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/input-polldev.h>
  14 #include <linux/io.h>
  15 #include <linux/kernel.h>
  16 #include <linux/mfd/syscon.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/regmap.h>
  21
  22 /* polling interval in ms */
  23 #define POLL_INTERVAL           3
  24
  25 #define DEBOUNCE_COUNT          1
  26
  27 /* sensor values are 12-bit wide */
  28 #define MAX_12BIT               ((1 << 12) - 1)
  29
  30 #define PENDOWN_MASK            0x1
  31
  32 #define X_OFFSET                0x0
  33 #define Y_OFFSET                0x2
  34
  35 struct ts4800_ts {
  36         struct input_polled_dev *poll_dev;
  37         struct device           *dev;
  38         char                    phys[32];
  39
  40         void __iomem            *base;
  41         struct regmap           *regmap;
  42         unsigned int            reg;
  43         unsigned int            bit;
  44
  45         bool                    pendown;
  46         int                     debounce;
  47 };
  48
  49 static void ts4800_ts_open(struct input_polled_dev *dev)
  50 {
  51         struct ts4800_ts *ts = dev->private;
  52         int ret;
  53
  54         ts->pendown = false;
  55         ts->debounce = DEBOUNCE_COUNT;
  56
  57         ret = regmap_update_bits(ts->regmap, ts->reg, ts->bit, ts->bit);
  58         if (ret)
  59                 dev_warn(ts->dev, "Failed to enable touchscreen\n");
  60 }
  61
  62 static void ts4800_ts_close(struct input_polled_dev *dev)
  63 {
  64         struct ts4800_ts *ts = dev->private;
  65         int ret;
  66
  67         ret = regmap_update_bits(ts->regmap, ts->reg, ts->bit, 0);
  68         if (ret)
  69                 dev_warn(ts->dev, "Failed to disable touchscreen\n");
  70
  71 }
  72
  73 static void ts4800_ts_poll(struct input_polled_dev *dev)
  74 {
  75         struct input_dev *input_dev = dev->input;
  76         struct ts4800_ts *ts = dev->private;
  77         u16 last_x = readw(ts->base + X_OFFSET);
  78         u16 last_y = readw(ts->base + Y_OFFSET);
  79         bool pendown = last_x & PENDOWN_MASK;
  80
  81         if (pendown) {
  82                 if (ts->debounce) {
  83                         ts->debounce--;
  84                         return;
  85                 }
  86
  87                 if (!ts->pendown) {
  88                         input_report_key(input_dev, BTN_TOUCH, 1);
  89                         ts->pendown = true;
  90                 }
  91
  92                 last_x = ((~last_x) >> 4) & MAX_12BIT;
  93                 last_y = ((~last_y) >> 4) & MAX_12BIT;
  94
  95                 input_report_abs(input_dev, ABS_X, last_x);
  96                 input_report_abs(input_dev, ABS_Y, last_y);
  97                 input_sync(input_dev);
  98         } else if (ts->pendown) {
  99                 ts->pendown = false;
 100                 ts->debounce = DEBOUNCE_COUNT;
 101                 input_report_key(input_dev, BTN_TOUCH, 0);
 102                 input_sync(input_dev);
 103         }
 104 }
 105
 106 static int ts4800_parse_dt(struct platform_device *pdev,
 107                            struct ts4800_ts *ts)
 108 {
 109         struct device *dev = &pdev->dev;
 110         struct device_node *np = dev->of_node;
 111         struct device_node *syscon_np;
 112         u32 reg, bit;
 113         int error;
 114
 115         syscon_np = of_parse_phandle(np, "syscon", 0);
 116         if (!syscon_np) {
 117                 dev_err(dev, "no syscon property\n");
 118                 return -ENODEV;
 119         }
 120
 121         error = of_property_read_u32_index(np, "syscon", 1, &reg);
 122         if (error < 0) {
 123                 dev_err(dev, "no offset in syscon\n");
 124                 return error;
 125         }
 126
 127         ts->reg = reg;
 128
 129         error = of_property_read_u32_index(np, "syscon", 2, &bit);
 130         if (error < 0) {
 131                 dev_err(dev, "no bit in syscon\n");
 132                 return error;
 133         }
 134
 135         ts->bit = BIT(bit);
 136
 137         ts->regmap = syscon_node_to_regmap(syscon_np);
 138         if (IS_ERR(ts->regmap)) {
 139                 dev_err(dev, "cannot get parent's regmap\n");
 140                 return PTR_ERR(ts->regmap);
 141         }
 142
 143         return 0;
 144 }
 145
 146 static int ts4800_ts_probe(struct platform_device *pdev)
 147 {
 148         struct input_polled_dev *poll_dev;
 149         struct ts4800_ts *ts;
 150         struct resource *res;
 151         int error;
 152
 153         ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
 154         if (!ts)
 155                 return -ENOMEM;
 156
 157         error = ts4800_parse_dt(pdev, ts);
 158         if (error)
 159                 return error;
 160
 161         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 162         ts->base = devm_ioremap_resource(&pdev->dev, res);
 163         if (IS_ERR(ts->base))
 164                 return PTR_ERR(ts->base);
 165
 166         poll_dev = devm_input_allocate_polled_device(&pdev->dev);
 167         if (!poll_dev)
 168                 return -ENOMEM;
 169
 170         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&pdev->dev));
 171         ts->poll_dev = poll_dev;
 172         ts->dev = &pdev->dev;
 173
 174         poll_dev->private = ts;
 175         poll_dev->poll_interval = POLL_INTERVAL;
 176         poll_dev->open = ts4800_ts_open;
 177         poll_dev->close = ts4800_ts_close;
 178         poll_dev->poll = ts4800_ts_poll;
 179
 180         poll_dev->input->name = "TS-4800 Touchscreen";
 181         poll_dev->input->phys = ts->phys;
 182
 183         input_set_capability(poll_dev->input, EV_KEY, BTN_TOUCH);
 184         input_set_abs_params(poll_dev->input, ABS_X, 0, MAX_12BIT, 0, 0);
 185         input_set_abs_params(poll_dev->input, ABS_Y, 0, MAX_12BIT, 0, 0);
 186
 187         error = input_register_polled_device(poll_dev);
 188         if (error) {
 189                 dev_err(&pdev->dev,
 190                         "Unabled to register polled input device (%d)\n",
 191                         error);
 192                 return error;
 193         }
 194
 195         return 0;
 196 }
 197
 198 static const struct of_device_id ts4800_ts_of_match[] = {
 199         { .compatible = "technologic,ts4800-ts", },
 200         { },
 201 };
 202 MODULE_DEVICE_TABLE(of, ts4800_ts_of_match);
 203
 204 static struct platform_driver ts4800_ts_driver = {
 205         .driver = {
 206                 .name = "ts4800-ts",
 207                 .of_match_table = ts4800_ts_of_match,
 208         },
 209         .probe = ts4800_ts_probe,
 210 };
 211 module_platform_driver(ts4800_ts_driver);
 212
 213 MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
 214 MODULE_DESCRIPTION("TS-4800 Touchscreen Driver");
 215 MODULE_LICENSE("GPL v2");
 216 MODULE_ALIAS("platform:ts4800_ts");