xref: /openbmc/linux/drivers/tty/serial/sc16is7xx.c (revision 0da85d1e)
1 /*
2  * SC16IS7xx tty serial driver - Copyright (C) 2014 GridPoint
3  * Author: Jon Ringle <jringle@gridpoint.com>
4  *
5  *  Based on max310x.c, by Alexander Shiyan <shc_work@mail.ru>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  */
13 
14 #include <linux/bitops.h>
15 #include <linux/clk.h>
16 #include <linux/delay.h>
17 #include <linux/device.h>
18 #include <linux/gpio.h>
19 #include <linux/i2c.h>
20 #include <linux/module.h>
21 #include <linux/of.h>
22 #include <linux/of_device.h>
23 #include <linux/regmap.h>
24 #include <linux/serial_core.h>
25 #include <linux/serial.h>
26 #include <linux/tty.h>
27 #include <linux/tty_flip.h>
28 #include <linux/uaccess.h>
29 
30 #define SC16IS7XX_NAME			"sc16is7xx"
31 
32 /* SC16IS7XX register definitions */
33 #define SC16IS7XX_RHR_REG		(0x00) /* RX FIFO */
34 #define SC16IS7XX_THR_REG		(0x00) /* TX FIFO */
35 #define SC16IS7XX_IER_REG		(0x01) /* Interrupt enable */
36 #define SC16IS7XX_IIR_REG		(0x02) /* Interrupt Identification */
37 #define SC16IS7XX_FCR_REG		(0x02) /* FIFO control */
38 #define SC16IS7XX_LCR_REG		(0x03) /* Line Control */
39 #define SC16IS7XX_MCR_REG		(0x04) /* Modem Control */
40 #define SC16IS7XX_LSR_REG		(0x05) /* Line Status */
41 #define SC16IS7XX_MSR_REG		(0x06) /* Modem Status */
42 #define SC16IS7XX_SPR_REG		(0x07) /* Scratch Pad */
43 #define SC16IS7XX_TXLVL_REG		(0x08) /* TX FIFO level */
44 #define SC16IS7XX_RXLVL_REG		(0x09) /* RX FIFO level */
45 #define SC16IS7XX_IODIR_REG		(0x0a) /* I/O Direction
46 						* - only on 75x/76x
47 						*/
48 #define SC16IS7XX_IOSTATE_REG		(0x0b) /* I/O State
49 						* - only on 75x/76x
50 						*/
51 #define SC16IS7XX_IOINTENA_REG		(0x0c) /* I/O Interrupt Enable
52 						* - only on 75x/76x
53 						*/
54 #define SC16IS7XX_IOCONTROL_REG		(0x0e) /* I/O Control
55 						* - only on 75x/76x
56 						*/
57 #define SC16IS7XX_EFCR_REG		(0x0f) /* Extra Features Control */
58 
59 /* TCR/TLR Register set: Only if ((MCR[2] == 1) && (EFR[4] == 1)) */
60 #define SC16IS7XX_TCR_REG		(0x06) /* Transmit control */
61 #define SC16IS7XX_TLR_REG		(0x07) /* Trigger level */
62 
63 /* Special Register set: Only if ((LCR[7] == 1) && (LCR != 0xBF)) */
64 #define SC16IS7XX_DLL_REG		(0x00) /* Divisor Latch Low */
65 #define SC16IS7XX_DLH_REG		(0x01) /* Divisor Latch High */
66 
67 /* Enhanced Register set: Only if (LCR == 0xBF) */
68 #define SC16IS7XX_EFR_REG		(0x02) /* Enhanced Features */
69 #define SC16IS7XX_XON1_REG		(0x04) /* Xon1 word */
70 #define SC16IS7XX_XON2_REG		(0x05) /* Xon2 word */
71 #define SC16IS7XX_XOFF1_REG		(0x06) /* Xoff1 word */
72 #define SC16IS7XX_XOFF2_REG		(0x07) /* Xoff2 word */
73 
74 /* IER register bits */
75 #define SC16IS7XX_IER_RDI_BIT		(1 << 0) /* Enable RX data interrupt */
76 #define SC16IS7XX_IER_THRI_BIT		(1 << 1) /* Enable TX holding register
77 						  * interrupt */
78 #define SC16IS7XX_IER_RLSI_BIT		(1 << 2) /* Enable RX line status
79 						  * interrupt */
80 #define SC16IS7XX_IER_MSI_BIT		(1 << 3) /* Enable Modem status
81 						  * interrupt */
82 
83 /* IER register bits - write only if (EFR[4] == 1) */
84 #define SC16IS7XX_IER_SLEEP_BIT		(1 << 4) /* Enable Sleep mode */
85 #define SC16IS7XX_IER_XOFFI_BIT		(1 << 5) /* Enable Xoff interrupt */
86 #define SC16IS7XX_IER_RTSI_BIT		(1 << 6) /* Enable nRTS interrupt */
87 #define SC16IS7XX_IER_CTSI_BIT		(1 << 7) /* Enable nCTS interrupt */
88 
89 /* FCR register bits */
90 #define SC16IS7XX_FCR_FIFO_BIT		(1 << 0) /* Enable FIFO */
91 #define SC16IS7XX_FCR_RXRESET_BIT	(1 << 1) /* Reset RX FIFO */
92 #define SC16IS7XX_FCR_TXRESET_BIT	(1 << 2) /* Reset TX FIFO */
93 #define SC16IS7XX_FCR_RXLVLL_BIT	(1 << 6) /* RX Trigger level LSB */
94 #define SC16IS7XX_FCR_RXLVLH_BIT	(1 << 7) /* RX Trigger level MSB */
95 
96 /* FCR register bits - write only if (EFR[4] == 1) */
97 #define SC16IS7XX_FCR_TXLVLL_BIT	(1 << 4) /* TX Trigger level LSB */
98 #define SC16IS7XX_FCR_TXLVLH_BIT	(1 << 5) /* TX Trigger level MSB */
99 
100 /* IIR register bits */
101 #define SC16IS7XX_IIR_NO_INT_BIT	(1 << 0) /* No interrupts pending */
102 #define SC16IS7XX_IIR_ID_MASK		0x3e     /* Mask for the interrupt ID */
103 #define SC16IS7XX_IIR_THRI_SRC		0x02     /* TX holding register empty */
104 #define SC16IS7XX_IIR_RDI_SRC		0x04     /* RX data interrupt */
105 #define SC16IS7XX_IIR_RLSE_SRC		0x06     /* RX line status error */
106 #define SC16IS7XX_IIR_RTOI_SRC		0x0c     /* RX time-out interrupt */
107 #define SC16IS7XX_IIR_MSI_SRC		0x00     /* Modem status interrupt
108 						  * - only on 75x/76x
109 						  */
110 #define SC16IS7XX_IIR_INPIN_SRC		0x30     /* Input pin change of state
111 						  * - only on 75x/76x
112 						  */
113 #define SC16IS7XX_IIR_XOFFI_SRC		0x10     /* Received Xoff */
114 #define SC16IS7XX_IIR_CTSRTS_SRC	0x20     /* nCTS,nRTS change of state
115 						  * from active (LOW)
116 						  * to inactive (HIGH)
117 						  */
118 /* LCR register bits */
119 #define SC16IS7XX_LCR_LENGTH0_BIT	(1 << 0) /* Word length bit 0 */
120 #define SC16IS7XX_LCR_LENGTH1_BIT	(1 << 1) /* Word length bit 1
121 						  *
122 						  * Word length bits table:
123 						  * 00 -> 5 bit words
124 						  * 01 -> 6 bit words
125 						  * 10 -> 7 bit words
126 						  * 11 -> 8 bit words
127 						  */
128 #define SC16IS7XX_LCR_STOPLEN_BIT	(1 << 2) /* STOP length bit
129 						  *
130 						  * STOP length bit table:
131 						  * 0 -> 1 stop bit
132 						  * 1 -> 1-1.5 stop bits if
133 						  *      word length is 5,
134 						  *      2 stop bits otherwise
135 						  */
136 #define SC16IS7XX_LCR_PARITY_BIT	(1 << 3) /* Parity bit enable */
137 #define SC16IS7XX_LCR_EVENPARITY_BIT	(1 << 4) /* Even parity bit enable */
138 #define SC16IS7XX_LCR_FORCEPARITY_BIT	(1 << 5) /* 9-bit multidrop parity */
139 #define SC16IS7XX_LCR_TXBREAK_BIT	(1 << 6) /* TX break enable */
140 #define SC16IS7XX_LCR_DLAB_BIT		(1 << 7) /* Divisor Latch enable */
141 #define SC16IS7XX_LCR_WORD_LEN_5	(0x00)
142 #define SC16IS7XX_LCR_WORD_LEN_6	(0x01)
143 #define SC16IS7XX_LCR_WORD_LEN_7	(0x02)
144 #define SC16IS7XX_LCR_WORD_LEN_8	(0x03)
145 #define SC16IS7XX_LCR_CONF_MODE_A	SC16IS7XX_LCR_DLAB_BIT /* Special
146 								* reg set */
147 #define SC16IS7XX_LCR_CONF_MODE_B	0xBF                   /* Enhanced
148 								* reg set */
149 
150 /* MCR register bits */
151 #define SC16IS7XX_MCR_DTR_BIT		(1 << 0) /* DTR complement
152 						  * - only on 75x/76x
153 						  */
154 #define SC16IS7XX_MCR_RTS_BIT		(1 << 1) /* RTS complement */
155 #define SC16IS7XX_MCR_TCRTLR_BIT	(1 << 2) /* TCR/TLR register enable */
156 #define SC16IS7XX_MCR_LOOP_BIT		(1 << 4) /* Enable loopback test mode */
157 #define SC16IS7XX_MCR_XONANY_BIT	(1 << 5) /* Enable Xon Any
158 						  * - write enabled
159 						  * if (EFR[4] == 1)
160 						  */
161 #define SC16IS7XX_MCR_IRDA_BIT		(1 << 6) /* Enable IrDA mode
162 						  * - write enabled
163 						  * if (EFR[4] == 1)
164 						  */
165 #define SC16IS7XX_MCR_CLKSEL_BIT	(1 << 7) /* Divide clock by 4
166 						  * - write enabled
167 						  * if (EFR[4] == 1)
168 						  */
169 
170 /* LSR register bits */
171 #define SC16IS7XX_LSR_DR_BIT		(1 << 0) /* Receiver data ready */
172 #define SC16IS7XX_LSR_OE_BIT		(1 << 1) /* Overrun Error */
173 #define SC16IS7XX_LSR_PE_BIT		(1 << 2) /* Parity Error */
174 #define SC16IS7XX_LSR_FE_BIT		(1 << 3) /* Frame Error */
175 #define SC16IS7XX_LSR_BI_BIT		(1 << 4) /* Break Interrupt */
176 #define SC16IS7XX_LSR_BRK_ERROR_MASK	0x1E     /* BI, FE, PE, OE bits */
177 #define SC16IS7XX_LSR_THRE_BIT		(1 << 5) /* TX holding register empty */
178 #define SC16IS7XX_LSR_TEMT_BIT		(1 << 6) /* Transmitter empty */
179 #define SC16IS7XX_LSR_FIFOE_BIT		(1 << 7) /* Fifo Error */
180 
181 /* MSR register bits */
182 #define SC16IS7XX_MSR_DCTS_BIT		(1 << 0) /* Delta CTS Clear To Send */
183 #define SC16IS7XX_MSR_DDSR_BIT		(1 << 1) /* Delta DSR Data Set Ready
184 						  * or (IO4)
185 						  * - only on 75x/76x
186 						  */
187 #define SC16IS7XX_MSR_DRI_BIT		(1 << 2) /* Delta RI Ring Indicator
188 						  * or (IO7)
189 						  * - only on 75x/76x
190 						  */
191 #define SC16IS7XX_MSR_DCD_BIT		(1 << 3) /* Delta CD Carrier Detect
192 						  * or (IO6)
193 						  * - only on 75x/76x
194 						  */
195 #define SC16IS7XX_MSR_CTS_BIT		(1 << 0) /* CTS */
196 #define SC16IS7XX_MSR_DSR_BIT		(1 << 1) /* DSR (IO4)
197 						  * - only on 75x/76x
198 						  */
199 #define SC16IS7XX_MSR_RI_BIT		(1 << 2) /* RI (IO7)
200 						  * - only on 75x/76x
201 						  */
202 #define SC16IS7XX_MSR_CD_BIT		(1 << 3) /* CD (IO6)
203 						  * - only on 75x/76x
204 						  */
205 #define SC16IS7XX_MSR_DELTA_MASK	0x0F     /* Any of the delta bits! */
206 
207 /*
208  * TCR register bits
209  * TCR trigger levels are available from 0 to 60 characters with a granularity
210  * of four.
211  * The programmer must program the TCR such that TCR[3:0] > TCR[7:4]. There is
212  * no built-in hardware check to make sure this condition is met. Also, the TCR
213  * must be programmed with this condition before auto RTS or software flow
214  * control is enabled to avoid spurious operation of the device.
215  */
216 #define SC16IS7XX_TCR_RX_HALT(words)	((((words) / 4) & 0x0f) << 0)
217 #define SC16IS7XX_TCR_RX_RESUME(words)	((((words) / 4) & 0x0f) << 4)
218 
219 /*
220  * TLR register bits
221  * If TLR[3:0] or TLR[7:4] are logical 0, the selectable trigger levels via the
222  * FIFO Control Register (FCR) are used for the transmit and receive FIFO
223  * trigger levels. Trigger levels from 4 characters to 60 characters are
224  * available with a granularity of four.
225  *
226  * When the trigger level setting in TLR is zero, the SC16IS740/750/760 uses the
227  * trigger level setting defined in FCR. If TLR has non-zero trigger level value
228  * the trigger level defined in FCR is discarded. This applies to both transmit
229  * FIFO and receive FIFO trigger level setting.
230  *
231  * When TLR is used for RX trigger level control, FCR[7:6] should be left at the
232  * default state, that is, '00'.
233  */
234 #define SC16IS7XX_TLR_TX_TRIGGER(words)	((((words) / 4) & 0x0f) << 0)
235 #define SC16IS7XX_TLR_RX_TRIGGER(words)	((((words) / 4) & 0x0f) << 4)
236 
237 /* IOControl register bits (Only 750/760) */
238 #define SC16IS7XX_IOCONTROL_LATCH_BIT	(1 << 0) /* Enable input latching */
239 #define SC16IS7XX_IOCONTROL_GPIO_BIT	(1 << 1) /* Enable GPIO[7:4] */
240 #define SC16IS7XX_IOCONTROL_SRESET_BIT	(1 << 3) /* Software Reset */
241 
242 /* EFCR register bits */
243 #define SC16IS7XX_EFCR_9BIT_MODE_BIT	(1 << 0) /* Enable 9-bit or Multidrop
244 						  * mode (RS485) */
245 #define SC16IS7XX_EFCR_RXDISABLE_BIT	(1 << 1) /* Disable receiver */
246 #define SC16IS7XX_EFCR_TXDISABLE_BIT	(1 << 2) /* Disable transmitter */
247 #define SC16IS7XX_EFCR_AUTO_RS485_BIT	(1 << 4) /* Auto RS485 RTS direction */
248 #define SC16IS7XX_EFCR_RTS_INVERT_BIT	(1 << 5) /* RTS output inversion */
249 #define SC16IS7XX_EFCR_IRDA_MODE_BIT	(1 << 7) /* IrDA mode
250 						  * 0 = rate upto 115.2 kbit/s
251 						  *   - Only 750/760
252 						  * 1 = rate upto 1.152 Mbit/s
253 						  *   - Only 760
254 						  */
255 
256 /* EFR register bits */
257 #define SC16IS7XX_EFR_AUTORTS_BIT	(1 << 6) /* Auto RTS flow ctrl enable */
258 #define SC16IS7XX_EFR_AUTOCTS_BIT	(1 << 7) /* Auto CTS flow ctrl enable */
259 #define SC16IS7XX_EFR_XOFF2_DETECT_BIT	(1 << 5) /* Enable Xoff2 detection */
260 #define SC16IS7XX_EFR_ENABLE_BIT	(1 << 4) /* Enable enhanced functions
261 						  * and writing to IER[7:4],
262 						  * FCR[5:4], MCR[7:5]
263 						  */
264 #define SC16IS7XX_EFR_SWFLOW3_BIT	(1 << 3) /* SWFLOW bit 3 */
265 #define SC16IS7XX_EFR_SWFLOW2_BIT	(1 << 2) /* SWFLOW bit 2
266 						  *
267 						  * SWFLOW bits 3 & 2 table:
268 						  * 00 -> no transmitter flow
269 						  *       control
270 						  * 01 -> transmitter generates
271 						  *       XON2 and XOFF2
272 						  * 10 -> transmitter generates
273 						  *       XON1 and XOFF1
274 						  * 11 -> transmitter generates
275 						  *       XON1, XON2, XOFF1 and
276 						  *       XOFF2
277 						  */
278 #define SC16IS7XX_EFR_SWFLOW1_BIT	(1 << 1) /* SWFLOW bit 2 */
279 #define SC16IS7XX_EFR_SWFLOW0_BIT	(1 << 0) /* SWFLOW bit 3
280 						  *
281 						  * SWFLOW bits 3 & 2 table:
282 						  * 00 -> no received flow
283 						  *       control
284 						  * 01 -> receiver compares
285 						  *       XON2 and XOFF2
286 						  * 10 -> receiver compares
287 						  *       XON1 and XOFF1
288 						  * 11 -> receiver compares
289 						  *       XON1, XON2, XOFF1 and
290 						  *       XOFF2
291 						  */
292 
293 /* Misc definitions */
294 #define SC16IS7XX_FIFO_SIZE		(64)
295 #define SC16IS7XX_REG_SHIFT		2
296 
297 struct sc16is7xx_devtype {
298 	char	name[10];
299 	int	nr_gpio;
300 	int	nr_uart;
301 };
302 
303 struct sc16is7xx_one {
304 	struct uart_port		port;
305 	struct work_struct		tx_work;
306 	struct work_struct		md_work;
307 };
308 
309 struct sc16is7xx_port {
310 	struct uart_driver		uart;
311 	struct sc16is7xx_devtype	*devtype;
312 	struct regmap			*regmap;
313 	struct mutex			mutex;
314 	struct clk			*clk;
315 #ifdef CONFIG_GPIOLIB
316 	struct gpio_chip		gpio;
317 #endif
318 	unsigned char			buf[SC16IS7XX_FIFO_SIZE];
319 	struct sc16is7xx_one		p[0];
320 };
321 
322 #define to_sc16is7xx_one(p,e)	((container_of((p), struct sc16is7xx_one, e)))
323 
324 static u8 sc16is7xx_port_read(struct uart_port *port, u8 reg)
325 {
326 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
327 	unsigned int val = 0;
328 
329 	regmap_read(s->regmap,
330 		    (reg << SC16IS7XX_REG_SHIFT) | port->line, &val);
331 
332 	return val;
333 }
334 
335 static void sc16is7xx_port_write(struct uart_port *port, u8 reg, u8 val)
336 {
337 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
338 
339 	regmap_write(s->regmap,
340 		     (reg << SC16IS7XX_REG_SHIFT) | port->line, val);
341 }
342 
343 static void sc16is7xx_port_update(struct uart_port *port, u8 reg,
344 				  u8 mask, u8 val)
345 {
346 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
347 
348 	regmap_update_bits(s->regmap,
349 			   (reg << SC16IS7XX_REG_SHIFT) | port->line,
350 			   mask, val);
351 }
352 
353 
354 static void sc16is7xx_power(struct uart_port *port, int on)
355 {
356 	sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
357 			      SC16IS7XX_IER_SLEEP_BIT,
358 			      on ? 0 : SC16IS7XX_IER_SLEEP_BIT);
359 }
360 
361 static const struct sc16is7xx_devtype sc16is74x_devtype = {
362 	.name		= "SC16IS74X",
363 	.nr_gpio	= 0,
364 	.nr_uart	= 1,
365 };
366 
367 static const struct sc16is7xx_devtype sc16is750_devtype = {
368 	.name		= "SC16IS750",
369 	.nr_gpio	= 8,
370 	.nr_uart	= 1,
371 };
372 
373 static const struct sc16is7xx_devtype sc16is752_devtype = {
374 	.name		= "SC16IS752",
375 	.nr_gpio	= 8,
376 	.nr_uart	= 2,
377 };
378 
379 static const struct sc16is7xx_devtype sc16is760_devtype = {
380 	.name		= "SC16IS760",
381 	.nr_gpio	= 8,
382 	.nr_uart	= 1,
383 };
384 
385 static const struct sc16is7xx_devtype sc16is762_devtype = {
386 	.name		= "SC16IS762",
387 	.nr_gpio	= 8,
388 	.nr_uart	= 2,
389 };
390 
391 static bool sc16is7xx_regmap_volatile(struct device *dev, unsigned int reg)
392 {
393 	switch (reg >> SC16IS7XX_REG_SHIFT) {
394 	case SC16IS7XX_RHR_REG:
395 	case SC16IS7XX_IIR_REG:
396 	case SC16IS7XX_LSR_REG:
397 	case SC16IS7XX_MSR_REG:
398 	case SC16IS7XX_TXLVL_REG:
399 	case SC16IS7XX_RXLVL_REG:
400 	case SC16IS7XX_IOSTATE_REG:
401 		return true;
402 	default:
403 		break;
404 	}
405 
406 	return false;
407 }
408 
409 static bool sc16is7xx_regmap_precious(struct device *dev, unsigned int reg)
410 {
411 	switch (reg >> SC16IS7XX_REG_SHIFT) {
412 	case SC16IS7XX_RHR_REG:
413 		return true;
414 	default:
415 		break;
416 	}
417 
418 	return false;
419 }
420 
421 static int sc16is7xx_set_baud(struct uart_port *port, int baud)
422 {
423 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
424 	u8 lcr;
425 	u8 prescaler = 0;
426 	unsigned long clk = port->uartclk, div = clk / 16 / baud;
427 
428 	if (div > 0xffff) {
429 		prescaler = SC16IS7XX_MCR_CLKSEL_BIT;
430 		div /= 4;
431 	}
432 
433 	lcr = sc16is7xx_port_read(port, SC16IS7XX_LCR_REG);
434 
435 	/* Open the LCR divisors for configuration */
436 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
437 			     SC16IS7XX_LCR_CONF_MODE_B);
438 
439 	/* Enable enhanced features */
440 	regcache_cache_bypass(s->regmap, true);
441 	sc16is7xx_port_write(port, SC16IS7XX_EFR_REG,
442 			     SC16IS7XX_EFR_ENABLE_BIT);
443 	regcache_cache_bypass(s->regmap, false);
444 
445 	/* Put LCR back to the normal mode */
446 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
447 
448 	sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
449 			      SC16IS7XX_MCR_CLKSEL_BIT,
450 			      prescaler);
451 
452 	/* Open the LCR divisors for configuration */
453 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
454 			     SC16IS7XX_LCR_CONF_MODE_A);
455 
456 	/* Write the new divisor */
457 	regcache_cache_bypass(s->regmap, true);
458 	sc16is7xx_port_write(port, SC16IS7XX_DLH_REG, div / 256);
459 	sc16is7xx_port_write(port, SC16IS7XX_DLL_REG, div % 256);
460 	regcache_cache_bypass(s->regmap, false);
461 
462 	/* Put LCR back to the normal mode */
463 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
464 
465 	return DIV_ROUND_CLOSEST(clk / 16, div);
466 }
467 
468 static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
469 				unsigned int iir)
470 {
471 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
472 	unsigned int lsr = 0, ch, flag, bytes_read, i;
473 	bool read_lsr = (iir == SC16IS7XX_IIR_RLSE_SRC) ? true : false;
474 
475 	if (unlikely(rxlen >= sizeof(s->buf))) {
476 		dev_warn_ratelimited(port->dev,
477 				     "Port %i: Possible RX FIFO overrun: %d\n",
478 				     port->line, rxlen);
479 		port->icount.buf_overrun++;
480 		/* Ensure sanity of RX level */
481 		rxlen = sizeof(s->buf);
482 	}
483 
484 	while (rxlen) {
485 		/* Only read lsr if there are possible errors in FIFO */
486 		if (read_lsr) {
487 			lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
488 			if (!(lsr & SC16IS7XX_LSR_FIFOE_BIT))
489 				read_lsr = false; /* No errors left in FIFO */
490 		} else
491 			lsr = 0;
492 
493 		if (read_lsr) {
494 			s->buf[0] = sc16is7xx_port_read(port, SC16IS7XX_RHR_REG);
495 			bytes_read = 1;
496 		} else {
497 			regcache_cache_bypass(s->regmap, true);
498 			regmap_raw_read(s->regmap, SC16IS7XX_RHR_REG,
499 					s->buf, rxlen);
500 			regcache_cache_bypass(s->regmap, false);
501 			bytes_read = rxlen;
502 		}
503 
504 		lsr &= SC16IS7XX_LSR_BRK_ERROR_MASK;
505 
506 		port->icount.rx++;
507 		flag = TTY_NORMAL;
508 
509 		if (unlikely(lsr)) {
510 			if (lsr & SC16IS7XX_LSR_BI_BIT) {
511 				port->icount.brk++;
512 				if (uart_handle_break(port))
513 					continue;
514 			} else if (lsr & SC16IS7XX_LSR_PE_BIT)
515 				port->icount.parity++;
516 			else if (lsr & SC16IS7XX_LSR_FE_BIT)
517 				port->icount.frame++;
518 			else if (lsr & SC16IS7XX_LSR_OE_BIT)
519 				port->icount.overrun++;
520 
521 			lsr &= port->read_status_mask;
522 			if (lsr & SC16IS7XX_LSR_BI_BIT)
523 				flag = TTY_BREAK;
524 			else if (lsr & SC16IS7XX_LSR_PE_BIT)
525 				flag = TTY_PARITY;
526 			else if (lsr & SC16IS7XX_LSR_FE_BIT)
527 				flag = TTY_FRAME;
528 			else if (lsr & SC16IS7XX_LSR_OE_BIT)
529 				flag = TTY_OVERRUN;
530 		}
531 
532 		for (i = 0; i < bytes_read; ++i) {
533 			ch = s->buf[i];
534 			if (uart_handle_sysrq_char(port, ch))
535 				continue;
536 
537 			if (lsr & port->ignore_status_mask)
538 				continue;
539 
540 			uart_insert_char(port, lsr, SC16IS7XX_LSR_OE_BIT, ch,
541 					 flag);
542 		}
543 		rxlen -= bytes_read;
544 	}
545 
546 	tty_flip_buffer_push(&port->state->port);
547 }
548 
549 static void sc16is7xx_handle_tx(struct uart_port *port)
550 {
551 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
552 	struct circ_buf *xmit = &port->state->xmit;
553 	unsigned int txlen, to_send, i;
554 
555 	if (unlikely(port->x_char)) {
556 		sc16is7xx_port_write(port, SC16IS7XX_THR_REG, port->x_char);
557 		port->icount.tx++;
558 		port->x_char = 0;
559 		return;
560 	}
561 
562 	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
563 		return;
564 
565 	/* Get length of data pending in circular buffer */
566 	to_send = uart_circ_chars_pending(xmit);
567 	if (likely(to_send)) {
568 		/* Limit to size of TX FIFO */
569 		txlen = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG);
570 		to_send = (to_send > txlen) ? txlen : to_send;
571 
572 		/* Add data to send */
573 		port->icount.tx += to_send;
574 
575 		/* Convert to linear buffer */
576 		for (i = 0; i < to_send; ++i) {
577 			s->buf[i] = xmit->buf[xmit->tail];
578 			xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
579 		}
580 		regcache_cache_bypass(s->regmap, true);
581 		regmap_raw_write(s->regmap, SC16IS7XX_THR_REG, s->buf, to_send);
582 		regcache_cache_bypass(s->regmap, false);
583 	}
584 
585 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
586 		uart_write_wakeup(port);
587 }
588 
589 static void sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
590 {
591 	struct uart_port *port = &s->p[portno].port;
592 
593 	do {
594 		unsigned int iir, msr, rxlen;
595 
596 		iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG);
597 		if (iir & SC16IS7XX_IIR_NO_INT_BIT)
598 			break;
599 
600 		iir &= SC16IS7XX_IIR_ID_MASK;
601 
602 		switch (iir) {
603 		case SC16IS7XX_IIR_RDI_SRC:
604 		case SC16IS7XX_IIR_RLSE_SRC:
605 		case SC16IS7XX_IIR_RTOI_SRC:
606 		case SC16IS7XX_IIR_XOFFI_SRC:
607 			rxlen = sc16is7xx_port_read(port, SC16IS7XX_RXLVL_REG);
608 			if (rxlen)
609 				sc16is7xx_handle_rx(port, rxlen, iir);
610 			break;
611 
612 		case SC16IS7XX_IIR_CTSRTS_SRC:
613 			msr = sc16is7xx_port_read(port, SC16IS7XX_MSR_REG);
614 			uart_handle_cts_change(port,
615 					       !!(msr & SC16IS7XX_MSR_CTS_BIT));
616 			break;
617 		case SC16IS7XX_IIR_THRI_SRC:
618 			mutex_lock(&s->mutex);
619 			sc16is7xx_handle_tx(port);
620 			mutex_unlock(&s->mutex);
621 			break;
622 		default:
623 			dev_err_ratelimited(port->dev,
624 					    "Port %i: Unexpected interrupt: %x",
625 					    port->line, iir);
626 			break;
627 		}
628 	} while (1);
629 }
630 
631 static irqreturn_t sc16is7xx_ist(int irq, void *dev_id)
632 {
633 	struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;
634 	int i;
635 
636 	for (i = 0; i < s->uart.nr; ++i)
637 		sc16is7xx_port_irq(s, i);
638 
639 	return IRQ_HANDLED;
640 }
641 
642 static void sc16is7xx_wq_proc(struct work_struct *ws)
643 {
644 	struct sc16is7xx_one *one = to_sc16is7xx_one(ws, tx_work);
645 	struct sc16is7xx_port *s = dev_get_drvdata(one->port.dev);
646 
647 	mutex_lock(&s->mutex);
648 	sc16is7xx_handle_tx(&one->port);
649 	mutex_unlock(&s->mutex);
650 }
651 
652 static void sc16is7xx_stop_tx(struct uart_port* port)
653 {
654 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
655 	struct circ_buf *xmit = &one->port.state->xmit;
656 
657 	/* handle rs485 */
658 	if (port->rs485.flags & SER_RS485_ENABLED) {
659 		/* do nothing if current tx not yet completed */
660 		int lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
661 		if (!(lsr & SC16IS7XX_LSR_TEMT_BIT))
662 			return;
663 
664 		if (uart_circ_empty(xmit) &&
665 		    (port->rs485.delay_rts_after_send > 0))
666 			mdelay(port->rs485.delay_rts_after_send);
667 	}
668 
669 	sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
670 			      SC16IS7XX_IER_THRI_BIT,
671 			      0);
672 }
673 
674 static void sc16is7xx_stop_rx(struct uart_port* port)
675 {
676 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
677 
678 	one->port.read_status_mask &= ~SC16IS7XX_LSR_DR_BIT;
679 	sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
680 			      SC16IS7XX_LSR_DR_BIT,
681 			      0);
682 }
683 
684 static void sc16is7xx_start_tx(struct uart_port *port)
685 {
686 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
687 
688 	/* handle rs485 */
689 	if ((port->rs485.flags & SER_RS485_ENABLED) &&
690 	    (port->rs485.delay_rts_before_send > 0)) {
691 		mdelay(port->rs485.delay_rts_before_send);
692 	}
693 
694 	if (!work_pending(&one->tx_work))
695 		schedule_work(&one->tx_work);
696 }
697 
698 static unsigned int sc16is7xx_tx_empty(struct uart_port *port)
699 {
700 	unsigned int lvl, lsr;
701 
702 	lvl = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG);
703 	lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
704 
705 	return ((lsr & SC16IS7XX_LSR_THRE_BIT) && !lvl) ? TIOCSER_TEMT : 0;
706 }
707 
708 static unsigned int sc16is7xx_get_mctrl(struct uart_port *port)
709 {
710 	/* DCD and DSR are not wired and CTS/RTS is handled automatically
711 	 * so just indicate DSR and CAR asserted
712 	 */
713 	return TIOCM_DSR | TIOCM_CAR;
714 }
715 
716 static void sc16is7xx_md_proc(struct work_struct *ws)
717 {
718 	struct sc16is7xx_one *one = to_sc16is7xx_one(ws, md_work);
719 
720 	sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG,
721 			      SC16IS7XX_MCR_LOOP_BIT,
722 			      (one->port.mctrl & TIOCM_LOOP) ?
723 				      SC16IS7XX_MCR_LOOP_BIT : 0);
724 }
725 
726 static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
727 {
728 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
729 
730 	schedule_work(&one->md_work);
731 }
732 
733 static void sc16is7xx_break_ctl(struct uart_port *port, int break_state)
734 {
735 	sc16is7xx_port_update(port, SC16IS7XX_LCR_REG,
736 			      SC16IS7XX_LCR_TXBREAK_BIT,
737 			      break_state ? SC16IS7XX_LCR_TXBREAK_BIT : 0);
738 }
739 
740 static void sc16is7xx_set_termios(struct uart_port *port,
741 				  struct ktermios *termios,
742 				  struct ktermios *old)
743 {
744 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
745 	unsigned int lcr, flow = 0;
746 	int baud;
747 
748 	/* Mask termios capabilities we don't support */
749 	termios->c_cflag &= ~CMSPAR;
750 
751 	/* Word size */
752 	switch (termios->c_cflag & CSIZE) {
753 	case CS5:
754 		lcr = SC16IS7XX_LCR_WORD_LEN_5;
755 		break;
756 	case CS6:
757 		lcr = SC16IS7XX_LCR_WORD_LEN_6;
758 		break;
759 	case CS7:
760 		lcr = SC16IS7XX_LCR_WORD_LEN_7;
761 		break;
762 	case CS8:
763 		lcr = SC16IS7XX_LCR_WORD_LEN_8;
764 		break;
765 	default:
766 		lcr = SC16IS7XX_LCR_WORD_LEN_8;
767 		termios->c_cflag &= ~CSIZE;
768 		termios->c_cflag |= CS8;
769 		break;
770 	}
771 
772 	/* Parity */
773 	if (termios->c_cflag & PARENB) {
774 		lcr |= SC16IS7XX_LCR_PARITY_BIT;
775 		if (!(termios->c_cflag & PARODD))
776 			lcr |= SC16IS7XX_LCR_EVENPARITY_BIT;
777 	}
778 
779 	/* Stop bits */
780 	if (termios->c_cflag & CSTOPB)
781 		lcr |= SC16IS7XX_LCR_STOPLEN_BIT; /* 2 stops */
782 
783 	/* Set read status mask */
784 	port->read_status_mask = SC16IS7XX_LSR_OE_BIT;
785 	if (termios->c_iflag & INPCK)
786 		port->read_status_mask |= SC16IS7XX_LSR_PE_BIT |
787 					  SC16IS7XX_LSR_FE_BIT;
788 	if (termios->c_iflag & (BRKINT | PARMRK))
789 		port->read_status_mask |= SC16IS7XX_LSR_BI_BIT;
790 
791 	/* Set status ignore mask */
792 	port->ignore_status_mask = 0;
793 	if (termios->c_iflag & IGNBRK)
794 		port->ignore_status_mask |= SC16IS7XX_LSR_BI_BIT;
795 	if (!(termios->c_cflag & CREAD))
796 		port->ignore_status_mask |= SC16IS7XX_LSR_BRK_ERROR_MASK;
797 
798 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
799 			     SC16IS7XX_LCR_CONF_MODE_B);
800 
801 	/* Configure flow control */
802 	regcache_cache_bypass(s->regmap, true);
803 	sc16is7xx_port_write(port, SC16IS7XX_XON1_REG, termios->c_cc[VSTART]);
804 	sc16is7xx_port_write(port, SC16IS7XX_XOFF1_REG, termios->c_cc[VSTOP]);
805 	if (termios->c_cflag & CRTSCTS)
806 		flow |= SC16IS7XX_EFR_AUTOCTS_BIT |
807 			SC16IS7XX_EFR_AUTORTS_BIT;
808 	if (termios->c_iflag & IXON)
809 		flow |= SC16IS7XX_EFR_SWFLOW3_BIT;
810 	if (termios->c_iflag & IXOFF)
811 		flow |= SC16IS7XX_EFR_SWFLOW1_BIT;
812 
813 	sc16is7xx_port_write(port, SC16IS7XX_EFR_REG, flow);
814 	regcache_cache_bypass(s->regmap, false);
815 
816 	/* Update LCR register */
817 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
818 
819 	/* Get baud rate generator configuration */
820 	baud = uart_get_baud_rate(port, termios, old,
821 				  port->uartclk / 16 / 4 / 0xffff,
822 				  port->uartclk / 16);
823 
824 	/* Setup baudrate generator */
825 	baud = sc16is7xx_set_baud(port, baud);
826 
827 	/* Update timeout according to new baud rate */
828 	uart_update_timeout(port, termios->c_cflag, baud);
829 }
830 
831 static int sc16is7xx_config_rs485(struct uart_port *port,
832 				  struct serial_rs485 *rs485)
833 {
834 	const u32 mask = SC16IS7XX_EFCR_AUTO_RS485_BIT |
835 			 SC16IS7XX_EFCR_RTS_INVERT_BIT;
836 	u32 efcr = 0;
837 
838 	if (rs485->flags & SER_RS485_ENABLED) {
839 		bool rts_during_rx, rts_during_tx;
840 
841 		rts_during_rx = rs485->flags & SER_RS485_RTS_AFTER_SEND;
842 		rts_during_tx = rs485->flags & SER_RS485_RTS_ON_SEND;
843 
844 		efcr |= SC16IS7XX_EFCR_AUTO_RS485_BIT;
845 
846 		if (!rts_during_rx && rts_during_tx)
847 			/* default */;
848 		else if (rts_during_rx && !rts_during_tx)
849 			efcr |= SC16IS7XX_EFCR_RTS_INVERT_BIT;
850 		else
851 			dev_err(port->dev,
852 				"unsupported RTS signalling on_send:%d after_send:%d - exactly one of RS485 RTS flags should be set\n",
853 				rts_during_tx, rts_during_rx);
854 	}
855 
856 	sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG, mask, efcr);
857 
858 	port->rs485 = *rs485;
859 
860 	return 0;
861 }
862 
863 static int sc16is7xx_startup(struct uart_port *port)
864 {
865 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
866 	unsigned int val;
867 
868 	sc16is7xx_power(port, 1);
869 
870 	/* Reset FIFOs*/
871 	val = SC16IS7XX_FCR_RXRESET_BIT | SC16IS7XX_FCR_TXRESET_BIT;
872 	sc16is7xx_port_write(port, SC16IS7XX_FCR_REG, val);
873 	udelay(5);
874 	sc16is7xx_port_write(port, SC16IS7XX_FCR_REG,
875 			     SC16IS7XX_FCR_FIFO_BIT);
876 
877 	/* Enable EFR */
878 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
879 			     SC16IS7XX_LCR_CONF_MODE_B);
880 
881 	regcache_cache_bypass(s->regmap, true);
882 
883 	/* Enable write access to enhanced features and internal clock div */
884 	sc16is7xx_port_write(port, SC16IS7XX_EFR_REG,
885 			     SC16IS7XX_EFR_ENABLE_BIT);
886 
887 	/* Enable TCR/TLR */
888 	sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
889 			      SC16IS7XX_MCR_TCRTLR_BIT,
890 			      SC16IS7XX_MCR_TCRTLR_BIT);
891 
892 	/* Configure flow control levels */
893 	/* Flow control halt level 48, resume level 24 */
894 	sc16is7xx_port_write(port, SC16IS7XX_TCR_REG,
895 			     SC16IS7XX_TCR_RX_RESUME(24) |
896 			     SC16IS7XX_TCR_RX_HALT(48));
897 
898 	regcache_cache_bypass(s->regmap, false);
899 
900 	/* Now, initialize the UART */
901 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, SC16IS7XX_LCR_WORD_LEN_8);
902 
903 	/* Enable the Rx and Tx FIFO */
904 	sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
905 			      SC16IS7XX_EFCR_RXDISABLE_BIT |
906 			      SC16IS7XX_EFCR_TXDISABLE_BIT,
907 			      0);
908 
909 	/* Enable RX, TX, CTS change interrupts */
910 	val = SC16IS7XX_IER_RDI_BIT | SC16IS7XX_IER_THRI_BIT |
911 	      SC16IS7XX_IER_CTSI_BIT;
912 	sc16is7xx_port_write(port, SC16IS7XX_IER_REG, val);
913 
914 	return 0;
915 }
916 
917 static void sc16is7xx_shutdown(struct uart_port *port)
918 {
919 	/* Disable all interrupts */
920 	sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0);
921 	/* Disable TX/RX */
922 	sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
923 			      SC16IS7XX_EFCR_RXDISABLE_BIT |
924 			      SC16IS7XX_EFCR_TXDISABLE_BIT,
925 			      SC16IS7XX_EFCR_RXDISABLE_BIT |
926 			      SC16IS7XX_EFCR_TXDISABLE_BIT);
927 
928 	sc16is7xx_power(port, 0);
929 }
930 
931 static const char *sc16is7xx_type(struct uart_port *port)
932 {
933 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
934 
935 	return (port->type == PORT_SC16IS7XX) ? s->devtype->name : NULL;
936 }
937 
938 static int sc16is7xx_request_port(struct uart_port *port)
939 {
940 	/* Do nothing */
941 	return 0;
942 }
943 
944 static void sc16is7xx_config_port(struct uart_port *port, int flags)
945 {
946 	if (flags & UART_CONFIG_TYPE)
947 		port->type = PORT_SC16IS7XX;
948 }
949 
950 static int sc16is7xx_verify_port(struct uart_port *port,
951 				 struct serial_struct *s)
952 {
953 	if ((s->type != PORT_UNKNOWN) && (s->type != PORT_SC16IS7XX))
954 		return -EINVAL;
955 	if (s->irq != port->irq)
956 		return -EINVAL;
957 
958 	return 0;
959 }
960 
961 static void sc16is7xx_pm(struct uart_port *port, unsigned int state,
962 			 unsigned int oldstate)
963 {
964 	sc16is7xx_power(port, (state == UART_PM_STATE_ON) ? 1 : 0);
965 }
966 
967 static void sc16is7xx_null_void(struct uart_port *port)
968 {
969 	/* Do nothing */
970 }
971 
972 static const struct uart_ops sc16is7xx_ops = {
973 	.tx_empty	= sc16is7xx_tx_empty,
974 	.set_mctrl	= sc16is7xx_set_mctrl,
975 	.get_mctrl	= sc16is7xx_get_mctrl,
976 	.stop_tx	= sc16is7xx_stop_tx,
977 	.start_tx	= sc16is7xx_start_tx,
978 	.stop_rx	= sc16is7xx_stop_rx,
979 	.break_ctl	= sc16is7xx_break_ctl,
980 	.startup	= sc16is7xx_startup,
981 	.shutdown	= sc16is7xx_shutdown,
982 	.set_termios	= sc16is7xx_set_termios,
983 	.type		= sc16is7xx_type,
984 	.request_port	= sc16is7xx_request_port,
985 	.release_port	= sc16is7xx_null_void,
986 	.config_port	= sc16is7xx_config_port,
987 	.verify_port	= sc16is7xx_verify_port,
988 	.pm		= sc16is7xx_pm,
989 };
990 
991 #ifdef CONFIG_GPIOLIB
992 static int sc16is7xx_gpio_get(struct gpio_chip *chip, unsigned offset)
993 {
994 	unsigned int val;
995 	struct sc16is7xx_port *s = container_of(chip, struct sc16is7xx_port,
996 						gpio);
997 	struct uart_port *port = &s->p[0].port;
998 
999 	val = sc16is7xx_port_read(port, SC16IS7XX_IOSTATE_REG);
1000 
1001 	return !!(val & BIT(offset));
1002 }
1003 
1004 static void sc16is7xx_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
1005 {
1006 	struct sc16is7xx_port *s = container_of(chip, struct sc16is7xx_port,
1007 						gpio);
1008 	struct uart_port *port = &s->p[0].port;
1009 
1010 	sc16is7xx_port_update(port, SC16IS7XX_IOSTATE_REG, BIT(offset),
1011 			      val ? BIT(offset) : 0);
1012 }
1013 
1014 static int sc16is7xx_gpio_direction_input(struct gpio_chip *chip,
1015 					  unsigned offset)
1016 {
1017 	struct sc16is7xx_port *s = container_of(chip, struct sc16is7xx_port,
1018 						gpio);
1019 	struct uart_port *port = &s->p[0].port;
1020 
1021 	sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset), 0);
1022 
1023 	return 0;
1024 }
1025 
1026 static int sc16is7xx_gpio_direction_output(struct gpio_chip *chip,
1027 					   unsigned offset, int val)
1028 {
1029 	struct sc16is7xx_port *s = container_of(chip, struct sc16is7xx_port,
1030 						gpio);
1031 	struct uart_port *port = &s->p[0].port;
1032 
1033 	sc16is7xx_port_update(port, SC16IS7XX_IOSTATE_REG, BIT(offset),
1034 			      val ? BIT(offset) : 0);
1035 	sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset),
1036 			      BIT(offset));
1037 
1038 	return 0;
1039 }
1040 #endif
1041 
1042 static int sc16is7xx_probe(struct device *dev,
1043 			   struct sc16is7xx_devtype *devtype,
1044 			   struct regmap *regmap, int irq, unsigned long flags)
1045 {
1046 	unsigned long freq, *pfreq = dev_get_platdata(dev);
1047 	int i, ret;
1048 	struct sc16is7xx_port *s;
1049 
1050 	if (IS_ERR(regmap))
1051 		return PTR_ERR(regmap);
1052 
1053 	/* Alloc port structure */
1054 	s = devm_kzalloc(dev, sizeof(*s) +
1055 			 sizeof(struct sc16is7xx_one) * devtype->nr_uart,
1056 			 GFP_KERNEL);
1057 	if (!s) {
1058 		dev_err(dev, "Error allocating port structure\n");
1059 		return -ENOMEM;
1060 	}
1061 
1062 	s->clk = devm_clk_get(dev, NULL);
1063 	if (IS_ERR(s->clk)) {
1064 		if (pfreq)
1065 			freq = *pfreq;
1066 		else
1067 			return PTR_ERR(s->clk);
1068 	} else {
1069 		clk_prepare_enable(s->clk);
1070 		freq = clk_get_rate(s->clk);
1071 	}
1072 
1073 	s->regmap = regmap;
1074 	s->devtype = devtype;
1075 	dev_set_drvdata(dev, s);
1076 
1077 	/* Register UART driver */
1078 	s->uart.owner		= THIS_MODULE;
1079 	s->uart.dev_name	= "ttySC";
1080 	s->uart.nr		= devtype->nr_uart;
1081 	ret = uart_register_driver(&s->uart);
1082 	if (ret) {
1083 		dev_err(dev, "Registering UART driver failed\n");
1084 		goto out_clk;
1085 	}
1086 
1087 #ifdef CONFIG_GPIOLIB
1088 	if (devtype->nr_gpio) {
1089 		/* Setup GPIO cotroller */
1090 		s->gpio.owner		 = THIS_MODULE;
1091 		s->gpio.dev		 = dev;
1092 		s->gpio.label		 = dev_name(dev);
1093 		s->gpio.direction_input	 = sc16is7xx_gpio_direction_input;
1094 		s->gpio.get		 = sc16is7xx_gpio_get;
1095 		s->gpio.direction_output = sc16is7xx_gpio_direction_output;
1096 		s->gpio.set		 = sc16is7xx_gpio_set;
1097 		s->gpio.base		 = -1;
1098 		s->gpio.ngpio		 = devtype->nr_gpio;
1099 		s->gpio.can_sleep	 = 1;
1100 		ret = gpiochip_add(&s->gpio);
1101 		if (ret)
1102 			goto out_uart;
1103 	}
1104 #endif
1105 
1106 	mutex_init(&s->mutex);
1107 
1108 	for (i = 0; i < devtype->nr_uart; ++i) {
1109 		/* Initialize port data */
1110 		s->p[i].port.line	= i;
1111 		s->p[i].port.dev	= dev;
1112 		s->p[i].port.irq	= irq;
1113 		s->p[i].port.type	= PORT_SC16IS7XX;
1114 		s->p[i].port.fifosize	= SC16IS7XX_FIFO_SIZE;
1115 		s->p[i].port.flags	= UPF_FIXED_TYPE | UPF_LOW_LATENCY;
1116 		s->p[i].port.iotype	= UPIO_PORT;
1117 		s->p[i].port.uartclk	= freq;
1118 		s->p[i].port.rs485_config = sc16is7xx_config_rs485;
1119 		s->p[i].port.ops	= &sc16is7xx_ops;
1120 		/* Disable all interrupts */
1121 		sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_IER_REG, 0);
1122 		/* Disable TX/RX */
1123 		sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_EFCR_REG,
1124 				     SC16IS7XX_EFCR_RXDISABLE_BIT |
1125 				     SC16IS7XX_EFCR_TXDISABLE_BIT);
1126 		/* Initialize queue for start TX */
1127 		INIT_WORK(&s->p[i].tx_work, sc16is7xx_wq_proc);
1128 		/* Initialize queue for changing mode */
1129 		INIT_WORK(&s->p[i].md_work, sc16is7xx_md_proc);
1130 		/* Register port */
1131 		uart_add_one_port(&s->uart, &s->p[i].port);
1132 		/* Go to suspend mode */
1133 		sc16is7xx_power(&s->p[i].port, 0);
1134 	}
1135 
1136 	/* Setup interrupt */
1137 	ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_ist,
1138 					IRQF_ONESHOT | flags, dev_name(dev), s);
1139 	if (!ret)
1140 		return 0;
1141 
1142 	for (i = 0; i < s->uart.nr; i++)
1143 		uart_remove_one_port(&s->uart, &s->p[i].port);
1144 
1145 	mutex_destroy(&s->mutex);
1146 
1147 #ifdef CONFIG_GPIOLIB
1148 	if (devtype->nr_gpio)
1149 		gpiochip_remove(&s->gpio);
1150 
1151 out_uart:
1152 #endif
1153 	uart_unregister_driver(&s->uart);
1154 
1155 out_clk:
1156 	if (!IS_ERR(s->clk))
1157 		clk_disable_unprepare(s->clk);
1158 
1159 	return ret;
1160 }
1161 
1162 static int sc16is7xx_remove(struct device *dev)
1163 {
1164 	struct sc16is7xx_port *s = dev_get_drvdata(dev);
1165 	int i;
1166 
1167 #ifdef CONFIG_GPIOLIB
1168 	if (s->devtype->nr_gpio)
1169 		gpiochip_remove(&s->gpio);
1170 #endif
1171 
1172 	for (i = 0; i < s->uart.nr; i++) {
1173 		cancel_work_sync(&s->p[i].tx_work);
1174 		cancel_work_sync(&s->p[i].md_work);
1175 		uart_remove_one_port(&s->uart, &s->p[i].port);
1176 		sc16is7xx_power(&s->p[i].port, 0);
1177 	}
1178 
1179 	mutex_destroy(&s->mutex);
1180 	uart_unregister_driver(&s->uart);
1181 	if (!IS_ERR(s->clk))
1182 		clk_disable_unprepare(s->clk);
1183 
1184 	return 0;
1185 }
1186 
1187 static const struct of_device_id __maybe_unused sc16is7xx_dt_ids[] = {
1188 	{ .compatible = "nxp,sc16is740",	.data = &sc16is74x_devtype, },
1189 	{ .compatible = "nxp,sc16is741",	.data = &sc16is74x_devtype, },
1190 	{ .compatible = "nxp,sc16is750",	.data = &sc16is750_devtype, },
1191 	{ .compatible = "nxp,sc16is752",	.data = &sc16is752_devtype, },
1192 	{ .compatible = "nxp,sc16is760",	.data = &sc16is760_devtype, },
1193 	{ .compatible = "nxp,sc16is762",	.data = &sc16is762_devtype, },
1194 	{ }
1195 };
1196 MODULE_DEVICE_TABLE(of, sc16is7xx_dt_ids);
1197 
1198 static struct regmap_config regcfg = {
1199 	.reg_bits = 7,
1200 	.pad_bits = 1,
1201 	.val_bits = 8,
1202 	.cache_type = REGCACHE_RBTREE,
1203 	.volatile_reg = sc16is7xx_regmap_volatile,
1204 	.precious_reg = sc16is7xx_regmap_precious,
1205 };
1206 
1207 static int sc16is7xx_i2c_probe(struct i2c_client *i2c,
1208 			       const struct i2c_device_id *id)
1209 {
1210 	struct sc16is7xx_devtype *devtype;
1211 	unsigned long flags = 0;
1212 	struct regmap *regmap;
1213 
1214 	if (i2c->dev.of_node) {
1215 		const struct of_device_id *of_id =
1216 				of_match_device(sc16is7xx_dt_ids, &i2c->dev);
1217 
1218 		devtype = (struct sc16is7xx_devtype *)of_id->data;
1219 	} else {
1220 		devtype = (struct sc16is7xx_devtype *)id->driver_data;
1221 		flags = IRQF_TRIGGER_FALLING;
1222 	}
1223 
1224 	regcfg.max_register = (0xf << SC16IS7XX_REG_SHIFT) |
1225 			      (devtype->nr_uart - 1);
1226 	regmap = devm_regmap_init_i2c(i2c, &regcfg);
1227 
1228 	return sc16is7xx_probe(&i2c->dev, devtype, regmap, i2c->irq, flags);
1229 }
1230 
1231 static int sc16is7xx_i2c_remove(struct i2c_client *client)
1232 {
1233 	return sc16is7xx_remove(&client->dev);
1234 }
1235 
1236 static const struct i2c_device_id sc16is7xx_i2c_id_table[] = {
1237 	{ "sc16is74x",	(kernel_ulong_t)&sc16is74x_devtype, },
1238 	{ "sc16is750",	(kernel_ulong_t)&sc16is750_devtype, },
1239 	{ "sc16is752",	(kernel_ulong_t)&sc16is752_devtype, },
1240 	{ "sc16is760",	(kernel_ulong_t)&sc16is760_devtype, },
1241 	{ "sc16is762",	(kernel_ulong_t)&sc16is762_devtype, },
1242 	{ }
1243 };
1244 MODULE_DEVICE_TABLE(i2c, sc16is7xx_i2c_id_table);
1245 
1246 static struct i2c_driver sc16is7xx_i2c_uart_driver = {
1247 	.driver = {
1248 		.name		= SC16IS7XX_NAME,
1249 		.owner		= THIS_MODULE,
1250 		.of_match_table	= of_match_ptr(sc16is7xx_dt_ids),
1251 	},
1252 	.probe		= sc16is7xx_i2c_probe,
1253 	.remove		= sc16is7xx_i2c_remove,
1254 	.id_table	= sc16is7xx_i2c_id_table,
1255 };
1256 module_i2c_driver(sc16is7xx_i2c_uart_driver);
1257 MODULE_ALIAS("i2c:sc16is7xx");
1258 
1259 MODULE_LICENSE("GPL");
1260 MODULE_AUTHOR("Jon Ringle <jringle@gridpoint.com>");
1261 MODULE_DESCRIPTION("SC16IS7XX serial driver");
1262