--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Raspberry Pi firmware based touchscreen driver
+ *
+ * Copyright (C) 2015, 2017 Raspberry Pi
+ * Copyright (C) 2018 Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
+ */
+
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/bitops.h>
+#include <linux/dma-mapping.h>
+#include <linux/platform_device.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/input-polldev.h>
+#include <linux/input/touchscreen.h>
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
+#define RPI_TS_DEFAULT_WIDTH 800
+#define RPI_TS_DEFAULT_HEIGHT 480
+
+#define RPI_TS_MAX_SUPPORTED_POINTS 10
+
+#define RPI_TS_FTS_TOUCH_DOWN 0
+#define RPI_TS_FTS_TOUCH_CONTACT 2
+
+#define RPI_TS_POLL_INTERVAL 17 /* 60fps */
+
+#define RPI_TS_NPOINTS_REG_INVALIDATE 99
+
+struct rpi_ts {
+ struct platform_device *pdev;
+ struct input_polled_dev *poll_dev;
+ struct touchscreen_properties prop;
+
+ void __iomem *fw_regs_va;
+ dma_addr_t fw_regs_phys;
+
+ int known_ids;
+};
+
+struct rpi_ts_regs {
+ u8 device_mode;
+ u8 gesture_id;
+ u8 num_points;
+ struct rpi_ts_touch {
+ u8 xh;
+ u8 xl;
+ u8 yh;
+ u8 yl;
+ u8 pressure; /* Not supported */
+ u8 area; /* Not supported */
+ } point[RPI_TS_MAX_SUPPORTED_POINTS];
+};
+
+static void rpi_ts_poll(struct input_polled_dev *dev)
+{
+ struct input_dev *input = dev->input;
+ struct rpi_ts *ts = dev->private;
+ struct rpi_ts_regs regs;
+ int modified_ids = 0;
+ long released_ids;
+ int event_type;
+ int touchid;
+ int x, y;
+ int i;
+
+ memcpy_fromio(®s, ts->fw_regs_va, sizeof(regs));
+ /*
+ * We poll the memory based register copy of the touchscreen chip using
+ * the number of points register to know whether the copy has been
+ * updated (we write 99 to the memory copy, the GPU will write between
+ * 0 - 10 points)
+ */
+ iowrite8(RPI_TS_NPOINTS_REG_INVALIDATE,
+ ts->fw_regs_va + offsetof(struct rpi_ts_regs, num_points));
+
+ if (regs.num_points == RPI_TS_NPOINTS_REG_INVALIDATE ||
+ (regs.num_points == 0 && ts->known_ids == 0))
+ return;
+
+ for (i = 0; i < regs.num_points; i++) {
+ x = (((int)regs.point[i].xh & 0xf) << 8) + regs.point[i].xl;
+ y = (((int)regs.point[i].yh & 0xf) << 8) + regs.point[i].yl;
+ touchid = (regs.point[i].yh >> 4) & 0xf;
+ event_type = (regs.point[i].xh >> 6) & 0x03;
+
+ modified_ids |= BIT(touchid);
+
+ if (event_type == RPI_TS_FTS_TOUCH_DOWN ||
+ event_type == RPI_TS_FTS_TOUCH_CONTACT) {
+ input_mt_slot(input, touchid);
+ input_mt_report_slot_state(input, MT_TOOL_FINGER, 1);
+ touchscreen_report_pos(input, &ts->prop, x, y, true);
+ }
+ }
+
+ released_ids = ts->known_ids & ~modified_ids;
+ for_each_set_bit(i, &released_ids, RPI_TS_MAX_SUPPORTED_POINTS) {
+ input_mt_slot(input, i);
+ input_mt_report_slot_state(input, MT_TOOL_FINGER, 0);
+ modified_ids &= ~(BIT(i));
+ }
+ ts->known_ids = modified_ids;
+
+ input_mt_sync_frame(input);
+ input_sync(input);
+}
+
+static void rpi_ts_dma_cleanup(void *data)
+{
+ struct rpi_ts *ts = data;
+ struct device *dev = &ts->pdev->dev;
+
+ dma_free_coherent(dev, PAGE_SIZE, ts->fw_regs_va, ts->fw_regs_phys);
+}
+
+static int rpi_ts_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct input_polled_dev *poll_dev;
+ struct device_node *fw_node;
+ struct rpi_firmware *fw;
+ struct input_dev *input;
+ struct rpi_ts *ts;
+ u32 touchbuf;
+ int error;
+
+ fw_node = of_get_parent(np);
+ if (!fw_node) {
+ dev_err(dev, "Missing firmware node\n");
+ return -ENOENT;
+ }
+
+ fw = rpi_firmware_get(fw_node);
+ of_node_put(fw_node);
+ if (!fw)
+ return -EPROBE_DEFER;
+
+ ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
+ if (!ts)
+ return -ENOMEM;
+ ts->pdev = pdev;
+
+ ts->fw_regs_va = dma_zalloc_coherent(dev, PAGE_SIZE, &ts->fw_regs_phys,
+ GFP_KERNEL);
+ if (!ts->fw_regs_va) {
+ dev_err(dev, "failed to dma_alloc_coherent\n");
+ return -ENOMEM;
+ }
+
+ error = devm_add_action_or_reset(dev, rpi_ts_dma_cleanup, ts);
+ if (error) {
+ dev_err(dev, "failed to devm_add_action_or_reset, %d\n", error);
+ return error;
+ }
+
+
+ touchbuf = (u32)ts->fw_regs_phys;
+ error = rpi_firmware_property(fw, RPI_FIRMWARE_FRAMEBUFFER_SET_TOUCHBUF,
+ &touchbuf, sizeof(touchbuf));
+
+ if (error || touchbuf != 0) {
+ dev_warn(dev, "Failed to set touchbuf, %d\n", error);
+ return error;
+ }
+
+ poll_dev = devm_input_allocate_polled_device(dev);
+ if (!poll_dev) {
+ dev_err(dev, "Failed to allocate input device\n");
+ return -ENOMEM;
+ }
+ ts->poll_dev = poll_dev;
+ input = poll_dev->input;
+
+ input->name = "raspberrypi-ts";
+ input->id.bustype = BUS_HOST;
+ poll_dev->poll_interval = RPI_TS_POLL_INTERVAL;
+ poll_dev->poll = rpi_ts_poll;
+ poll_dev->private = ts;
+
+ input_set_abs_params(input, ABS_MT_POSITION_X, 0,
+ RPI_TS_DEFAULT_WIDTH, 0, 0);
+ input_set_abs_params(input, ABS_MT_POSITION_Y, 0,
+ RPI_TS_DEFAULT_HEIGHT, 0, 0);
+ touchscreen_parse_properties(input, true, &ts->prop);
+
+ error = input_mt_init_slots(input, RPI_TS_MAX_SUPPORTED_POINTS,
+ INPUT_MT_DIRECT);
+ if (error) {
+ dev_err(dev, "could not init mt slots, %d\n", error);
+ return error;
+ }
+
+ error = input_register_polled_device(poll_dev);
+ if (error) {
+ dev_err(dev, "could not register input device, %d\n", error);
+ return error;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id rpi_ts_match[] = {
+ { .compatible = "raspberrypi,firmware-ts", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, rpi_ts_match);
+
+static struct platform_driver rpi_ts_driver = {
+ .driver = {
+ .name = "raspberrypi-ts",
+ .of_match_table = rpi_ts_match,
+ },
+ .probe = rpi_ts_probe,
+};
+module_platform_driver(rpi_ts_driver);
+
+MODULE_AUTHOR("Gordon Hollingworth");
+MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@suse.de>");
+MODULE_DESCRIPTION("Raspberry Pi firmware based touchscreen driver");
+MODULE_LICENSE("GPL v2");
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