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/slab.h> 18#include <linux/gpio.h> 19#include <linux/gpio_event.h> 20#include <linux/interrupt.h> 21 22struct gpio_axis_state { 23 struct input_dev *input_dev; 24 struct gpio_event_axis_info *info; 25 uint32_t pos; 26}; 27 28uint16_t gpio_axis_4bit_gray_map_table[] = { 29 [0x0] = 0x0, [0x1] = 0x1, /* 0000 0001 */ 30 [0x3] = 0x2, [0x2] = 0x3, /* 0011 0010 */ 31 [0x6] = 0x4, [0x7] = 0x5, /* 0110 0111 */ 32 [0x5] = 0x6, [0x4] = 0x7, /* 0101 0100 */ 33 [0xc] = 0x8, [0xd] = 0x9, /* 1100 1101 */ 34 [0xf] = 0xa, [0xe] = 0xb, /* 1111 1110 */ 35 [0xa] = 0xc, [0xb] = 0xd, /* 1010 1011 */ 36 [0x9] = 0xe, [0x8] = 0xf, /* 1001 1000 */ 37}; 38uint16_t gpio_axis_4bit_gray_map(struct gpio_event_axis_info *info, uint16_t in) 39{ 40 return gpio_axis_4bit_gray_map_table[in]; 41} 42 43uint16_t gpio_axis_5bit_singletrack_map_table[] = { 44 [0x10] = 0x00, [0x14] = 0x01, [0x1c] = 0x02, /* 10000 10100 11100 */ 45 [0x1e] = 0x03, [0x1a] = 0x04, [0x18] = 0x05, /* 11110 11010 11000 */ 46 [0x08] = 0x06, [0x0a] = 0x07, [0x0e] = 0x08, /* 01000 01010 01110 */ 47 [0x0f] = 0x09, [0x0d] = 0x0a, [0x0c] = 0x0b, /* 01111 01101 01100 */ 48 [0x04] = 0x0c, [0x05] = 0x0d, [0x07] = 0x0e, /* 00100 00101 00111 */ 49 [0x17] = 0x0f, [0x16] = 0x10, [0x06] = 0x11, /* 10111 10110 00110 */ 50 [0x02] = 0x12, [0x12] = 0x13, [0x13] = 0x14, /* 00010 10010 10011 */ 51 [0x1b] = 0x15, [0x0b] = 0x16, [0x03] = 0x17, /* 11011 01011 00011 */ 52 [0x01] = 0x18, [0x09] = 0x19, [0x19] = 0x1a, /* 00001 01001 11001 */ 53 [0x1d] = 0x1b, [0x15] = 0x1c, [0x11] = 0x1d, /* 11101 10101 10001 */ 54}; 55uint16_t gpio_axis_5bit_singletrack_map( 56 struct gpio_event_axis_info *info, uint16_t in) 57{ 58 return gpio_axis_5bit_singletrack_map_table[in]; 59} 60 61static void gpio_event_update_axis(struct gpio_axis_state *as, int report) 62{ 63 struct gpio_event_axis_info *ai = as->info; 64 int i; 65 int change; 66 uint16_t state = 0; 67 uint16_t pos; 68 uint16_t old_pos = as->pos; 69 for (i = ai->count - 1; i >= 0; i--) 70 state = (state << 1) | gpio_get_value(ai->gpio[i]); 71 pos = ai->map(ai, state); 72 if (ai->flags & GPIOEAF_PRINT_RAW) 73 pr_info("axis %d-%d raw %x, pos %d -> %d\n", 74 ai->type, ai->code, state, old_pos, pos); 75 if (report && pos != old_pos) { 76 if (ai->type == EV_REL) { 77 change = (ai->decoded_size + pos - old_pos) % 78 ai->decoded_size; 79 if (change > ai->decoded_size / 2) 80 change -= ai->decoded_size; 81 if (change == ai->decoded_size / 2) { 82 if (ai->flags & GPIOEAF_PRINT_EVENT) 83 pr_info("axis %d-%d unknown direction, " 84 "pos %d -> %d\n", ai->type, 85 ai->code, old_pos, pos); 86 change = 0; /* no closest direction */ 87 } 88 if (ai->flags & GPIOEAF_PRINT_EVENT) 89 pr_info("axis %d-%d change %d\n", 90 ai->type, ai->code, change); 91 input_report_rel(as->input_dev, ai->code, change); 92 } else { 93 if (ai->flags & GPIOEAF_PRINT_EVENT) 94 pr_info("axis %d-%d now %d\n", 95 ai->type, ai->code, pos); 96 input_event(as->input_dev, ai->type, ai->code, pos); 97 } 98 input_sync(as->input_dev); 99 } 100 as->pos = pos; 101} 102 103static irqreturn_t gpio_axis_irq_handler(int irq, void *dev_id) 104{ 105 struct gpio_axis_state *as = dev_id; 106 gpio_event_update_axis(as, 1); 107 return IRQ_HANDLED; 108} 109 110int gpio_event_axis_func(struct input_dev *input_dev, 111 struct gpio_event_info *info, void **data, int func) 112{ 113 int ret; 114 int i; 115 int irq; 116 struct gpio_event_axis_info *ai; 117 struct gpio_axis_state *as; 118 119 ai = container_of(info, struct gpio_event_axis_info, info); 120 if (func == GPIO_EVENT_FUNC_SUSPEND) { 121 for (i = 0; i < ai->count; i++) 122 disable_irq(gpio_to_irq(ai->gpio[i])); 123 return 0; 124 } 125 if (func == GPIO_EVENT_FUNC_RESUME) { 126 for (i = 0; i < ai->count; i++) 127 enable_irq(gpio_to_irq(ai->gpio[i])); 128 return 0; 129 } 130 131 if (func == GPIO_EVENT_FUNC_INIT) { 132 *data = as = kmalloc(sizeof(*as), GFP_KERNEL); 133 if (as == NULL) { 134 ret = -ENOMEM; 135 goto err_alloc_axis_state_failed; 136 } 137 as->input_dev = input_dev; 138 as->info = ai; 139 140 input_set_capability(input_dev, ai->type, ai->code); 141 if (ai->type == EV_ABS) { 142 input_set_abs_params(input_dev, ai->code, 0, 143 ai->decoded_size - 1, 0, 0); 144 } 145 for (i = 0; i < ai->count; i++) { 146 ret = gpio_request(ai->gpio[i], "gpio_event_axis"); 147 if (ret < 0) 148 goto err_request_gpio_failed; 149 ret = gpio_direction_input(ai->gpio[i]); 150 if (ret < 0) 151 goto err_gpio_direction_input_failed; 152 ret = irq = gpio_to_irq(ai->gpio[i]); 153 if (ret < 0) 154 goto err_get_irq_num_failed; 155 ret = request_irq(irq, gpio_axis_irq_handler, 156 IRQF_TRIGGER_RISING | 157 IRQF_TRIGGER_FALLING, 158 "gpio_event_axis", as); 159 if (ret < 0) 160 goto err_request_irq_failed; 161 } 162 gpio_event_update_axis(as, 0); 163 return 0; 164 } 165 166 ret = 0; 167 as = *data; 168 for (i = ai->count - 1; i >= 0; i--) { 169 free_irq(gpio_to_irq(ai->gpio[i]), as); 170err_request_irq_failed: 171err_get_irq_num_failed: 172err_gpio_direction_input_failed: 173 gpio_free(ai->gpio[i]); 174err_request_gpio_failed: 175 ; 176 } 177 kfree(as); 178 *data = NULL; 179err_alloc_axis_state_failed: 180 return ret; 181} 182