[PATCH v3 1/4 RESEND] USB: serial: cp210x: New register access functions.

From: Konstantin Shkolnyy
Date: Sat Jan 16 2016 - 14:46:16 EST


cp210x_get_config and cp210x_set_config are cumbersome to use. This change
introduces new register access functions to replace them. New functions
are not yet called - the switch is done gradually in following changes.

Signed-off-by: Konstantin Shkolnyy <konstantin.shkolnyy@xxxxxxxxx>
---
change in v3: Presented new function addition as a separate patch #1,
to simplify code review.

drivers/usb/serial/cp210x.c | 166 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 166 insertions(+)

diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index fd67958..324eb7e 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -323,6 +323,172 @@ struct cp210x_comm_status {
#define PURGE_ALL 0x000f

/*
+ * Reads a variable-sized block of CP210X_ registers, identified by req.
+ * Returns data into buf in native USB byte order.
+ */
+static int cp210x_read_reg_block(struct usb_serial_port *port, u8 req,
+ void *buf, int bufsize)
+{
+ struct usb_serial *serial = port->serial;
+ struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
+ void *dmabuf;
+ int result;
+
+ dmabuf = kmalloc(bufsize, GFP_KERNEL);
+ if (!dmabuf) {
+ /*
+ * FIXME Some callers don't bother to check for error,
+ * at least give them consistent junk until they are fixed
+ */
+ memset(buf, 0, bufsize);
+ return -ENOMEM;
+ }
+
+ result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
+ req, REQTYPE_INTERFACE_TO_HOST, 0,
+ port_priv->bInterfaceNumber, dmabuf, bufsize,
+ USB_CTRL_SET_TIMEOUT);
+ if (result == bufsize) {
+ memcpy(buf, dmabuf, bufsize);
+ result = 0;
+ } else {
+ dev_err(&port->dev, "failed get req 0x%x size %d status: %d\n",
+ req, bufsize, result);
+ if (result >= 0)
+ result = -EPROTO;
+
+ /*
+ * FIXME Some callers don't bother to check for error,
+ * at least give them consistent junk until they are fixed
+ */
+ memset(buf, 0, bufsize);
+ }
+
+ kfree(dmabuf);
+
+ return result;
+}
+
+/*
+ * Reads any 32-bit CP210X_ register identified by req.
+ */
+static int cp210x_read_u32_reg(struct usb_serial_port *port, u8 req, u32 *val)
+{
+ __le32 le32_val;
+ int err;
+
+ err = cp210x_read_reg_block(port, req, &le32_val, sizeof(le32_val));
+ if (err) {
+ /*
+ * FIXME Some callers don't bother to check for error,
+ * at least give them consistent junk until they are fixed
+ */
+ *val = 0;
+ return err;
+ }
+
+ *val = le32_to_cpu(le32_val);
+
+ return 0;
+}
+
+/*
+ * Reads any 16-bit CP210X_ register identified by req.
+ */
+static int cp210x_read_u16_reg(struct usb_serial_port *port, u8 req, u16 *val)
+{
+ __le16 le16_val;
+ int err;
+
+ err = cp210x_read_reg_block(port, req, &le16_val, sizeof(le16_val));
+ if (err)
+ return err;
+
+ *val = le16_to_cpu(le16_val);
+
+ return 0;
+}
+
+/*
+ * Reads any 8-bit CP210X_ register identified by req.
+ */
+static int cp210x_read_u8_reg(struct usb_serial_port *port, u8 req, u8 *val)
+{
+ return cp210x_read_reg_block(port, req, val, sizeof(*val));
+}
+
+/*
+ * Writes any 16-bit CP210X_ register (req) whose value is passed
+ * entirely in the wValue field of the USB request.
+ */
+static int cp210x_write_u16_reg(struct usb_serial_port *port, u8 req, u16 val)
+{
+ struct usb_serial *serial = port->serial;
+ struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
+ int result;
+
+ result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
+ req, REQTYPE_HOST_TO_INTERFACE, val,
+ port_priv->bInterfaceNumber, NULL, 0,
+ USB_CTRL_SET_TIMEOUT);
+ if (result < 0) {
+ dev_err(&port->dev, "failed set request 0x%x status: %d\n",
+ req, result);
+ }
+
+ return result;
+}
+
+/*
+ * Writes a variable-sized block of CP210X_ registers, identified by req.
+ * Data in buf must be in native USB byte order.
+ */
+static int cp210x_write_reg_block(struct usb_serial_port *port, u8 req,
+ void *buf, int bufsize)
+{
+ struct usb_serial *serial = port->serial;
+ struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
+ void *dmabuf;
+ int result;
+
+ dmabuf = kmalloc(bufsize, GFP_KERNEL);
+ if (!dmabuf)
+ return -ENOMEM;
+
+ memcpy(dmabuf, buf, bufsize);
+
+ result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
+ req, REQTYPE_HOST_TO_INTERFACE, 0,
+ port_priv->bInterfaceNumber, dmabuf, bufsize,
+ USB_CTRL_SET_TIMEOUT);
+
+ kfree(dmabuf);
+
+ if (result == bufsize) {
+ result = 0;
+ } else {
+ dev_err(&port->dev, "failed set req 0x%x size %d status: %d\n",
+ req, bufsize, result);
+ if (result >= 0)
+ result = -EPROTO;
+ }
+
+ return result;
+}
+
+/*
+ * Writes any 32-bit CP210X_ register identified by req.
+ */
+static int cp210x_write_u32_reg(struct usb_serial_port *port, u8 req, u32 val)
+{
+ __le32 le32_val;
+
+ le32_val = cpu_to_le32(val);
+
+ return cp210x_write_reg_block(port, req, &le32_val, sizeof(le32_val));
+}
+
+/*
* cp210x_get_config
* Reads from the CP210x configuration registers
* 'size' is specified in bytes.
--
1.8.4.5