xref: /linux/drivers/usb/serial/cp210x.c (revision 37f0e658eeeac720f3d558cf5aaf9edf0705ff23)
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 #define DRIVER_DESC "Silicon Labs CP210x RS232 serial adaptor driver"
28 
29 /*
30  * Function Prototypes
31  */
32 static int cp210x_open(struct tty_struct *tty, struct usb_serial_port *);
33 static void cp210x_close(struct usb_serial_port *);
34 static void cp210x_get_termios(struct tty_struct *, struct usb_serial_port *);
35 static void cp210x_get_termios_port(struct usb_serial_port *port,
36 	unsigned int *cflagp, unsigned int *baudp);
37 static void cp210x_change_speed(struct tty_struct *, struct usb_serial_port *,
38 							struct ktermios *);
39 static void cp210x_set_termios(struct tty_struct *, struct usb_serial_port *,
40 							struct ktermios*);
41 static bool cp210x_tx_empty(struct usb_serial_port *port);
42 static int cp210x_tiocmget(struct tty_struct *);
43 static int cp210x_tiocmset(struct tty_struct *, unsigned int, unsigned int);
44 static int cp210x_tiocmset_port(struct usb_serial_port *port,
45 		unsigned int, unsigned int);
46 static void cp210x_break_ctl(struct tty_struct *, int);
47 static int cp210x_port_probe(struct usb_serial_port *);
48 static int cp210x_port_remove(struct usb_serial_port *);
49 static void cp210x_dtr_rts(struct usb_serial_port *p, int on);
50 
51 static const struct usb_device_id id_table[] = {
52 	{ USB_DEVICE(0x045B, 0x0053) }, /* Renesas RX610 RX-Stick */
53 	{ USB_DEVICE(0x0471, 0x066A) }, /* AKTAKOM ACE-1001 cable */
54 	{ USB_DEVICE(0x0489, 0xE000) }, /* Pirelli Broadband S.p.A, DP-L10 SIP/GSM Mobile */
55 	{ USB_DEVICE(0x0489, 0xE003) }, /* Pirelli Broadband S.p.A, DP-L10 SIP/GSM Mobile */
56 	{ USB_DEVICE(0x0745, 0x1000) }, /* CipherLab USB CCD Barcode Scanner 1000 */
57 	{ USB_DEVICE(0x0846, 0x1100) }, /* NetGear Managed Switch M4100 series, M5300 series, M7100 series */
58 	{ USB_DEVICE(0x08e6, 0x5501) }, /* Gemalto Prox-PU/CU contactless smartcard reader */
59 	{ USB_DEVICE(0x08FD, 0x000A) }, /* Digianswer A/S , ZigBee/802.15.4 MAC Device */
60 	{ USB_DEVICE(0x0908, 0x01FF) }, /* Siemens RUGGEDCOM USB Serial Console */
61 	{ USB_DEVICE(0x0BED, 0x1100) }, /* MEI (TM) Cashflow-SC Bill/Voucher Acceptor */
62 	{ USB_DEVICE(0x0BED, 0x1101) }, /* MEI series 2000 Combo Acceptor */
63 	{ USB_DEVICE(0x0FCF, 0x1003) }, /* Dynastream ANT development board */
64 	{ USB_DEVICE(0x0FCF, 0x1004) }, /* Dynastream ANT2USB */
65 	{ USB_DEVICE(0x0FCF, 0x1006) }, /* Dynastream ANT development board */
66 	{ USB_DEVICE(0x0FDE, 0xCA05) }, /* OWL Wireless Electricity Monitor CM-160 */
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, 0x80C4) }, /* Cygnal Integrated Products, Inc., Optris infrared thermometer */
83 	{ USB_DEVICE(0x10C4, 0x80CA) }, /* Degree Controls Inc */
84 	{ USB_DEVICE(0x10C4, 0x80DD) }, /* Tracient RFID */
85 	{ USB_DEVICE(0x10C4, 0x80F6) }, /* Suunto sports instrument */
86 	{ USB_DEVICE(0x10C4, 0x8115) }, /* Arygon NFC/Mifare Reader */
87 	{ USB_DEVICE(0x10C4, 0x813D) }, /* Burnside Telecom Deskmobile */
88 	{ USB_DEVICE(0x10C4, 0x813F) }, /* Tams Master Easy Control */
89 	{ USB_DEVICE(0x10C4, 0x814A) }, /* West Mountain Radio RIGblaster P&P */
90 	{ USB_DEVICE(0x10C4, 0x814B) }, /* West Mountain Radio RIGtalk */
91 	{ USB_DEVICE(0x2405, 0x0003) }, /* West Mountain Radio RIGblaster Advantage */
92 	{ USB_DEVICE(0x10C4, 0x8156) }, /* B&G H3000 link cable */
93 	{ USB_DEVICE(0x10C4, 0x815E) }, /* Helicomm IP-Link 1220-DVM */
94 	{ USB_DEVICE(0x10C4, 0x815F) }, /* Timewave HamLinkUSB */
95 	{ USB_DEVICE(0x10C4, 0x818B) }, /* AVIT Research USB to TTL */
96 	{ USB_DEVICE(0x10C4, 0x819F) }, /* MJS USB Toslink Switcher */
97 	{ USB_DEVICE(0x10C4, 0x81A6) }, /* ThinkOptics WavIt */
98 	{ USB_DEVICE(0x10C4, 0x81A9) }, /* Multiplex RC Interface */
99 	{ USB_DEVICE(0x10C4, 0x81AC) }, /* MSD Dash Hawk */
100 	{ USB_DEVICE(0x10C4, 0x81AD) }, /* INSYS USB Modem */
101 	{ USB_DEVICE(0x10C4, 0x81C8) }, /* Lipowsky Industrie Elektronik GmbH, Baby-JTAG */
102 	{ USB_DEVICE(0x10C4, 0x81D7) }, /* IAI Corp. RCB-CV-USB USB to RS485 Adaptor */
103 	{ USB_DEVICE(0x10C4, 0x81E2) }, /* Lipowsky Industrie Elektronik GmbH, Baby-LIN */
104 	{ USB_DEVICE(0x10C4, 0x81E7) }, /* Aerocomm Radio */
105 	{ USB_DEVICE(0x10C4, 0x81E8) }, /* Zephyr Bioharness */
106 	{ USB_DEVICE(0x10C4, 0x81F2) }, /* C1007 HF band RFID controller */
107 	{ USB_DEVICE(0x10C4, 0x8218) }, /* Lipowsky Industrie Elektronik GmbH, HARP-1 */
108 	{ USB_DEVICE(0x10C4, 0x822B) }, /* Modem EDGE(GSM) Comander 2 */
109 	{ USB_DEVICE(0x10C4, 0x826B) }, /* Cygnal Integrated Products, Inc., Fasttrax GPS demonstration module */
110 	{ USB_DEVICE(0x10C4, 0x8281) }, /* Nanotec Plug & Drive */
111 	{ USB_DEVICE(0x10C4, 0x8293) }, /* Telegesis ETRX2USB */
112 	{ USB_DEVICE(0x10C4, 0x82F4) }, /* Starizona MicroTouch */
113 	{ USB_DEVICE(0x10C4, 0x82F9) }, /* Procyon AVS */
114 	{ USB_DEVICE(0x10C4, 0x8341) }, /* Siemens MC35PU GPRS Modem */
115 	{ USB_DEVICE(0x10C4, 0x8382) }, /* Cygnal Integrated Products, Inc. */
116 	{ USB_DEVICE(0x10C4, 0x83A8) }, /* Amber Wireless AMB2560 */
117 	{ USB_DEVICE(0x10C4, 0x83D8) }, /* DekTec DTA Plus VHF/UHF Booster/Attenuator */
118 	{ USB_DEVICE(0x10C4, 0x8411) }, /* Kyocera GPS Module */
119 	{ USB_DEVICE(0x10C4, 0x8418) }, /* IRZ Automation Teleport SG-10 GSM/GPRS Modem */
120 	{ USB_DEVICE(0x10C4, 0x846E) }, /* BEI USB Sensor Interface (VCP) */
121 	{ USB_DEVICE(0x10C4, 0x8477) }, /* Balluff RFID */
122 	{ USB_DEVICE(0x10C4, 0x84B6) }, /* Starizona Hyperion */
123 	{ USB_DEVICE(0x10C4, 0x85EA) }, /* AC-Services IBUS-IF */
124 	{ USB_DEVICE(0x10C4, 0x85EB) }, /* AC-Services CIS-IBUS */
125 	{ USB_DEVICE(0x10C4, 0x85F8) }, /* Virtenio Preon32 */
126 	{ USB_DEVICE(0x10C4, 0x8664) }, /* AC-Services CAN-IF */
127 	{ USB_DEVICE(0x10C4, 0x8665) }, /* AC-Services OBD-IF */
128 	{ USB_DEVICE(0x10C4, 0x8856) },	/* CEL EM357 ZigBee USB Stick - LR */
129 	{ USB_DEVICE(0x10C4, 0x8857) },	/* CEL EM357 ZigBee USB Stick */
130 	{ USB_DEVICE(0x10C4, 0x88A4) }, /* MMB Networks ZigBee USB Device */
131 	{ USB_DEVICE(0x10C4, 0x88A5) }, /* Planet Innovation Ingeni ZigBee USB Device */
132 	{ USB_DEVICE(0x10C4, 0x8946) }, /* Ketra N1 Wireless Interface */
133 	{ USB_DEVICE(0x10C4, 0x8977) },	/* CEL MeshWorks DevKit Device */
134 	{ USB_DEVICE(0x10C4, 0x8998) }, /* KCF Technologies PRN */
135 	{ USB_DEVICE(0x10C4, 0x8A2A) }, /* HubZ dual ZigBee and Z-Wave dongle */
136 	{ USB_DEVICE(0x10C4, 0xEA60) }, /* Silicon Labs factory default */
137 	{ USB_DEVICE(0x10C4, 0xEA61) }, /* Silicon Labs factory default */
138 	{ USB_DEVICE(0x10C4, 0xEA70) }, /* Silicon Labs factory default */
139 	{ USB_DEVICE(0x10C4, 0xEA71) }, /* Infinity GPS-MIC-1 Radio Monophone */
140 	{ USB_DEVICE(0x10C4, 0xF001) }, /* Elan Digital Systems USBscope50 */
141 	{ USB_DEVICE(0x10C4, 0xF002) }, /* Elan Digital Systems USBwave12 */
142 	{ USB_DEVICE(0x10C4, 0xF003) }, /* Elan Digital Systems USBpulse100 */
143 	{ USB_DEVICE(0x10C4, 0xF004) }, /* Elan Digital Systems USBcount50 */
144 	{ USB_DEVICE(0x10C5, 0xEA61) }, /* Silicon Labs MobiData GPRS USB Modem */
145 	{ USB_DEVICE(0x10CE, 0xEA6A) }, /* Silicon Labs MobiData GPRS USB Modem 100EU */
146 	{ USB_DEVICE(0x12B8, 0xEC60) }, /* Link G4 ECU */
147 	{ USB_DEVICE(0x12B8, 0xEC62) }, /* Link G4+ ECU */
148 	{ USB_DEVICE(0x13AD, 0x9999) }, /* Baltech card reader */
149 	{ USB_DEVICE(0x1555, 0x0004) }, /* Owen AC4 USB-RS485 Converter */
150 	{ USB_DEVICE(0x166A, 0x0201) }, /* Clipsal 5500PACA C-Bus Pascal Automation Controller */
151 	{ USB_DEVICE(0x166A, 0x0301) }, /* Clipsal 5800PC C-Bus Wireless PC Interface */
152 	{ USB_DEVICE(0x166A, 0x0303) }, /* Clipsal 5500PCU C-Bus USB interface */
153 	{ USB_DEVICE(0x166A, 0x0304) }, /* Clipsal 5000CT2 C-Bus Black and White Touchscreen */
154 	{ USB_DEVICE(0x166A, 0x0305) }, /* Clipsal C-5000CT2 C-Bus Spectrum Colour Touchscreen */
155 	{ USB_DEVICE(0x166A, 0x0401) }, /* Clipsal L51xx C-Bus Architectural Dimmer */
156 	{ USB_DEVICE(0x166A, 0x0101) }, /* Clipsal 5560884 C-Bus Multi-room Audio Matrix Switcher */
157 	{ USB_DEVICE(0x16C0, 0x09B0) }, /* Lunatico Seletek */
158 	{ USB_DEVICE(0x16C0, 0x09B1) }, /* Lunatico Seletek */
159 	{ USB_DEVICE(0x16D6, 0x0001) }, /* Jablotron serial interface */
160 	{ USB_DEVICE(0x16DC, 0x0010) }, /* W-IE-NE-R Plein & Baus GmbH PL512 Power Supply */
161 	{ USB_DEVICE(0x16DC, 0x0011) }, /* W-IE-NE-R Plein & Baus GmbH RCM Remote Control for MARATON Power Supply */
162 	{ USB_DEVICE(0x16DC, 0x0012) }, /* W-IE-NE-R Plein & Baus GmbH MPOD Multi Channel Power Supply */
163 	{ USB_DEVICE(0x16DC, 0x0015) }, /* W-IE-NE-R Plein & Baus GmbH CML Control, Monitoring and Data Logger */
164 	{ USB_DEVICE(0x17A8, 0x0001) }, /* Kamstrup Optical Eye/3-wire */
165 	{ USB_DEVICE(0x17A8, 0x0005) }, /* Kamstrup M-Bus Master MultiPort 250D */
166 	{ USB_DEVICE(0x17F4, 0xAAAA) }, /* Wavesense Jazz blood glucose meter */
167 	{ USB_DEVICE(0x1843, 0x0200) }, /* Vaisala USB Instrument Cable */
168 	{ USB_DEVICE(0x18EF, 0xE00F) }, /* ELV USB-I2C-Interface */
169 	{ USB_DEVICE(0x18EF, 0xE025) }, /* ELV Marble Sound Board 1 */
170 	{ USB_DEVICE(0x1901, 0x0190) }, /* GE B850 CP2105 Recorder interface */
171 	{ USB_DEVICE(0x1901, 0x0193) }, /* GE B650 CP2104 PMC interface */
172 	{ USB_DEVICE(0x1901, 0x0194) },	/* GE Healthcare Remote Alarm Box */
173 	{ USB_DEVICE(0x19CF, 0x3000) }, /* Parrot NMEA GPS Flight Recorder */
174 	{ USB_DEVICE(0x1ADB, 0x0001) }, /* Schweitzer Engineering C662 Cable */
175 	{ USB_DEVICE(0x1B1C, 0x1C00) }, /* Corsair USB Dongle */
176 	{ USB_DEVICE(0x1BA4, 0x0002) },	/* Silicon Labs 358x factory default */
177 	{ USB_DEVICE(0x1BE3, 0x07A6) }, /* WAGO 750-923 USB Service Cable */
178 	{ USB_DEVICE(0x1D6F, 0x0010) }, /* Seluxit ApS RF Dongle */
179 	{ USB_DEVICE(0x1E29, 0x0102) }, /* Festo CPX-USB */
180 	{ USB_DEVICE(0x1E29, 0x0501) }, /* Festo CMSP */
181 	{ USB_DEVICE(0x1FB9, 0x0100) }, /* Lake Shore Model 121 Current Source */
182 	{ USB_DEVICE(0x1FB9, 0x0200) }, /* Lake Shore Model 218A Temperature Monitor */
183 	{ USB_DEVICE(0x1FB9, 0x0201) }, /* Lake Shore Model 219 Temperature Monitor */
184 	{ USB_DEVICE(0x1FB9, 0x0202) }, /* Lake Shore Model 233 Temperature Transmitter */
185 	{ USB_DEVICE(0x1FB9, 0x0203) }, /* Lake Shore Model 235 Temperature Transmitter */
186 	{ USB_DEVICE(0x1FB9, 0x0300) }, /* Lake Shore Model 335 Temperature Controller */
187 	{ USB_DEVICE(0x1FB9, 0x0301) }, /* Lake Shore Model 336 Temperature Controller */
188 	{ USB_DEVICE(0x1FB9, 0x0302) }, /* Lake Shore Model 350 Temperature Controller */
189 	{ USB_DEVICE(0x1FB9, 0x0303) }, /* Lake Shore Model 371 AC Bridge */
190 	{ USB_DEVICE(0x1FB9, 0x0400) }, /* Lake Shore Model 411 Handheld Gaussmeter */
191 	{ USB_DEVICE(0x1FB9, 0x0401) }, /* Lake Shore Model 425 Gaussmeter */
192 	{ USB_DEVICE(0x1FB9, 0x0402) }, /* Lake Shore Model 455A Gaussmeter */
193 	{ USB_DEVICE(0x1FB9, 0x0403) }, /* Lake Shore Model 475A Gaussmeter */
194 	{ USB_DEVICE(0x1FB9, 0x0404) }, /* Lake Shore Model 465 Three Axis Gaussmeter */
195 	{ USB_DEVICE(0x1FB9, 0x0600) }, /* Lake Shore Model 625A Superconducting MPS */
196 	{ USB_DEVICE(0x1FB9, 0x0601) }, /* Lake Shore Model 642A Magnet Power Supply */
197 	{ USB_DEVICE(0x1FB9, 0x0602) }, /* Lake Shore Model 648 Magnet Power Supply */
198 	{ USB_DEVICE(0x1FB9, 0x0700) }, /* Lake Shore Model 737 VSM Controller */
199 	{ USB_DEVICE(0x1FB9, 0x0701) }, /* Lake Shore Model 776 Hall Matrix */
200 	{ USB_DEVICE(0x2626, 0xEA60) }, /* Aruba Networks 7xxx USB Serial Console */
201 	{ USB_DEVICE(0x3195, 0xF190) }, /* Link Instruments MSO-19 */
202 	{ USB_DEVICE(0x3195, 0xF280) }, /* Link Instruments MSO-28 */
203 	{ USB_DEVICE(0x3195, 0xF281) }, /* Link Instruments MSO-28 */
204 	{ USB_DEVICE(0x413C, 0x9500) }, /* DW700 GPS USB interface */
205 	{ } /* Terminating Entry */
206 };
207 
208 MODULE_DEVICE_TABLE(usb, id_table);
209 
210 struct cp210x_port_private {
211 	__u8			bInterfaceNumber;
212 	bool			has_swapped_line_ctl;
213 };
214 
215 static struct usb_serial_driver cp210x_device = {
216 	.driver = {
217 		.owner =	THIS_MODULE,
218 		.name =		"cp210x",
219 	},
220 	.id_table		= id_table,
221 	.num_ports		= 1,
222 	.bulk_in_size		= 256,
223 	.bulk_out_size		= 256,
224 	.open			= cp210x_open,
225 	.close			= cp210x_close,
226 	.break_ctl		= cp210x_break_ctl,
227 	.set_termios		= cp210x_set_termios,
228 	.tx_empty		= cp210x_tx_empty,
229 	.tiocmget		= cp210x_tiocmget,
230 	.tiocmset		= cp210x_tiocmset,
231 	.port_probe		= cp210x_port_probe,
232 	.port_remove		= cp210x_port_remove,
233 	.dtr_rts		= cp210x_dtr_rts
234 };
235 
236 static struct usb_serial_driver * const serial_drivers[] = {
237 	&cp210x_device, NULL
238 };
239 
240 /* Config request types */
241 #define REQTYPE_HOST_TO_INTERFACE	0x41
242 #define REQTYPE_INTERFACE_TO_HOST	0xc1
243 #define REQTYPE_HOST_TO_DEVICE	0x40
244 #define REQTYPE_DEVICE_TO_HOST	0xc0
245 
246 /* Config request codes */
247 #define CP210X_IFC_ENABLE	0x00
248 #define CP210X_SET_BAUDDIV	0x01
249 #define CP210X_GET_BAUDDIV	0x02
250 #define CP210X_SET_LINE_CTL	0x03
251 #define CP210X_GET_LINE_CTL	0x04
252 #define CP210X_SET_BREAK	0x05
253 #define CP210X_IMM_CHAR		0x06
254 #define CP210X_SET_MHS		0x07
255 #define CP210X_GET_MDMSTS	0x08
256 #define CP210X_SET_XON		0x09
257 #define CP210X_SET_XOFF		0x0A
258 #define CP210X_SET_EVENTMASK	0x0B
259 #define CP210X_GET_EVENTMASK	0x0C
260 #define CP210X_SET_CHAR		0x0D
261 #define CP210X_GET_CHARS	0x0E
262 #define CP210X_GET_PROPS	0x0F
263 #define CP210X_GET_COMM_STATUS	0x10
264 #define CP210X_RESET		0x11
265 #define CP210X_PURGE		0x12
266 #define CP210X_SET_FLOW		0x13
267 #define CP210X_GET_FLOW		0x14
268 #define CP210X_EMBED_EVENTS	0x15
269 #define CP210X_GET_EVENTSTATE	0x16
270 #define CP210X_SET_CHARS	0x19
271 #define CP210X_GET_BAUDRATE	0x1D
272 #define CP210X_SET_BAUDRATE	0x1E
273 
274 /* CP210X_IFC_ENABLE */
275 #define UART_ENABLE		0x0001
276 #define UART_DISABLE		0x0000
277 
278 /* CP210X_(SET|GET)_BAUDDIV */
279 #define BAUD_RATE_GEN_FREQ	0x384000
280 
281 /* CP210X_(SET|GET)_LINE_CTL */
282 #define BITS_DATA_MASK		0X0f00
283 #define BITS_DATA_5		0X0500
284 #define BITS_DATA_6		0X0600
285 #define BITS_DATA_7		0X0700
286 #define BITS_DATA_8		0X0800
287 #define BITS_DATA_9		0X0900
288 
289 #define BITS_PARITY_MASK	0x00f0
290 #define BITS_PARITY_NONE	0x0000
291 #define BITS_PARITY_ODD		0x0010
292 #define BITS_PARITY_EVEN	0x0020
293 #define BITS_PARITY_MARK	0x0030
294 #define BITS_PARITY_SPACE	0x0040
295 
296 #define BITS_STOP_MASK		0x000f
297 #define BITS_STOP_1		0x0000
298 #define BITS_STOP_1_5		0x0001
299 #define BITS_STOP_2		0x0002
300 
301 /* CP210X_SET_BREAK */
302 #define BREAK_ON		0x0001
303 #define BREAK_OFF		0x0000
304 
305 /* CP210X_(SET_MHS|GET_MDMSTS) */
306 #define CONTROL_DTR		0x0001
307 #define CONTROL_RTS		0x0002
308 #define CONTROL_CTS		0x0010
309 #define CONTROL_DSR		0x0020
310 #define CONTROL_RING		0x0040
311 #define CONTROL_DCD		0x0080
312 #define CONTROL_WRITE_DTR	0x0100
313 #define CONTROL_WRITE_RTS	0x0200
314 
315 /* CP210X_GET_COMM_STATUS returns these 0x13 bytes */
316 struct cp210x_comm_status {
317 	__le32   ulErrors;
318 	__le32   ulHoldReasons;
319 	__le32   ulAmountInInQueue;
320 	__le32   ulAmountInOutQueue;
321 	u8       bEofReceived;
322 	u8       bWaitForImmediate;
323 	u8       bReserved;
324 } __packed;
325 
326 /*
327  * CP210X_PURGE - 16 bits passed in wValue of USB request.
328  * SiLabs app note AN571 gives a strange description of the 4 bits:
329  * bit 0 or bit 2 clears the transmit queue and 1 or 3 receive.
330  * writing 1 to all, however, purges cp2108 well enough to avoid the hang.
331  */
332 #define PURGE_ALL		0x000f
333 
334 /*
335  * Reads a variable-sized block of CP210X_ registers, identified by req.
336  * Returns data into buf in native USB byte order.
337  */
338 static int cp210x_read_reg_block(struct usb_serial_port *port, u8 req,
339 		void *buf, int bufsize)
340 {
341 	struct usb_serial *serial = port->serial;
342 	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
343 	void *dmabuf;
344 	int result;
345 
346 	dmabuf = kmalloc(bufsize, GFP_KERNEL);
347 	if (!dmabuf) {
348 		/*
349 		 * FIXME Some callers don't bother to check for error,
350 		 * at least give them consistent junk until they are fixed
351 		 */
352 		memset(buf, 0, bufsize);
353 		return -ENOMEM;
354 	}
355 
356 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
357 			req, REQTYPE_INTERFACE_TO_HOST, 0,
358 			port_priv->bInterfaceNumber, dmabuf, bufsize,
359 			USB_CTRL_SET_TIMEOUT);
360 	if (result == bufsize) {
361 		memcpy(buf, dmabuf, bufsize);
362 		result = 0;
363 	} else {
364 		dev_err(&port->dev, "failed get req 0x%x size %d status: %d\n",
365 				req, bufsize, result);
366 		if (result >= 0)
367 			result = -EPROTO;
368 
369 		/*
370 		 * FIXME Some callers don't bother to check for error,
371 		 * at least give them consistent junk until they are fixed
372 		 */
373 		memset(buf, 0, bufsize);
374 	}
375 
376 	kfree(dmabuf);
377 
378 	return result;
379 }
380 
381 /*
382  * Reads any 32-bit CP210X_ register identified by req.
383  */
384 static int cp210x_read_u32_reg(struct usb_serial_port *port, u8 req, u32 *val)
385 {
386 	__le32 le32_val;
387 	int err;
388 
389 	err = cp210x_read_reg_block(port, req, &le32_val, sizeof(le32_val));
390 	if (err) {
391 		/*
392 		 * FIXME Some callers don't bother to check for error,
393 		 * at least give them consistent junk until they are fixed
394 		 */
395 		*val = 0;
396 		return err;
397 	}
398 
399 	*val = le32_to_cpu(le32_val);
400 
401 	return 0;
402 }
403 
404 /*
405  * Reads any 16-bit CP210X_ register identified by req.
406  */
407 static int cp210x_read_u16_reg(struct usb_serial_port *port, u8 req, u16 *val)
408 {
409 	__le16 le16_val;
410 	int err;
411 
412 	err = cp210x_read_reg_block(port, req, &le16_val, sizeof(le16_val));
413 	if (err)
414 		return err;
415 
416 	*val = le16_to_cpu(le16_val);
417 
418 	return 0;
419 }
420 
421 /*
422  * Reads any 8-bit CP210X_ register identified by req.
423  */
424 static int cp210x_read_u8_reg(struct usb_serial_port *port, u8 req, u8 *val)
425 {
426 	return cp210x_read_reg_block(port, req, val, sizeof(*val));
427 }
428 
429 /*
430  * Writes any 16-bit CP210X_ register (req) whose value is passed
431  * entirely in the wValue field of the USB request.
432  */
433 static int cp210x_write_u16_reg(struct usb_serial_port *port, u8 req, u16 val)
434 {
435 	struct usb_serial *serial = port->serial;
436 	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
437 	int result;
438 
439 	result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
440 			req, REQTYPE_HOST_TO_INTERFACE, val,
441 			port_priv->bInterfaceNumber, NULL, 0,
442 			USB_CTRL_SET_TIMEOUT);
443 	if (result < 0) {
444 		dev_err(&port->dev, "failed set request 0x%x status: %d\n",
445 				req, result);
446 	}
447 
448 	return result;
449 }
450 
451 /*
452  * Writes a variable-sized block of CP210X_ registers, identified by req.
453  * Data in buf must be in native USB byte order.
454  */
455 static int cp210x_write_reg_block(struct usb_serial_port *port, u8 req,
456 		void *buf, int bufsize)
457 {
458 	struct usb_serial *serial = port->serial;
459 	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
460 	void *dmabuf;
461 	int result;
462 
463 	dmabuf = kmalloc(bufsize, GFP_KERNEL);
464 	if (!dmabuf)
465 		return -ENOMEM;
466 
467 	memcpy(dmabuf, buf, bufsize);
468 
469 	result = usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
470 			req, REQTYPE_HOST_TO_INTERFACE, 0,
471 			port_priv->bInterfaceNumber, dmabuf, bufsize,
472 			USB_CTRL_SET_TIMEOUT);
473 
474 	kfree(dmabuf);
475 
476 	if (result == bufsize) {
477 		result = 0;
478 	} else {
479 		dev_err(&port->dev, "failed set req 0x%x size %d status: %d\n",
480 				req, bufsize, result);
481 		if (result >= 0)
482 			result = -EPROTO;
483 	}
484 
485 	return result;
486 }
487 
488 /*
489  * Writes any 32-bit CP210X_ register identified by req.
490  */
491 static int cp210x_write_u32_reg(struct usb_serial_port *port, u8 req, u32 val)
492 {
493 	__le32 le32_val;
494 
495 	le32_val = cpu_to_le32(val);
496 
497 	return cp210x_write_reg_block(port, req, &le32_val, sizeof(le32_val));
498 }
499 
500 /*
501  * Detect CP2108 GET_LINE_CTL bug and activate workaround.
502  * Write a known good value 0x800, read it back.
503  * If it comes back swapped the bug is detected.
504  * Preserve the original register value.
505  */
506 static int cp210x_detect_swapped_line_ctl(struct usb_serial_port *port)
507 {
508 	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
509 	u16 line_ctl_save;
510 	u16 line_ctl_test;
511 	int err;
512 
513 	err = cp210x_read_u16_reg(port, CP210X_GET_LINE_CTL, &line_ctl_save);
514 	if (err)
515 		return err;
516 
517 	err = cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, 0x800);
518 	if (err)
519 		return err;
520 
521 	err = cp210x_read_u16_reg(port, CP210X_GET_LINE_CTL, &line_ctl_test);
522 	if (err)
523 		return err;
524 
525 	if (line_ctl_test == 8) {
526 		port_priv->has_swapped_line_ctl = true;
527 		line_ctl_save = swab16(line_ctl_save);
528 	}
529 
530 	return cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, line_ctl_save);
531 }
532 
533 /*
534  * Must always be called instead of cp210x_read_u16_reg(CP210X_GET_LINE_CTL)
535  * to workaround cp2108 bug and get correct value.
536  */
537 static int cp210x_get_line_ctl(struct usb_serial_port *port, u16 *ctl)
538 {
539 	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
540 	int err;
541 
542 	err = cp210x_read_u16_reg(port, CP210X_GET_LINE_CTL, ctl);
543 	if (err)
544 		return err;
545 
546 	/* Workaround swapped bytes in 16-bit value from CP210X_GET_LINE_CTL */
547 	if (port_priv->has_swapped_line_ctl)
548 		*ctl = swab16(*ctl);
549 
550 	return 0;
551 }
552 
553 /*
554  * cp210x_quantise_baudrate
555  * Quantises the baud rate as per AN205 Table 1
556  */
557 static unsigned int cp210x_quantise_baudrate(unsigned int baud)
558 {
559 	if (baud <= 300)
560 		baud = 300;
561 	else if (baud <= 600)      baud = 600;
562 	else if (baud <= 1200)     baud = 1200;
563 	else if (baud <= 1800)     baud = 1800;
564 	else if (baud <= 2400)     baud = 2400;
565 	else if (baud <= 4000)     baud = 4000;
566 	else if (baud <= 4803)     baud = 4800;
567 	else if (baud <= 7207)     baud = 7200;
568 	else if (baud <= 9612)     baud = 9600;
569 	else if (baud <= 14428)    baud = 14400;
570 	else if (baud <= 16062)    baud = 16000;
571 	else if (baud <= 19250)    baud = 19200;
572 	else if (baud <= 28912)    baud = 28800;
573 	else if (baud <= 38601)    baud = 38400;
574 	else if (baud <= 51558)    baud = 51200;
575 	else if (baud <= 56280)    baud = 56000;
576 	else if (baud <= 58053)    baud = 57600;
577 	else if (baud <= 64111)    baud = 64000;
578 	else if (baud <= 77608)    baud = 76800;
579 	else if (baud <= 117028)   baud = 115200;
580 	else if (baud <= 129347)   baud = 128000;
581 	else if (baud <= 156868)   baud = 153600;
582 	else if (baud <= 237832)   baud = 230400;
583 	else if (baud <= 254234)   baud = 250000;
584 	else if (baud <= 273066)   baud = 256000;
585 	else if (baud <= 491520)   baud = 460800;
586 	else if (baud <= 567138)   baud = 500000;
587 	else if (baud <= 670254)   baud = 576000;
588 	else if (baud < 1000000)
589 		baud = 921600;
590 	else if (baud > 2000000)
591 		baud = 2000000;
592 	return baud;
593 }
594 
595 static int cp210x_open(struct tty_struct *tty, struct usb_serial_port *port)
596 {
597 	int result;
598 
599 	result = cp210x_write_u16_reg(port, CP210X_IFC_ENABLE, UART_ENABLE);
600 	if (result) {
601 		dev_err(&port->dev, "%s - Unable to enable UART\n", __func__);
602 		return result;
603 	}
604 
605 	/* Configure the termios structure */
606 	cp210x_get_termios(tty, port);
607 
608 	/* The baud rate must be initialised on cp2104 */
609 	if (tty)
610 		cp210x_change_speed(tty, port, NULL);
611 
612 	return usb_serial_generic_open(tty, port);
613 }
614 
615 static void cp210x_close(struct usb_serial_port *port)
616 {
617 	usb_serial_generic_close(port);
618 
619 	/* Clear both queues; cp2108 needs this to avoid an occasional hang */
620 	cp210x_write_u16_reg(port, CP210X_PURGE, PURGE_ALL);
621 
622 	cp210x_write_u16_reg(port, CP210X_IFC_ENABLE, UART_DISABLE);
623 }
624 
625 /*
626  * Read how many bytes are waiting in the TX queue.
627  */
628 static int cp210x_get_tx_queue_byte_count(struct usb_serial_port *port,
629 		u32 *count)
630 {
631 	struct usb_serial *serial = port->serial;
632 	struct cp210x_port_private *port_priv = usb_get_serial_port_data(port);
633 	struct cp210x_comm_status *sts;
634 	int result;
635 
636 	sts = kmalloc(sizeof(*sts), GFP_KERNEL);
637 	if (!sts)
638 		return -ENOMEM;
639 
640 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
641 			CP210X_GET_COMM_STATUS, REQTYPE_INTERFACE_TO_HOST,
642 			0, port_priv->bInterfaceNumber, sts, sizeof(*sts),
643 			USB_CTRL_GET_TIMEOUT);
644 	if (result == sizeof(*sts)) {
645 		*count = le32_to_cpu(sts->ulAmountInOutQueue);
646 		result = 0;
647 	} else {
648 		dev_err(&port->dev, "failed to get comm status: %d\n", result);
649 		if (result >= 0)
650 			result = -EPROTO;
651 	}
652 
653 	kfree(sts);
654 
655 	return result;
656 }
657 
658 static bool cp210x_tx_empty(struct usb_serial_port *port)
659 {
660 	int err;
661 	u32 count;
662 
663 	err = cp210x_get_tx_queue_byte_count(port, &count);
664 	if (err)
665 		return true;
666 
667 	return !count;
668 }
669 
670 /*
671  * cp210x_get_termios
672  * Reads the baud rate, data bits, parity, stop bits and flow control mode
673  * from the device, corrects any unsupported values, and configures the
674  * termios structure to reflect the state of the device
675  */
676 static void cp210x_get_termios(struct tty_struct *tty,
677 	struct usb_serial_port *port)
678 {
679 	unsigned int baud;
680 
681 	if (tty) {
682 		cp210x_get_termios_port(tty->driver_data,
683 			&tty->termios.c_cflag, &baud);
684 		tty_encode_baud_rate(tty, baud, baud);
685 	} else {
686 		unsigned int cflag;
687 		cflag = 0;
688 		cp210x_get_termios_port(port, &cflag, &baud);
689 	}
690 }
691 
692 /*
693  * cp210x_get_termios_port
694  * This is the heart of cp210x_get_termios which always uses a &usb_serial_port.
695  */
696 static void cp210x_get_termios_port(struct usb_serial_port *port,
697 	unsigned int *cflagp, unsigned int *baudp)
698 {
699 	struct device *dev = &port->dev;
700 	unsigned int cflag;
701 	u8 modem_ctl[16];
702 	u32 baud;
703 	u16 bits;
704 
705 	cp210x_read_u32_reg(port, CP210X_GET_BAUDRATE, &baud);
706 
707 	dev_dbg(dev, "%s - baud rate = %d\n", __func__, baud);
708 	*baudp = baud;
709 
710 	cflag = *cflagp;
711 
712 	cp210x_get_line_ctl(port, &bits);
713 	cflag &= ~CSIZE;
714 	switch (bits & BITS_DATA_MASK) {
715 	case BITS_DATA_5:
716 		dev_dbg(dev, "%s - data bits = 5\n", __func__);
717 		cflag |= CS5;
718 		break;
719 	case BITS_DATA_6:
720 		dev_dbg(dev, "%s - data bits = 6\n", __func__);
721 		cflag |= CS6;
722 		break;
723 	case BITS_DATA_7:
724 		dev_dbg(dev, "%s - data bits = 7\n", __func__);
725 		cflag |= CS7;
726 		break;
727 	case BITS_DATA_8:
728 		dev_dbg(dev, "%s - data bits = 8\n", __func__);
729 		cflag |= CS8;
730 		break;
731 	case BITS_DATA_9:
732 		dev_dbg(dev, "%s - data bits = 9 (not supported, using 8 data bits)\n", __func__);
733 		cflag |= CS8;
734 		bits &= ~BITS_DATA_MASK;
735 		bits |= BITS_DATA_8;
736 		cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
737 		break;
738 	default:
739 		dev_dbg(dev, "%s - Unknown number of data bits, using 8\n", __func__);
740 		cflag |= CS8;
741 		bits &= ~BITS_DATA_MASK;
742 		bits |= BITS_DATA_8;
743 		cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
744 		break;
745 	}
746 
747 	switch (bits & BITS_PARITY_MASK) {
748 	case BITS_PARITY_NONE:
749 		dev_dbg(dev, "%s - parity = NONE\n", __func__);
750 		cflag &= ~PARENB;
751 		break;
752 	case BITS_PARITY_ODD:
753 		dev_dbg(dev, "%s - parity = ODD\n", __func__);
754 		cflag |= (PARENB|PARODD);
755 		break;
756 	case BITS_PARITY_EVEN:
757 		dev_dbg(dev, "%s - parity = EVEN\n", __func__);
758 		cflag &= ~PARODD;
759 		cflag |= PARENB;
760 		break;
761 	case BITS_PARITY_MARK:
762 		dev_dbg(dev, "%s - parity = MARK\n", __func__);
763 		cflag |= (PARENB|PARODD|CMSPAR);
764 		break;
765 	case BITS_PARITY_SPACE:
766 		dev_dbg(dev, "%s - parity = SPACE\n", __func__);
767 		cflag &= ~PARODD;
768 		cflag |= (PARENB|CMSPAR);
769 		break;
770 	default:
771 		dev_dbg(dev, "%s - Unknown parity mode, disabling parity\n", __func__);
772 		cflag &= ~PARENB;
773 		bits &= ~BITS_PARITY_MASK;
774 		cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
775 		break;
776 	}
777 
778 	cflag &= ~CSTOPB;
779 	switch (bits & BITS_STOP_MASK) {
780 	case BITS_STOP_1:
781 		dev_dbg(dev, "%s - stop bits = 1\n", __func__);
782 		break;
783 	case BITS_STOP_1_5:
784 		dev_dbg(dev, "%s - stop bits = 1.5 (not supported, using 1 stop bit)\n", __func__);
785 		bits &= ~BITS_STOP_MASK;
786 		cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
787 		break;
788 	case BITS_STOP_2:
789 		dev_dbg(dev, "%s - stop bits = 2\n", __func__);
790 		cflag |= CSTOPB;
791 		break;
792 	default:
793 		dev_dbg(dev, "%s - Unknown number of stop bits, using 1 stop bit\n", __func__);
794 		bits &= ~BITS_STOP_MASK;
795 		cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits);
796 		break;
797 	}
798 
799 	cp210x_read_reg_block(port, CP210X_GET_FLOW, modem_ctl,
800 			sizeof(modem_ctl));
801 	if (modem_ctl[0] & 0x08) {
802 		dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);
803 		cflag |= CRTSCTS;
804 	} else {
805 		dev_dbg(dev, "%s - flow control = NONE\n", __func__);
806 		cflag &= ~CRTSCTS;
807 	}
808 
809 	*cflagp = cflag;
810 }
811 
812 /*
813  * CP2101 supports the following baud rates:
814  *
815  *	300, 600, 1200, 1800, 2400, 4800, 7200, 9600, 14400, 19200, 28800,
816  *	38400, 56000, 57600, 115200, 128000, 230400, 460800, 921600
817  *
818  * CP2102 and CP2103 support the following additional rates:
819  *
820  *	4000, 16000, 51200, 64000, 76800, 153600, 250000, 256000, 500000,
821  *	576000
822  *
823  * The device will map a requested rate to a supported one, but the result
824  * of requests for rates greater than 1053257 is undefined (see AN205).
825  *
826  * CP2104, CP2105 and CP2110 support most rates up to 2M, 921k and 1M baud,
827  * respectively, with an error less than 1%. The actual rates are determined
828  * by
829  *
830  *	div = round(freq / (2 x prescale x request))
831  *	actual = freq / (2 x prescale x div)
832  *
833  * For CP2104 and CP2105 freq is 48Mhz and prescale is 4 for request <= 365bps
834  * or 1 otherwise.
835  * For CP2110 freq is 24Mhz and prescale is 4 for request <= 300bps or 1
836  * otherwise.
837  */
838 static void cp210x_change_speed(struct tty_struct *tty,
839 		struct usb_serial_port *port, struct ktermios *old_termios)
840 {
841 	u32 baud;
842 
843 	baud = tty->termios.c_ospeed;
844 
845 	/* This maps the requested rate to a rate valid on cp2102 or cp2103,
846 	 * or to an arbitrary rate in [1M,2M].
847 	 *
848 	 * NOTE: B0 is not implemented.
849 	 */
850 	baud = cp210x_quantise_baudrate(baud);
851 
852 	dev_dbg(&port->dev, "%s - setting baud rate to %u\n", __func__, baud);
853 	if (cp210x_write_u32_reg(port, CP210X_SET_BAUDRATE, baud)) {
854 		dev_warn(&port->dev, "failed to set baud rate to %u\n", baud);
855 		if (old_termios)
856 			baud = old_termios->c_ospeed;
857 		else
858 			baud = 9600;
859 	}
860 
861 	tty_encode_baud_rate(tty, baud, baud);
862 }
863 
864 static void cp210x_set_termios(struct tty_struct *tty,
865 		struct usb_serial_port *port, struct ktermios *old_termios)
866 {
867 	struct device *dev = &port->dev;
868 	unsigned int cflag, old_cflag;
869 	u16 bits;
870 	u8 modem_ctl[16];
871 
872 	cflag = tty->termios.c_cflag;
873 	old_cflag = old_termios->c_cflag;
874 
875 	if (tty->termios.c_ospeed != old_termios->c_ospeed)
876 		cp210x_change_speed(tty, port, old_termios);
877 
878 	/* If the number of data bits is to be updated */
879 	if ((cflag & CSIZE) != (old_cflag & CSIZE)) {
880 		cp210x_get_line_ctl(port, &bits);
881 		bits &= ~BITS_DATA_MASK;
882 		switch (cflag & CSIZE) {
883 		case CS5:
884 			bits |= BITS_DATA_5;
885 			dev_dbg(dev, "%s - data bits = 5\n", __func__);
886 			break;
887 		case CS6:
888 			bits |= BITS_DATA_6;
889 			dev_dbg(dev, "%s - data bits = 6\n", __func__);
890 			break;
891 		case CS7:
892 			bits |= BITS_DATA_7;
893 			dev_dbg(dev, "%s - data bits = 7\n", __func__);
894 			break;
895 		case CS8:
896 			bits |= BITS_DATA_8;
897 			dev_dbg(dev, "%s - data bits = 8\n", __func__);
898 			break;
899 		/*case CS9:
900 			bits |= BITS_DATA_9;
901 			dev_dbg(dev, "%s - data bits = 9\n", __func__);
902 			break;*/
903 		default:
904 			dev_dbg(dev, "cp210x driver does not support the number of bits requested, using 8 bit mode\n");
905 			bits |= BITS_DATA_8;
906 			break;
907 		}
908 		if (cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits))
909 			dev_dbg(dev, "Number of data bits requested not supported by device\n");
910 	}
911 
912 	if ((cflag     & (PARENB|PARODD|CMSPAR)) !=
913 	    (old_cflag & (PARENB|PARODD|CMSPAR))) {
914 		cp210x_get_line_ctl(port, &bits);
915 		bits &= ~BITS_PARITY_MASK;
916 		if (cflag & PARENB) {
917 			if (cflag & CMSPAR) {
918 				if (cflag & PARODD) {
919 					bits |= BITS_PARITY_MARK;
920 					dev_dbg(dev, "%s - parity = MARK\n", __func__);
921 				} else {
922 					bits |= BITS_PARITY_SPACE;
923 					dev_dbg(dev, "%s - parity = SPACE\n", __func__);
924 				}
925 			} else {
926 				if (cflag & PARODD) {
927 					bits |= BITS_PARITY_ODD;
928 					dev_dbg(dev, "%s - parity = ODD\n", __func__);
929 				} else {
930 					bits |= BITS_PARITY_EVEN;
931 					dev_dbg(dev, "%s - parity = EVEN\n", __func__);
932 				}
933 			}
934 		}
935 		if (cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits))
936 			dev_dbg(dev, "Parity mode not supported by device\n");
937 	}
938 
939 	if ((cflag & CSTOPB) != (old_cflag & CSTOPB)) {
940 		cp210x_get_line_ctl(port, &bits);
941 		bits &= ~BITS_STOP_MASK;
942 		if (cflag & CSTOPB) {
943 			bits |= BITS_STOP_2;
944 			dev_dbg(dev, "%s - stop bits = 2\n", __func__);
945 		} else {
946 			bits |= BITS_STOP_1;
947 			dev_dbg(dev, "%s - stop bits = 1\n", __func__);
948 		}
949 		if (cp210x_write_u16_reg(port, CP210X_SET_LINE_CTL, bits))
950 			dev_dbg(dev, "Number of stop bits requested not supported by device\n");
951 	}
952 
953 	if ((cflag & CRTSCTS) != (old_cflag & CRTSCTS)) {
954 
955 		/* Only bytes 0, 4 and 7 out of first 8 have functional bits */
956 
957 		cp210x_read_reg_block(port, CP210X_GET_FLOW, modem_ctl,
958 				sizeof(modem_ctl));
959 		dev_dbg(dev, "%s - read modem controls = %02x .. .. .. %02x .. .. %02x\n",
960 			__func__, modem_ctl[0], modem_ctl[4], modem_ctl[7]);
961 
962 		if (cflag & CRTSCTS) {
963 			modem_ctl[0] &= ~0x7B;
964 			modem_ctl[0] |= 0x09;
965 			modem_ctl[4] = 0x80;
966 			/* FIXME - why clear reserved bits just read? */
967 			modem_ctl[5] = 0;
968 			modem_ctl[6] = 0;
969 			modem_ctl[7] = 0;
970 			dev_dbg(dev, "%s - flow control = CRTSCTS\n", __func__);
971 		} else {
972 			modem_ctl[0] &= ~0x7B;
973 			modem_ctl[0] |= 0x01;
974 			/* FIXME - OR here instead of assignment looks wrong */
975 			modem_ctl[4] |= 0x40;
976 			dev_dbg(dev, "%s - flow control = NONE\n", __func__);
977 		}
978 
979 		dev_dbg(dev, "%s - write modem controls = %02x .. .. .. %02x .. .. %02x\n",
980 			__func__, modem_ctl[0], modem_ctl[4], modem_ctl[7]);
981 		cp210x_write_reg_block(port, CP210X_SET_FLOW, modem_ctl,
982 				sizeof(modem_ctl));
983 	}
984 
985 }
986 
987 static int cp210x_tiocmset(struct tty_struct *tty,
988 		unsigned int set, unsigned int clear)
989 {
990 	struct usb_serial_port *port = tty->driver_data;
991 	return cp210x_tiocmset_port(port, set, clear);
992 }
993 
994 static int cp210x_tiocmset_port(struct usb_serial_port *port,
995 		unsigned int set, unsigned int clear)
996 {
997 	u16 control = 0;
998 
999 	if (set & TIOCM_RTS) {
1000 		control |= CONTROL_RTS;
1001 		control |= CONTROL_WRITE_RTS;
1002 	}
1003 	if (set & TIOCM_DTR) {
1004 		control |= CONTROL_DTR;
1005 		control |= CONTROL_WRITE_DTR;
1006 	}
1007 	if (clear & TIOCM_RTS) {
1008 		control &= ~CONTROL_RTS;
1009 		control |= CONTROL_WRITE_RTS;
1010 	}
1011 	if (clear & TIOCM_DTR) {
1012 		control &= ~CONTROL_DTR;
1013 		control |= CONTROL_WRITE_DTR;
1014 	}
1015 
1016 	dev_dbg(&port->dev, "%s - control = 0x%.4x\n", __func__, control);
1017 
1018 	return cp210x_write_u16_reg(port, CP210X_SET_MHS, control);
1019 }
1020 
1021 static void cp210x_dtr_rts(struct usb_serial_port *p, int on)
1022 {
1023 	if (on)
1024 		cp210x_tiocmset_port(p, TIOCM_DTR|TIOCM_RTS, 0);
1025 	else
1026 		cp210x_tiocmset_port(p, 0, TIOCM_DTR|TIOCM_RTS);
1027 }
1028 
1029 static int cp210x_tiocmget(struct tty_struct *tty)
1030 {
1031 	struct usb_serial_port *port = tty->driver_data;
1032 	u8 control;
1033 	int result;
1034 
1035 	cp210x_read_u8_reg(port, CP210X_GET_MDMSTS, &control);
1036 
1037 	result = ((control & CONTROL_DTR) ? TIOCM_DTR : 0)
1038 		|((control & CONTROL_RTS) ? TIOCM_RTS : 0)
1039 		|((control & CONTROL_CTS) ? TIOCM_CTS : 0)
1040 		|((control & CONTROL_DSR) ? TIOCM_DSR : 0)
1041 		|((control & CONTROL_RING)? TIOCM_RI  : 0)
1042 		|((control & CONTROL_DCD) ? TIOCM_CD  : 0);
1043 
1044 	dev_dbg(&port->dev, "%s - control = 0x%.2x\n", __func__, control);
1045 
1046 	return result;
1047 }
1048 
1049 static void cp210x_break_ctl(struct tty_struct *tty, int break_state)
1050 {
1051 	struct usb_serial_port *port = tty->driver_data;
1052 	u16 state;
1053 
1054 	if (break_state == 0)
1055 		state = BREAK_OFF;
1056 	else
1057 		state = BREAK_ON;
1058 	dev_dbg(&port->dev, "%s - turning break %s\n", __func__,
1059 		state == BREAK_OFF ? "off" : "on");
1060 	cp210x_write_u16_reg(port, CP210X_SET_BREAK, state);
1061 }
1062 
1063 static int cp210x_port_probe(struct usb_serial_port *port)
1064 {
1065 	struct usb_serial *serial = port->serial;
1066 	struct usb_host_interface *cur_altsetting;
1067 	struct cp210x_port_private *port_priv;
1068 	int ret;
1069 
1070 	port_priv = kzalloc(sizeof(*port_priv), GFP_KERNEL);
1071 	if (!port_priv)
1072 		return -ENOMEM;
1073 
1074 	cur_altsetting = serial->interface->cur_altsetting;
1075 	port_priv->bInterfaceNumber = cur_altsetting->desc.bInterfaceNumber;
1076 
1077 	usb_set_serial_port_data(port, port_priv);
1078 
1079 	ret = cp210x_detect_swapped_line_ctl(port);
1080 	if (ret) {
1081 		kfree(port_priv);
1082 		return ret;
1083 	}
1084 
1085 	return 0;
1086 }
1087 
1088 static int cp210x_port_remove(struct usb_serial_port *port)
1089 {
1090 	struct cp210x_port_private *port_priv;
1091 
1092 	port_priv = usb_get_serial_port_data(port);
1093 	kfree(port_priv);
1094 
1095 	return 0;
1096 }
1097 
1098 module_usb_serial_driver(serial_drivers, id_table);
1099 
1100 MODULE_DESCRIPTION(DRIVER_DESC);
1101 MODULE_LICENSE("GPL");
1102