
 184 MODULE_LICENSE("GPL v2");
 185 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org >");
 186 MODULE_AUTHOR("Claudio Mignanti <c.mignanti@gmail.com>");
 187 MODULE_DESCRIPTION(DRV_DESC);
 188 MODULE_VERSION(DRV_VERSION);