Commit 95fd4f47 authored by Johan Hovold's avatar Johan Hovold
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USB: serial: cp210x: make line-speed quantisation data driven 



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: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
parent 3528651e

drivers/usb/serial/cp210x.c

+56 −43
Original line number Diff line number Diff line
@@ -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)) {

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