drivers/input/touchscreen/ts4800-ts.c

   1 /*
   2  * Touchscreen driver for the TS-4800 board
   3  *
   4  * Copyright (c) 2015 - Savoir-faire Linux
   5  *
   6  * This file is licensed under the terms of the GNU General Public
   7  * License version 2. This program is licensed "as is" without any
   8  * warranty of any kind, whether express or implied.
   9  */
  10
  11 #include <linux/bitops.h>
  12 #include <linux/input.h>
  13 #include <linux/io.h>
  14 #include <linux/kernel.h>
  15 #include <linux/mfd/syscon.h>
  16 #include <linux/module.h>
  17 #include <linux/of.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/regmap.h>
  20
  21 /* polling interval in ms */
  22 #define POLL_INTERVAL           3
  23
  24 #define DEBOUNCE_COUNT          1
  25
  26 /* sensor values are 12-bit wide */
  27 #define MAX_12BIT               ((1 << 12) - 1)
  28
  29 #define PENDOWN_MASK            0x1
  30
  31 #define X_OFFSET                0x0
  32 #define Y_OFFSET                0x2
  33
  34 struct ts4800_ts {
  35         struct input_dev        *input;
  36         struct device           *dev;
  37         char                    phys[32];
  38
  39         void __iomem            *base;
  40         struct regmap           *regmap;
  41         unsigned int            reg;
  42         unsigned int            bit;
  43
  44         bool                    pendown;
  45         int                     debounce;
  46 };
  47
  48 static int ts4800_ts_open(struct input_dev *input_dev)
  49 {
  50         struct ts4800_ts *ts = input_get_drvdata(input_dev);
  51         int error;
  52
  53         ts->pendown = false;
  54         ts->debounce = DEBOUNCE_COUNT;
  55
  56         error = regmap_update_bits(ts->regmap, ts->reg, ts->bit, ts->bit);
  57         if (error) {
  58                 dev_warn(ts->dev, "Failed to enable touchscreen: %d\n", error);
  59                 return error;
  60         }
  61
  62         return 0;
  63 }
  64
  65 static void ts4800_ts_close(struct input_dev *input_dev)
  66 {
  67         struct ts4800_ts *ts = input_get_drvdata(input_dev);
  68         int ret;
  69
  70         ret = regmap_update_bits(ts->regmap, ts->reg, ts->bit, 0);
  71         if (ret)
  72                 dev_warn(ts->dev, "Failed to disable touchscreen\n");
  73
  74 }
  75
  76 static void ts4800_ts_poll(struct input_dev *input_dev)
  77 {
  78         struct ts4800_ts *ts = input_get_drvdata(input_dev);
  79         u16 last_x = readw(ts->base + X_OFFSET);
  80         u16 last_y = readw(ts->base + Y_OFFSET);
  81         bool pendown = last_x & PENDOWN_MASK;
  82
  83         if (pendown) {
  84                 if (ts->debounce) {
  85                         ts->debounce--;
  86                         return;
  87                 }
  88
  89                 if (!ts->pendown) {
  90                         input_report_key(input_dev, BTN_TOUCH, 1);
  91                         ts->pendown = true;
  92                 }
  93
  94                 last_x = ((~last_x) >> 4) & MAX_12BIT;
  95                 last_y = ((~last_y) >> 4) & MAX_12BIT;
  96
  97                 input_report_abs(input_dev, ABS_X, last_x);
  98                 input_report_abs(input_dev, ABS_Y, last_y);
  99                 input_sync(input_dev);
 100         } else if (ts->pendown) {
 101                 ts->pendown = false;
 102                 ts->debounce = DEBOUNCE_COUNT;
 103                 input_report_key(input_dev, BTN_TOUCH, 0);
 104                 input_sync(input_dev);
 105         }
 106 }
 107
 108 static int ts4800_parse_dt(struct platform_device *pdev,
 109                            struct ts4800_ts *ts)
 110 {
 111         struct device *dev = &pdev->dev;
 112         struct device_node *np = dev->of_node;
 113         struct device_node *syscon_np;
 114         u32 reg, bit;
 115         int error;
 116
 117         syscon_np = of_parse_phandle(np, "syscon", 0);
 118         if (!syscon_np) {
 119                 dev_err(dev, "no syscon property\n");
 120                 return -ENODEV;
 121         }
 122
 123         ts->regmap = syscon_node_to_regmap(syscon_np);
 124         of_node_put(syscon_np);
 125         if (IS_ERR(ts->regmap)) {
 126                 dev_err(dev, "cannot get parent's regmap\n");
 127                 return PTR_ERR(ts->regmap);
 128         }
 129
 130         error = of_property_read_u32_index(np, "syscon", 1, &reg);
 131         if (error < 0) {
 132                 dev_err(dev, "no offset in syscon\n");
 133                 return error;
 134         }
 135
 136         ts->reg = reg;
 137
 138         error = of_property_read_u32_index(np, "syscon", 2, &bit);
 139         if (error < 0) {
 140                 dev_err(dev, "no bit in syscon\n");
 141                 return error;
 142         }
 143
 144         ts->bit = BIT(bit);
 145
 146         return 0;
 147 }
 148
 149 static int ts4800_ts_probe(struct platform_device *pdev)
 150 {
 151         struct input_dev *input_dev;
 152         struct ts4800_ts *ts;
 153         int error;
 154
 155         ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
 156         if (!ts)
 157                 return -ENOMEM;
 158
 159         error = ts4800_parse_dt(pdev, ts);
 160         if (error)
 161                 return error;
 162
 163         ts->base = devm_platform_ioremap_resource(pdev, 0);
 164         if (IS_ERR(ts->base))
 165                 return PTR_ERR(ts->base);
 166
 167         input_dev = devm_input_allocate_device(&pdev->dev);
 168         if (!input_dev)
 169                 return -ENOMEM;
 170
 171         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&pdev->dev));
 172         ts->input = input_dev;
 173         ts->dev = &pdev->dev;
 174
 175         input_set_drvdata(input_dev, ts);
 176
 177         input_dev->name = "TS-4800 Touchscreen";
 178         input_dev->phys = ts->phys;
 179
 180         input_dev->open = ts4800_ts_open;
 181         input_dev->close = ts4800_ts_close;
 182
 183         input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
 184         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
 185         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
 186
 187         error = input_setup_polling(input_dev, ts4800_ts_poll);
 188         if (error) {
 189                 dev_err(&pdev->dev, "Unable to set up polling: %d\n", error);
 190                 return error;
 191         }
 192
 193         input_set_poll_interval(input_dev, POLL_INTERVAL);
 194
 195         error = input_register_device(input_dev);
 196         if (error) {
 197                 dev_err(&pdev->dev,
 198                         "Unable to register input device: %d\n", error);
 199                 return error;
 200         }
 201
 202         return 0;
 203 }
 204
 205 static const struct of_device_id ts4800_ts_of_match[] = {
 206         { .compatible = "technologic,ts4800-ts", },
 207         { },
 208 };
 209 MODULE_DEVICE_TABLE(of, ts4800_ts_of_match);
 210
 211 static struct platform_driver ts4800_ts_driver = {
 212         .driver = {
 213                 .name = "ts4800-ts",
 214                 .of_match_table = ts4800_ts_of_match,
 215         },
 216         .probe = ts4800_ts_probe,
 217 };
 218 module_platform_driver(ts4800_ts_driver);
 219
 220 MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
 221 MODULE_DESCRIPTION("TS-4800 Touchscreen Driver");
 222 MODULE_LICENSE("GPL v2");
 223 MODULE_ALIAS("platform:ts4800_ts");