linux/drivers/input/touchscreen/raspberrypi-ts.c
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   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/touchscreen.h>
  20#include <soc/bcm2835/raspberrypi-firmware.h>
  21
  22#define RPI_TS_DEFAULT_WIDTH    800
  23#define RPI_TS_DEFAULT_HEIGHT   480
  24
  25#define RPI_TS_MAX_SUPPORTED_POINTS     10
  26
  27#define RPI_TS_FTS_TOUCH_DOWN           0
  28#define RPI_TS_FTS_TOUCH_CONTACT        2
  29
  30#define RPI_TS_POLL_INTERVAL            17      /* 60fps */
  31
  32#define RPI_TS_NPOINTS_REG_INVALIDATE   99
  33
  34struct rpi_ts {
  35        struct platform_device *pdev;
  36        struct input_dev *input;
  37        struct touchscreen_properties prop;
  38
  39        void __iomem *fw_regs_va;
  40        dma_addr_t fw_regs_phys;
  41
  42        int known_ids;
  43};
  44
  45struct rpi_ts_regs {
  46        u8 device_mode;
  47        u8 gesture_id;
  48        u8 num_points;
  49        struct rpi_ts_touch {
  50                u8 xh;
  51                u8 xl;
  52                u8 yh;
  53                u8 yl;
  54                u8 pressure; /* Not supported */
  55                u8 area;     /* Not supported */
  56        } point[RPI_TS_MAX_SUPPORTED_POINTS];
  57};
  58
  59static void rpi_ts_poll(struct input_dev *input)
  60{
  61        struct rpi_ts *ts = input_get_drvdata(input);
  62        struct rpi_ts_regs regs;
  63        int modified_ids = 0;
  64        long released_ids;
  65        int event_type;
  66        int touchid;
  67        int x, y;
  68        int i;
  69
  70        memcpy_fromio(&regs, ts->fw_regs_va, sizeof(regs));
  71        /*
  72         * We poll the memory based register copy of the touchscreen chip using
  73         * the number of points register to know whether the copy has been
  74         * updated (we write 99 to the memory copy, the GPU will write between
  75         * 0 - 10 points)
  76         */
  77        iowrite8(RPI_TS_NPOINTS_REG_INVALIDATE,
  78                 ts->fw_regs_va + offsetof(struct rpi_ts_regs, num_points));
  79
  80        if (regs.num_points == RPI_TS_NPOINTS_REG_INVALIDATE ||
  81            (regs.num_points == 0 && ts->known_ids == 0))
  82                return;
  83
  84        for (i = 0; i < regs.num_points; i++) {
  85                x = (((int)regs.point[i].xh & 0xf) << 8) + regs.point[i].xl;
  86                y = (((int)regs.point[i].yh & 0xf) << 8) + regs.point[i].yl;
  87                touchid = (regs.point[i].yh >> 4) & 0xf;
  88                event_type = (regs.point[i].xh >> 6) & 0x03;
  89
  90                modified_ids |= BIT(touchid);
  91
  92                if (event_type == RPI_TS_FTS_TOUCH_DOWN ||
  93                    event_type == RPI_TS_FTS_TOUCH_CONTACT) {
  94                        input_mt_slot(input, touchid);
  95                        input_mt_report_slot_state(input, MT_TOOL_FINGER, 1);
  96                        touchscreen_report_pos(input, &ts->prop, x, y, true);
  97                }
  98        }
  99
 100        released_ids = ts->known_ids & ~modified_ids;
 101        for_each_set_bit(i, &released_ids, RPI_TS_MAX_SUPPORTED_POINTS) {
 102                input_mt_slot(input, i);
 103                input_mt_report_slot_state(input, MT_TOOL_FINGER, 0);
 104                modified_ids &= ~(BIT(i));
 105        }
 106        ts->known_ids = modified_ids;
 107
 108        input_mt_sync_frame(input);
 109        input_sync(input);
 110}
 111
 112static void rpi_ts_dma_cleanup(void *data)
 113{
 114        struct rpi_ts *ts = data;
 115        struct device *dev = &ts->pdev->dev;
 116
 117        dma_free_coherent(dev, PAGE_SIZE, ts->fw_regs_va, ts->fw_regs_phys);
 118}
 119
 120static int rpi_ts_probe(struct platform_device *pdev)
 121{
 122        struct device *dev = &pdev->dev;
 123        struct device_node *np = dev->of_node;
 124        struct input_dev *input;
 125        struct device_node *fw_node;
 126        struct rpi_firmware *fw;
 127        struct rpi_ts *ts;
 128        u32 touchbuf;
 129        int error;
 130
 131        fw_node = of_get_parent(np);
 132        if (!fw_node) {
 133                dev_err(dev, "Missing firmware node\n");
 134                return -ENOENT;
 135        }
 136
 137        fw = rpi_firmware_get(fw_node);
 138        of_node_put(fw_node);
 139        if (!fw)
 140                return -EPROBE_DEFER;
 141
 142        ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
 143        if (!ts)
 144                return -ENOMEM;
 145        ts->pdev = pdev;
 146
 147        ts->fw_regs_va = dma_alloc_coherent(dev, PAGE_SIZE, &ts->fw_regs_phys,
 148                                            GFP_KERNEL);
 149        if (!ts->fw_regs_va) {
 150                dev_err(dev, "failed to dma_alloc_coherent\n");
 151                return -ENOMEM;
 152        }
 153
 154        error = devm_add_action_or_reset(dev, rpi_ts_dma_cleanup, ts);
 155        if (error) {
 156                dev_err(dev, "failed to devm_add_action_or_reset, %d\n", error);
 157                return error;
 158        }
 159
 160        touchbuf = (u32)ts->fw_regs_phys;
 161        error = rpi_firmware_property(fw, RPI_FIRMWARE_FRAMEBUFFER_SET_TOUCHBUF,
 162                                      &touchbuf, sizeof(touchbuf));
 163
 164        if (error || touchbuf != 0) {
 165                dev_warn(dev, "Failed to set touchbuf, %d\n", error);
 166                return error;
 167        }
 168
 169        input = devm_input_allocate_device(dev);
 170        if (!input) {
 171                dev_err(dev, "Failed to allocate input device\n");
 172                return -ENOMEM;
 173        }
 174
 175        ts->input = input;
 176        input_set_drvdata(input, ts);
 177
 178        input->name = "raspberrypi-ts";
 179        input->id.bustype = BUS_HOST;
 180
 181        input_set_abs_params(input, ABS_MT_POSITION_X, 0,
 182                             RPI_TS_DEFAULT_WIDTH, 0, 0);
 183        input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
 184                             RPI_TS_DEFAULT_HEIGHT, 0, 0);
 185        touchscreen_parse_properties(input, true, &ts->prop);
 186
 187        error = input_mt_init_slots(input, RPI_TS_MAX_SUPPORTED_POINTS,
 188                                    INPUT_MT_DIRECT);
 189        if (error) {
 190                dev_err(dev, "could not init mt slots, %d\n", error);
 191                return error;
 192        }
 193
 194        error = input_setup_polling(input, rpi_ts_poll);
 195        if (error) {
 196                dev_err(dev, "could not set up polling mode, %d\n", error);
 197                return error;
 198        }
 199
 200        input_set_poll_interval(input, RPI_TS_POLL_INTERVAL);
 201
 202        error = input_register_device(input);
 203        if (error) {
 204                dev_err(dev, "could not register input device, %d\n", error);
 205                return error;
 206        }
 207
 208        return 0;
 209}
 210
 211static const struct of_device_id rpi_ts_match[] = {
 212        { .compatible = "raspberrypi,firmware-ts", },
 213        {},
 214};
 215MODULE_DEVICE_TABLE(of, rpi_ts_match);
 216
 217static struct platform_driver rpi_ts_driver = {
 218        .driver = {
 219                .name = "raspberrypi-ts",
 220                .of_match_table = rpi_ts_match,
 221        },
 222        .probe = rpi_ts_probe,
 223};
 224module_platform_driver(rpi_ts_driver);
 225
 226MODULE_AUTHOR("Gordon Hollingworth");
 227MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>");
 228MODULE_DESCRIPTION("Raspberry Pi firmware based touchscreen driver");
 229MODULE_LICENSE("GPL v2");
 230