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Message-Id: <1461982943-19664-1-git-send-email-konstantin.shkolnyy@gmail.com>
Date: Fri, 29 Apr 2016 21:22:23 -0500
From: Konstantin Shkolnyy <konstantin.shkolnyy@...il.com>
To: johan@...nel.org
Cc: linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
Konstantin Shkolnyy <konstantin.shkolnyy@...il.com>
Subject: [PATCH v2 2/3] USB: serial: cp210x: Added comments to CRTSCTS flag code.
Replaced magic numbers used in the CRTSCTS flag code with symbolic names
from the chip specification.
Signed-off-by: Konstantin Shkolnyy <konstantin.shkolnyy@...il.com>
---
Changes in v2:
Improved CRTSCTS fix based on feedback. Dropped get_termios error handling.
drivers/usb/serial/cp210x.c | 93 +++++++++++++++++++++++++++++++++------------
1 file changed, 69 insertions(+), 24 deletions(-)
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
index abcdb63..da0567c 100644
--- a/drivers/usb/serial/cp210x.c
+++ b/drivers/usb/serial/cp210x.c
@@ -323,6 +323,40 @@ struct cp210x_comm_status {
*/
#define PURGE_ALL 0x000f
+/* CP210X_GET_FLOW/CP210X_SET_FLOW read/write these 0x10 bytes */
+struct cp210x_flow_ctl {
+ __le32 ulControlHandshake;
+ __le32 ulFlowReplace;
+ __le32 ulXonLimit;
+ __le32 ulXoffLimit;
+} __packed;
+
+/* cp210x_flow_ctl::ulControlHandshake */
+#define SERIAL_DTR_MASK 0x00000003
+#define SERIAL_CTS_HANDSHAKE 0x00000008
+#define SERIAL_DSR_HANDSHAKE 0x00000010
+#define SERIAL_DCD_HANDSHAKE 0x00000020
+#define SERIAL_DSR_SENSITIVITY 0x00000040
+
+/* values for cp210x_flow_ctl::ulControlHandshake::SERIAL_DTR_MASK */
+#define SERIAL_DTR_INACTIVE 0x00000000
+#define SERIAL_DTR_ACTIVE 0x00000001
+#define SERIAL_DTR_FLOW_CTL 0x00000002
+
+/* cp210x_flow_ctl::ulFlowReplace */
+#define SERIAL_AUTO_TRANSMIT 0x00000001
+#define SERIAL_AUTO_RECEIVE 0x00000002
+#define SERIAL_ERROR_CHAR 0x00000004
+#define SERIAL_NULL_STRIPPING 0x00000008
+#define SERIAL_BREAK_CHAR 0x00000010
+#define SERIAL_RTS_MASK 0x000000c0
+#define SERIAL_XOFF_CONTINUE 0x80000000
+
+/* values for cp210x_flow_ctl::ulFlowReplace::SERIAL_RTS_MASK */
+#define SERIAL_RTS_INACTIVE 0x00000000
+#define SERIAL_RTS_ACTIVE 0x00000040
+#define SERIAL_RTS_FLOW_CTL 0x00000080
+
/*
* Reads a variable-sized block of CP210X_ registers, identified by req.
* Returns data into buf in native USB byte order.
@@ -690,7 +724,7 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
{
struct device *dev = &port->dev;
unsigned int cflag;
- u8 modem_ctl[16];
+ struct cp210x_flow_ctl flow_ctl;
u32 baud;
u16 bits;
@@ -788,9 +822,9 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
break;
}
- cp210x_read_reg_block(port, CP210X_GET_FLOW, modem_ctl,
- sizeof(modem_ctl));
- if (modem_ctl[0] & 0x08) {
+ cp210x_read_reg_block(port, CP210X_GET_FLOW, &flow_ctl,
+ sizeof(flow_ctl));
+ if (le32_to_cpu(flow_ctl.ulControlHandshake) & SERIAL_CTS_HANDSHAKE) {
dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);
cflag |= CRTSCTS;
} else {
@@ -859,7 +893,6 @@ static void cp210x_set_termios(struct tty_struct *tty,
struct device *dev = &port->dev;
unsigned int cflag, old_cflag;
u16 bits;
- u8 modem_ctl[16];
cflag = tty->termios.c_cflag;
old_cflag = old_termios->c_cflag;
@@ -944,33 +977,45 @@ static void cp210x_set_termios(struct tty_struct *tty,
if ((cflag & CRTSCTS) != (old_cflag & CRTSCTS)) {
- /* Only bytes 0, 4 and 7 out of first 8 have functional bits */
+ struct cp210x_flow_ctl flow_ctl;
+ u32 ControlHandshake;
+ u32 FlowReplace;
- 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]);
+ cp210x_read_reg_block(port, CP210X_GET_FLOW, &flow_ctl,
+ sizeof(flow_ctl));
+ ControlHandshake = le32_to_cpu(flow_ctl.ulControlHandshake);
+ FlowReplace = le32_to_cpu(flow_ctl.ulFlowReplace);
+ dev_dbg(dev, "%s - read ulControlHandshake=%08x ulFlowReplace=%08x\n",
+ __func__, ControlHandshake, FlowReplace);
if (cflag & CRTSCTS) {
- modem_ctl[0] &= ~0x7B;
- modem_ctl[0] |= 0x09;
- modem_ctl[4] = 0x80;
- /* FIXME - why clear reserved bits just read? */
- modem_ctl[5] = 0;
- modem_ctl[6] = 0;
- modem_ctl[7] = 0;
+ ControlHandshake &= ~(SERIAL_DTR_MASK |
+ SERIAL_CTS_HANDSHAKE | SERIAL_DSR_HANDSHAKE |
+ SERIAL_DCD_HANDSHAKE | SERIAL_DSR_SENSITIVITY);
+ ControlHandshake |= SERIAL_DTR_ACTIVE;
+ ControlHandshake |= SERIAL_CTS_HANDSHAKE;
+ /* FIXME why clear bits unrelated to flow control */
+ /* FIXME why clear _XOFF_CONTINUE which is never set */
+ FlowReplace &= ~0xffffffff;
+ FlowReplace |= SERIAL_RTS_FLOW_CTL;
dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);
} else {
- modem_ctl[0] &= ~0x7B;
- modem_ctl[0] |= 0x01;
- modem_ctl[4] = 0x40;
+ ControlHandshake &= ~(SERIAL_DTR_MASK |
+ SERIAL_CTS_HANDSHAKE | SERIAL_DSR_HANDSHAKE |
+ SERIAL_DCD_HANDSHAKE | SERIAL_DSR_SENSITIVITY);
+ ControlHandshake |= SERIAL_DTR_ACTIVE;
+ /* FIXME - why clear bits unrelated to flow control */
+ FlowReplace &= ~0xff;
+ FlowReplace |= SERIAL_RTS_ACTIVE;
dev_dbg(dev, "%s - flow control = NONE\n", __func__);
}
- 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));
+ dev_dbg(dev, "%s - write ulControlHandshake=%08x ulFlowReplace=%08x\n",
+ __func__, ControlHandshake, FlowReplace);
+ flow_ctl.ulControlHandshake = cpu_to_le32(ControlHandshake);
+ flow_ctl.ulFlowReplace = cpu_to_le32(FlowReplace);
+ cp210x_write_reg_block(port, CP210X_SET_FLOW, &flow_ctl,
+ sizeof(flow_ctl));
}
}
--
1.8.4.5
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