Input: silead - add pen support

Some Silead touchscreens have support for an active (battery powered)
pen, add support for this.

So far pen-support has only been seen on X86/ACPI (non devicetree) devs,
IOW it is not used in actual devicetree files. The devicetree-bindings
maintainers have requested properties like these to not be added to the
devicetree-bindings, so the new properties are deliberately not added
to the existing silead devicetree-bindings documentation.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20211122220637.11386-3-hdegoede@redhat.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/touchscreen/silead.c b/drivers/input/touchscreen/silead.c
index caa25af53e6ee1ff6fe696cb36ec858e019f646f..3eef8c01090fd528e69f38328c78f5b0b095fb00 100644 (file)
--- a/drivers/input/touchscreen/silead.c
+++ b/drivers/input/touchscreen/silead.c
@@ -67,6 +67,7 @@ struct silead_ts_data {
        struct i2c_client *client;
        struct gpio_desc *gpio_power;
        struct input_dev *input;
+       struct input_dev *pen_input;
        struct regulator_bulk_data regulators[2];
        char fw_name[64];
        struct touchscreen_properties prop;
@@ -77,6 +78,11 @@ struct silead_ts_data {
        int id[SILEAD_MAX_FINGERS];
        u32 efi_fw_min_max[4];
        bool efi_fw_min_max_set;
+       bool pen_supported;
+       bool pen_down;
+       u32 pen_x_res;
+       u32 pen_y_res;
+       int pen_up_count;
 };
 
 struct silead_fw_data {
@@ -144,6 +150,40 @@ static int silead_ts_request_input_dev(struct silead_ts_data *data)
        error = input_register_device(data->input);
        if (error) {
                dev_err(dev, "Failed to register input device: %d\n", error);
+                       return error;
+       }
+
+       return 0;
+}
+
+static int silead_ts_request_pen_input_dev(struct silead_ts_data *data)
+{
+       struct device *dev = &data->client->dev;
+       int error;
+
+       if (!data->pen_supported)
+               return 0;
+
+       data->pen_input = devm_input_allocate_device(dev);
+       if (!data->pen_input)
+               return -ENOMEM;
+
+       input_set_abs_params(data->pen_input, ABS_X, 0, 4095, 0, 0);
+       input_set_abs_params(data->pen_input, ABS_Y, 0, 4095, 0, 0);
+       input_set_capability(data->pen_input, EV_KEY, BTN_TOUCH);
+       input_set_capability(data->pen_input, EV_KEY, BTN_TOOL_PEN);
+       set_bit(INPUT_PROP_DIRECT, data->pen_input->propbit);
+       touchscreen_parse_properties(data->pen_input, false, &data->prop);
+       input_abs_set_res(data->pen_input, ABS_X, data->pen_x_res);
+       input_abs_set_res(data->pen_input, ABS_Y, data->pen_y_res);
+
+       data->pen_input->name = SILEAD_TS_NAME " pen";
+       data->pen_input->phys = "input/pen";
+       data->input->id.bustype = BUS_I2C;
+
+       error = input_register_device(data->pen_input);
+       if (error) {
+               dev_err(dev, "Failed to register pen input device: %d\n", error);
                return error;
        }
 
@@ -161,6 +201,45 @@ static void silead_ts_set_power(struct i2c_client *client,
        }
 }
 
+static bool silead_ts_handle_pen_data(struct silead_ts_data *data, u8 *buf)
+{
+       u8 *coord = buf + SILEAD_POINT_DATA_LEN;
+       struct input_mt_pos pos;
+
+       if (!data->pen_supported || buf[2] != 0x00 || buf[3] != 0x00)
+               return false;
+
+       if (buf[0] == 0x00 && buf[1] == 0x00 && data->pen_down) {
+               data->pen_up_count++;
+               if (data->pen_up_count == 6) {
+                       data->pen_down = false;
+                       goto sync;
+               }
+               return true;
+       }
+
+       if (buf[0] == 0x01 && buf[1] == 0x08) {
+               touchscreen_set_mt_pos(&pos, &data->prop,
+                       get_unaligned_le16(&coord[SILEAD_POINT_X_OFF]) & 0xfff,
+                       get_unaligned_le16(&coord[SILEAD_POINT_Y_OFF]) & 0xfff);
+
+               input_report_abs(data->pen_input, ABS_X, pos.x);
+               input_report_abs(data->pen_input, ABS_Y, pos.y);
+
+               data->pen_up_count = 0;
+               data->pen_down = true;
+               goto sync;
+       }
+
+       return false;
+
+sync:
+       input_report_key(data->pen_input, BTN_TOOL_PEN, data->pen_down);
+       input_report_key(data->pen_input, BTN_TOUCH, data->pen_down);
+       input_sync(data->pen_input);
+       return true;
+}
+
 static void silead_ts_read_data(struct i2c_client *client)
 {
        struct silead_ts_data *data = i2c_get_clientdata(client);
@@ -183,6 +262,9 @@ static void silead_ts_read_data(struct i2c_client *client)
                buf[0] = data->max_fingers;
        }
 
+       if (silead_ts_handle_pen_data(data, buf))
+               goto sync; /* Pen is down, release all previous touches */
+
        touch_nr = 0;
        bufp = buf + SILEAD_POINT_DATA_LEN;
        for (i = 0; i < buf[0]; i++, bufp += SILEAD_POINT_DATA_LEN) {
@@ -225,6 +307,7 @@ static void silead_ts_read_data(struct i2c_client *client)
                        data->pos[i].y, data->id[i], data->slots[i]);
        }
 
+sync:
        input_mt_sync_frame(input);
        input_report_key(input, KEY_LEFTMETA, softbutton_pressed);
        input_sync(input);
@@ -356,6 +439,14 @@ static int silead_ts_load_fw(struct i2c_client *client)
                                                       ARRAY_SIZE(data->efi_fw_min_max));
                if (!error)
                        data->efi_fw_min_max_set = true;
+
+               /* The EFI (platform) embedded fw does not have pen support */
+               if (data->pen_supported) {
+                       dev_warn(dev, "Warning loading '%s' from filesystem failed, using EFI embedded copy.\n",
+                                data->fw_name);
+                       dev_warn(dev, "Warning pen support is known to be broken in the EFI embedded fw version\n");
+                       data->pen_supported = false;
+               }
        }
 
        fw_size = fw->size / sizeof(*fw_data);
@@ -513,6 +604,10 @@ static void silead_ts_read_props(struct i2c_client *client)
                         "silead/%s", str);
        else
                dev_dbg(dev, "Firmware file name read error. Using default.");
+
+       data->pen_supported = device_property_read_bool(dev, "silead,pen-supported");
+       device_property_read_u32(dev, "silead,pen-resolution-x", &data->pen_x_res);
+       device_property_read_u32(dev, "silead,pen-resolution-y", &data->pen_y_res);
 }
 
 #ifdef CONFIG_ACPI
@@ -625,6 +720,10 @@ static int silead_ts_probe(struct i2c_client *client,
        if (error)
                return error;
 
+       error = silead_ts_request_pen_input_dev(data);
+       if (error)
+               return error;
+
        error = devm_request_threaded_irq(dev, client->irq,
                                          NULL, silead_ts_threaded_irq_handler,
                                          IRQF_ONESHOT, client->name, data);