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

   1 /*
   2  *  Custom GPIO-based PWM driver
   3  *
   4  *  Based on w1-gpio-custom by Copyright (C) 2007 Gabor Juhos <juhosg at openwrt.org>
   5  *  Copyright (C) 2010 Claudio Mignanti <c.mignanti@gmail.com >
   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
  19  *      bus1
  20  *      .....
  21  *      bus10   <id>,<pin>,<od>
  22  *
  23  *  where:
  24  *
  25  *  <id>        ID to used as device_id for the corresponding bus (required)
  26  *  <pin>       GPIO pin ID for PWM channel (required)
  27  * *
  28  *  If this driver is built into the kernel, you can use the following kernel
  29  *  command line parameters, with the same values as the corresponding module
  30  *  parameters listed above:
  31  *
  32  *      pwm-gpio-custom.bus0
  33  *      pwm-gpio-custom.bus1
  34  *      pwm-gpio-custom.bunN
  35  *      pwm-gpio-custom.bus10
  36  */
  37
  38 #include <linux/kernel.h>
  39 #include <linux/module.h>
  40 #include <linux/init.h>
  41 #include <linux/platform_device.h>
  42
  43 #include <linux/pwm/pwm.h>
  44
  45 #define DRV_NAME        "pwm-gpio-custom"
  46 #define DRV_DESC        "Custom GPIO-based pwm driver"
  47 #define DRV_VERSION     "0.1.0"
  48
  49 #define PFX             DRV_NAME ": "
  50
  51 #define BUS_PARAM_ID            0
  52 #define BUS_PARAM_PIN           1
  53
  54 #define BUS_PARAM_REQUIRED      2
  55 #define BUS_PARAM_COUNT         2
  56 #define BUS_COUNT_MAX           10
  57
  58 static unsigned int bus0[BUS_PARAM_COUNT] __initdata;
  59 static unsigned int bus1[BUS_PARAM_COUNT] __initdata;
  60 static unsigned int bus2[BUS_PARAM_COUNT] __initdata;
  61 static unsigned int bus3[BUS_PARAM_COUNT] __initdata;
  62 static unsigned int bus4[BUS_PARAM_COUNT] __initdata;
  63 static unsigned int bus5[BUS_PARAM_COUNT] __initdata;
  64 static unsigned int bus6[BUS_PARAM_COUNT] __initdata;
  65 static unsigned int bus7[BUS_PARAM_COUNT] __initdata;
  66 static unsigned int bus8[BUS_PARAM_COUNT] __initdata;
  67 static unsigned int bus9[BUS_PARAM_COUNT] __initdata;
  68
  69 static unsigned int bus_nump[BUS_COUNT_MAX] __initdata;
  70
  71 #define BUS_PARM_DESC " config -> id,pin"
  72
  73 module_param_array(bus0, uint, &bus_nump[0], 0);
  74 MODULE_PARM_DESC(bus0, "bus0" BUS_PARM_DESC);
  75 module_param_array(bus1, uint, &bus_nump[1], 0);
  76 MODULE_PARM_DESC(bus1, "bus1" BUS_PARM_DESC);
  77 module_param_array(bus2, uint, &bus_nump[2], 0);
  78 MODULE_PARM_DESC(bus2, "bus2" BUS_PARM_DESC);
  79 module_param_array(bus3, uint, &bus_nump[3], 0);
  80 MODULE_PARM_DESC(bus3, "bus3" BUS_PARM_DESC);
  81 module_param_array(bus4, uint, &bus_nump[4], 0);
  82 MODULE_PARM_DESC(bus4, "bus4" BUS_PARM_DESC);
  83 module_param_array(bus5, uint, &bus_nump[5], 0);
  84 MODULE_PARM_DESC(bus5, "bus5" BUS_PARM_DESC);
  85 module_param_array(bus6, uint, &bus_nump[6], 0);
  86 MODULE_PARM_DESC(bus6, "bus6" BUS_PARM_DESC);
  87 module_param_array(bus7, uint, &bus_nump[7], 0);
  88 MODULE_PARM_DESC(bus7, "bus7" BUS_PARM_DESC);
  89 module_param_array(bus8, uint, &bus_nump[8], 0);
  90 MODULE_PARM_DESC(bus8, "bus8" BUS_PARM_DESC);
  91 module_param_array(bus9, uint, &bus_nump[9], 0);
  92 MODULE_PARM_DESC(bus9, "bus9" BUS_PARM_DESC);
  93
  94 static struct platform_device *devices[BUS_COUNT_MAX];
  95 static unsigned int nr_devices;
  96
  97 static void pwm_gpio_custom_cleanup(void)
  98 {
  99         int i;
 100
 101         for (i = 0; i < nr_devices; i++)
 102                 if (devices[i])
 103                         platform_device_put(devices[i]);
 104 }
 105
 106 static int __init pwm_gpio_custom_add_one(unsigned int id, unsigned int *params)
 107 {
 108         struct platform_device *pdev;
 109         struct gpio_pwm_platform_data pdata;
 110         int err;
 111
 112         if (!bus_nump[id])
 113                 return 0;
 114
 115         if (bus_nump[id] < BUS_PARAM_REQUIRED) {
 116                 printk(KERN_ERR PFX "not enough parameters for bus%d\n", id);
 117                 err = -EINVAL;
 118                 goto err;
 119         }
 120
 121         pdev = platform_device_alloc("gpio_pwm", params[BUS_PARAM_ID]);
 122         if (!pdev) {
 123                 err = -ENOMEM;
 124                 goto err;
 125         }
 126
 127         pdata.gpio = params[BUS_PARAM_PIN];
 128
 129         err = platform_device_add_data(pdev, &pdata, sizeof(pdata));
 130         if (err)
 131                 goto err_put;
 132
 133         err = platform_device_add(pdev);
 134         if (err)
 135                 goto err_put;
 136
 137         devices[nr_devices++] = pdev;
 138         return 0;
 139
 140  err_put:
 141         platform_device_put(pdev);
 142  err:
 143         return err;
 144 }
 145
 146 static int __init pwm_gpio_custom_probe(void)
 147 {
 148         int err;
 149
 150         nr_devices = 0;
 151         printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
 152
 153         err = pwm_gpio_custom_add_one(0, bus0);
 154         if (err) goto err;
 155
 156         err = pwm_gpio_custom_add_one(1, bus1);
 157         if (err) goto err;
 158
 159         err = pwm_gpio_custom_add_one(2, bus2);
 160         if (err) goto err;
 161
 162         err = pwm_gpio_custom_add_one(3, bus3);
 163         if (err) goto err;
 164
 165         err = pwm_gpio_custom_add_one(4, bus4);
 166         if (err) goto err;
 167
 168         err = pwm_gpio_custom_add_one(5, bus5);
 169         if (err) goto err;
 170
 171         err = pwm_gpio_custom_add_one(6, bus6);
 172         if (err) goto err;
 173
 174         err = pwm_gpio_custom_add_one(7, bus7);
 175         if (err) goto err;
 176
 177         err = pwm_gpio_custom_add_one(8, bus8);
 178         if (err) goto err;
 179
 180         err = pwm_gpio_custom_add_one(9, bus9);
 181         if (err) goto err;
 182
 183         if (!nr_devices) {
 184                 printk(KERN_ERR PFX "no bus parameter(s) specified\n");
 185                 err = -ENODEV;
 186                 goto err;
 187         }
 188
 189         return 0;
 190
 191 err:
 192         pwm_gpio_custom_cleanup();
 193         return err;
 194 }
 195
 196 #ifdef MODULE
 197 static int __init pwm_gpio_custom_init(void)
 198 {
 199         return pwm_gpio_custom_probe();
 200 }
 201 module_init(pwm_gpio_custom_init);
 202
 203 static void __exit pwm_gpio_custom_exit(void)
 204 {
 205         pwm_gpio_custom_cleanup();
 206 }
 207 module_exit(pwm_gpio_custom_exit);
 208 #else
 209 subsys_initcall(pwm_gpio_custom_probe);
 210 #endif /* MODULE*/
 211
 212 MODULE_LICENSE("GPL v2");
 213 MODULE_AUTHOR("Bifferos <bifferos at yahoo.co.uk >");
 214 MODULE_AUTHOR("Claudio Mignanti <c.mignanti@gmail.com >");
 215 MODULE_DESCRIPTION(DRV_DESC);
 216 MODULE_VERSION(DRV_VERSION);
 217