[PATCH 2/4] cp210x: Unify code for set/get config control messages

[Petr Tesarik <ptesarik@suse.com>]

From: Petr Tesarik <ptesarik@suse.cz>

There is a lot of overlap between the two functions (e.g. calculation
of the buffer size), so this removes a bit of code duplication, but
most importantly, a more generic function can be easily reused for
other message types.

Signed-off-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/usb/serial/cp210x.c | 109 ++++++++++++++++++++------------------------
 1 file changed, 49 insertions(+), 60 deletions(-)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 1bae015..69f03b6 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -307,14 +307,17 @@ enum cp210x_request_type {
 #define CONTROL_WRITE_RTS	0x0200
 
 /*
- * cp210x_get_config
- * Reads from the CP210x configuration registers
+ * cp210x_control_msg
+ * Sends a generic control message, taking care of endianness
+ * and error messages.
  * 'size' is specified in bytes.
- * 'data' is a pointer to a pre-allocated array of integers large
- * enough to hold 'size' bytes (with 4 bytes to each integer)
+ * 'data' is a pointer to the input/output buffer. For output, it holds
+ * the data (in host order) to be sent. For input, it receives data from
+ * the device and must be big enough to hold 'size' bytes.
  */
-static int cp210x_get_config(struct usb_serial_port *port, u8 request,
-		unsigned int *data, int size)
+static int cp210x_control_msg(struct usb_serial_port *port, u8 request,
+			      u8 requesttype, u16 value, u32 *data, int size,
+			      int timeout)
 {
 	struct usb_serial *serial = port->serial;
 	struct cp210x_serial_private *spriv = usb_get_serial_data(serial);
@@ -328,20 +331,22 @@ static int cp210x_get_config(struct usb_serial_port *port, u8 request,
 	if (!buf)
 		return -ENOMEM;
 
-	/* Issue the request, attempting to read 'size' bytes */
-	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
-				request, REQTYPE_INTERFACE_TO_HOST, 0x0000,
-				spriv->bInterfaceNumber, buf, size,
-				USB_CTRL_GET_TIMEOUT);
+	if (!(requesttype & USB_DIR_IN)) {
+		for (i = 0; i < length; i++)
+			buf[i] = cpu_to_le32(data[i]);
+	}
 
-	/* Convert data into an array of integers */
-	for (i = 0; i < length; i++)
-		data[i] = le32_to_cpu(buf[i]);
+	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
+				 request, requesttype, value,
+				 spriv->bInterfaceNumber, buf, size, timeout);
 
-	kfree(buf);
+	if (requesttype & USB_DIR_IN) {
+		for (i = 0; i < length; i++)
+			data[i] = le32_to_cpu(buf[i]);
+	}
 
 	if (result != size) {
-		dev_dbg(&port->dev, "%s - Unable to send config request, request=0x%x size=%d result=%d\n",
+		dev_dbg(&port->dev, "%s - Unable to send request, request=0x%x size=%d result=%d\n",
 			__func__, request, size, result);
 		if (result > 0)
 			result = -EPROTO;
@@ -349,7 +354,23 @@ static int cp210x_get_config(struct usb_serial_port *port, u8 request,
 		return result;
 	}
 
-	return 0;
+	kfree(buf);
+
+	return result;
+}
+
+/*
+ * cp210x_get_config
+ * Reads from the CP210x configuration registers
+ * 'size' is specified in bytes.
+ * 'data' is a pointer to a pre-allocated array of integers large
+ * enough to hold 'size' bytes (with 4 bytes to each integer)
+ */
+static int cp210x_get_config(struct usb_serial_port *port, u8 request,
+		unsigned int *data, int size)
+{
+	return cp210x_control_msg(port, request, REQTYPE_INTERFACE_TO_HOST,
+				0x0000, data, size, USB_CTRL_GET_TIMEOUT);
 }
 
 /*
@@ -361,48 +382,14 @@ static int cp210x_get_config(struct usb_serial_port *port, u8 request,
 static int cp210x_set_config(struct usb_serial_port *port, u8 request,
 		unsigned int *data, int size)
 {
-	struct usb_serial *serial = port->serial;
-	struct cp210x_serial_private *spriv = usb_get_serial_data(serial);
-	__le32 *buf;
-	int result, i, length;
-
-	/* Number of integers required to contain the array */
-	length = (((size - 1) | 3) + 1) / 4;
-
-	buf = kmalloc(length * sizeof(__le32), GFP_KERNEL);
-	if (!buf)
-		return -ENOMEM;
-
-	/* Array of integers into bytes */
-	for (i = 0; i < length; i++)
-		buf[i] = cpu_to_le32(data[i]);
-
-	if (size > 2) {
-		result = usb_control_msg(serial->dev,
-				usb_sndctrlpipe(serial->dev, 0),
-				request, REQTYPE_HOST_TO_INTERFACE, 0x0000,
-				spriv->bInterfaceNumber, buf, size,
-				USB_CTRL_SET_TIMEOUT);
-	} else {
-		result = usb_control_msg(serial->dev,
-				usb_sndctrlpipe(serial->dev, 0),
-				request, REQTYPE_HOST_TO_INTERFACE, data[0],
-				spriv->bInterfaceNumber, NULL, 0,
-				USB_CTRL_SET_TIMEOUT);
-	}
-
-	kfree(buf);
-
-	if ((size > 2 && result != size) || result < 0) {
-		dev_dbg(&port->dev, "%s - Unable to send request, request=0x%x size=%d result=%d\n",
-			__func__, request, size, result);
-		if (result > 0)
-			result = -EPROTO;
-
-		return result;
-	}
-
-	return 0;
+	if (size > 2)
+		return cp210x_control_msg(port, request,
+				REQTYPE_HOST_TO_INTERFACE, 0x0000,
+				data, size, USB_CTRL_SET_TIMEOUT);
+	else
+		return cp210x_control_msg(port, request,
+				REQTYPE_HOST_TO_INTERFACE, data[0],
+				NULL, 0, USB_CTRL_SET_TIMEOUT);
 }
 
 /*
@@ -413,7 +400,9 @@ static int cp210x_set_config(struct usb_serial_port *port, u8 request,
 static inline int cp210x_set_config_single(struct usb_serial_port *port,
 		u8 request, unsigned int data)
 {
-	return cp210x_set_config(port, request, &data, 2);
+	return cp210x_control_msg(port, request,
+			REQTYPE_HOST_TO_INTERFACE, data,
+			NULL, 0, USB_CTRL_SET_TIMEOUT);
 }
 
 /*
-- 
2.1.4