Input: surface3_spi - add surface pen support for Surface 3

This change creates a second input device which will handle input from
a Surface Pen. The Surface Pen supplies a different packet header than
touch events, so it is simple to handle one or the other.

This patch handles both the newer Surface Pen with one button, and the
older variant with a second button to switch to Eraser mode.

Signed-off-by: Stephen Just <stephenjust@gmail.com>
Reviewed-and-tested-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/touchscreen/surface3_spi.c b/drivers/input/touchscreen/surface3_spi.c
index e6cea7ed3d0eb50a52441bcfe5d369c277a8a725..e12fb9b63f3113294f4b745d4c8320dfcc1b016c 100644 (file)
--- a/drivers/input/touchscreen/surface3_spi.c
+++ b/drivers/input/touchscreen/surface3_spi.c
@@ -27,11 +27,14 @@
 #define SURFACE3_PACKET_SIZE   264
 
 #define SURFACE3_REPORT_TOUCH  0xd2
+#define SURFACE3_REPORT_PEN    0x16
 
 struct surface3_ts_data {
        struct spi_device *spi;
        struct gpio_desc *gpiod_rst[2];
        struct input_dev *input_dev;
+       struct input_dev *pen_input_dev;
+       int pen_tool;
 
        u8 rd_buf[SURFACE3_PACKET_SIZE]         ____cacheline_aligned;
 };
@@ -48,6 +51,14 @@ struct surface3_ts_data_finger {
        u32 padding;
 } __packed;
 
+struct surface3_ts_data_pen {
+       u8 status;
+       __le16 x;
+       __le16 y;
+       __le16 pressure;
+       u8 padding;
+} __packed;
+
 static int surface3_spi_read(struct surface3_ts_data *ts_data)
 {
        struct spi_device *spi = ts_data->spi;
@@ -113,6 +124,53 @@ static void surface3_spi_process_touch(struct surface3_ts_data *ts_data, u8 *dat
        input_sync(ts_data->input_dev);
 }
 
+static void surface3_spi_report_pen(struct surface3_ts_data *ts_data,
+                                   struct surface3_ts_data_pen *pen)
+{
+       struct input_dev *dev = ts_data->pen_input_dev;
+       int st = pen->status;
+       int prox = st & 0x01;
+       int rubber = st & 0x18;
+       int tool = (prox && rubber) ? BTN_TOOL_RUBBER : BTN_TOOL_PEN;
+
+       /* fake proximity out to switch tools */
+       if (ts_data->pen_tool != tool) {
+               input_report_key(dev, ts_data->pen_tool, 0);
+               input_sync(dev);
+               ts_data->pen_tool = tool;
+       }
+
+       input_report_key(dev, BTN_TOUCH, st & 0x12);
+
+       input_report_key(dev, ts_data->pen_tool, prox);
+
+       if (st) {
+               input_report_key(dev,
+                                BTN_STYLUS,
+                                st & 0x04);
+
+               input_report_abs(dev,
+                                ABS_X,
+                                get_unaligned_le16(&pen->x));
+               input_report_abs(dev,
+                                ABS_Y,
+                                get_unaligned_le16(&pen->y));
+               input_report_abs(dev,
+                                ABS_PRESSURE,
+                                get_unaligned_le16(&pen->pressure));
+       }
+}
+
+static void surface3_spi_process_pen(struct surface3_ts_data *ts_data, u8 *data)
+{
+       struct surface3_ts_data_pen *pen;
+
+       pen = (struct surface3_ts_data_pen *)&data[15];
+
+       surface3_spi_report_pen(ts_data, pen);
+       input_sync(ts_data->pen_input_dev);
+}
+
 static void surface3_spi_process(struct surface3_ts_data *ts_data)
 {
        const char header[] = {
@@ -125,12 +183,19 @@ static void surface3_spi_process(struct surface3_ts_data *ts_data)
                        "%s header error: %*ph, ignoring...\n",
                        __func__, (int)sizeof(header), data);
 
-       if (data[9] == SURFACE3_REPORT_TOUCH)
+       switch (data[9]) {
+       case SURFACE3_REPORT_TOUCH:
                surface3_spi_process_touch(ts_data, data);
-       else
+               break;
+       case SURFACE3_REPORT_PEN:
+               surface3_spi_process_pen(ts_data, data);
+               break;
+       default:
                dev_err(&ts_data->spi->dev,
                        "%s unknown packet type: %x, ignoring...\n",
                        __func__, data[9]);
+               break;
+       }
 }
 
 static irqreturn_t surface3_spi_irq_handler(int irq, void *dev_id)
@@ -224,6 +289,47 @@ static int surface3_spi_create_touch_input(struct surface3_ts_data *data)
        return 0;
 }
 
+static int surface3_spi_create_pen_input(struct surface3_ts_data *data)
+{
+       struct input_dev *input;
+       int error;
+
+       input = devm_input_allocate_device(&data->spi->dev);
+       if (!input)
+               return -ENOMEM;
+
+       data->pen_input_dev = input;
+       data->pen_tool = BTN_TOOL_PEN;
+
+       __set_bit(INPUT_PROP_DIRECT, input->propbit);
+       __set_bit(INPUT_PROP_POINTER, input->propbit);
+       input_set_abs_params(input, ABS_X, 0, 9600, 0, 0);
+       input_abs_set_res(input, ABS_X, 40);
+       input_set_abs_params(input, ABS_Y, 0, 7200, 0, 0);
+       input_abs_set_res(input, ABS_Y, 48);
+       input_set_abs_params(input, ABS_PRESSURE, 0, 1024, 0, 0);
+       input_set_capability(input, EV_KEY, BTN_TOUCH);
+       input_set_capability(input, EV_KEY, BTN_STYLUS);
+       input_set_capability(input, EV_KEY, BTN_TOOL_PEN);
+       input_set_capability(input, EV_KEY, BTN_TOOL_RUBBER);
+
+       input->name = "Surface3 SPI Pen Input";
+       input->phys = "input/ts";
+       input->id.bustype = BUS_SPI;
+       input->id.vendor = 0x045e;     /* Microsoft */
+       input->id.product = 0x0002;
+       input->id.version = 0x0000;
+
+       error = input_register_device(input);
+       if (error) {
+               dev_err(&data->spi->dev,
+                       "Failed to register input device: %d", error);
+               return error;
+       }
+
+       return 0;
+}
+
 static int surface3_spi_probe(struct spi_device *spi)
 {
        struct surface3_ts_data *data;
@@ -255,6 +361,10 @@ static int surface3_spi_probe(struct spi_device *spi)
        if (error)
                return error;
 
+       error = surface3_spi_create_pen_input(data);
+       if (error)
+               return error;
+
        error = devm_request_threaded_irq(&spi->dev, spi->irq,
                                          NULL, surface3_spi_irq_handler,
                                          IRQF_ONESHOT,