Implement set profile resolution dpi

Works only in Logitech with adjustable DPI for now (MX Master).

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>

src/driver-etekcity.c

@@ -354,6 +354,12 @@ etekcity_write_button(struct ratbag_button *button)
 	return 0;
 }
 
+static int
+etekcity_write_resolution_dpi(struct ratbag_profile *profile, int dpi)
+{
+	return -ENOTSUP;
+}
+
 static int
 etekcity_probe(struct ratbag_device *device, const struct ratbag_id id)
 {
@@ -439,4 +445,5 @@ struct ratbag_driver etekcity_driver = {
 	.has_capability = etekcity_has_capability,
 	.read_button = etekcity_read_button,
 	.write_button = etekcity_write_button,
+	.write_resolution_dpi = etekcity_write_resolution_dpi,
 };

src/driver-hidpp20.c

@@ -73,6 +73,18 @@ hidpp20drv_write_button(struct ratbag_button *button)
 static int
 hidpp20drv_has_capability(const struct ratbag_device *device, enum ratbag_capability cap)
 {
+	/*
+	 * We need to force the non const, but we will not change anything,
+	 * promise!
+	 */
+	struct hidpp20drv_data *drv_data = ratbag_get_drv_data((struct ratbag_device *)device);
+
+	switch (cap) {
+	case RATBAG_CAP_SWITCHABLE_RESOLUTION:
+		return !!(drv_data->capabilities & HIDPP_CAP_SWITCHABLE_RESOLUTION_2201);
+	default:
+		return 0;
+	}
 	return 0;
 }
 
@@ -85,7 +97,7 @@ hidpp20drv_current_profile(struct ratbag_device *device)
 static int
 hidpp20drv_set_current_profile(struct ratbag_device *device, unsigned int index)
 {
-	return -1;
+	return -ENOTSUP;
 }
 
 static int
@@ -136,6 +148,58 @@ hidpp20drv_read_resolution_dpi(struct ratbag_device *device)
 	return 0;
 }
 
+static int
+hidpp20drv_write_resolution_dpi(struct ratbag_profile *profile, int dpi)
+{
+	struct ratbag_device *device = profile->device;
+	struct ratbag *ratbag = device->ratbag;
+	struct hidpp20drv_data *drv_data = ratbag_get_drv_data(device);
+	struct hidpp20_sensor *sensors, *sensor;
+	int rc, i;
+
+	if (!(drv_data->capabilities & HIDPP_CAP_SWITCHABLE_RESOLUTION_2201))
+		return -ENOTSUP;
+
+	rc = hidpp20_adjustable_dpi_get_sensors(device, &sensors);
+	if (rc < 0) {
+		log_error(ratbag,
+			  "Error while requesting resolution: %s (%d)\n",
+			  strerror(-rc), rc);
+		return 0;
+	} else if (rc == 0) {
+		log_error(ratbag, "Error, no compatible sensors found.\n");
+		return 0;
+	}
+
+	/* just for clarity, we use the first available sensor only */
+	sensor = &sensors[0];
+
+	/* validate that the sensor accepts the given DPI */
+	rc = -EINVAL;
+	if (dpi < sensor->dpi_min || dpi > sensor->dpi_max)
+		goto out;
+	if (sensor->dpi_steps) {
+		for (i = sensor->dpi_min; i < dpi; i += sensor->dpi_steps) {
+		}
+		if (i != dpi)
+			goto out;
+	} else {
+		i = 0;
+		while (sensor->dpi_list[i]) {
+			if (sensor->dpi_list[i] == dpi)
+				break;
+		}
+		if (sensor->dpi_list[i] != dpi)
+			goto out;
+	}
+
+	rc = hidpp20_adjustable_dpi_set_sensor_dpi(device, sensor, dpi);
+
+out:
+	free(sensors);
+	return rc;
+}
+
 static void
 hidpp20drv_read_profile(struct ratbag_profile *profile, unsigned int index)
 {
@@ -334,4 +398,5 @@ struct ratbag_driver hidpp20_driver = {
 	.has_capability = hidpp20drv_has_capability,
 	.read_button = hidpp20drv_read_button,
 	.write_button = hidpp20drv_write_button,
+	.write_resolution_dpi = hidpp20drv_write_resolution_dpi,
 };

src/hidpp20.c

@@ -578,6 +578,40 @@ err:
 	return rc;
 }
 
+int hidpp20_adjustable_dpi_set_sensor_dpi(struct ratbag_device *device,
+					  struct hidpp20_sensor *sensor, uint16_t dpi)
+{
+	uint8_t feature_index, feature_type, feature_version;
+	int rc;
+	union hidpp20_message msg = {
+		.msg.report_id = REPORT_ID_LONG,
+		.msg.device_idx = 0xff,
+		.msg.address = CMD_ADJUSTABLE_DPI_SET_SENSOR_DPI,
+		.msg.parameters[0] = sensor->index,
+		.msg.parameters[1] = dpi >> 8,
+		.msg.parameters[2] = dpi & 0xff,
+	};
+
+	rc = hidpp_root_get_feature(device,
+				    HIDPP_PAGE_ADJUSTABLE_DPI,
+				    &feature_index,
+				    &feature_type,
+				    &feature_version);
+	if (rc)
+		return rc;
+
+	msg.msg.sub_id = feature_index;
+
+	rc = hidpp20_request_command(device, &msg);
+	if (rc)
+		return rc;
+
+	if (hidpp20_get_unaligned_u16(&msg.msg.parameters[1]) != dpi)
+		return -EIO;
+
+	return 0;
+}
+
 /* -------------------------------------------------------------------------- */
 /* 0x1b04: Special keys and mouse buttons                                     */
 /* -------------------------------------------------------------------------- */

src/hidpp20.h

@@ -130,6 +130,13 @@ struct hidpp20_sensor {
 int hidpp20_adjustable_dpi_get_sensors(struct ratbag_device *device,
 				       struct hidpp20_sensor **sensors_list);
 
+/**
+ * set the current dpi of the provided sensor. sensor must have been
+ * allocated by  hidpp20_adjustable_dpi_get_sensors()
+ */
+int hidpp20_adjustable_dpi_set_sensor_dpi(struct ratbag_device *device,
+					  struct hidpp20_sensor *sensor, uint16_t dpi);
+
 /* -------------------------------------------------------------------------- */
 /* 0x1b04: Special keys and mouse buttons                                     */
 /* -------------------------------------------------------------------------- */

src/libratbag-private.h

@@ -163,6 +163,13 @@ struct ratbag_driver {
 	 */
 	int (*write_button)(struct ratbag_button *button);
 
+	/** For the given profile, overwrite the current resolution
+	 * of the sensor expressed in DPI, and commit it to the hardware.
+	 *
+	 * Mandatory if the driver exports RATBAG_CAP_SWITCHABLE_RESOLUTION.
+	 */
+	int (*write_resolution_dpi)(struct ratbag_profile *profile, int dpi);
+
 	/* private */
 	struct list link;
 };

src/libratbag.c

@@ -607,6 +607,17 @@ ratbag_profile_get_resolution_dpi(const struct ratbag_profile *profile)
 	return profile->current_dpi;
 }
 
+LIBRATBAG_EXPORT int
+ratbag_profile_set_resolution_dpi(struct ratbag_profile *profile, int dpi)
+{
+	if (!ratbag_device_has_capability(profile->device,
+					  RATBAG_CAP_SWITCHABLE_RESOLUTION))
+		return -ENOTSUP;
+
+	assert(profile->device->driver->write_resolution_dpi);
+	return profile->device->driver->write_resolution_dpi(profile, dpi);
+}
+
 LIBRATBAG_EXPORT int
 ratbag_profile_get_report_rate_hz(const struct ratbag_profile *profile)
 {

src/libratbag.sym

@@ -23,6 +23,7 @@ global:
 	ratbag_profile_get_button_by_index;
 	ratbag_profile_get_report_rate_hz;
 	ratbag_profile_get_resolution_dpi;
+	ratbag_profile_set_resolution_dpi;
 	ratbag_profile_ref;
 	ratbag_profile_unref;
 	ratbag_ref;

tools/ratbag-command.c

@@ -488,10 +488,71 @@ static const struct ratbag_cmd cmd_list = {
 	.help = "List the available devices",
 };
 
+static int
+ratbag_cmd_switch_dpi(struct ratbag *ratbag, uint32_t flags, int argc, char **argv)
+{
+	const char *path;
+	struct ratbag_device *device;
+	struct ratbag_button *button_6, *button_7;
+	struct ratbag_profile *profile = NULL;
+	int rc = 1, commit = 0;
+	int dpi;
+
+	if (argc != 2) {
+		usage();
+		return 1;
+	}
+
+	dpi = atoi(argv[0]);
+	path = argv[1];
+
+	device = ratbag_cmd_open_device(ratbag, path);
+	if (!device) {
+		error("Looks like '%s' is not supported\n", path);
+		return 1;
+	}
+
+	if (!ratbag_device_has_capability(device,
+					  RATBAG_CAP_SWITCHABLE_RESOLUTION)) {
+		error("Looks like '%s' has no switchable resolution\n", path);
+		goto out;
+	}
+
+	profile = ratbag_device_get_active_profile(device);
+	if (!profile) {
+		error("Huh hoh, something bad happened, unable to retrieve the active profile\n");
+		goto out;
+	}
+
+	rc = ratbag_profile_set_resolution_dpi(profile, dpi);
+	if (!rc)
+		printf("Switched the current resolution profile of '%s' to %d dpi\n",
+		       ratbag_device_get_name(device),
+		       dpi);
+	else
+		error("can't seem to be able to change the dpi: %s (%d)\n",
+		      strerror(-rc),
+		      rc);
+
+out:
+	profile = ratbag_profile_unref(profile);
+
+	device = ratbag_device_unref(device);
+	return rc;
+}
+
+static const struct ratbag_cmd cmd_switch_dpi = {
+	.name = "switch-dpi",
+	.cmd = ratbag_cmd_switch_dpi,
+	.args = "N",
+	.help = "Switch the resolution of the mouse in the active profile",
+};
+
 static const struct ratbag_cmd *ratbag_commands[] = {
 	&cmd_info,
-	&cmd_switch_etekcity,
 	&cmd_list,
+	&cmd_switch_etekcity,
+	&cmd_switch_dpi,
 	&cmd_switch_profile,
 	NULL,
 };