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