Re: [PATCH v3 4/4] USB: serial: cp210x: Switch to new register access functions for large registers
From: Martyn Welch
Date: Thu Jan 14 2016 - 12:52:07 EST
On 02/01/16 03:12, Konstantin Shkolnyy wrote:
Change to use new large register access functions instead of
cp210x_get_config and cp210x_set_config and remove the old functions since
they are now unused.
Signed-off-by: Konstantin Shkolnyy <konstantin.shkolnyy-Re5JQEeQqe8AvxtiuMwx3w@xxxxxxxxxxxxxxxx>
---
change in v3: Presented new function addition as a separate patch #1,
to simplify code review.
drivers/usb/serial/cp210x.c | 137 ++++++++------------------------------------
1 file changed, 24 insertions(+), 113 deletions(-)
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index 1339d77..ce80d5f 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -489,105 +489,6 @@ static int cp210x_write_u32_reg(struct usb_serial_port *port, u8 req, u32 val)
}
/*
- * 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)
-{
- struct usb_serial *serial = port->serial;
- struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
- __le32 *buf;
- int result, i, length;
-
- /* Number of integers required to contain the array */
- length = (((size - 1) | 3) + 1) / 4;
-
- buf = kcalloc(length, sizeof(__le32), GFP_KERNEL);
- 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,
- port_priv->bInterfaceNumber, buf, size,
- USB_CTRL_GET_TIMEOUT);
-
- /* Convert data into an array of integers */
- for (i = 0; i < length; i++)
- data[i] = le32_to_cpu(buf[i]);
-
- kfree(buf);
-
- if (result != size) {
- dev_dbg(&port->dev, "%s - Unable to send config request, request=0x%x size=%d result=%d\n",
- __func__, request, size, result);
- if (result > 0)
- result = -EPROTO;
-
- return result;
- }
-
- return 0;
-}
-
-/*
- * cp210x_set_config
- * Writes to the CP210x configuration registers
- * Values less than 16 bits wide are sent directly
- * 'size' is specified in bytes.
- */
-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_port_private *port_priv = usb_get_serial_port_data(port);
- __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,
- port_priv->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],
- port_priv->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;
-}
-
-/*
* Detect CP2108 GET_LINE_CTL bug and activate workaround.
* Write a known good value 0x800, read it back.
* If it comes back swapped the bug is detected.
@@ -786,7 +687,8 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
unsigned int *cflagp, unsigned int *baudp)
{
struct device *dev = &port->dev;
- unsigned int cflag, modem_ctl[4];
+ unsigned int cflag;
+ u8 modem_ctl[16];
u32 baud;
u16 bits;
@@ -884,8 +786,9 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
break;
}
- cp210x_get_config(port, CP210X_GET_FLOW, modem_ctl, 16);
- if (modem_ctl[0] & 0x0008) {
+ cp210x_read_reg_block(port, CP210X_GET_FLOW, modem_ctl,
+ sizeof(modem_ctl));
+ if (modem_ctl[0] & 8) {
dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);
cflag |= CRTSCTS;
} else {
@@ -954,7 +857,7 @@ static void cp210x_set_termios(struct tty_struct *tty,
struct device *dev = &port->dev;
unsigned int cflag, old_cflag;
u16 bits;
- unsigned int modem_ctl[4];
+ u8 modem_ctl[16];
cflag = tty->termios.c_cflag;
old_cflag = old_termios->c_cflag;
@@ -1038,27 +941,35 @@ static void cp210x_set_termios(struct tty_struct *tty,
}
if ((cflag & CRTSCTS) != (old_cflag & CRTSCTS)) {
- cp210x_get_config(port, CP210X_GET_FLOW, modem_ctl, 16);
- dev_dbg(dev, "%s - read modem controls = 0x%.4x 0x%.4x 0x%.4x 0x%.4x\n",
- __func__, modem_ctl[0], modem_ctl[1],
- modem_ctl[2], modem_ctl[3]);
+
+ /* Only bytes 0, 4 and 7 out of first 8 have functional bits */
+
+ cp210x_read_reg_block(port, CP210X_GET_FLOW, modem_ctl,
+ sizeof(modem_ctl));
+ dev_dbg(dev, "%s - read modem controls = %02x .. .. .. %02x .. .. %02x\n",
+ __func__, modem_ctl[0], modem_ctl[4], modem_ctl[7]);
if (cflag & CRTSCTS) {
modem_ctl[0] &= ~0x7B;
modem_ctl[0] |= 0x09;
- modem_ctl[1] = 0x80;
+ modem_ctl[4] = 0x80;
+ /* FIXME - why clear reserved bits just read? */
+ modem_ctl[5] = 0;
+ modem_ctl[6] = 0;
+ modem_ctl[7] = 0;
dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);
} else {
modem_ctl[0] &= ~0x7B;
modem_ctl[0] |= 0x01;
- modem_ctl[1] |= 0x40;
+ /* FIXME - OR here istead of assignment looks wrong */
s/istead/instead/
I'm a little unsure about FIXME comments being added rather than the
issue being addressed. If I'm reading this right, then this is the
control for the RTS/CTS lines, could the operation without these bits
being cleared/ORed be checked by using a serial cable (connected to
another serial port) and writing data with and without flow control
enabled through a terminal emulator?
Martyn
+ modem_ctl[4] |= 0x40;
dev_dbg(dev, "%s - flow control = NONE\n", __func__);
}
- dev_dbg(dev, "%s - write modem controls = 0x%.4x 0x%.4x 0x%.4x 0x%.4x\n",
- __func__, modem_ctl[0], modem_ctl[1],
- modem_ctl[2], modem_ctl[3]);
- cp210x_set_config(port, CP210X_SET_FLOW, modem_ctl, 16);
+ dev_dbg(dev, "%s - write modem controls = %02x .. .. .. %02x .. .. %02x\n",
+ __func__, modem_ctl[0], modem_ctl[4], modem_ctl[7]);
+ cp210x_write_reg_block(port, CP210X_SET_FLOW, modem_ctl,
+ sizeof(modem_ctl));
}
}