xref: /linux/drivers/usb/serial/cp210x.c (revision 791b7d7cf69de11275e4dccec2f538eec02cbff6)
1 /*
2  * Silicon Laboratories CP210x USB to RS232 serial adaptor driver
3  *
4  * Copyright (C) 2005 Craig Shelley (craig@microtron.org.uk)
5  *
6  *	This program is free software; you can redistribute it and/or
7  *	modify it under the terms of the GNU General Public License version
8  *	2 as published by the Free Software Foundation.
9  *
10  * Support to set flow control line levels using TIOCMGET and TIOCMSET
11  * thanks to Karl Hiramoto karl@hiramoto.org. RTSCTS hardware flow
12  * control thanks to Munir Nassar nassarmu@real-time.com
13  *
14  */
15 
16 #include <linux/kernel.h>
17 #include <linux/errno.h>
18 #include <linux/slab.h>
19 #include <linux/tty.h>
20 #include <linux/tty_flip.h>
21 #include <linux/module.h>
22 #include <linux/moduleparam.h>
23 #include <linux/usb.h>
24 #include <linux/uaccess.h>
25 #include <linux/usb/serial.h>
26 
27 /*
28  * Version Information
29  */
30 #define DRIVER_VERSION "v0.09"
31 #define DRIVER_DESC "Silicon Labs CP210x RS232 serial adaptor driver"
32 
33 /*
34  * Function Prototypes
35  */
36 static int cp210x_open(struct tty_struct *tty, struct usb_serial_port *);
37 static void cp210x_close(struct usb_serial_port *);
38 static void cp210x_get_termios(struct tty_struct *,
39 	struct usb_serial_port *port);
40 static void cp210x_get_termios_port(struct usb_serial_port *port,
41 	unsigned int *cflagp, unsigned int *baudp);
42 static void cp210x_set_termios(struct tty_struct *, struct usb_serial_port *,
43 							struct ktermios*);
44 static int cp210x_tiocmget(struct tty_struct *);
45 static int cp210x_tiocmset(struct tty_struct *, unsigned int, unsigned int);
46 static int cp210x_tiocmset_port(struct usb_serial_port *port,
47 		unsigned int, unsigned int);
48 static void cp210x_break_ctl(struct tty_struct *, int);
49 static int cp210x_startup(struct usb_serial *);
50 static void cp210x_dtr_rts(struct usb_serial_port *p, int on);
51 
52 static bool debug;
53 
54 static const struct usb_device_id id_table[] = {
55 	{ USB_DEVICE(0x045B, 0x0053) }, /* Renesas RX610 RX-Stick */
56 	{ USB_DEVICE(0x0471, 0x066A) }, /* AKTAKOM ACE-1001 cable */
57 	{ USB_DEVICE(0x0489, 0xE000) }, /* Pirelli Broadband S.p.A, DP-L10 SIP/GSM Mobile */
58 	{ USB_DEVICE(0x0489, 0xE003) }, /* Pirelli Broadband S.p.A, DP-L10 SIP/GSM Mobile */
59 	{ USB_DEVICE(0x0745, 0x1000) }, /* CipherLab USB CCD Barcode Scanner 1000 */
60 	{ USB_DEVICE(0x08e6, 0x5501) }, /* Gemalto Prox-PU/CU contactless smartcard reader */
61 	{ USB_DEVICE(0x08FD, 0x000A) }, /* Digianswer A/S , ZigBee/802.15.4 MAC Device */
62 	{ USB_DEVICE(0x0BED, 0x1100) }, /* MEI (TM) Cashflow-SC Bill/Voucher Acceptor */
63 	{ USB_DEVICE(0x0BED, 0x1101) }, /* MEI series 2000 Combo Acceptor */
64 	{ USB_DEVICE(0x0FCF, 0x1003) }, /* Dynastream ANT development board */
65 	{ USB_DEVICE(0x0FCF, 0x1004) }, /* Dynastream ANT2USB */
66 	{ USB_DEVICE(0x0FCF, 0x1006) }, /* Dynastream ANT development board */
67 	{ USB_DEVICE(0x10A6, 0xAA26) }, /* Knock-off DCU-11 cable */
68 	{ USB_DEVICE(0x10AB, 0x10C5) }, /* Siemens MC60 Cable */
69 	{ USB_DEVICE(0x10B5, 0xAC70) }, /* Nokia CA-42 USB */
70 	{ USB_DEVICE(0x10C4, 0x0F91) }, /* Vstabi */
71 	{ USB_DEVICE(0x10C4, 0x1101) }, /* Arkham Technology DS101 Bus Monitor */
72 	{ USB_DEVICE(0x10C4, 0x1601) }, /* Arkham Technology DS101 Adapter */
73 	{ USB_DEVICE(0x10C4, 0x800A) }, /* SPORTident BSM7-D-USB main station */
74 	{ USB_DEVICE(0x10C4, 0x803B) }, /* Pololu USB-serial converter */
75 	{ USB_DEVICE(0x10C4, 0x8044) }, /* Cygnal Debug Adapter */
76 	{ USB_DEVICE(0x10C4, 0x804E) }, /* Software Bisque Paramount ME build-in converter */
77 	{ USB_DEVICE(0x10C4, 0x8053) }, /* Enfora EDG1228 */
78 	{ USB_DEVICE(0x10C4, 0x8054) }, /* Enfora GSM2228 */
79 	{ USB_DEVICE(0x10C4, 0x8066) }, /* Argussoft In-System Programmer */
80 	{ USB_DEVICE(0x10C4, 0x806F) }, /* IMS USB to RS422 Converter Cable */
81 	{ USB_DEVICE(0x10C4, 0x807A) }, /* Crumb128 board */
82 	{ USB_DEVICE(0x10C4, 0x80CA) }, /* Degree Controls Inc */
83 	{ USB_DEVICE(0x10C4, 0x80DD) }, /* Tracient RFID */
84 	{ USB_DEVICE(0x10C4, 0x80F6) }, /* Suunto sports instrument */
85 	{ USB_DEVICE(0x10C4, 0x8115) }, /* Arygon NFC/Mifare Reader */
86 	{ USB_DEVICE(0x10C4, 0x813D) }, /* Burnside Telecom Deskmobile */
87 	{ USB_DEVICE(0x10C4, 0x813F) }, /* Tams Master Easy Control */
88 	{ USB_DEVICE(0x10C4, 0x814A) }, /* West Mountain Radio RIGblaster P&P */
89 	{ USB_DEVICE(0x10C4, 0x814B) }, /* West Mountain Radio RIGtalk */
90 	{ USB_DEVICE(0x10C4, 0x8156) }, /* B&G H3000 link cable */
91 	{ USB_DEVICE(0x10C4, 0x815E) }, /* Helicomm IP-Link 1220-DVM */
92 	{ USB_DEVICE(0x10C4, 0x818B) }, /* AVIT Research USB to TTL */
93 	{ USB_DEVICE(0x10C4, 0x819F) }, /* MJS USB Toslink Switcher */
94 	{ USB_DEVICE(0x10C4, 0x81A6) }, /* ThinkOptics WavIt */
95 	{ USB_DEVICE(0x10C4, 0x81A9) }, /* Multiplex RC Interface */
96 	{ USB_DEVICE(0x10C4, 0x81AC) }, /* MSD Dash Hawk */
97 	{ USB_DEVICE(0x10C4, 0x81AD) }, /* INSYS USB Modem */
98 	{ USB_DEVICE(0x10C4, 0x81C8) }, /* Lipowsky Industrie Elektronik GmbH, Baby-JTAG */
99 	{ USB_DEVICE(0x10C4, 0x81E2) }, /* Lipowsky Industrie Elektronik GmbH, Baby-LIN */
100 	{ USB_DEVICE(0x10C4, 0x81E7) }, /* Aerocomm Radio */
101 	{ USB_DEVICE(0x10C4, 0x81E8) }, /* Zephyr Bioharness */
102 	{ USB_DEVICE(0x10C4, 0x81F2) }, /* C1007 HF band RFID controller */
103 	{ USB_DEVICE(0x10C4, 0x8218) }, /* Lipowsky Industrie Elektronik GmbH, HARP-1 */
104 	{ USB_DEVICE(0x10C4, 0x822B) }, /* Modem EDGE(GSM) Comander 2 */
105 	{ USB_DEVICE(0x10C4, 0x826B) }, /* Cygnal Integrated Products, Inc., Fasttrax GPS demonstration module */
106 	{ USB_DEVICE(0x10C4, 0x8293) }, /* Telegesis ETRX2USB */
107 	{ USB_DEVICE(0x10C4, 0x82F9) }, /* Procyon AVS */
108 	{ USB_DEVICE(0x10C4, 0x8341) }, /* Siemens MC35PU GPRS Modem */
109 	{ USB_DEVICE(0x10C4, 0x8382) }, /* Cygnal Integrated Products, Inc. */
110 	{ USB_DEVICE(0x10C4, 0x83A8) }, /* Amber Wireless AMB2560 */
111 	{ USB_DEVICE(0x10C4, 0x83D8) }, /* DekTec DTA Plus VHF/UHF Booster/Attenuator */
112 	{ USB_DEVICE(0x10C4, 0x8411) }, /* Kyocera GPS Module */
113 	{ USB_DEVICE(0x10C4, 0x8418) }, /* IRZ Automation Teleport SG-10 GSM/GPRS Modem */
114 	{ USB_DEVICE(0x10C4, 0x846E) }, /* BEI USB Sensor Interface (VCP) */
115 	{ USB_DEVICE(0x10C4, 0x8477) }, /* Balluff RFID */
116 	{ USB_DEVICE(0x10C4, 0x85EA) }, /* AC-Services IBUS-IF */
117 	{ USB_DEVICE(0x10C4, 0x85EB) }, /* AC-Services CIS-IBUS */
118 	{ USB_DEVICE(0x10C4, 0x8664) }, /* AC-Services CAN-IF */
119 	{ USB_DEVICE(0x10C4, 0x8665) }, /* AC-Services OBD-IF */
120 	{ USB_DEVICE(0x10C4, 0xEA60) }, /* Silicon Labs factory default */
121 	{ USB_DEVICE(0x10C4, 0xEA61) }, /* Silicon Labs factory default */
122 	{ USB_DEVICE(0x10C4, 0xEA71) }, /* Infinity GPS-MIC-1 Radio Monophone */
123 	{ USB_DEVICE(0x10C4, 0xF001) }, /* Elan Digital Systems USBscope50 */
124 	{ USB_DEVICE(0x10C4, 0xF002) }, /* Elan Digital Systems USBwave12 */
125 	{ USB_DEVICE(0x10C4, 0xF003) }, /* Elan Digital Systems USBpulse100 */
126 	{ USB_DEVICE(0x10C4, 0xF004) }, /* Elan Digital Systems USBcount50 */
127 	{ USB_DEVICE(0x10C5, 0xEA61) }, /* Silicon Labs MobiData GPRS USB Modem */
128 	{ USB_DEVICE(0x10CE, 0xEA6A) }, /* Silicon Labs MobiData GPRS USB Modem 100EU */
129 	{ USB_DEVICE(0x13AD, 0x9999) }, /* Baltech card reader */
130 	{ USB_DEVICE(0x1555, 0x0004) }, /* Owen AC4 USB-RS485 Converter */
131 	{ USB_DEVICE(0x166A, 0x0303) }, /* Clipsal 5500PCU C-Bus USB interface */
132 	{ USB_DEVICE(0x16D6, 0x0001) }, /* Jablotron serial interface */
133 	{ USB_DEVICE(0x16DC, 0x0010) }, /* W-IE-NE-R Plein & Baus GmbH PL512 Power Supply */
134 	{ USB_DEVICE(0x16DC, 0x0011) }, /* W-IE-NE-R Plein & Baus GmbH RCM Remote Control for MARATON Power Supply */
135 	{ USB_DEVICE(0x16DC, 0x0012) }, /* W-IE-NE-R Plein & Baus GmbH MPOD Multi Channel Power Supply */
136 	{ USB_DEVICE(0x16DC, 0x0015) }, /* W-IE-NE-R Plein & Baus GmbH CML Control, Monitoring and Data Logger */
137 	{ USB_DEVICE(0x17F4, 0xAAAA) }, /* Wavesense Jazz blood glucose meter */
138 	{ USB_DEVICE(0x1843, 0x0200) }, /* Vaisala USB Instrument Cable */
139 	{ USB_DEVICE(0x18EF, 0xE00F) }, /* ELV USB-I2C-Interface */
140 	{ USB_DEVICE(0x1BE3, 0x07A6) }, /* WAGO 750-923 USB Service Cable */
141 	{ USB_DEVICE(0x3195, 0xF190) }, /* Link Instruments MSO-19 */
142 	{ USB_DEVICE(0x413C, 0x9500) }, /* DW700 GPS USB interface */
143 	{ } /* Terminating Entry */
144 };
145 
146 MODULE_DEVICE_TABLE(usb, id_table);
147 
148 static struct usb_driver cp210x_driver = {
149 	.name		= "cp210x",
150 	.probe		= usb_serial_probe,
151 	.disconnect	= usb_serial_disconnect,
152 	.id_table	= id_table,
153 	.no_dynamic_id	= 	1,
154 };
155 
156 static struct usb_serial_driver cp210x_device = {
157 	.driver = {
158 		.owner =	THIS_MODULE,
159 		.name = 	"cp210x",
160 	},
161 	.usb_driver		= &cp210x_driver,
162 	.id_table		= id_table,
163 	.num_ports		= 1,
164 	.bulk_in_size		= 256,
165 	.bulk_out_size		= 256,
166 	.open			= cp210x_open,
167 	.close			= cp210x_close,
168 	.break_ctl		= cp210x_break_ctl,
169 	.set_termios		= cp210x_set_termios,
170 	.tiocmget 		= cp210x_tiocmget,
171 	.tiocmset		= cp210x_tiocmset,
172 	.attach			= cp210x_startup,
173 	.dtr_rts		= cp210x_dtr_rts
174 };
175 
176 /* Config request types */
177 #define REQTYPE_HOST_TO_DEVICE	0x41
178 #define REQTYPE_DEVICE_TO_HOST	0xc1
179 
180 /* Config request codes */
181 #define CP210X_IFC_ENABLE	0x00
182 #define CP210X_SET_BAUDDIV	0x01
183 #define CP210X_GET_BAUDDIV	0x02
184 #define CP210X_SET_LINE_CTL	0x03
185 #define CP210X_GET_LINE_CTL	0x04
186 #define CP210X_SET_BREAK	0x05
187 #define CP210X_IMM_CHAR		0x06
188 #define CP210X_SET_MHS		0x07
189 #define CP210X_GET_MDMSTS	0x08
190 #define CP210X_SET_XON		0x09
191 #define CP210X_SET_XOFF		0x0A
192 #define CP210X_SET_EVENTMASK	0x0B
193 #define CP210X_GET_EVENTMASK	0x0C
194 #define CP210X_SET_CHAR		0x0D
195 #define CP210X_GET_CHARS	0x0E
196 #define CP210X_GET_PROPS	0x0F
197 #define CP210X_GET_COMM_STATUS	0x10
198 #define CP210X_RESET		0x11
199 #define CP210X_PURGE		0x12
200 #define CP210X_SET_FLOW		0x13
201 #define CP210X_GET_FLOW		0x14
202 #define CP210X_EMBED_EVENTS	0x15
203 #define CP210X_GET_EVENTSTATE	0x16
204 #define CP210X_SET_CHARS	0x19
205 
206 /* CP210X_IFC_ENABLE */
207 #define UART_ENABLE		0x0001
208 #define UART_DISABLE		0x0000
209 
210 /* CP210X_(SET|GET)_BAUDDIV */
211 #define BAUD_RATE_GEN_FREQ	0x384000
212 
213 /* CP210X_(SET|GET)_LINE_CTL */
214 #define BITS_DATA_MASK		0X0f00
215 #define BITS_DATA_5		0X0500
216 #define BITS_DATA_6		0X0600
217 #define BITS_DATA_7		0X0700
218 #define BITS_DATA_8		0X0800
219 #define BITS_DATA_9		0X0900
220 
221 #define BITS_PARITY_MASK	0x00f0
222 #define BITS_PARITY_NONE	0x0000
223 #define BITS_PARITY_ODD		0x0010
224 #define BITS_PARITY_EVEN	0x0020
225 #define BITS_PARITY_MARK	0x0030
226 #define BITS_PARITY_SPACE	0x0040
227 
228 #define BITS_STOP_MASK		0x000f
229 #define BITS_STOP_1		0x0000
230 #define BITS_STOP_1_5		0x0001
231 #define BITS_STOP_2		0x0002
232 
233 /* CP210X_SET_BREAK */
234 #define BREAK_ON		0x0001
235 #define BREAK_OFF		0x0000
236 
237 /* CP210X_(SET_MHS|GET_MDMSTS) */
238 #define CONTROL_DTR		0x0001
239 #define CONTROL_RTS		0x0002
240 #define CONTROL_CTS		0x0010
241 #define CONTROL_DSR		0x0020
242 #define CONTROL_RING		0x0040
243 #define CONTROL_DCD		0x0080
244 #define CONTROL_WRITE_DTR	0x0100
245 #define CONTROL_WRITE_RTS	0x0200
246 
247 /*
248  * cp210x_get_config
249  * Reads from the CP210x configuration registers
250  * 'size' is specified in bytes.
251  * 'data' is a pointer to a pre-allocated array of integers large
252  * enough to hold 'size' bytes (with 4 bytes to each integer)
253  */
254 static int cp210x_get_config(struct usb_serial_port *port, u8 request,
255 		unsigned int *data, int size)
256 {
257 	struct usb_serial *serial = port->serial;
258 	__le32 *buf;
259 	int result, i, length;
260 
261 	/* Number of integers required to contain the array */
262 	length = (((size - 1) | 3) + 1)/4;
263 
264 	buf = kcalloc(length, sizeof(__le32), GFP_KERNEL);
265 	if (!buf) {
266 		dev_err(&port->dev, "%s - out of memory.\n", __func__);
267 		return -ENOMEM;
268 	}
269 
270 	/* Issue the request, attempting to read 'size' bytes */
271 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
272 				request, REQTYPE_DEVICE_TO_HOST, 0x0000,
273 				0, buf, size, 300);
274 
275 	/* Convert data into an array of integers */
276 	for (i = 0; i < length; i++)
277 		data[i] = le32_to_cpu(buf[i]);
278 
279 	kfree(buf);
280 
281 	if (result != size) {
282 		dbg("%s - Unable to send config request, "
283 				"request=0x%x size=%d result=%d\n",
284 				__func__, request, size, result);
285 		if (result > 0)
286 			result = -EPROTO;
287 
288 		return result;
289 	}
290 
291 	return 0;
292 }
293 
294 /*
295  * cp210x_set_config
296  * Writes to the CP210x configuration registers
297  * Values less than 16 bits wide are sent directly
298  * 'size' is specified in bytes.
299  */
300 static int cp210x_set_config(struct usb_serial_port *port, u8 request,
301 		unsigned int *data, int size)
302 {
303 	struct usb_serial *serial = port->serial;
304 	__le32 *buf;
305 	int result, i, length;
306 
307 	/* Number of integers required to contain the array */
308 	length = (((size - 1) | 3) + 1)/4;
309 
310 	buf = kmalloc(length * sizeof(__le32), GFP_KERNEL);
311 	if (!buf) {
312 		dev_err(&port->dev, "%s - out of memory.\n",
313 				__func__);
314 		return -ENOMEM;
315 	}
316 
317 	/* Array of integers into bytes */
318 	for (i = 0; i < length; i++)
319 		buf[i] = cpu_to_le32(data[i]);
320 
321 	if (size > 2) {
322 		result = usb_control_msg(serial->dev,
323 				usb_sndctrlpipe(serial->dev, 0),
324 				request, REQTYPE_HOST_TO_DEVICE, 0x0000,
325 				0, buf, size, 300);
326 	} else {
327 		result = usb_control_msg(serial->dev,
328 				usb_sndctrlpipe(serial->dev, 0),
329 				request, REQTYPE_HOST_TO_DEVICE, data[0],
330 				0, NULL, 0, 300);
331 	}
332 
333 	kfree(buf);
334 
335 	if ((size > 2 && result != size) || result < 0) {
336 		dbg("%s - Unable to send request, "
337 				"request=0x%x size=%d result=%d\n",
338 				__func__, request, size, result);
339 		if (result > 0)
340 			result = -EPROTO;
341 
342 		return result;
343 	}
344 
345 	return 0;
346 }
347 
348 /*
349  * cp210x_set_config_single
350  * Convenience function for calling cp210x_set_config on single data values
351  * without requiring an integer pointer
352  */
353 static inline int cp210x_set_config_single(struct usb_serial_port *port,
354 		u8 request, unsigned int data)
355 {
356 	return cp210x_set_config(port, request, &data, 2);
357 }
358 
359 /*
360  * cp210x_quantise_baudrate
361  * Quantises the baud rate as per AN205 Table 1
362  */
363 static unsigned int cp210x_quantise_baudrate(unsigned int baud) {
364 	if      (baud <= 56)       baud = 0;
365 	else if (baud <= 300)      baud = 300;
366 	else if (baud <= 600)      baud = 600;
367 	else if (baud <= 1200)     baud = 1200;
368 	else if (baud <= 1800)     baud = 1800;
369 	else if (baud <= 2400)     baud = 2400;
370 	else if (baud <= 4000)     baud = 4000;
371 	else if (baud <= 4803)     baud = 4800;
372 	else if (baud <= 7207)     baud = 7200;
373 	else if (baud <= 9612)     baud = 9600;
374 	else if (baud <= 14428)    baud = 14400;
375 	else if (baud <= 16062)    baud = 16000;
376 	else if (baud <= 19250)    baud = 19200;
377 	else if (baud <= 28912)    baud = 28800;
378 	else if (baud <= 38601)    baud = 38400;
379 	else if (baud <= 51558)    baud = 51200;
380 	else if (baud <= 56280)    baud = 56000;
381 	else if (baud <= 58053)    baud = 57600;
382 	else if (baud <= 64111)    baud = 64000;
383 	else if (baud <= 77608)    baud = 76800;
384 	else if (baud <= 117028)   baud = 115200;
385 	else if (baud <= 129347)   baud = 128000;
386 	else if (baud <= 156868)   baud = 153600;
387 	else if (baud <= 237832)   baud = 230400;
388 	else if (baud <= 254234)   baud = 250000;
389 	else if (baud <= 273066)   baud = 256000;
390 	else if (baud <= 491520)   baud = 460800;
391 	else if (baud <= 567138)   baud = 500000;
392 	else if (baud <= 670254)   baud = 576000;
393 	else if (baud <= 1053257)  baud = 921600;
394 	else if (baud <= 1474560)  baud = 1228800;
395 	else if (baud <= 2457600)  baud = 1843200;
396 	else                       baud = 3686400;
397 	return baud;
398 }
399 
400 static int cp210x_open(struct tty_struct *tty, struct usb_serial_port *port)
401 {
402 	int result;
403 
404 	dbg("%s - port %d", __func__, port->number);
405 
406 	result = cp210x_set_config_single(port, CP210X_IFC_ENABLE,
407 								UART_ENABLE);
408 	if (result) {
409 		dev_err(&port->dev, "%s - Unable to enable UART\n", __func__);
410 		return result;
411 	}
412 
413 	result = usb_serial_generic_open(tty, port);
414 	if (result)
415 		return result;
416 
417 	/* Configure the termios structure */
418 	cp210x_get_termios(tty, port);
419 	return 0;
420 }
421 
422 static void cp210x_close(struct usb_serial_port *port)
423 {
424 	dbg("%s - port %d", __func__, port->number);
425 
426 	usb_serial_generic_close(port);
427 
428 	mutex_lock(&port->serial->disc_mutex);
429 	if (!port->serial->disconnected)
430 		cp210x_set_config_single(port, CP210X_IFC_ENABLE, UART_DISABLE);
431 	mutex_unlock(&port->serial->disc_mutex);
432 }
433 
434 /*
435  * cp210x_get_termios
436  * Reads the baud rate, data bits, parity, stop bits and flow control mode
437  * from the device, corrects any unsupported values, and configures the
438  * termios structure to reflect the state of the device
439  */
440 static void cp210x_get_termios(struct tty_struct *tty,
441 	struct usb_serial_port *port)
442 {
443 	unsigned int baud;
444 
445 	if (tty) {
446 		cp210x_get_termios_port(tty->driver_data,
447 			&tty->termios->c_cflag, &baud);
448 		tty_encode_baud_rate(tty, baud, baud);
449 	}
450 
451 	else {
452 		unsigned int cflag;
453 		cflag = 0;
454 		cp210x_get_termios_port(port, &cflag, &baud);
455 	}
456 }
457 
458 /*
459  * cp210x_get_termios_port
460  * This is the heart of cp210x_get_termios which always uses a &usb_serial_port.
461  */
462 static void cp210x_get_termios_port(struct usb_serial_port *port,
463 	unsigned int *cflagp, unsigned int *baudp)
464 {
465 	unsigned int cflag, modem_ctl[4];
466 	unsigned int baud;
467 	unsigned int bits;
468 
469 	dbg("%s - port %d", __func__, port->number);
470 
471 	cp210x_get_config(port, CP210X_GET_BAUDDIV, &baud, 2);
472 	/* Convert to baudrate */
473 	if (baud)
474 		baud = cp210x_quantise_baudrate((BAUD_RATE_GEN_FREQ + baud/2)/ baud);
475 
476 	dbg("%s - baud rate = %d", __func__, baud);
477 	*baudp = baud;
478 
479 	cflag = *cflagp;
480 
481 	cp210x_get_config(port, CP210X_GET_LINE_CTL, &bits, 2);
482 	cflag &= ~CSIZE;
483 	switch (bits & BITS_DATA_MASK) {
484 	case BITS_DATA_5:
485 		dbg("%s - data bits = 5", __func__);
486 		cflag |= CS5;
487 		break;
488 	case BITS_DATA_6:
489 		dbg("%s - data bits = 6", __func__);
490 		cflag |= CS6;
491 		break;
492 	case BITS_DATA_7:
493 		dbg("%s - data bits = 7", __func__);
494 		cflag |= CS7;
495 		break;
496 	case BITS_DATA_8:
497 		dbg("%s - data bits = 8", __func__);
498 		cflag |= CS8;
499 		break;
500 	case BITS_DATA_9:
501 		dbg("%s - data bits = 9 (not supported, using 8 data bits)",
502 								__func__);
503 		cflag |= CS8;
504 		bits &= ~BITS_DATA_MASK;
505 		bits |= BITS_DATA_8;
506 		cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
507 		break;
508 	default:
509 		dbg("%s - Unknown number of data bits, using 8", __func__);
510 		cflag |= CS8;
511 		bits &= ~BITS_DATA_MASK;
512 		bits |= BITS_DATA_8;
513 		cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
514 		break;
515 	}
516 
517 	switch (bits & BITS_PARITY_MASK) {
518 	case BITS_PARITY_NONE:
519 		dbg("%s - parity = NONE", __func__);
520 		cflag &= ~PARENB;
521 		break;
522 	case BITS_PARITY_ODD:
523 		dbg("%s - parity = ODD", __func__);
524 		cflag |= (PARENB|PARODD);
525 		break;
526 	case BITS_PARITY_EVEN:
527 		dbg("%s - parity = EVEN", __func__);
528 		cflag &= ~PARODD;
529 		cflag |= PARENB;
530 		break;
531 	case BITS_PARITY_MARK:
532 		dbg("%s - parity = MARK", __func__);
533 		cflag |= (PARENB|PARODD|CMSPAR);
534 		break;
535 	case BITS_PARITY_SPACE:
536 		dbg("%s - parity = SPACE", __func__);
537 		cflag &= ~PARODD;
538 		cflag |= (PARENB|CMSPAR);
539 		break;
540 	default:
541 		dbg("%s - Unknown parity mode, disabling parity", __func__);
542 		cflag &= ~PARENB;
543 		bits &= ~BITS_PARITY_MASK;
544 		cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
545 		break;
546 	}
547 
548 	cflag &= ~CSTOPB;
549 	switch (bits & BITS_STOP_MASK) {
550 	case BITS_STOP_1:
551 		dbg("%s - stop bits = 1", __func__);
552 		break;
553 	case BITS_STOP_1_5:
554 		dbg("%s - stop bits = 1.5 (not supported, using 1 stop bit)",
555 								__func__);
556 		bits &= ~BITS_STOP_MASK;
557 		cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
558 		break;
559 	case BITS_STOP_2:
560 		dbg("%s - stop bits = 2", __func__);
561 		cflag |= CSTOPB;
562 		break;
563 	default:
564 		dbg("%s - Unknown number of stop bits, using 1 stop bit",
565 								__func__);
566 		bits &= ~BITS_STOP_MASK;
567 		cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2);
568 		break;
569 	}
570 
571 	cp210x_get_config(port, CP210X_GET_FLOW, modem_ctl, 16);
572 	if (modem_ctl[0] & 0x0008) {
573 		dbg("%s - flow control = CRTSCTS", __func__);
574 		cflag |= CRTSCTS;
575 	} else {
576 		dbg("%s - flow control = NONE", __func__);
577 		cflag &= ~CRTSCTS;
578 	}
579 
580 	*cflagp = cflag;
581 }
582 
583 static void cp210x_set_termios(struct tty_struct *tty,
584 		struct usb_serial_port *port, struct ktermios *old_termios)
585 {
586 	unsigned int cflag, old_cflag;
587 	unsigned int baud = 0, bits;
588 	unsigned int modem_ctl[4];
589 
590 	dbg("%s - port %d", __func__, port->number);
591 
592 	if (!tty)
593 		return;
594 
595 	cflag = tty->termios->c_cflag;
596 	old_cflag = old_termios->c_cflag;
597 	baud = cp210x_quantise_baudrate(tty_get_baud_rate(tty));
598 
599 	/* If the baud rate is to be updated*/
600 	if (baud != tty_termios_baud_rate(old_termios) && baud != 0) {
601 		dbg("%s - Setting baud rate to %d baud", __func__,
602 				baud);
603 		if (cp210x_set_config_single(port, CP210X_SET_BAUDDIV,
604 					((BAUD_RATE_GEN_FREQ + baud/2) / baud))) {
605 			dbg("Baud rate requested not supported by device");
606 			baud = tty_termios_baud_rate(old_termios);
607 		}
608 	}
609 	/* Report back the resulting baud rate */
610 	tty_encode_baud_rate(tty, baud, baud);
611 
612 	/* If the number of data bits is to be updated */
613 	if ((cflag & CSIZE) != (old_cflag & CSIZE)) {
614 		cp210x_get_config(port, CP210X_GET_LINE_CTL, &bits, 2);
615 		bits &= ~BITS_DATA_MASK;
616 		switch (cflag & CSIZE) {
617 		case CS5:
618 			bits |= BITS_DATA_5;
619 			dbg("%s - data bits = 5", __func__);
620 			break;
621 		case CS6:
622 			bits |= BITS_DATA_6;
623 			dbg("%s - data bits = 6", __func__);
624 			break;
625 		case CS7:
626 			bits |= BITS_DATA_7;
627 			dbg("%s - data bits = 7", __func__);
628 			break;
629 		case CS8:
630 			bits |= BITS_DATA_8;
631 			dbg("%s - data bits = 8", __func__);
632 			break;
633 		/*case CS9:
634 			bits |= BITS_DATA_9;
635 			dbg("%s - data bits = 9", __func__);
636 			break;*/
637 		default:
638 			dbg("cp210x driver does not "
639 					"support the number of bits requested,"
640 					" using 8 bit mode\n");
641 				bits |= BITS_DATA_8;
642 				break;
643 		}
644 		if (cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2))
645 			dbg("Number of data bits requested "
646 					"not supported by device\n");
647 	}
648 
649 	if ((cflag     & (PARENB|PARODD|CMSPAR)) !=
650 	    (old_cflag & (PARENB|PARODD|CMSPAR))) {
651 		cp210x_get_config(port, CP210X_GET_LINE_CTL, &bits, 2);
652 		bits &= ~BITS_PARITY_MASK;
653 		if (cflag & PARENB) {
654 			if (cflag & CMSPAR) {
655 			    if (cflag & PARODD) {
656 				    bits |= BITS_PARITY_MARK;
657 				    dbg("%s - parity = MARK", __func__);
658 			    } else {
659 				    bits |= BITS_PARITY_SPACE;
660 				    dbg("%s - parity = SPACE", __func__);
661 			    }
662 			} else {
663 			    if (cflag & PARODD) {
664 				    bits |= BITS_PARITY_ODD;
665 				    dbg("%s - parity = ODD", __func__);
666 			    } else {
667 				    bits |= BITS_PARITY_EVEN;
668 				    dbg("%s - parity = EVEN", __func__);
669 			    }
670 			}
671 		}
672 		if (cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2))
673 			dbg("Parity mode not supported "
674 					"by device\n");
675 	}
676 
677 	if ((cflag & CSTOPB) != (old_cflag & CSTOPB)) {
678 		cp210x_get_config(port, CP210X_GET_LINE_CTL, &bits, 2);
679 		bits &= ~BITS_STOP_MASK;
680 		if (cflag & CSTOPB) {
681 			bits |= BITS_STOP_2;
682 			dbg("%s - stop bits = 2", __func__);
683 		} else {
684 			bits |= BITS_STOP_1;
685 			dbg("%s - stop bits = 1", __func__);
686 		}
687 		if (cp210x_set_config(port, CP210X_SET_LINE_CTL, &bits, 2))
688 			dbg("Number of stop bits requested "
689 					"not supported by device\n");
690 	}
691 
692 	if ((cflag & CRTSCTS) != (old_cflag & CRTSCTS)) {
693 		cp210x_get_config(port, CP210X_GET_FLOW, modem_ctl, 16);
694 		dbg("%s - read modem controls = 0x%.4x 0x%.4x 0x%.4x 0x%.4x",
695 				__func__, modem_ctl[0], modem_ctl[1],
696 				modem_ctl[2], modem_ctl[3]);
697 
698 		if (cflag & CRTSCTS) {
699 			modem_ctl[0] &= ~0x7B;
700 			modem_ctl[0] |= 0x09;
701 			modem_ctl[1] = 0x80;
702 			dbg("%s - flow control = CRTSCTS", __func__);
703 		} else {
704 			modem_ctl[0] &= ~0x7B;
705 			modem_ctl[0] |= 0x01;
706 			modem_ctl[1] |= 0x40;
707 			dbg("%s - flow control = NONE", __func__);
708 		}
709 
710 		dbg("%s - write modem controls = 0x%.4x 0x%.4x 0x%.4x 0x%.4x",
711 				__func__, modem_ctl[0], modem_ctl[1],
712 				modem_ctl[2], modem_ctl[3]);
713 		cp210x_set_config(port, CP210X_SET_FLOW, modem_ctl, 16);
714 	}
715 
716 }
717 
718 static int cp210x_tiocmset (struct tty_struct *tty,
719 		unsigned int set, unsigned int clear)
720 {
721 	struct usb_serial_port *port = tty->driver_data;
722 	return cp210x_tiocmset_port(port, set, clear);
723 }
724 
725 static int cp210x_tiocmset_port(struct usb_serial_port *port,
726 		unsigned int set, unsigned int clear)
727 {
728 	unsigned int control = 0;
729 
730 	dbg("%s - port %d", __func__, port->number);
731 
732 	if (set & TIOCM_RTS) {
733 		control |= CONTROL_RTS;
734 		control |= CONTROL_WRITE_RTS;
735 	}
736 	if (set & TIOCM_DTR) {
737 		control |= CONTROL_DTR;
738 		control |= CONTROL_WRITE_DTR;
739 	}
740 	if (clear & TIOCM_RTS) {
741 		control &= ~CONTROL_RTS;
742 		control |= CONTROL_WRITE_RTS;
743 	}
744 	if (clear & TIOCM_DTR) {
745 		control &= ~CONTROL_DTR;
746 		control |= CONTROL_WRITE_DTR;
747 	}
748 
749 	dbg("%s - control = 0x%.4x", __func__, control);
750 
751 	return cp210x_set_config(port, CP210X_SET_MHS, &control, 2);
752 }
753 
754 static void cp210x_dtr_rts(struct usb_serial_port *p, int on)
755 {
756 	if (on)
757 		cp210x_tiocmset_port(p, TIOCM_DTR|TIOCM_RTS, 0);
758 	else
759 		cp210x_tiocmset_port(p, 0, TIOCM_DTR|TIOCM_RTS);
760 }
761 
762 static int cp210x_tiocmget (struct tty_struct *tty)
763 {
764 	struct usb_serial_port *port = tty->driver_data;
765 	unsigned int control;
766 	int result;
767 
768 	dbg("%s - port %d", __func__, port->number);
769 
770 	cp210x_get_config(port, CP210X_GET_MDMSTS, &control, 1);
771 
772 	result = ((control & CONTROL_DTR) ? TIOCM_DTR : 0)
773 		|((control & CONTROL_RTS) ? TIOCM_RTS : 0)
774 		|((control & CONTROL_CTS) ? TIOCM_CTS : 0)
775 		|((control & CONTROL_DSR) ? TIOCM_DSR : 0)
776 		|((control & CONTROL_RING)? TIOCM_RI  : 0)
777 		|((control & CONTROL_DCD) ? TIOCM_CD  : 0);
778 
779 	dbg("%s - control = 0x%.2x", __func__, control);
780 
781 	return result;
782 }
783 
784 static void cp210x_break_ctl (struct tty_struct *tty, int break_state)
785 {
786 	struct usb_serial_port *port = tty->driver_data;
787 	unsigned int state;
788 
789 	dbg("%s - port %d", __func__, port->number);
790 	if (break_state == 0)
791 		state = BREAK_OFF;
792 	else
793 		state = BREAK_ON;
794 	dbg("%s - turning break %s", __func__,
795 			state == BREAK_OFF ? "off" : "on");
796 	cp210x_set_config(port, CP210X_SET_BREAK, &state, 2);
797 }
798 
799 static int cp210x_startup(struct usb_serial *serial)
800 {
801 	/* cp210x buffers behave strangely unless device is reset */
802 	usb_reset_device(serial->dev);
803 	return 0;
804 }
805 
806 static int __init cp210x_init(void)
807 {
808 	int retval;
809 
810 	retval = usb_serial_register(&cp210x_device);
811 	if (retval)
812 		return retval; /* Failed to register */
813 
814 	retval = usb_register(&cp210x_driver);
815 	if (retval) {
816 		/* Failed to register */
817 		usb_serial_deregister(&cp210x_device);
818 		return retval;
819 	}
820 
821 	/* Success */
822 	printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
823 	       DRIVER_DESC "\n");
824 	return 0;
825 }
826 
827 static void __exit cp210x_exit(void)
828 {
829 	usb_deregister(&cp210x_driver);
830 	usb_serial_deregister(&cp210x_device);
831 }
832 
833 module_init(cp210x_init);
834 module_exit(cp210x_exit);
835 
836 MODULE_DESCRIPTION(DRIVER_DESC);
837 MODULE_VERSION(DRIVER_VERSION);
838 MODULE_LICENSE("GPL");
839 
840 module_param(debug, bool, S_IRUGO | S_IWUSR);
841 MODULE_PARM_DESC(debug, "Enable verbose debugging messages");
842