Input: cyapa - add gen3 trackpad read baseline support

Add read baseline function supported for gen3 trackpad device, it can be
used through sysfs baseline interface.
Signed-off-by: Dudley Du <dudl@cypress.com>
Tested-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/cyapa_gen3.c

@@ -783,6 +783,76 @@ static int cyapa_gen3_do_fw_update(struct cyapa *cyapa,
 	return 0;
 }
 
+static ssize_t cyapa_gen3_show_baseline(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct cyapa *cyapa = dev_get_drvdata(dev);
+	int max_baseline, min_baseline;
+	int tries;
+	int ret;
+
+	ret = cyapa_read_byte(cyapa, CYAPA_CMD_DEV_STATUS);
+	if (ret < 0) {
+		dev_err(dev, "Error reading dev status. err = %d\n", ret);
+		goto out;
+	}
+	if ((ret & CYAPA_DEV_NORMAL) != CYAPA_DEV_NORMAL) {
+		dev_warn(dev, "Trackpad device is busy. device state = 0x%x\n",
+			 ret);
+		ret = -EAGAIN;
+		goto out;
+	}
+
+	ret = cyapa_write_byte(cyapa, CYAPA_CMD_SOFT_RESET,
+			       OP_REPORT_BASELINE_MASK);
+	if (ret < 0) {
+		dev_err(dev, "Failed to send report baseline command. %d\n",
+			ret);
+		goto out;
+	}
+
+	tries = 3;  /* Try for 30 to 60 ms */
+	do {
+		usleep_range(10000, 20000);
+
+		ret = cyapa_read_byte(cyapa, CYAPA_CMD_DEV_STATUS);
+		if (ret < 0) {
+			dev_err(dev, "Error reading dev status. err = %d\n",
+				ret);
+			goto out;
+		}
+		if ((ret & CYAPA_DEV_NORMAL) == CYAPA_DEV_NORMAL)
+			break;
+	} while (--tries);
+
+	if (tries == 0) {
+		dev_err(dev, "Device timed out going to Normal state.\n");
+		ret = -ETIMEDOUT;
+		goto out;
+	}
+
+	ret = cyapa_read_byte(cyapa, CYAPA_CMD_MAX_BASELINE);
+	if (ret < 0) {
+		dev_err(dev, "Failed to read max baseline. err = %d\n", ret);
+		goto out;
+	}
+	max_baseline = ret;
+
+	ret = cyapa_read_byte(cyapa, CYAPA_CMD_MIN_BASELINE);
+	if (ret < 0) {
+		dev_err(dev, "Failed to read min baseline. err = %d\n", ret);
+		goto out;
+	}
+	min_baseline = ret;
+
+	dev_dbg(dev, "Baseline report successful. Max: %d Min: %d\n",
+		max_baseline, min_baseline);
+	ret = scnprintf(buf, PAGE_SIZE, "%d %d\n", max_baseline, min_baseline);
+
+out:
+	return ret;
+}
+
 /*
  * cyapa_get_wait_time_for_pwr_cmd
  *
@@ -1104,6 +1174,8 @@ const struct cyapa_dev_ops cyapa_gen3_ops = {
 	.bl_deactivate = cyapa_gen3_bl_deactivate,
 	.bl_initiate = cyapa_gen3_bl_initiate,
 
+	.show_baseline = cyapa_gen3_show_baseline,
+
 	.initialize = cyapa_gen3_initialize,
 
 	.state_parse = cyapa_gen3_state_parse,