[PATCH RFC 1/2] input: add official Raspberry Pi's 7" touchscreen driver
From: Nicolas Saenz Julienne
Date: Wed Dec 05 2018 - 17:13:09 EST
Adds support to Raspberry Pi's 7" touchscreen device. Instead of using
a conventional bus all information is copied into a memory mapped area
by RPi's VC4 firmware.
Based on the driver found in RPi's downstream kernel repository.
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>
---
drivers/input/touchscreen/Kconfig | 12 +
drivers/input/touchscreen/Makefile | 1 +
drivers/input/touchscreen/raspberrypi-ts.c | 252 +++++++++++++++++++++
3 files changed, 265 insertions(+)
create mode 100644 drivers/input/touchscreen/raspberrypi-ts.c
diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 2a80675cfd94..8d0fcb3dc8a8 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -696,6 +696,18 @@ config TOUCHSCREEN_EDT_FT5X06
To compile this driver as a module, choose M here: the
module will be called edt-ft5x06.
+config TOUCHSCREEN_RASPBERRYPI_TS
+ tristate "Raspberry Pi's firmware base touch screen support"
+ depends on OF
+ help
+ Say Y here if you have the official Raspberry Pi 7' touchscren
+ connected on your system.
+
+ If unsure, say N.
+
+ To compile this driver as a module, choose M here: the
+ module will be called raspberrypi-ts.
+
config TOUCHSCREEN_MIGOR
tristate "Renesas MIGO-R touchscreen"
depends on (SH_MIGOR || COMPILE_TEST) && I2C
diff --git a/drivers/input/touchscreen/Makefile b/drivers/input/touchscreen/Makefile
index 5911a4190cd2..3eccb1925e89 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -109,3 +109,4 @@ obj-$(CONFIG_TOUCHSCREEN_ZET6223) += zet6223.o
obj-$(CONFIG_TOUCHSCREEN_ZFORCE) += zforce_ts.o
obj-$(CONFIG_TOUCHSCREEN_COLIBRI_VF50) += colibri-vf50-ts.o
obj-$(CONFIG_TOUCHSCREEN_ROHM_BU21023) += rohm_bu21023.o
+obj-$(CONFIG_TOUCHSCREEN_RASPBERRYPI_TS) += raspberrypi-ts.o
diff --git a/drivers/input/touchscreen/raspberrypi-ts.c b/drivers/input/touchscreen/raspberrypi-ts.c
new file mode 100644
index 000000000000..9d29411a5674
--- /dev/null
+++ b/drivers/input/touchscreen/raspberrypi-ts.c
@@ -0,0 +1,252 @@
+/*
+ * Raspberry Pi 3 firmware based touchscreen driver
+ *
+ * Copyright (C) 2015, 2017 Raspberry Pi
+ * Copyright (C) 2018 Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/io.h>
+#include <linux/slab.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/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
+
+struct rpi_ts {
+ struct input_dev *input;
+ struct touchscreen_properties prop;
+
+ void __iomem *ts_base;
+ dma_addr_t bus_addr;
+
+ struct delayed_work work;
+ int known_ids;
+};
+
+struct rpi_ts_regs {
+ uint8_t device_mode;
+ uint8_t gesture_id;
+ uint8_t num_points;
+ struct rpi_ts_touch {
+ uint8_t xh;
+ uint8_t xl;
+ uint8_t yh;
+ uint8_t yl;
+ uint8_t pressure; /* Not supported */
+ uint8_t area; /* Not supported */
+ } point[RPI_TS_MAX_SUPPORTED_POINTS];
+};
+
+/*
+ * This process polls the memory based register copy of the touch screen chip
+ * registers 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)
+ */
+static void rpi_ts_work(struct work_struct *work)
+{
+ struct rpi_ts *ts = container_of(work, struct rpi_ts, work.work);
+ struct input_dev *input = ts->input;
+ struct rpi_ts_regs regs;
+ int modified_ids = 0;
+ int released_ids;
+ int event_type;
+ int touchid;
+ int x, y;
+ int i;
+
+ memcpy_fromio(®s, ts->ts_base, sizeof(struct rpi_ts_regs));
+ iowrite8(99, ts->ts_base + offsetof(struct rpi_ts_regs, num_points));
+
+ if (regs.num_points == 99 ||
+ (regs.num_points == 0 && ts->known_ids == 0))
+ goto out;
+
+ 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 (i = 0; released_ids && i < RPI_TS_MAX_SUPPORTED_POINTS; i++) {
+ if (released_ids & BIT(i)) {
+ 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_report_pointer_emulation(ts->input, true);
+ input_sync(ts->input);
+
+out:
+ schedule_delayed_work(&ts->work, msecs_to_jiffies(17)); /* 60 fps */
+}
+
+static int rpi_ts_open(struct input_dev *dev)
+{
+ struct rpi_ts *ts = input_get_drvdata(dev);
+
+ schedule_delayed_work(&ts->work, 0);
+
+ return 0;
+}
+
+static void rpi_ts_close(struct input_dev *dev)
+{
+ struct rpi_ts *ts = input_get_drvdata(dev);
+
+ cancel_delayed_work_sync(&ts->work);
+}
+
+static int rpi_ts_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct device_node *fw_node;
+ struct input_dev *input;
+ struct rpi_firmware *fw;
+ struct rpi_ts *ts;
+ u32 touchbuf;
+ int err = 0;
+
+ fw_node = of_get_parent(np);
+ if (!fw_node) {
+ dev_err(dev, "Missing firmware node\n");
+ return -ENOENT;
+ }
+
+ fw = rpi_firmware_get(fw_node);
+ if (!fw)
+ return -EPROBE_DEFER;
+
+ ts = devm_kzalloc(dev, sizeof(struct rpi_ts), GFP_KERNEL);
+ if (!ts) {
+ dev_err(dev, "Failed to allocate memory\n");
+ return -ENOMEM;
+ }
+
+ input = input_allocate_device();
+ if (!input) {
+ dev_err(dev, "Failed to allocate input device\n");
+ return -ENOMEM;
+ }
+ ts->input = input;
+
+ ts->ts_base = dma_zalloc_coherent(dev, PAGE_SIZE, &ts->bus_addr,
+ GFP_KERNEL);
+ if (!ts->ts_base) {
+ dev_err(dev, "failed to dma_alloc_coherent\n");
+ err = -ENOMEM;
+ goto undegister_input_device;
+ }
+
+ touchbuf = (u32)ts->bus_addr;
+ err = rpi_firmware_property(fw, RPI_FIRMWARE_FRAMEBUFFER_SET_TOUCHBUF,
+ &touchbuf, sizeof(touchbuf));
+
+ if (err || touchbuf != 0) {
+ dev_warn(dev, "Failed to set touchbuf, trying to get err:%x\n",
+ err);
+ goto clean_dma_buf;
+ }
+
+ INIT_DELAYED_WORK(&ts->work, rpi_ts_work);
+ platform_set_drvdata(pdev, ts);
+
+ input->name = "raspberrypi-ts";
+ input->id.bustype = BUS_HOST;
+ input->open = rpi_ts_open;
+ input->close = rpi_ts_close;
+ input->dev.parent = &pdev->dev;
+
+ __set_bit(EV_KEY, input->evbit);
+ __set_bit(EV_SYN, input->evbit);
+ __set_bit(EV_ABS, input->evbit);
+
+ 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);
+
+ input_mt_init_slots(input, RPI_TS_MAX_SUPPORTED_POINTS,
+ INPUT_MT_DIRECT);
+
+ input_set_drvdata(input, ts);
+
+ err = input_register_device(input);
+ if (err) {
+ dev_err(dev, "could not register input device, %d\n",
+ err);
+ goto clean_dma_buf;
+ }
+ return 0;
+
+clean_dma_buf:
+ dma_free_coherent(dev, PAGE_SIZE, ts->ts_base, ts->bus_addr);
+undegister_input_device:
+ input_unregister_device(ts->input);
+
+ return err;
+}
+
+static int rpi_ts_remove(struct platform_device *pdev)
+{
+ struct rpi_ts *ts = (struct rpi_ts *)platform_get_drvdata(pdev);
+
+ input_unregister_device(ts->input);
+ dma_free_coherent(&pdev->dev, PAGE_SIZE, ts->ts_base, ts->bus_addr);
+ 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",
+ .owner = THIS_MODULE,
+ .of_match_table = rpi_ts_match,
+ },
+ .probe = rpi_ts_probe,
+ .remove = rpi_ts_remove,
+};
+
+module_platform_driver(rpi_ts_driver);
+
+MODULE_AUTHOR("Gordon Hollingworth");
+MODULE_AUTHOR("Nicolas Saenz Julienne <nsaenzjulienne@xxxxxxx>");
+MODULE_DESCRIPTION("Raspberry Pi 3 firmware based touchscreen driver");
+MODULE_LICENSE("GPL");
--
2.19.2