Input: add official Raspberry Pi's touchscreen driver

Add's support to Raspberry Pi's 7" Touch device. Instead of using a
conventional bus all information is copied into a memory mapped area by
RPi's firmware.

Based on the driver found in RPi's kernel repository.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

4 files changed, 266 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/input/touchscreen/raspberrypi,firmware-ts.txt b/Documentation/devicetree/bindings/input/touchscreen/raspberrypi,firmware-ts.txt
new file mode 100644
index 000000000000..2a1af240ccc3
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/raspberrypi,firmware-ts.txt
@@ -0,0 +1,26 @@
+Raspberry Pi firmware based 7" touchscreen
+=====================================
+
+Required properties:
+ - compatible: "raspberrypi,firmware-ts"
+
+Optional properties:
+ - firmware: Reference to RPi's firmware device node
+ - touchscreen-size-x: See touchscreen.txt
+ - touchscreen-size-y: See touchscreen.txt
+ - touchscreen-inverted-x: See touchscreen.txt
+ - touchscreen-inverted-y: See touchscreen.txt
+ - touchscreen-swapped-x-y: See touchscreen.txt
+
+Example:
+
+firmware: firmware-rpi {
+        compatible = "raspberrypi,bcm2835-firmware";
+        mboxes = <&mailbox>;
+
+        ts: touchscreen {
+                compatible = "raspberrypi,firmware-ts";
+                touchscreen-size-x = <800>;
+                touchscreen-size-y = <480>;
+        };
+};
diff --git a/drivers/input/touchscreen/Kconfig b/drivers/input/touchscreen/Kconfig
index 5374bd573e66..a391eacf8cf6 100644
--- a/drivers/input/touchscreen/Kconfig
+++ b/drivers/input/touchscreen/Kconfig
@@ -683,6 +683,18 @@ config TOUCHSCREEN_EDT_FT5X06
           To compile this driver as a module, choose M here: the
           module will be called edt-ft5x06.
 
+config TOUCHSCREEN_RASPBERRYPI_FW
+        tristate "Raspberry Pi's firmware base touch screen support"
+        depends on RASPBERRYPI_FIRMWARE || COMPILE_TEST
+        help
+          Say Y here if you have the official Raspberry Pi 7 inch screen 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 c2175163152d..aca7cb04910b 100644
--- a/drivers/input/touchscreen/Makefile
+++ b/drivers/input/touchscreen/Makefile
@@ -108,3 +108,4 @@ 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_FW)        += 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..f456c1125bd6
--- /dev/null
+++ b/drivers/input/touchscreen/raspberrypi-ts.c
@@ -0,0 +1,227 @@
+// 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(&regs, 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");