drivers/input/touchscreen/tps6507x-ts.c

   1 /*
   2  * Touchscreen driver for the tps6507x chip.
   3  *
   4  * Copyright (c) 2009 RidgeRun (todd.fischer@ridgerun.com)
   5  *
   6  * Credits:
   7  *
   8  *    Using code from tsc2007, MtekVision Co., Ltd.
   9  *
  10  * For licencing details see kernel-base/COPYING
  11  *
  12  * TPS65070, TPS65073, TPS650731, and TPS650732 support
  13  * 10 bit touch screen interface.
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/workqueue.h>
  18 #include <linux/slab.h>
  19 #include <linux/input.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/mfd/tps6507x.h>
  22 #include <linux/input/tps6507x-ts.h>
  23 #include <linux/delay.h>
  24
  25 #define TSC_DEFAULT_POLL_PERIOD 30 /* ms */
  26 #define TPS_DEFAULT_MIN_PRESSURE 0x30
  27 #define MAX_10BIT ((1 << 10) - 1)
  28
  29 #define TPS6507X_ADCONFIG_CONVERT_TS (TPS6507X_ADCONFIG_AD_ENABLE | \
  30                                          TPS6507X_ADCONFIG_START_CONVERSION | \
  31                                          TPS6507X_ADCONFIG_INPUT_REAL_TSC)
  32 #define TPS6507X_ADCONFIG_POWER_DOWN_TS (TPS6507X_ADCONFIG_INPUT_REAL_TSC)
  33
  34 struct ts_event {
  35         u16     x;
  36         u16     y;
  37         u16     pressure;
  38 };
  39
  40 struct tps6507x_ts {
  41         struct device           *dev;
  42         struct input_dev        *input;
  43         struct tps6507x_dev     *mfd;
  44         char                    phys[32];
  45         struct ts_event         tc;
  46         u16                     min_pressure;
  47         bool                    pendown;
  48 };
  49
  50 static int tps6507x_read_u8(struct tps6507x_ts *tsc, u8 reg, u8 *data)
  51 {
  52         return tsc->mfd->read_dev(tsc->mfd, reg, 1, data);
  53 }
  54
  55 static int tps6507x_write_u8(struct tps6507x_ts *tsc, u8 reg, u8 data)
  56 {
  57         return tsc->mfd->write_dev(tsc->mfd, reg, 1, &data);
  58 }
  59
  60 static s32 tps6507x_adc_conversion(struct tps6507x_ts *tsc,
  61                                    u8 tsc_mode, u16 *value)
  62 {
  63         s32 ret;
  64         u8 adc_status;
  65         u8 result;
  66
  67         /* Route input signal to A/D converter */
  68
  69         ret = tps6507x_write_u8(tsc, TPS6507X_REG_TSCMODE, tsc_mode);
  70         if (ret) {
  71                 dev_err(tsc->dev, "TSC mode read failed\n");
  72                 goto err;
  73         }
  74
  75         /* Start A/D conversion */
  76
  77         ret = tps6507x_write_u8(tsc, TPS6507X_REG_ADCONFIG,
  78                                 TPS6507X_ADCONFIG_CONVERT_TS);
  79         if (ret) {
  80                 dev_err(tsc->dev, "ADC config write failed\n");
  81                 return ret;
  82         }
  83
  84         do {
  85                 ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADCONFIG,
  86                                        &adc_status);
  87                 if (ret) {
  88                         dev_err(tsc->dev, "ADC config read failed\n");
  89                         goto err;
  90                 }
  91         } while (adc_status & TPS6507X_ADCONFIG_START_CONVERSION);
  92
  93         ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADRESULT_2, &result);
  94         if (ret) {
  95                 dev_err(tsc->dev, "ADC result 2 read failed\n");
  96                 goto err;
  97         }
  98
  99         *value = (result & TPS6507X_REG_ADRESULT_2_MASK) << 8;
 100
 101         ret = tps6507x_read_u8(tsc, TPS6507X_REG_ADRESULT_1, &result);
 102         if (ret) {
 103                 dev_err(tsc->dev, "ADC result 1 read failed\n");
 104                 goto err;
 105         }
 106
 107         *value |= result;
 108
 109         dev_dbg(tsc->dev, "TSC channel %d = 0x%X\n", tsc_mode, *value);
 110
 111 err:
 112         return ret;
 113 }
 114
 115 /* Need to call tps6507x_adc_standby() after using A/D converter for the
 116  * touch screen interrupt to work properly.
 117  */
 118
 119 static s32 tps6507x_adc_standby(struct tps6507x_ts *tsc)
 120 {
 121         s32 ret;
 122         u8 val;
 123
 124         ret = tps6507x_write_u8(tsc,  TPS6507X_REG_ADCONFIG,
 125                                 TPS6507X_ADCONFIG_INPUT_TSC);
 126         if (ret)
 127                 return ret;
 128
 129         ret = tps6507x_write_u8(tsc, TPS6507X_REG_TSCMODE,
 130                                 TPS6507X_TSCMODE_STANDBY);
 131         if (ret)
 132                 return ret;
 133
 134         ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
 135         if (ret)
 136                 return ret;
 137
 138         while (val & TPS6507X_REG_TSC_INT) {
 139                 mdelay(10);
 140                 ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
 141                 if (ret)
 142                         return ret;
 143         }
 144
 145         return ret;
 146 }
 147
 148 static void tps6507x_ts_poll(struct input_dev *input_dev)
 149 {
 150         struct tps6507x_ts *tsc = input_get_drvdata(input_dev);
 151         bool pendown;
 152         s32 ret;
 153
 154         ret = tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_PRESSURE,
 155                                       &tsc->tc.pressure);
 156         if (ret)
 157                 goto done;
 158
 159         pendown = tsc->tc.pressure > tsc->min_pressure;
 160
 161         if (unlikely(!pendown && tsc->pendown)) {
 162                 dev_dbg(tsc->dev, "UP\n");
 163                 input_report_key(input_dev, BTN_TOUCH, 0);
 164                 input_report_abs(input_dev, ABS_PRESSURE, 0);
 165                 input_sync(input_dev);
 166                 tsc->pendown = false;
 167         }
 168
 169         if (pendown) {
 170
 171                 if (!tsc->pendown) {
 172                         dev_dbg(tsc->dev, "DOWN\n");
 173                         input_report_key(input_dev, BTN_TOUCH, 1);
 174                 } else
 175                         dev_dbg(tsc->dev, "still down\n");
 176
 177                 ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_X_POSITION,
 178                                                &tsc->tc.x);
 179                 if (ret)
 180                         goto done;
 181
 182                 ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_Y_POSITION,
 183                                                &tsc->tc.y);
 184                 if (ret)
 185                         goto done;
 186
 187                 input_report_abs(input_dev, ABS_X, tsc->tc.x);
 188                 input_report_abs(input_dev, ABS_Y, tsc->tc.y);
 189                 input_report_abs(input_dev, ABS_PRESSURE, tsc->tc.pressure);
 190                 input_sync(input_dev);
 191                 tsc->pendown = true;
 192         }
 193
 194 done:
 195         tps6507x_adc_standby(tsc);
 196 }
 197
 198 static int tps6507x_ts_probe(struct platform_device *pdev)
 199 {
 200         struct tps6507x_dev *tps6507x_dev = dev_get_drvdata(pdev->dev.parent);
 201         const struct tps6507x_board *tps_board;
 202         const struct touchscreen_init_data *init_data;
 203         struct tps6507x_ts *tsc;
 204         struct input_dev *input_dev;
 205         int error;
 206
 207         /*
 208          * tps_board points to pmic related constants
 209          * coming from the board-evm file.
 210          */
 211         tps_board = dev_get_platdata(tps6507x_dev->dev);
 212         if (!tps_board) {
 213                 dev_err(tps6507x_dev->dev,
 214                         "Could not find tps6507x platform data\n");
 215                 return -ENODEV;
 216         }
 217
 218         /*
 219          * init_data points to array of regulator_init structures
 220          * coming from the board-evm file.
 221          */
 222         init_data = tps_board->tps6507x_ts_init_data;
 223
 224         tsc = devm_kzalloc(&pdev->dev, sizeof(struct tps6507x_ts), GFP_KERNEL);
 225         if (!tsc) {
 226                 dev_err(tps6507x_dev->dev, "failed to allocate driver data\n");
 227                 return -ENOMEM;
 228         }
 229
 230         tsc->mfd = tps6507x_dev;
 231         tsc->dev = tps6507x_dev->dev;
 232         tsc->min_pressure = init_data ?
 233                         init_data->min_pressure : TPS_DEFAULT_MIN_PRESSURE;
 234
 235         snprintf(tsc->phys, sizeof(tsc->phys),
 236                  "%s/input0", dev_name(tsc->dev));
 237
 238         input_dev = devm_input_allocate_device(&pdev->dev);
 239         if (!input_dev) {
 240                 dev_err(tsc->dev, "Failed to allocate polled input device.\n");
 241                 return -ENOMEM;
 242         }
 243
 244         tsc->input = input_dev;
 245         input_set_drvdata(input_dev, tsc);
 246
 247         input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
 248         input_set_abs_params(input_dev, ABS_X, 0, MAX_10BIT, 0, 0);
 249         input_set_abs_params(input_dev, ABS_Y, 0, MAX_10BIT, 0, 0);
 250         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_10BIT, 0, 0);
 251
 252         input_dev->name = "TPS6507x Touchscreen";
 253         input_dev->phys = tsc->phys;
 254         input_dev->dev.parent = tsc->dev;
 255         input_dev->id.bustype = BUS_I2C;
 256         if (init_data) {
 257                 input_dev->id.vendor = init_data->vendor;
 258                 input_dev->id.product = init_data->product;
 259                 input_dev->id.version = init_data->version;
 260         }
 261
 262         error = tps6507x_adc_standby(tsc);
 263         if (error)
 264                 return error;
 265
 266         error = input_setup_polling(input_dev, tps6507x_ts_poll);
 267         if (error)
 268                 return error;
 269
 270         input_set_poll_interval(input_dev,
 271                                 init_data ? init_data->poll_period :
 272                                             TSC_DEFAULT_POLL_PERIOD);
 273
 274         error = input_register_device(input_dev);
 275         if (error)
 276                 return error;
 277
 278         return 0;
 279 }
 280
 281 static struct platform_driver tps6507x_ts_driver = {
 282         .driver = {
 283                 .name = "tps6507x-ts",
 284         },
 285         .probe = tps6507x_ts_probe,
 286 };
 287 module_platform_driver(tps6507x_ts_driver);
 288
 289 MODULE_AUTHOR("Todd Fischer <todd.fischer@ridgerun.com>");
 290 MODULE_DESCRIPTION("TPS6507x - TouchScreen driver");
 291 MODULE_LICENSE("GPL v2");
 292 MODULE_ALIAS("platform:tps6507x-ts");