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         s32 loops = 0;
 123         u8 val;
 124
 125         ret = tps6507x_write_u8(tsc,  TPS6507X_REG_ADCONFIG,
 126                                 TPS6507X_ADCONFIG_INPUT_TSC);
 127         if (ret)
 128                 return ret;
 129
 130         ret = tps6507x_write_u8(tsc, TPS6507X_REG_TSCMODE,
 131                                 TPS6507X_TSCMODE_STANDBY);
 132         if (ret)
 133                 return ret;
 134
 135         ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
 136         if (ret)
 137                 return ret;
 138
 139         while (val & TPS6507X_REG_TSC_INT) {
 140                 mdelay(10);
 141                 ret = tps6507x_read_u8(tsc, TPS6507X_REG_INT, &val);
 142                 if (ret)
 143                         return ret;
 144                 loops++;
 145         }
 146
 147         return ret;
 148 }
 149
 150 static void tps6507x_ts_poll(struct input_dev *input_dev)
 151 {
 152         struct tps6507x_ts *tsc = input_get_drvdata(input_dev);
 153         bool pendown;
 154         s32 ret;
 155
 156         ret = tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_PRESSURE,
 157                                       &tsc->tc.pressure);
 158         if (ret)
 159                 goto done;
 160
 161         pendown = tsc->tc.pressure > tsc->min_pressure;
 162
 163         if (unlikely(!pendown && tsc->pendown)) {
 164                 dev_dbg(tsc->dev, "UP\n");
 165                 input_report_key(input_dev, BTN_TOUCH, 0);
 166                 input_report_abs(input_dev, ABS_PRESSURE, 0);
 167                 input_sync(input_dev);
 168                 tsc->pendown = false;
 169         }
 170
 171         if (pendown) {
 172
 173                 if (!tsc->pendown) {
 174                         dev_dbg(tsc->dev, "DOWN\n");
 175                         input_report_key(input_dev, BTN_TOUCH, 1);
 176                 } else
 177                         dev_dbg(tsc->dev, "still down\n");
 178
 179                 ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_X_POSITION,
 180                                                &tsc->tc.x);
 181                 if (ret)
 182                         goto done;
 183
 184                 ret =  tps6507x_adc_conversion(tsc, TPS6507X_TSCMODE_Y_POSITION,
 185                                                &tsc->tc.y);
 186                 if (ret)
 187                         goto done;
 188
 189                 input_report_abs(input_dev, ABS_X, tsc->tc.x);
 190                 input_report_abs(input_dev, ABS_Y, tsc->tc.y);
 191                 input_report_abs(input_dev, ABS_PRESSURE, tsc->tc.pressure);
 192                 input_sync(input_dev);
 193                 tsc->pendown = true;
 194         }
 195
 196 done:
 197         tps6507x_adc_standby(tsc);
 198 }
 199
 200 static int tps6507x_ts_probe(struct platform_device *pdev)
 201 {
 202         struct tps6507x_dev *tps6507x_dev = dev_get_drvdata(pdev->dev.parent);
 203         const struct tps6507x_board *tps_board;
 204         const struct touchscreen_init_data *init_data;
 205         struct tps6507x_ts *tsc;
 206         struct input_dev *input_dev;
 207         int error;
 208
 209         /*
 210          * tps_board points to pmic related constants
 211          * coming from the board-evm file.
 212          */
 213         tps_board = dev_get_platdata(tps6507x_dev->dev);
 214         if (!tps_board) {
 215                 dev_err(tps6507x_dev->dev,
 216                         "Could not find tps6507x platform data\n");
 217                 return -ENODEV;
 218         }
 219
 220         /*
 221          * init_data points to array of regulator_init structures
 222          * coming from the board-evm file.
 223          */
 224         init_data = tps_board->tps6507x_ts_init_data;
 225
 226         tsc = devm_kzalloc(&pdev->dev, sizeof(struct tps6507x_ts), GFP_KERNEL);
 227         if (!tsc) {
 228                 dev_err(tps6507x_dev->dev, "failed to allocate driver data\n");
 229                 return -ENOMEM;
 230         }
 231
 232         tsc->mfd = tps6507x_dev;
 233         tsc->dev = tps6507x_dev->dev;
 234         tsc->min_pressure = init_data ?
 235                         init_data->min_pressure : TPS_DEFAULT_MIN_PRESSURE;
 236
 237         snprintf(tsc->phys, sizeof(tsc->phys),
 238                  "%s/input0", dev_name(tsc->dev));
 239
 240         input_dev = devm_input_allocate_device(&pdev->dev);
 241         if (!input_dev) {
 242                 dev_err(tsc->dev, "Failed to allocate polled input device.\n");
 243                 return -ENOMEM;
 244         }
 245
 246         tsc->input = input_dev;
 247         input_set_drvdata(input_dev, tsc);
 248
 249         input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
 250         input_set_abs_params(input_dev, ABS_X, 0, MAX_10BIT, 0, 0);
 251         input_set_abs_params(input_dev, ABS_Y, 0, MAX_10BIT, 0, 0);
 252         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_10BIT, 0, 0);
 253
 254         input_dev->name = "TPS6507x Touchscreen";
 255         input_dev->phys = tsc->phys;
 256         input_dev->dev.parent = tsc->dev;
 257         input_dev->id.bustype = BUS_I2C;
 258         if (init_data) {
 259                 input_dev->id.vendor = init_data->vendor;
 260                 input_dev->id.product = init_data->product;
 261                 input_dev->id.version = init_data->version;
 262         }
 263
 264         error = tps6507x_adc_standby(tsc);
 265         if (error)
 266                 return error;
 267
 268         error = input_setup_polling(input_dev, tps6507x_ts_poll);
 269         if (error)
 270                 return error;
 271
 272         input_set_poll_interval(input_dev,
 273                                 init_data ? init_data->poll_period :
 274                                             TSC_DEFAULT_POLL_PERIOD);
 275
 276         error = input_register_device(input_dev);
 277         if (error)
 278                 return error;
 279
 280         return 0;
 281 }
 282
 283 static struct platform_driver tps6507x_ts_driver = {
 284         .driver = {
 285                 .name = "tps6507x-ts",
 286         },
 287         .probe = tps6507x_ts_probe,
 288 };
 289 module_platform_driver(tps6507x_ts_driver);
 290
 291 MODULE_AUTHOR("Todd Fischer <todd.fischer@ridgerun.com>");
 292 MODULE_DESCRIPTION("TPS6507x - TouchScreen driver");
 293 MODULE_LICENSE("GPL v2");
 294 MODULE_ALIAS("platform:tps6507x-ts");