Input: elan_i2c - add product IDs FW names

Previously the elan_i2c touchpad driver would simply request the firmware
"/lib/firmware/elan_i2c.bin", which does not work well if there are
multiple such devices in the system.

Let's append the "product ID" (by using the same function as the sysfs
interface for consistency) to the filename.  This results in filenames of
the form "/lib/firmware/elan_i2c_72.0.bin", allowing you to support
multiple elan_i2c touchpads on the same device by simply naming each
device's FW with its corresponding product ID.  This way when you trigger a
fw update the driver will load the correct binary.
Signed-off-by: Charlie Mooney <charliemooney@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/mouse/elan_i2c.h

@@ -28,7 +28,8 @@
 #define ETP_PRESSURE_OFFSET	25
 
 /* IAP Firmware handling */
-#define ETP_FW_NAME		"elan_i2c.bin"
+#define ETP_PRODUCT_ID_FORMAT_STRING	"%d.0"
+#define ETP_FW_NAME		"elan_i2c_" ETP_PRODUCT_ID_FORMAT_STRING ".bin"
 #define ETP_IAP_START_ADDR	0x0083
 #define ETP_FW_IAP_PAGE_ERR	(1 << 5)
 #define ETP_FW_IAP_INTF_ERR	(1 << 4)

drivers/input/mouse/elan_i2c_core.c

@@ -4,7 +4,7 @@
  * Copyright (c) 2013 ELAN Microelectronics Corp.
  *
  * Author: 林政維 (Duson Lin) <dusonlin@emc.com.tw>
- * Version: 1.5.8
+ * Version: 1.5.9
  *
  * Based on cyapa driver:
  * copyright (c) 2011-2012 Cypress Semiconductor, Inc.
@@ -40,7 +40,7 @@
 #include "elan_i2c.h"
 
 #define DRIVER_NAME		"elan_i2c"
-#define ELAN_DRIVER_VERSION	"1.5.8"
+#define ELAN_DRIVER_VERSION	"1.5.9"
 #define ETP_MAX_PRESSURE	255
 #define ETP_FWIDTH_REDUCE	90
 #define ETP_FINGER_WIDTH	15
@@ -438,7 +438,8 @@ static ssize_t elan_sysfs_read_product_id(struct device *dev,
 	struct i2c_client *client = to_i2c_client(dev);
 	struct elan_tp_data *data = i2c_get_clientdata(client);
 
-	return sprintf(buf, "%d.0\n", data->product_id);
+	return sprintf(buf, ETP_PRODUCT_ID_FORMAT_STRING "\n",
+		       data->product_id);
 }
 
 static ssize_t elan_sysfs_read_fw_ver(struct device *dev,
@@ -477,14 +478,23 @@ static ssize_t elan_sysfs_update_fw(struct device *dev,
 {
 	struct elan_tp_data *data = dev_get_drvdata(dev);
 	const struct firmware *fw;
+	char *fw_name;
 	int error;
 	const u8 *fw_signature;
 	static const u8 signature[] = {0xAA, 0x55, 0xCC, 0x33, 0xFF, 0xFF};
 
-	error = request_firmware(&fw, ETP_FW_NAME, dev);
+	/* Look for a firmware with the product id appended. */
+	fw_name = kasprintf(GFP_KERNEL, ETP_FW_NAME, data->product_id);
+	if (!fw_name) {
+		dev_err(dev, "failed to allocate memory for firmware name\n");
+		return -ENOMEM;
+	}
+
+	dev_info(dev, "requesting fw '%s'\n", fw_name);
+	error = request_firmware(&fw, fw_name, dev);
+	kfree(fw_name);
 	if (error) {
-		dev_err(dev, "cannot load firmware %s: %d\n",
-			ETP_FW_NAME, error);
+		dev_err(dev, "failed to request firmware: %d\n", error);
 		return error;
 	}