drivers/input/touchscreen/raspberrypi-ts.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Raspberry Pi firmware based touchscreen driver
   4  *
   5  * Copyright (C) 2015, 2017 Raspberry Pi
   6  * Copyright (C) 2018 Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
   7  */
   8
   9 #include <linux/io.h>
  10 #include <linux/of.h>
  11 #include <linux/slab.h>
  12 #include <linux/device.h>
  13 #include <linux/module.h>
  14 #include <linux/bitops.h>
  15 #include <linux/dma-mapping.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/input.h>
  18 #include <linux/input/mt.h>
  19 #include <linux/input-polldev.h>
  20 #include <linux/input/touchscreen.h>
  21 #include <soc/bcm2835/raspberrypi-firmware.h>
  22
  23 #define RPI_TS_DEFAULT_WIDTH    800
  24 #define RPI_TS_DEFAULT_HEIGHT   480
  25
  26 #define RPI_TS_MAX_SUPPORTED_POINTS     10
  27
  28 #define RPI_TS_FTS_TOUCH_DOWN           0
  29 #define RPI_TS_FTS_TOUCH_CONTACT        2
  30
  31 #define RPI_TS_POLL_INTERVAL            17      /* 60fps */
  32
  33 #define RPI_TS_NPOINTS_REG_INVALIDATE   99
  34
  35 struct rpi_ts {
  36         struct platform_device *pdev;
  37         struct input_polled_dev *poll_dev;
  38         struct touchscreen_properties prop;
  39
  40         void __iomem *fw_regs_va;
  41         dma_addr_t fw_regs_phys;
  42
  43         int known_ids;
  44 };
  45
  46 struct rpi_ts_regs {
  47         u8 device_mode;
  48         u8 gesture_id;
  49         u8 num_points;
  50         struct rpi_ts_touch {
  51                 u8 xh;
  52                 u8 xl;
  53                 u8 yh;
  54                 u8 yl;
  55                 u8 pressure; /* Not supported */
  56                 u8 area;     /* Not supported */
  57         } point[RPI_TS_MAX_SUPPORTED_POINTS];
  58 };
  59
  60 static void rpi_ts_poll(struct input_polled_dev *dev)
  61 {
  62         struct input_dev *input = dev->input;
  63         struct rpi_ts *ts = dev->private;
  64         struct rpi_ts_regs regs;
  65         int modified_ids = 0;
  66         long released_ids;
  67         int event_type;
  68         int touchid;
  69         int x, y;
  70         int i;
  71
  72         memcpy_fromio(&regs, ts->fw_regs_va, sizeof(regs));
  73         /*
  74          * We poll the memory based register copy of the touchscreen chip using
  75          * the number of points register to know whether the copy has been
  76          * updated (we write 99 to the memory copy, the GPU will write between
  77          * 0 - 10 points)
  78          */
  79         iowrite8(RPI_TS_NPOINTS_REG_INVALIDATE,
  80                  ts->fw_regs_va + offsetof(struct rpi_ts_regs, num_points));
  81
  82         if (regs.num_points == RPI_TS_NPOINTS_REG_INVALIDATE ||
  83             (regs.num_points == 0 && ts->known_ids == 0))
  84                 return;
  85
  86         for (i = 0; i < regs.num_points; i++) {
  87                 x = (((int)regs.point[i].xh & 0xf) << 8) + regs.point[i].xl;
  88                 y = (((int)regs.point[i].yh & 0xf) << 8) + regs.point[i].yl;
  89                 touchid = (regs.point[i].yh >> 4) & 0xf;
  90                 event_type = (regs.point[i].xh >> 6) & 0x03;
  91
  92                 modified_ids |= BIT(touchid);
  93
  94                 if (event_type == RPI_TS_FTS_TOUCH_DOWN ||
  95                     event_type == RPI_TS_FTS_TOUCH_CONTACT) {
  96                         input_mt_slot(input, touchid);
  97                         input_mt_report_slot_state(input, MT_TOOL_FINGER, 1);
  98                         touchscreen_report_pos(input, &ts->prop, x, y, true);
  99                 }
 100         }
 101
 102         released_ids = ts->known_ids & ~modified_ids;
 103         for_each_set_bit(i, &released_ids, RPI_TS_MAX_SUPPORTED_POINTS) {
 104                 input_mt_slot(input, i);
 105                 input_mt_report_slot_state(input, MT_TOOL_FINGER, 0);
 106                 modified_ids &= ~(BIT(i));
 107         }
 108         ts->known_ids = modified_ids;
 109
 110         input_mt_sync_frame(input);
 111         input_sync(input);
 112 }
 113
 114 static void rpi_ts_dma_cleanup(void *data)
 115 {
 116         struct rpi_ts *ts = data;
 117         struct device *dev = &ts->pdev->dev;
 118
 119         dma_free_coherent(dev, PAGE_SIZE, ts->fw_regs_va, ts->fw_regs_phys);
 120 }
 121
 122 static int rpi_ts_probe(struct platform_device *pdev)
 123 {
 124         struct device *dev = &pdev->dev;
 125         struct device_node *np = dev->of_node;
 126         struct input_polled_dev *poll_dev;
 127         struct device_node *fw_node;
 128         struct rpi_firmware *fw;
 129         struct input_dev *input;
 130         struct rpi_ts *ts;
 131         u32 touchbuf;
 132         int error;
 133
 134         fw_node = of_get_parent(np);
 135         if (!fw_node) {
 136                 dev_err(dev, "Missing firmware node\n");
 137                 return -ENOENT;
 138         }
 139
 140         fw = rpi_firmware_get(fw_node);
 141         of_node_put(fw_node);
 142         if (!fw)
 143                 return -EPROBE_DEFER;
 144
 145         ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
 146         if (!ts)
 147                 return -ENOMEM;
 148         ts->pdev = pdev;
 149
 150         ts->fw_regs_va = dma_alloc_coherent(dev, PAGE_SIZE, &ts->fw_regs_phys,
 151                                             GFP_KERNEL);
 152         if (!ts->fw_regs_va) {
 153                 dev_err(dev, "failed to dma_alloc_coherent\n");
 154                 return -ENOMEM;
 155         }
 156
 157         error = devm_add_action_or_reset(dev, rpi_ts_dma_cleanup, ts);
 158         if (error) {
 159                 dev_err(dev, "failed to devm_add_action_or_reset, %d\n", error);
 160                 return error;
 161         }
 162
 163
 164         touchbuf = (u32)ts->fw_regs_phys;
 165         error = rpi_firmware_property(fw, RPI_FIRMWARE_FRAMEBUFFER_SET_TOUCHBUF,
 166                                       &touchbuf, sizeof(touchbuf));
 167
 168         if (error || touchbuf != 0) {
 169                 dev_warn(dev, "Failed to set touchbuf, %d\n", error);
 170                 return error;
 171         }
 172
 173         poll_dev = devm_input_allocate_polled_device(dev);
 174         if (!poll_dev) {
 175                 dev_err(dev, "Failed to allocate input device\n");
 176                 return -ENOMEM;
 177         }
 178         ts->poll_dev = poll_dev;
 179         input = poll_dev->input;
 180
 181         input->name = "raspberrypi-ts";
 182         input->id.bustype = BUS_HOST;
 183         poll_dev->poll_interval = RPI_TS_POLL_INTERVAL;
 184         poll_dev->poll = rpi_ts_poll;
 185         poll_dev->private = ts;
 186
 187         input_set_abs_params(input, ABS_MT_POSITION_X, 0,
 188                              RPI_TS_DEFAULT_WIDTH, 0, 0);
 189         input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
 190                              RPI_TS_DEFAULT_HEIGHT, 0, 0);
 191         touchscreen_parse_properties(input, true, &ts->prop);
 192
 193         error = input_mt_init_slots(input, RPI_TS_MAX_SUPPORTED_POINTS,
 194                                     INPUT_MT_DIRECT);
 195         if (error) {
 196                 dev_err(dev, "could not init mt slots, %d\n", error);
 197                 return error;
 198         }
 199
 200         error = input_register_polled_device(poll_dev);
 201         if (error) {
 202                 dev_err(dev, "could not register input device, %d\n", error);
 203                 return error;
 204         }
 205
 206         return 0;
 207 }
 208
 209 static const struct of_device_id rpi_ts_match[] = {
 210         { .compatible = "raspberrypi,firmware-ts", },
 211         {},
 212 };
 213 MODULE_DEVICE_TABLE(of, rpi_ts_match);
 214
 215 static struct platform_driver rpi_ts_driver = {
 216         .driver = {
 217                 .name   = "raspberrypi-ts",
 218                 .of_match_table = rpi_ts_match,
 219         },
 220         .probe          = rpi_ts_probe,
 221 };
 222 module_platform_driver(rpi_ts_driver);
 223
 224 MODULE_AUTHOR("Gordon Hollingworth");
 225 MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>");
 226 MODULE_DESCRIPTION("Raspberry Pi firmware based touchscreen driver");
 227 MODULE_LICENSE("GPL v2");