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USB: pl2303: clean up baud-rate handling

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Clean up baud-rate handling somewhat.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johan Hovold 2013-06-26 16:47:28 +02:00 committed by Greg Kroah-Hartman
parent 15e7cead1e
commit b2d6d98fc7
1 changed files with 41 additions and 49 deletions
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90
drivers/usb/serial/pl2303.c
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@ -29,6 +29,7 @@
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <asm/unaligned.h>
#include "pl2303.h"
/*
@ -275,65 +276,56 @@ static void pl2303_encode_baudrate(struct tty_struct *tty,
struct usb_serial *serial = port->serial;
struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
int baud;
int baud_floor, baud_ceil;
int k;
int i;
/* NOTE: Only the values defined in baud_sup are supported !
/*
* NOTE: Only the values defined in baud_sup are supported!
* => if unsupported values are set, the PL2303 seems to use
* 9600 baud (at least my PL2303X always does)
*/
baud = tty_get_baud_rate(tty);
dev_dbg(&port->dev, "baud requested = %d\n", baud);
if (baud) {
/* Set baudrate to nearest supported value */
for (k=0; k<ARRAY_SIZE(baud_sup); k++) {
if (baud_sup[k] / baud) {
baud_ceil = baud_sup[k];
if (k==0) {
baud = baud_ceil;
} else {
baud_floor = baud_sup[k-1];
if ((baud_ceil % baud)
> (baud % baud_floor))
baud = baud_floor;
else
baud = baud_ceil;
}
break;
}
}
if (baud > 1228800) {
/* type_0, type_1 only support up to 1228800 baud */
if (spriv->type != HX)
baud = 1228800;
else if (baud > 6000000)
baud = 6000000;
}
dev_dbg(&port->dev, "baud set = %d\n", baud);
if (baud <= 115200) {
buf[0] = baud & 0xff;
buf[1] = (baud >> 8) & 0xff;
buf[2] = (baud >> 16) & 0xff;
buf[3] = (baud >> 24) & 0xff;
} else {
/* apparently the formula for higher speeds is:
* baudrate = 12M * 32 / (2^buf[1]) / buf[0]
*/
unsigned tmp = 12*1000*1000*32 / baud;
buf[3] = 0x80;
buf[2] = 0;
buf[1] = (tmp >= 256);
while (tmp >= 256) {
tmp >>= 2;
buf[1] <<= 1;
}
buf[0] = tmp;
if (!baud)
return;
/* Set baudrate to nearest supported value */
for (i = 0; i < ARRAY_SIZE(baud_sup); ++i) {
if (baud_sup[i] > baud)
break;
}
if (i == ARRAY_SIZE(baud_sup))
baud = baud_sup[i - 1];
else if (i > 0 && (baud_sup[i] - baud) > (baud - baud_sup[i - 1]))
baud = baud_sup[i - 1];
else
baud = baud_sup[i];
/* type_0, type_1 only support up to 1228800 baud */
if (spriv->type != HX)
baud = max_t(int, baud, 1228800);
if (baud <= 115200) {
put_unaligned_le32(baud, buf);
} else {
/*
* Apparently the formula for higher speeds is:
* baudrate = 12M * 32 / (2^buf[1]) / buf[0]
*/
unsigned tmp = 12000000 * 32 / baud;
buf[3] = 0x80;
buf[2] = 0;
buf[1] = (tmp >= 256);
while (tmp >= 256) {
tmp >>= 2;
buf[1] <<= 1;
}
buf[0] = tmp;
}
/* Save resulting baud rate */
if (baud)
tty_encode_baud_rate(tty, baud, baud);
tty_encode_baud_rate(tty, baud, baud);
dev_dbg(&port->dev, "baud set = %d\n", baud);
}
static void pl2303_set_termios(struct tty_struct *tty,