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 #include <linux/workqueue.h>
  43
  44 #include <linux/pwm/pwm.h>
  45
  46 #define DRV_NAME        "pwm-gpio-custom"
  47 #define DRV_DESC        "Custom GPIO-based pwm driver"
  48 #define DRV_VERSION     "0.1.0"
  49
  50 #define PFX             DRV_NAME ": "
  51
  52 #define BUS_PARAM_ID            0
  53 #define BUS_PARAM_PIN           1
  54
  55 #define BUS_PARAM_REQUIRED      2
  56 #define BUS_PARAM_COUNT         2
  57 #define BUS_COUNT_MAX           10
  58
  59 static unsigned int bus0[BUS_PARAM_COUNT] __initdata;
  60 static unsigned int bus1[BUS_PARAM_COUNT] __initdata;
  61 static unsigned int bus2[BUS_PARAM_COUNT] __initdata;
  62 static unsigned int bus3[BUS_PARAM_COUNT] __initdata;
  63 static unsigned int bus4[BUS_PARAM_COUNT] __initdata;
  64 static unsigned int bus5[BUS_PARAM_COUNT] __initdata;
  65 static unsigned int bus6[BUS_PARAM_COUNT] __initdata;
  66 static unsigned int bus7[BUS_PARAM_COUNT] __initdata;
  67 static unsigned int bus8[BUS_PARAM_COUNT] __initdata;
  68 static unsigned int bus9[BUS_PARAM_COUNT] __initdata;
  69
  70 static unsigned int bus_nump[BUS_COUNT_MAX] __initdata;
  71
  72 #define BUS_PARM_DESC " config -> id,pin"
  73
  74 module_param_array(bus0, uint, &bus_nump[0], 0);
  75 MODULE_PARM_DESC(bus0, "bus0" BUS_PARM_DESC);
  76 module_param_array(bus1, uint, &bus_nump[1], 0);
  77 MODULE_PARM_DESC(bus1, "bus1" BUS_PARM_DESC);
  78 module_param_array(bus2, uint, &bus_nump[2], 0);
  79 MODULE_PARM_DESC(bus2, "bus2" BUS_PARM_DESC);
  80 module_param_array(bus3, uint, &bus_nump[3], 0);
  81 MODULE_PARM_DESC(bus3, "bus3" BUS_PARM_DESC);
  82 module_param_array(bus4, uint, &bus_nump[4], 0);
  83 MODULE_PARM_DESC(bus4, "bus4" BUS_PARM_DESC);
  84 module_param_array(bus5, uint, &bus_nump[5], 0);
  85 MODULE_PARM_DESC(bus5, "bus5" BUS_PARM_DESC);
  86 module_param_array(bus6, uint, &bus_nump[6], 0);
  87 MODULE_PARM_DESC(bus6, "bus6" BUS_PARM_DESC);
  88 module_param_array(bus7, uint, &bus_nump[7], 0);
  89 MODULE_PARM_DESC(bus7, "bus7" BUS_PARM_DESC);
  90 module_param_array(bus8, uint, &bus_nump[8], 0);
  91 MODULE_PARM_DESC(bus8, "bus8" BUS_PARM_DESC);
  92 module_param_array(bus9, uint, &bus_nump[9], 0);
  93 MODULE_PARM_DESC(bus9, "bus9" BUS_PARM_DESC);
  94
  95 static struct platform_device *devices[BUS_COUNT_MAX];
  96 static unsigned int nr_devices;
  97
  98 static void pwm_gpio_custom_cleanup(void)
  99 {
 100         int i;
 101
 102         for (i = 0; i < nr_devices; i++)
 103                 if (devices[i])
 104                         platform_device_put(devices[i]);
 105 }
 106
 107 static int __init pwm_gpio_custom_add_one(unsigned int id, unsigned int *params)
 108 {
 109         struct platform_device *pdev;
 110         struct gpio_pwm_platform_data pdata;
 111         int err;
 112
 113         if (!bus_nump[id])
 114                 return 0;
 115
 116         if (bus_nump[id] < BUS_PARAM_REQUIRED) {
 117                 printk(KERN_ERR PFX "not enough parameters for bus%d\n", id);
 118                 err = -EINVAL;
 119                 goto err;
 120         }
 121
 122         pdev = platform_device_alloc("gpio_pwm", params[BUS_PARAM_ID]);
 123         if (!pdev) {
 124                 err = -ENOMEM;
 125                 goto err;
 126         }
 127
 128         pdata.gpio = params[BUS_PARAM_PIN];
 129
 130         err = platform_device_add_data(pdev, &pdata, sizeof(pdata));
 131         if (err)
 132                 goto err_put;
 133
 134         err = platform_device_add(pdev);
 135         if (err)
 136                 goto err_put;
 137
 138         devices[nr_devices++] = pdev;
 139         return 0;
 140
 141  err_put:
 142         platform_device_put(pdev);
 143  err:
 144         return err;
 145 }
 146
 147 static int __init pwm_gpio_custom_probe(void)
 148 {
 149         int err;
 150
 151         nr_devices = 0;
 152         printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
 153
 154         err = pwm_gpio_custom_add_one(0, bus0);
 155         if (err) goto err;
 156
 157         err = pwm_gpio_custom_add_one(1, bus1);
 158         if (err) goto err;
 159
 160         err = pwm_gpio_custom_add_one(2, bus2);
 161         if (err) goto err;
 162
 163         err = pwm_gpio_custom_add_one(3, bus3);
 164         if (err) goto err;
 165
 166         err = pwm_gpio_custom_add_one(4, bus4);
 167         if (err) goto err;
 168
 169         err = pwm_gpio_custom_add_one(5, bus5);
 170         if (err) goto err;
 171
 172         err = pwm_gpio_custom_add_one(6, bus6);
 173         if (err) goto err;
 174
 175         err = pwm_gpio_custom_add_one(7, bus7);
 176         if (err) goto err;
 177
 178         err = pwm_gpio_custom_add_one(8, bus8);
 179         if (err) goto err;
 180
 181         err = pwm_gpio_custom_add_one(9, bus9);
 182         if (err) goto err;
 183
 184         if (!nr_devices) {
 185                 printk(KERN_ERR PFX "no bus parameter(s) specified\n");
 186                 err = -ENODEV;
 187                 goto err;
 188         }
 189
 190         return 0;
 191
 192 err:
 193         pwm_gpio_custom_cleanup();
 194         return err;
 195 }
 196
 197 #ifdef MODULE
 198 static int __init pwm_gpio_custom_init(void)
 199 {
 200         return pwm_gpio_custom_probe();
 201 }
 202 module_init(pwm_gpio_custom_init);
 203
 204 static void __exit pwm_gpio_custom_exit(void)
 205 {
 206         pwm_gpio_custom_cleanup();
 207 }
 208 module_exit(pwm_gpio_custom_exit);
 209 #else
 210 subsys_initcall(pwm_gpio_custom_probe);
 211 #endif /* MODULE*/
 212
 213 MODULE_LICENSE("GPL v2");
 214 MODULE_AUTHOR("Bifferos <bifferos at yahoo.co.uk >");
 215 MODULE_AUTHOR("Claudio Mignanti <c.mignanti@gmail.com >");
 216 MODULE_DESCRIPTION(DRV_DESC);
 217 MODULE_VERSION(DRV_VERSION);
 218