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USB: serial: cp210x: make line-speed quantisation data driven

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Older cp210x devices only support a fixed set of line speeds to which a
requested speed is mapped. Reimplement this mapping using a table
instead of a long if-else construct.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
This commit is contained in:
Johan Hovold 2018-07-18 14:24:57 +02:00
parent 3528651e89
commit 95fd4f47c8
1 changed files with 56 additions and 43 deletions
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99
drivers/usb/serial/cp210x.c
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@ -752,48 +752,6 @@ static int cp210x_get_line_ctl(struct usb_serial_port *port, u16 *ctl)
return 0;
}
/*
* cp210x_quantise_baudrate
* Quantises the baud rate as per AN205 Table 1
*/
static unsigned int cp210x_quantise_baudrate(unsigned int baud)
{
if (baud <= 300)
baud = 300;
else if (baud <= 600) baud = 600;
else if (baud <= 1200) baud = 1200;
else if (baud <= 1800) baud = 1800;
else if (baud <= 2400) baud = 2400;
else if (baud <= 4000) baud = 4000;
else if (baud <= 4803) baud = 4800;
else if (baud <= 7207) baud = 7200;
else if (baud <= 9612) baud = 9600;
else if (baud <= 14428) baud = 14400;
else if (baud <= 16062) baud = 16000;
else if (baud <= 19250) baud = 19200;
else if (baud <= 28912) baud = 28800;
else if (baud <= 38601) baud = 38400;
else if (baud <= 51558) baud = 51200;
else if (baud <= 56280) baud = 56000;
else if (baud <= 58053) baud = 57600;
else if (baud <= 64111) baud = 64000;
else if (baud <= 77608) baud = 76800;
else if (baud <= 117028) baud = 115200;
else if (baud <= 129347) baud = 128000;
else if (baud <= 156868) baud = 153600;
else if (baud <= 237832) baud = 230400;
else if (baud <= 254234) baud = 250000;
else if (baud <= 273066) baud = 256000;
else if (baud <= 491520) baud = 460800;
else if (baud <= 567138) baud = 500000;
else if (baud <= 670254) baud = 576000;
else if (baud < 1000000)
baud = 921600;
else if (baud > 2000000)
baud = 2000000;
return baud;
}
static int cp210x_open(struct tty_struct *tty, struct usb_serial_port *port)
{
int result;
@ -1013,6 +971,58 @@ static void cp210x_get_termios_port(struct usb_serial_port *port,
*cflagp = cflag;
}
struct cp210x_rate {
speed_t rate;
speed_t high;
};
static const struct cp210x_rate cp210x_an205_table1[] = {
{ 300, 300 },
{ 600, 600 },
{ 1200, 1200 },
{ 1800, 1800 },
{ 2400, 2400 },
{ 4000, 4000 },
{ 4800, 4803 },
{ 7200, 7207 },
{ 9600, 9612 },
{ 14400, 14428 },
{ 16000, 16062 },
{ 19200, 19250 },
{ 28800, 28912 },
{ 38400, 38601 },
{ 51200, 51558 },
{ 56000, 56280 },
{ 57600, 58053 },
{ 64000, 64111 },
{ 76800, 77608 },
{ 115200, 117028 },
{ 128000, 129347 },
{ 153600, 156868 },
{ 230400, 237832 },
{ 250000, 254234 },
{ 256000, 273066 },
{ 460800, 491520 },
{ 500000, 567138 },
{ 576000, 670254 },
{ 921600, UINT_MAX }
};
/*
* Quantises the baud rate as per AN205 Table 1
*/
static speed_t cp210x_get_an205_rate(speed_t baud)
{
int i;
for (i = 0; i < ARRAY_SIZE(cp210x_an205_table1); ++i) {
if (baud <= cp210x_an205_table1[i].high)
break;
}
return cp210x_an205_table1[i].rate;
}
/*
* CP2101 supports the following baud rates:
*
@ -1051,7 +1061,10 @@ static void cp210x_change_speed(struct tty_struct *tty,
*
* NOTE: B0 is not implemented.
*/
baud = cp210x_quantise_baudrate(baud);
if (baud < 1000000)
baud = cp210x_get_an205_rate(baud);
else if (baud > 2000000)
baud = 2000000;
dev_dbg(&port->dev, "%s - setting baud rate to %u\n", __func__, baud);
if (cp210x_write_u32_reg(port, CP210X_SET_BAUDRATE, baud)) {