[PATCH 1/1] Input: atmel_mxt_ts - allow specification of firmware file name

[Jiada Wang <jiada_wang@xxxxxxxxxx>]

From: Nick Dyer <nick.dyer@xxxxxxxxxxx>

On platforms which have multiple device instances using this driver, the
firmware may be different on each device. This patch makes the user give
the name of the firmware file when flashing.

This also prevents accidental triggering of the firmware load process.

Signed-off-by: Nick Dyer <nick.dyer@xxxxxxxxxxx>
Acked-by: Benson Leung <bleung@xxxxxxxxxxxx>
Acked-by: Yufeng Shen <miletus@xxxxxxxxxxxx>
(cherry picked from ndyer/linux/for-upstream commit 76ebb7cee971cb42dfb0a3a9224403b8b09abcf1)
[gdavis: Forward port and fix conflicts.]
Signed-off-by: George G. Davis <george_davis@xxxxxxxxxx>
Signed-off-by: Jiada Wang <jiada_wang@xxxxxxxxxx>
---
 drivers/input/touchscreen/atmel_mxt_ts.c | 42 ++++++++++++++++++++----
 1 file changed, 36 insertions(+), 6 deletions(-)

diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
index a2189739e30f..024dee7a3571 100644
--- a/drivers/input/touchscreen/atmel_mxt_ts.c
+++ b/drivers/input/touchscreen/atmel_mxt_ts.c
@@ -30,8 +30,6 @@
 #include <media/videobuf2-v4l2.h>
 #include <media/videobuf2-vmalloc.h>
 
-/* Firmware files */
-#define MXT_FW_NAME		"maxtouch.fw"
 #define MXT_CFG_NAME		"maxtouch.cfg"
 #define MXT_CFG_MAGIC		"OBP_RAW V1"
 
@@ -308,6 +306,7 @@ struct mxt_data {
 	struct t7_config t7_cfg;
 	struct mxt_dbg dbg;
 	struct gpio_desc *reset_gpio;
+	char *fw_name;
 
 	/* Cached parameters from object table */
 	u16 T5_address;
@@ -2766,7 +2765,7 @@ static int mxt_check_firmware_format(struct device *dev,
 	return -EINVAL;
 }
 
-static int mxt_load_fw(struct device *dev, const char *fn)
+static int mxt_load_fw(struct device *dev)
 {
 	struct mxt_data *data = dev_get_drvdata(dev);
 	const struct firmware *fw = NULL;
@@ -2776,9 +2775,9 @@ static int mxt_load_fw(struct device *dev, const char *fn)
 	unsigned int frame = 0;
 	int ret;
 
-	ret = request_firmware(&fw, fn, dev);
+	ret = request_firmware(&fw, data->fw_name, dev);
 	if (ret) {
-		dev_err(dev, "Unable to open firmware %s\n", fn);
+		dev_err(dev, "Unable to open firmware %s\n", data->fw_name);
 		return ret;
 	}
 
@@ -2887,6 +2886,33 @@ static int mxt_load_fw(struct device *dev, const char *fn)
 	return ret;
 }
 
+static int mxt_update_file_name(struct device *dev, char **file_name,
+				const char *buf, size_t count)
+{
+	char *file_name_tmp;
+
+	/* Simple sanity check */
+	if (count > 64) {
+		dev_warn(dev, "File name too long\n");
+		return -EINVAL;
+	}
+
+	file_name_tmp = krealloc(*file_name, count + 1, GFP_KERNEL);
+	if (!file_name_tmp)
+		return -ENOMEM;
+
+	*file_name = file_name_tmp;
+	memcpy(*file_name, buf, count);
+
+	/* Echo into the sysfs entry may append newline at the end of buf */
+	if (buf[count - 1] == '\n')
+		(*file_name)[count - 1] = '\0';
+	else
+		(*file_name)[count] = '\0';
+
+	return 0;
+}
+
 static ssize_t mxt_update_fw_store(struct device *dev,
 					struct device_attribute *attr,
 					const char *buf, size_t count)
@@ -2894,7 +2920,11 @@ static ssize_t mxt_update_fw_store(struct device *dev,
 	struct mxt_data *data = dev_get_drvdata(dev);
 	int error;
 
-	error = mxt_load_fw(dev, MXT_FW_NAME);
+	error = mxt_update_file_name(dev, &data->fw_name, buf, count);
+	if (error)
+		return error;
+
+	error = mxt_load_fw(dev);
 	if (error) {
 		dev_err(dev, "The firmware update failed(%d)\n", error);
 		count = error;
-- 
2.17.1