drivers/staging/dream/gpio_axis.c

   1 /* drivers/input/misc/gpio_axis.c
   2  *
   3  * Copyright (C) 2007 Google, Inc.
   4  *
   5  * This software is licensed under the terms of the GNU General Public
   6  * License version 2, as published by the Free Software Foundation, and
   7  * may be copied, distributed, and modified under those terms.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/gpio.h>
  18 #include <linux/gpio_event.h>
  19 #include <linux/interrupt.h>
  20
  21 struct gpio_axis_state {
  22         struct input_dev *input_dev;
  23         struct gpio_event_axis_info *info;
  24         uint32_t pos;
  25 };
  26
  27 uint16_t gpio_axis_4bit_gray_map_table[] = {
  28         [0x0] = 0x0, [0x1] = 0x1, /* 0000 0001 */
  29         [0x3] = 0x2, [0x2] = 0x3, /* 0011 0010 */
  30         [0x6] = 0x4, [0x7] = 0x5, /* 0110 0111 */
  31         [0x5] = 0x6, [0x4] = 0x7, /* 0101 0100 */
  32         [0xc] = 0x8, [0xd] = 0x9, /* 1100 1101 */
  33         [0xf] = 0xa, [0xe] = 0xb, /* 1111 1110 */
  34         [0xa] = 0xc, [0xb] = 0xd, /* 1010 1011 */
  35         [0x9] = 0xe, [0x8] = 0xf, /* 1001 1000 */
  36 };
  37 uint16_t gpio_axis_4bit_gray_map(struct gpio_event_axis_info *info, uint16_t in)
  38 {
  39         return gpio_axis_4bit_gray_map_table[in];
  40 }
  41
  42 uint16_t gpio_axis_5bit_singletrack_map_table[] = {
  43         [0x10] = 0x00, [0x14] = 0x01, [0x1c] = 0x02, /*     10000 10100 11100 */
  44         [0x1e] = 0x03, [0x1a] = 0x04, [0x18] = 0x05, /*     11110 11010 11000 */
  45         [0x08] = 0x06, [0x0a] = 0x07, [0x0e] = 0x08, /*    01000 01010 01110  */
  46         [0x0f] = 0x09, [0x0d] = 0x0a, [0x0c] = 0x0b, /*    01111 01101 01100  */
  47         [0x04] = 0x0c, [0x05] = 0x0d, [0x07] = 0x0e, /*   00100 00101 00111   */
  48         [0x17] = 0x0f, [0x16] = 0x10, [0x06] = 0x11, /*   10111 10110 00110   */
  49         [0x02] = 0x12, [0x12] = 0x13, [0x13] = 0x14, /*  00010 10010 10011    */
  50         [0x1b] = 0x15, [0x0b] = 0x16, [0x03] = 0x17, /*  11011 01011 00011    */
  51         [0x01] = 0x18, [0x09] = 0x19, [0x19] = 0x1a, /* 00001 01001 11001     */
  52         [0x1d] = 0x1b, [0x15] = 0x1c, [0x11] = 0x1d, /* 11101 10101 10001     */
  53 };
  54 uint16_t gpio_axis_5bit_singletrack_map(
  55         struct gpio_event_axis_info *info, uint16_t in)
  56 {
  57         return gpio_axis_5bit_singletrack_map_table[in];
  58 }
  59
  60 static void gpio_event_update_axis(struct gpio_axis_state *as, int report)
  61 {
  62         struct gpio_event_axis_info *ai = as->info;
  63         int i;
  64         int change;
  65         uint16_t state = 0;
  66         uint16_t pos;
  67         uint16_t old_pos = as->pos;
  68         for (i = ai->count - 1; i >= 0; i--)
  69                 state = (state << 1) | gpio_get_value(ai->gpio[i]);
  70         pos = ai->map(ai, state);
  71         if (ai->flags & GPIOEAF_PRINT_RAW)
  72                 pr_info("axis %d-%d raw %x, pos %d -> %d\n",
  73                         ai->type, ai->code, state, old_pos, pos);
  74         if (report && pos != old_pos) {
  75                 if (ai->type == EV_REL) {
  76                         change = (ai->decoded_size + pos - old_pos) %
  77                                   ai->decoded_size;
  78                         if (change > ai->decoded_size / 2)
  79                                 change -= ai->decoded_size;
  80                         if (change == ai->decoded_size / 2) {
  81                                 if (ai->flags & GPIOEAF_PRINT_EVENT)
  82                                         pr_info("axis %d-%d unknown direction, "
  83                                                 "pos %d -> %d\n", ai->type,
  84                                                 ai->code, old_pos, pos);
  85                                 change = 0; /* no closest direction */
  86                         }
  87                         if (ai->flags & GPIOEAF_PRINT_EVENT)
  88                                 pr_info("axis %d-%d change %d\n",
  89                                         ai->type, ai->code, change);
  90                         input_report_rel(as->input_dev, ai->code, change);
  91                 } else {
  92                         if (ai->flags & GPIOEAF_PRINT_EVENT)
  93                                 pr_info("axis %d-%d now %d\n",
  94                                         ai->type, ai->code, pos);
  95                         input_event(as->input_dev, ai->type, ai->code, pos);
  96                 }
  97                 input_sync(as->input_dev);
  98         }
  99         as->pos = pos;
 100 }
 101
 102 static irqreturn_t gpio_axis_irq_handler(int irq, void *dev_id)
 103 {
 104         struct gpio_axis_state *as = dev_id;
 105         gpio_event_update_axis(as, 1);
 106         return IRQ_HANDLED;
 107 }
 108
 109 int gpio_event_axis_func(struct input_dev *input_dev,
 110                          struct gpio_event_info *info, void **data, int func)
 111 {
 112         int ret;
 113         int i;
 114         int irq;
 115         struct gpio_event_axis_info *ai;
 116         struct gpio_axis_state *as;
 117
 118         ai = container_of(info, struct gpio_event_axis_info, info);
 119         if (func == GPIO_EVENT_FUNC_SUSPEND) {
 120                 for (i = 0; i < ai->count; i++)
 121                         disable_irq(gpio_to_irq(ai->gpio[i]));
 122                 return 0;
 123         }
 124         if (func == GPIO_EVENT_FUNC_RESUME) {
 125                 for (i = 0; i < ai->count; i++)
 126                         enable_irq(gpio_to_irq(ai->gpio[i]));
 127                 return 0;
 128         }
 129
 130         if (func == GPIO_EVENT_FUNC_INIT) {
 131                 *data = as = kmalloc(sizeof(*as), GFP_KERNEL);
 132                 if (as == NULL) {
 133                         ret = -ENOMEM;
 134                         goto err_alloc_axis_state_failed;
 135                 }
 136                 as->input_dev = input_dev;
 137                 as->info = ai;
 138
 139                 input_set_capability(input_dev, ai->type, ai->code);
 140                 if (ai->type == EV_ABS) {
 141                         input_set_abs_params(input_dev, ai->code, 0,
 142                                              ai->decoded_size - 1, 0, 0);
 143                 }
 144                 for (i = 0; i < ai->count; i++) {
 145                         ret = gpio_request(ai->gpio[i], "gpio_event_axis");
 146                         if (ret < 0)
 147                                 goto err_request_gpio_failed;
 148                         ret = gpio_direction_input(ai->gpio[i]);
 149                         if (ret < 0)
 150                                 goto err_gpio_direction_input_failed;
 151                         ret = irq = gpio_to_irq(ai->gpio[i]);
 152                         if (ret < 0)
 153                                 goto err_get_irq_num_failed;
 154                         ret = request_irq(irq, gpio_axis_irq_handler,
 155                                           IRQF_TRIGGER_RISING |
 156                                           IRQF_TRIGGER_FALLING,
 157                                           "gpio_event_axis", as);
 158                         if (ret < 0)
 159                                 goto err_request_irq_failed;
 160                 }
 161                 gpio_event_update_axis(as, 0);
 162                 return 0;
 163         }
 164
 165         ret = 0;
 166         as = *data;
 167         for (i = ai->count - 1; i >= 0; i--) {
 168                 free_irq(gpio_to_irq(ai->gpio[i]), as);
 169 err_request_irq_failed:
 170 err_get_irq_num_failed:
 171 err_gpio_direction_input_failed:
 172                 gpio_free(ai->gpio[i]);
 173 err_request_gpio_failed:
 174                 ;
 175         }
 176         kfree(as);
 177         *data = NULL;
 178 err_alloc_axis_state_failed:
 179         return ret;
 180 }