xref: /openbmc/linux/drivers/tty/serial/sc16is7xx.c (revision db181ce0)
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 	struct serial_rs485		rs485;
309 };
310 
311 struct sc16is7xx_port {
312 	struct uart_driver		uart;
313 	struct sc16is7xx_devtype	*devtype;
314 	struct regmap			*regmap;
315 	struct mutex			mutex;
316 	struct clk			*clk;
317 #ifdef CONFIG_GPIOLIB
318 	struct gpio_chip		gpio;
319 #endif
320 	unsigned char			buf[SC16IS7XX_FIFO_SIZE];
321 	struct sc16is7xx_one		p[0];
322 };
323 
324 #define to_sc16is7xx_one(p,e)	((container_of((p), struct sc16is7xx_one, e)))
325 
326 static u8 sc16is7xx_port_read(struct uart_port *port, u8 reg)
327 {
328 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
329 	unsigned int val = 0;
330 
331 	regmap_read(s->regmap,
332 		    (reg << SC16IS7XX_REG_SHIFT) | port->line, &val);
333 
334 	return val;
335 }
336 
337 static void sc16is7xx_port_write(struct uart_port *port, u8 reg, u8 val)
338 {
339 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
340 
341 	regmap_write(s->regmap,
342 		     (reg << SC16IS7XX_REG_SHIFT) | port->line, val);
343 }
344 
345 static void sc16is7xx_port_update(struct uart_port *port, u8 reg,
346 				  u8 mask, u8 val)
347 {
348 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
349 
350 	regmap_update_bits(s->regmap,
351 			   (reg << SC16IS7XX_REG_SHIFT) | port->line,
352 			   mask, val);
353 }
354 
355 
356 static void sc16is7xx_power(struct uart_port *port, int on)
357 {
358 	sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
359 			      SC16IS7XX_IER_SLEEP_BIT,
360 			      on ? 0 : SC16IS7XX_IER_SLEEP_BIT);
361 }
362 
363 static const struct sc16is7xx_devtype sc16is74x_devtype = {
364 	.name		= "SC16IS74X",
365 	.nr_gpio	= 0,
366 	.nr_uart	= 1,
367 };
368 
369 static const struct sc16is7xx_devtype sc16is750_devtype = {
370 	.name		= "SC16IS750",
371 	.nr_gpio	= 8,
372 	.nr_uart	= 1,
373 };
374 
375 static const struct sc16is7xx_devtype sc16is752_devtype = {
376 	.name		= "SC16IS752",
377 	.nr_gpio	= 8,
378 	.nr_uart	= 2,
379 };
380 
381 static const struct sc16is7xx_devtype sc16is760_devtype = {
382 	.name		= "SC16IS760",
383 	.nr_gpio	= 8,
384 	.nr_uart	= 1,
385 };
386 
387 static const struct sc16is7xx_devtype sc16is762_devtype = {
388 	.name		= "SC16IS762",
389 	.nr_gpio	= 8,
390 	.nr_uart	= 2,
391 };
392 
393 static bool sc16is7xx_regmap_volatile(struct device *dev, unsigned int reg)
394 {
395 	switch (reg >> SC16IS7XX_REG_SHIFT) {
396 	case SC16IS7XX_RHR_REG:
397 	case SC16IS7XX_IIR_REG:
398 	case SC16IS7XX_LSR_REG:
399 	case SC16IS7XX_MSR_REG:
400 	case SC16IS7XX_TXLVL_REG:
401 	case SC16IS7XX_RXLVL_REG:
402 	case SC16IS7XX_IOSTATE_REG:
403 		return true;
404 	default:
405 		break;
406 	}
407 
408 	return false;
409 }
410 
411 static bool sc16is7xx_regmap_precious(struct device *dev, unsigned int reg)
412 {
413 	switch (reg >> SC16IS7XX_REG_SHIFT) {
414 	case SC16IS7XX_RHR_REG:
415 		return true;
416 	default:
417 		break;
418 	}
419 
420 	return false;
421 }
422 
423 static int sc16is7xx_set_baud(struct uart_port *port, int baud)
424 {
425 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
426 	u8 lcr;
427 	u8 prescaler = 0;
428 	unsigned long clk = port->uartclk, div = clk / 16 / baud;
429 
430 	if (div > 0xffff) {
431 		prescaler = SC16IS7XX_MCR_CLKSEL_BIT;
432 		div /= 4;
433 	}
434 
435 	lcr = sc16is7xx_port_read(port, SC16IS7XX_LCR_REG);
436 
437 	/* Open the LCR divisors for configuration */
438 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
439 			     SC16IS7XX_LCR_CONF_MODE_B);
440 
441 	/* Enable enhanced features */
442 	regcache_cache_bypass(s->regmap, true);
443 	sc16is7xx_port_write(port, SC16IS7XX_EFR_REG,
444 			     SC16IS7XX_EFR_ENABLE_BIT);
445 	regcache_cache_bypass(s->regmap, false);
446 
447 	/* Put LCR back to the normal mode */
448 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
449 
450 	sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
451 			      SC16IS7XX_MCR_CLKSEL_BIT,
452 			      prescaler);
453 
454 	/* Open the LCR divisors for configuration */
455 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
456 			     SC16IS7XX_LCR_CONF_MODE_A);
457 
458 	/* Write the new divisor */
459 	regcache_cache_bypass(s->regmap, true);
460 	sc16is7xx_port_write(port, SC16IS7XX_DLH_REG, div / 256);
461 	sc16is7xx_port_write(port, SC16IS7XX_DLL_REG, div % 256);
462 	regcache_cache_bypass(s->regmap, false);
463 
464 	/* Put LCR back to the normal mode */
465 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
466 
467 	return DIV_ROUND_CLOSEST(clk / 16, div);
468 }
469 
470 static void sc16is7xx_handle_rx(struct uart_port *port, unsigned int rxlen,
471 				unsigned int iir)
472 {
473 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
474 	unsigned int lsr = 0, ch, flag, bytes_read, i;
475 	bool read_lsr = (iir == SC16IS7XX_IIR_RLSE_SRC) ? true : false;
476 
477 	if (unlikely(rxlen >= sizeof(s->buf))) {
478 		dev_warn_ratelimited(port->dev,
479 				     "Port %i: Possible RX FIFO overrun: %d\n",
480 				     port->line, rxlen);
481 		port->icount.buf_overrun++;
482 		/* Ensure sanity of RX level */
483 		rxlen = sizeof(s->buf);
484 	}
485 
486 	while (rxlen) {
487 		/* Only read lsr if there are possible errors in FIFO */
488 		if (read_lsr) {
489 			lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
490 			if (!(lsr & SC16IS7XX_LSR_FIFOE_BIT))
491 				read_lsr = false; /* No errors left in FIFO */
492 		} else
493 			lsr = 0;
494 
495 		if (read_lsr) {
496 			s->buf[0] = sc16is7xx_port_read(port, SC16IS7XX_RHR_REG);
497 			bytes_read = 1;
498 		} else {
499 			regcache_cache_bypass(s->regmap, true);
500 			regmap_raw_read(s->regmap, SC16IS7XX_RHR_REG,
501 					s->buf, rxlen);
502 			regcache_cache_bypass(s->regmap, false);
503 			bytes_read = rxlen;
504 		}
505 
506 		lsr &= SC16IS7XX_LSR_BRK_ERROR_MASK;
507 
508 		port->icount.rx++;
509 		flag = TTY_NORMAL;
510 
511 		if (unlikely(lsr)) {
512 			if (lsr & SC16IS7XX_LSR_BI_BIT) {
513 				port->icount.brk++;
514 				if (uart_handle_break(port))
515 					continue;
516 			} else if (lsr & SC16IS7XX_LSR_PE_BIT)
517 				port->icount.parity++;
518 			else if (lsr & SC16IS7XX_LSR_FE_BIT)
519 				port->icount.frame++;
520 			else if (lsr & SC16IS7XX_LSR_OE_BIT)
521 				port->icount.overrun++;
522 
523 			lsr &= port->read_status_mask;
524 			if (lsr & SC16IS7XX_LSR_BI_BIT)
525 				flag = TTY_BREAK;
526 			else if (lsr & SC16IS7XX_LSR_PE_BIT)
527 				flag = TTY_PARITY;
528 			else if (lsr & SC16IS7XX_LSR_FE_BIT)
529 				flag = TTY_FRAME;
530 			else if (lsr & SC16IS7XX_LSR_OE_BIT)
531 				flag = TTY_OVERRUN;
532 		}
533 
534 		for (i = 0; i < bytes_read; ++i) {
535 			ch = s->buf[i];
536 			if (uart_handle_sysrq_char(port, ch))
537 				continue;
538 
539 			if (lsr & port->ignore_status_mask)
540 				continue;
541 
542 			uart_insert_char(port, lsr, SC16IS7XX_LSR_OE_BIT, ch,
543 					 flag);
544 		}
545 		rxlen -= bytes_read;
546 	}
547 
548 	tty_flip_buffer_push(&port->state->port);
549 }
550 
551 static void sc16is7xx_handle_tx(struct uart_port *port)
552 {
553 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
554 	struct circ_buf *xmit = &port->state->xmit;
555 	unsigned int txlen, to_send, i;
556 
557 	if (unlikely(port->x_char)) {
558 		sc16is7xx_port_write(port, SC16IS7XX_THR_REG, port->x_char);
559 		port->icount.tx++;
560 		port->x_char = 0;
561 		return;
562 	}
563 
564 	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
565 		return;
566 
567 	/* Get length of data pending in circular buffer */
568 	to_send = uart_circ_chars_pending(xmit);
569 	if (likely(to_send)) {
570 		/* Limit to size of TX FIFO */
571 		txlen = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG);
572 		to_send = (to_send > txlen) ? txlen : to_send;
573 
574 		/* Add data to send */
575 		port->icount.tx += to_send;
576 
577 		/* Convert to linear buffer */
578 		for (i = 0; i < to_send; ++i) {
579 			s->buf[i] = xmit->buf[xmit->tail];
580 			xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
581 		}
582 		regcache_cache_bypass(s->regmap, true);
583 		regmap_raw_write(s->regmap, SC16IS7XX_THR_REG, s->buf, to_send);
584 		regcache_cache_bypass(s->regmap, false);
585 	}
586 
587 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
588 		uart_write_wakeup(port);
589 }
590 
591 static void sc16is7xx_port_irq(struct sc16is7xx_port *s, int portno)
592 {
593 	struct uart_port *port = &s->p[portno].port;
594 
595 	do {
596 		unsigned int iir, msr, rxlen;
597 
598 		iir = sc16is7xx_port_read(port, SC16IS7XX_IIR_REG);
599 		if (iir & SC16IS7XX_IIR_NO_INT_BIT)
600 			break;
601 
602 		iir &= SC16IS7XX_IIR_ID_MASK;
603 
604 		switch (iir) {
605 		case SC16IS7XX_IIR_RDI_SRC:
606 		case SC16IS7XX_IIR_RLSE_SRC:
607 		case SC16IS7XX_IIR_RTOI_SRC:
608 		case SC16IS7XX_IIR_XOFFI_SRC:
609 			rxlen = sc16is7xx_port_read(port, SC16IS7XX_RXLVL_REG);
610 			if (rxlen)
611 				sc16is7xx_handle_rx(port, rxlen, iir);
612 			break;
613 
614 		case SC16IS7XX_IIR_CTSRTS_SRC:
615 			msr = sc16is7xx_port_read(port, SC16IS7XX_MSR_REG);
616 			uart_handle_cts_change(port,
617 					       !!(msr & SC16IS7XX_MSR_CTS_BIT));
618 			break;
619 		case SC16IS7XX_IIR_THRI_SRC:
620 			mutex_lock(&s->mutex);
621 			sc16is7xx_handle_tx(port);
622 			mutex_unlock(&s->mutex);
623 			break;
624 		default:
625 			dev_err_ratelimited(port->dev,
626 					    "Port %i: Unexpected interrupt: %x",
627 					    port->line, iir);
628 			break;
629 		}
630 	} while (1);
631 }
632 
633 static irqreturn_t sc16is7xx_ist(int irq, void *dev_id)
634 {
635 	struct sc16is7xx_port *s = (struct sc16is7xx_port *)dev_id;
636 	int i;
637 
638 	for (i = 0; i < s->uart.nr; ++i)
639 		sc16is7xx_port_irq(s, i);
640 
641 	return IRQ_HANDLED;
642 }
643 
644 static void sc16is7xx_wq_proc(struct work_struct *ws)
645 {
646 	struct sc16is7xx_one *one = to_sc16is7xx_one(ws, tx_work);
647 	struct sc16is7xx_port *s = dev_get_drvdata(one->port.dev);
648 
649 	mutex_lock(&s->mutex);
650 	sc16is7xx_handle_tx(&one->port);
651 	mutex_unlock(&s->mutex);
652 }
653 
654 static void sc16is7xx_stop_tx(struct uart_port* port)
655 {
656 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
657 	struct circ_buf *xmit = &one->port.state->xmit;
658 
659 	/* handle rs485 */
660 	if (one->rs485.flags & SER_RS485_ENABLED) {
661 		/* do nothing if current tx not yet completed */
662 		int lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
663 		if (!(lsr & SC16IS7XX_LSR_TEMT_BIT))
664 			return;
665 
666 		if (uart_circ_empty(xmit) &&
667 		    (one->rs485.delay_rts_after_send > 0))
668 			mdelay(one->rs485.delay_rts_after_send);
669 	}
670 
671 	sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
672 			      SC16IS7XX_IER_THRI_BIT,
673 			      0);
674 }
675 
676 static void sc16is7xx_stop_rx(struct uart_port* port)
677 {
678 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
679 
680 	one->port.read_status_mask &= ~SC16IS7XX_LSR_DR_BIT;
681 	sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
682 			      SC16IS7XX_LSR_DR_BIT,
683 			      0);
684 }
685 
686 static void sc16is7xx_start_tx(struct uart_port *port)
687 {
688 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
689 
690 	/* handle rs485 */
691 	if ((one->rs485.flags & SER_RS485_ENABLED) &&
692 	    (one->rs485.delay_rts_before_send > 0)) {
693 		mdelay(one->rs485.delay_rts_before_send);
694 	}
695 
696 	if (!work_pending(&one->tx_work))
697 		schedule_work(&one->tx_work);
698 }
699 
700 static unsigned int sc16is7xx_tx_empty(struct uart_port *port)
701 {
702 	unsigned int lvl, lsr;
703 
704 	lvl = sc16is7xx_port_read(port, SC16IS7XX_TXLVL_REG);
705 	lsr = sc16is7xx_port_read(port, SC16IS7XX_LSR_REG);
706 
707 	return ((lsr & SC16IS7XX_LSR_THRE_BIT) && !lvl) ? TIOCSER_TEMT : 0;
708 }
709 
710 static unsigned int sc16is7xx_get_mctrl(struct uart_port *port)
711 {
712 	/* DCD and DSR are not wired and CTS/RTS is handled automatically
713 	 * so just indicate DSR and CAR asserted
714 	 */
715 	return TIOCM_DSR | TIOCM_CAR;
716 }
717 
718 static void sc16is7xx_md_proc(struct work_struct *ws)
719 {
720 	struct sc16is7xx_one *one = to_sc16is7xx_one(ws, md_work);
721 
722 	sc16is7xx_port_update(&one->port, SC16IS7XX_MCR_REG,
723 			      SC16IS7XX_MCR_LOOP_BIT,
724 			      (one->port.mctrl & TIOCM_LOOP) ?
725 				      SC16IS7XX_MCR_LOOP_BIT : 0);
726 }
727 
728 static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
729 {
730 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
731 
732 	schedule_work(&one->md_work);
733 }
734 
735 static void sc16is7xx_break_ctl(struct uart_port *port, int break_state)
736 {
737 	sc16is7xx_port_update(port, SC16IS7XX_LCR_REG,
738 			      SC16IS7XX_LCR_TXBREAK_BIT,
739 			      break_state ? SC16IS7XX_LCR_TXBREAK_BIT : 0);
740 }
741 
742 static void sc16is7xx_set_termios(struct uart_port *port,
743 				  struct ktermios *termios,
744 				  struct ktermios *old)
745 {
746 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
747 	unsigned int lcr, flow = 0;
748 	int baud;
749 
750 	/* Mask termios capabilities we don't support */
751 	termios->c_cflag &= ~CMSPAR;
752 
753 	/* Word size */
754 	switch (termios->c_cflag & CSIZE) {
755 	case CS5:
756 		lcr = SC16IS7XX_LCR_WORD_LEN_5;
757 		break;
758 	case CS6:
759 		lcr = SC16IS7XX_LCR_WORD_LEN_6;
760 		break;
761 	case CS7:
762 		lcr = SC16IS7XX_LCR_WORD_LEN_7;
763 		break;
764 	case CS8:
765 		lcr = SC16IS7XX_LCR_WORD_LEN_8;
766 		break;
767 	default:
768 		lcr = SC16IS7XX_LCR_WORD_LEN_8;
769 		termios->c_cflag &= ~CSIZE;
770 		termios->c_cflag |= CS8;
771 		break;
772 	}
773 
774 	/* Parity */
775 	if (termios->c_cflag & PARENB) {
776 		lcr |= SC16IS7XX_LCR_PARITY_BIT;
777 		if (!(termios->c_cflag & PARODD))
778 			lcr |= SC16IS7XX_LCR_EVENPARITY_BIT;
779 	}
780 
781 	/* Stop bits */
782 	if (termios->c_cflag & CSTOPB)
783 		lcr |= SC16IS7XX_LCR_STOPLEN_BIT; /* 2 stops */
784 
785 	/* Set read status mask */
786 	port->read_status_mask = SC16IS7XX_LSR_OE_BIT;
787 	if (termios->c_iflag & INPCK)
788 		port->read_status_mask |= SC16IS7XX_LSR_PE_BIT |
789 					  SC16IS7XX_LSR_FE_BIT;
790 	if (termios->c_iflag & (BRKINT | PARMRK))
791 		port->read_status_mask |= SC16IS7XX_LSR_BI_BIT;
792 
793 	/* Set status ignore mask */
794 	port->ignore_status_mask = 0;
795 	if (termios->c_iflag & IGNBRK)
796 		port->ignore_status_mask |= SC16IS7XX_LSR_BI_BIT;
797 	if (!(termios->c_cflag & CREAD))
798 		port->ignore_status_mask |= SC16IS7XX_LSR_BRK_ERROR_MASK;
799 
800 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
801 			     SC16IS7XX_LCR_CONF_MODE_B);
802 
803 	/* Configure flow control */
804 	regcache_cache_bypass(s->regmap, true);
805 	sc16is7xx_port_write(port, SC16IS7XX_XON1_REG, termios->c_cc[VSTART]);
806 	sc16is7xx_port_write(port, SC16IS7XX_XOFF1_REG, termios->c_cc[VSTOP]);
807 	if (termios->c_cflag & CRTSCTS)
808 		flow |= SC16IS7XX_EFR_AUTOCTS_BIT |
809 			SC16IS7XX_EFR_AUTORTS_BIT;
810 	if (termios->c_iflag & IXON)
811 		flow |= SC16IS7XX_EFR_SWFLOW3_BIT;
812 	if (termios->c_iflag & IXOFF)
813 		flow |= SC16IS7XX_EFR_SWFLOW1_BIT;
814 
815 	sc16is7xx_port_write(port, SC16IS7XX_EFR_REG, flow);
816 	regcache_cache_bypass(s->regmap, false);
817 
818 	/* Update LCR register */
819 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr);
820 
821 	/* Get baud rate generator configuration */
822 	baud = uart_get_baud_rate(port, termios, old,
823 				  port->uartclk / 16 / 4 / 0xffff,
824 				  port->uartclk / 16);
825 
826 	/* Setup baudrate generator */
827 	baud = sc16is7xx_set_baud(port, baud);
828 
829 	/* Update timeout according to new baud rate */
830 	uart_update_timeout(port, termios->c_cflag, baud);
831 }
832 
833 #if defined(TIOCSRS485) && defined(TIOCGRS485)
834 static void sc16is7xx_config_rs485(struct uart_port *port,
835 				   struct serial_rs485 *rs485)
836 {
837 	struct sc16is7xx_one *one = to_sc16is7xx_one(port, port);
838 
839 	one->rs485 = *rs485;
840 
841 	if (one->rs485.flags & SER_RS485_ENABLED) {
842 		sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
843 				      SC16IS7XX_EFCR_AUTO_RS485_BIT,
844 				      SC16IS7XX_EFCR_AUTO_RS485_BIT);
845 	} else {
846 		sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
847 				      SC16IS7XX_EFCR_AUTO_RS485_BIT,
848 				      0);
849 	}
850 }
851 #endif
852 
853 static int sc16is7xx_ioctl(struct uart_port *port, unsigned int cmd,
854 			   unsigned long arg)
855 {
856 #if defined(TIOCSRS485) && defined(TIOCGRS485)
857 	struct serial_rs485 rs485;
858 
859 	switch (cmd) {
860 	case TIOCSRS485:
861 		if (copy_from_user(&rs485, (void __user *)arg, sizeof(rs485)))
862 			return -EFAULT;
863 
864 		sc16is7xx_config_rs485(port, &rs485);
865 		return 0;
866 	case TIOCGRS485:
867 		if (copy_to_user((void __user *)arg,
868 				 &(to_sc16is7xx_one(port, port)->rs485),
869 				 sizeof(rs485)))
870 			return -EFAULT;
871 		return 0;
872 	default:
873 		break;
874 	}
875 #endif
876 
877 	return -ENOIOCTLCMD;
878 }
879 
880 static int sc16is7xx_startup(struct uart_port *port)
881 {
882 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
883 	unsigned int val;
884 
885 	sc16is7xx_power(port, 1);
886 
887 	/* Reset FIFOs*/
888 	val = SC16IS7XX_FCR_RXRESET_BIT | SC16IS7XX_FCR_TXRESET_BIT;
889 	sc16is7xx_port_write(port, SC16IS7XX_FCR_REG, val);
890 	udelay(5);
891 	sc16is7xx_port_write(port, SC16IS7XX_FCR_REG,
892 			     SC16IS7XX_FCR_FIFO_BIT);
893 
894 	/* Enable EFR */
895 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG,
896 			     SC16IS7XX_LCR_CONF_MODE_B);
897 
898 	regcache_cache_bypass(s->regmap, true);
899 
900 	/* Enable write access to enhanced features and internal clock div */
901 	sc16is7xx_port_write(port, SC16IS7XX_EFR_REG,
902 			     SC16IS7XX_EFR_ENABLE_BIT);
903 
904 	/* Enable TCR/TLR */
905 	sc16is7xx_port_update(port, SC16IS7XX_MCR_REG,
906 			      SC16IS7XX_MCR_TCRTLR_BIT,
907 			      SC16IS7XX_MCR_TCRTLR_BIT);
908 
909 	/* Configure flow control levels */
910 	/* Flow control halt level 48, resume level 24 */
911 	sc16is7xx_port_write(port, SC16IS7XX_TCR_REG,
912 			     SC16IS7XX_TCR_RX_RESUME(24) |
913 			     SC16IS7XX_TCR_RX_HALT(48));
914 
915 	regcache_cache_bypass(s->regmap, false);
916 
917 	/* Now, initialize the UART */
918 	sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, SC16IS7XX_LCR_WORD_LEN_8);
919 
920 	/* Enable the Rx and Tx FIFO */
921 	sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
922 			      SC16IS7XX_EFCR_RXDISABLE_BIT |
923 			      SC16IS7XX_EFCR_TXDISABLE_BIT,
924 			      0);
925 
926 	/* Enable RX, TX, CTS change interrupts */
927 	val = SC16IS7XX_IER_RDI_BIT | SC16IS7XX_IER_THRI_BIT |
928 	      SC16IS7XX_IER_CTSI_BIT;
929 	sc16is7xx_port_write(port, SC16IS7XX_IER_REG, val);
930 
931 	return 0;
932 }
933 
934 static void sc16is7xx_shutdown(struct uart_port *port)
935 {
936 	/* Disable all interrupts */
937 	sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0);
938 	/* Disable TX/RX */
939 	sc16is7xx_port_write(port, SC16IS7XX_EFCR_REG,
940 			     SC16IS7XX_EFCR_RXDISABLE_BIT |
941 			     SC16IS7XX_EFCR_TXDISABLE_BIT);
942 
943 	sc16is7xx_power(port, 0);
944 }
945 
946 static const char *sc16is7xx_type(struct uart_port *port)
947 {
948 	struct sc16is7xx_port *s = dev_get_drvdata(port->dev);
949 
950 	return (port->type == PORT_SC16IS7XX) ? s->devtype->name : NULL;
951 }
952 
953 static int sc16is7xx_request_port(struct uart_port *port)
954 {
955 	/* Do nothing */
956 	return 0;
957 }
958 
959 static void sc16is7xx_config_port(struct uart_port *port, int flags)
960 {
961 	if (flags & UART_CONFIG_TYPE)
962 		port->type = PORT_SC16IS7XX;
963 }
964 
965 static int sc16is7xx_verify_port(struct uart_port *port,
966 				 struct serial_struct *s)
967 {
968 	if ((s->type != PORT_UNKNOWN) && (s->type != PORT_SC16IS7XX))
969 		return -EINVAL;
970 	if (s->irq != port->irq)
971 		return -EINVAL;
972 
973 	return 0;
974 }
975 
976 static void sc16is7xx_pm(struct uart_port *port, unsigned int state,
977 			 unsigned int oldstate)
978 {
979 	sc16is7xx_power(port, (state == UART_PM_STATE_ON) ? 1 : 0);
980 }
981 
982 static void sc16is7xx_null_void(struct uart_port *port)
983 {
984 	/* Do nothing */
985 }
986 
987 static const struct uart_ops sc16is7xx_ops = {
988 	.tx_empty	= sc16is7xx_tx_empty,
989 	.set_mctrl	= sc16is7xx_set_mctrl,
990 	.get_mctrl	= sc16is7xx_get_mctrl,
991 	.stop_tx	= sc16is7xx_stop_tx,
992 	.start_tx	= sc16is7xx_start_tx,
993 	.stop_rx	= sc16is7xx_stop_rx,
994 	.enable_ms	= sc16is7xx_null_void,
995 	.break_ctl	= sc16is7xx_break_ctl,
996 	.startup	= sc16is7xx_startup,
997 	.shutdown	= sc16is7xx_shutdown,
998 	.set_termios	= sc16is7xx_set_termios,
999 	.type		= sc16is7xx_type,
1000 	.request_port	= sc16is7xx_request_port,
1001 	.release_port	= sc16is7xx_null_void,
1002 	.config_port	= sc16is7xx_config_port,
1003 	.verify_port	= sc16is7xx_verify_port,
1004 	.ioctl		= sc16is7xx_ioctl,
1005 	.pm		= sc16is7xx_pm,
1006 };
1007 
1008 #ifdef CONFIG_GPIOLIB
1009 static int sc16is7xx_gpio_get(struct gpio_chip *chip, unsigned offset)
1010 {
1011 	unsigned int val;
1012 	struct sc16is7xx_port *s = container_of(chip, struct sc16is7xx_port,
1013 						gpio);
1014 	struct uart_port *port = &s->p[0].port;
1015 
1016 	val = sc16is7xx_port_read(port, SC16IS7XX_IOSTATE_REG);
1017 
1018 	return !!(val & BIT(offset));
1019 }
1020 
1021 static void sc16is7xx_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
1022 {
1023 	struct sc16is7xx_port *s = container_of(chip, struct sc16is7xx_port,
1024 						gpio);
1025 	struct uart_port *port = &s->p[0].port;
1026 
1027 	sc16is7xx_port_update(port, SC16IS7XX_IOSTATE_REG, BIT(offset),
1028 			      val ? BIT(offset) : 0);
1029 }
1030 
1031 static int sc16is7xx_gpio_direction_input(struct gpio_chip *chip,
1032 					  unsigned offset)
1033 {
1034 	struct sc16is7xx_port *s = container_of(chip, struct sc16is7xx_port,
1035 						gpio);
1036 	struct uart_port *port = &s->p[0].port;
1037 
1038 	sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset), 0);
1039 
1040 	return 0;
1041 }
1042 
1043 static int sc16is7xx_gpio_direction_output(struct gpio_chip *chip,
1044 					   unsigned offset, int val)
1045 {
1046 	struct sc16is7xx_port *s = container_of(chip, struct sc16is7xx_port,
1047 						gpio);
1048 	struct uart_port *port = &s->p[0].port;
1049 
1050 	sc16is7xx_port_update(port, SC16IS7XX_IOSTATE_REG, BIT(offset),
1051 			      val ? BIT(offset) : 0);
1052 	sc16is7xx_port_update(port, SC16IS7XX_IODIR_REG, BIT(offset),
1053 			      BIT(offset));
1054 
1055 	return 0;
1056 }
1057 #endif
1058 
1059 static int sc16is7xx_probe(struct device *dev,
1060 			   struct sc16is7xx_devtype *devtype,
1061 			   struct regmap *regmap, int irq, unsigned long flags)
1062 {
1063 	unsigned long freq, *pfreq = dev_get_platdata(dev);
1064 	struct clk *clk;
1065 	int i, ret;
1066 	struct sc16is7xx_port *s;
1067 
1068 	if (IS_ERR(regmap))
1069 		return PTR_ERR(regmap);
1070 
1071 	/* Alloc port structure */
1072 	s = devm_kzalloc(dev, sizeof(*s) +
1073 			 sizeof(struct sc16is7xx_one) * devtype->nr_uart,
1074 			 GFP_KERNEL);
1075 	if (!s) {
1076 		dev_err(dev, "Error allocating port structure\n");
1077 		return -ENOMEM;
1078 	}
1079 
1080 	clk = devm_clk_get(dev, NULL);
1081 	if (IS_ERR(clk)) {
1082 		if (pfreq)
1083 			freq = *pfreq;
1084 		else
1085 			return PTR_ERR(clk);
1086 	} else {
1087 		freq = clk_get_rate(clk);
1088 	}
1089 
1090 	s->regmap = regmap;
1091 	s->devtype = devtype;
1092 	dev_set_drvdata(dev, s);
1093 
1094 	/* Register UART driver */
1095 	s->uart.owner		= THIS_MODULE;
1096 	s->uart.dev_name	= "ttySC";
1097 	s->uart.nr		= devtype->nr_uart;
1098 	ret = uart_register_driver(&s->uart);
1099 	if (ret) {
1100 		dev_err(dev, "Registering UART driver failed\n");
1101 		goto out_clk;
1102 	}
1103 
1104 #ifdef CONFIG_GPIOLIB
1105 	if (devtype->nr_gpio) {
1106 		/* Setup GPIO cotroller */
1107 		s->gpio.owner		 = THIS_MODULE;
1108 		s->gpio.dev		 = dev;
1109 		s->gpio.label		 = dev_name(dev);
1110 		s->gpio.direction_input	 = sc16is7xx_gpio_direction_input;
1111 		s->gpio.get		 = sc16is7xx_gpio_get;
1112 		s->gpio.direction_output = sc16is7xx_gpio_direction_output;
1113 		s->gpio.set		 = sc16is7xx_gpio_set;
1114 		s->gpio.base		 = -1;
1115 		s->gpio.ngpio		 = devtype->nr_gpio;
1116 		s->gpio.can_sleep	 = 1;
1117 		ret = gpiochip_add(&s->gpio);
1118 		if (ret)
1119 			goto out_uart;
1120 	}
1121 #endif
1122 
1123 	mutex_init(&s->mutex);
1124 
1125 	for (i = 0; i < devtype->nr_uart; ++i) {
1126 		/* Initialize port data */
1127 		s->p[i].port.line	= i;
1128 		s->p[i].port.dev	= dev;
1129 		s->p[i].port.irq	= irq;
1130 		s->p[i].port.type	= PORT_SC16IS7XX;
1131 		s->p[i].port.fifosize	= SC16IS7XX_FIFO_SIZE;
1132 		s->p[i].port.flags	= UPF_FIXED_TYPE | UPF_LOW_LATENCY;
1133 		s->p[i].port.iotype	= UPIO_PORT;
1134 		s->p[i].port.uartclk	= freq;
1135 		s->p[i].port.ops	= &sc16is7xx_ops;
1136 		/* Disable all interrupts */
1137 		sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_IER_REG, 0);
1138 		/* Disable TX/RX */
1139 		sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_EFCR_REG,
1140 				     SC16IS7XX_EFCR_RXDISABLE_BIT |
1141 				     SC16IS7XX_EFCR_TXDISABLE_BIT);
1142 		/* Initialize queue for start TX */
1143 		INIT_WORK(&s->p[i].tx_work, sc16is7xx_wq_proc);
1144 		/* Initialize queue for changing mode */
1145 		INIT_WORK(&s->p[i].md_work, sc16is7xx_md_proc);
1146 		/* Register port */
1147 		uart_add_one_port(&s->uart, &s->p[i].port);
1148 		/* Go to suspend mode */
1149 		sc16is7xx_power(&s->p[i].port, 0);
1150 	}
1151 
1152 	/* Setup interrupt */
1153 	ret = devm_request_threaded_irq(dev, irq, NULL, sc16is7xx_ist,
1154 					IRQF_ONESHOT | flags, dev_name(dev), s);
1155 	if (!ret)
1156 		return 0;
1157 
1158 	mutex_destroy(&s->mutex);
1159 
1160 #ifdef CONFIG_GPIOLIB
1161 	if (devtype->nr_gpio)
1162 		WARN_ON(gpiochip_remove(&s->gpio));
1163 
1164 out_uart:
1165 #endif
1166 	uart_unregister_driver(&s->uart);
1167 
1168 out_clk:
1169 	if (!IS_ERR(s->clk))
1170 		clk_disable_unprepare(s->clk);
1171 
1172 	return ret;
1173 }
1174 
1175 static int sc16is7xx_remove(struct device *dev)
1176 {
1177 	struct sc16is7xx_port *s = dev_get_drvdata(dev);
1178 	int i, ret = 0;
1179 
1180 #ifdef CONFIG_GPIOLIB
1181 	if (s->devtype->nr_gpio) {
1182 		ret = gpiochip_remove(&s->gpio);
1183 		if (ret)
1184 			return ret;
1185 	}
1186 #endif
1187 
1188 	for (i = 0; i < s->uart.nr; i++) {
1189 		cancel_work_sync(&s->p[i].tx_work);
1190 		cancel_work_sync(&s->p[i].md_work);
1191 		uart_remove_one_port(&s->uart, &s->p[i].port);
1192 		sc16is7xx_power(&s->p[i].port, 0);
1193 	}
1194 
1195 	mutex_destroy(&s->mutex);
1196 	uart_unregister_driver(&s->uart);
1197 	if (!IS_ERR(s->clk))
1198 		clk_disable_unprepare(s->clk);
1199 
1200 	return ret;
1201 }
1202 
1203 static const struct of_device_id __maybe_unused sc16is7xx_dt_ids[] = {
1204 	{ .compatible = "nxp,sc16is740",	.data = &sc16is74x_devtype, },
1205 	{ .compatible = "nxp,sc16is741",	.data = &sc16is74x_devtype, },
1206 	{ .compatible = "nxp,sc16is750",	.data = &sc16is750_devtype, },
1207 	{ .compatible = "nxp,sc16is752",	.data = &sc16is752_devtype, },
1208 	{ .compatible = "nxp,sc16is760",	.data = &sc16is760_devtype, },
1209 	{ .compatible = "nxp,sc16is762",	.data = &sc16is762_devtype, },
1210 	{ }
1211 };
1212 MODULE_DEVICE_TABLE(of, sc16is7xx_dt_ids);
1213 
1214 static struct regmap_config regcfg = {
1215 	.reg_bits = 7,
1216 	.pad_bits = 1,
1217 	.val_bits = 8,
1218 	.cache_type = REGCACHE_RBTREE,
1219 	.volatile_reg = sc16is7xx_regmap_volatile,
1220 	.precious_reg = sc16is7xx_regmap_precious,
1221 };
1222 
1223 static int sc16is7xx_i2c_probe(struct i2c_client *i2c,
1224 			       const struct i2c_device_id *id)
1225 {
1226 	struct sc16is7xx_devtype *devtype;
1227 	unsigned long flags = 0;
1228 	struct regmap *regmap;
1229 
1230 	if (i2c->dev.of_node) {
1231 		const struct of_device_id *of_id =
1232 				of_match_device(sc16is7xx_dt_ids, &i2c->dev);
1233 
1234 		devtype = (struct sc16is7xx_devtype *)of_id->data;
1235 	} else {
1236 		devtype = (struct sc16is7xx_devtype *)id->driver_data;
1237 		flags = IRQF_TRIGGER_FALLING;
1238 	}
1239 
1240 	regcfg.max_register = (0xf << SC16IS7XX_REG_SHIFT) |
1241 			      (devtype->nr_uart - 1);
1242 	regmap = devm_regmap_init_i2c(i2c, &regcfg);
1243 
1244 	return sc16is7xx_probe(&i2c->dev, devtype, regmap, i2c->irq, flags);
1245 }
1246 
1247 static int sc16is7xx_i2c_remove(struct i2c_client *client)
1248 {
1249 	return sc16is7xx_remove(&client->dev);
1250 }
1251 
1252 static const struct i2c_device_id sc16is7xx_i2c_id_table[] = {
1253 	{ "sc16is74x",	(kernel_ulong_t)&sc16is74x_devtype, },
1254 	{ "sc16is750",	(kernel_ulong_t)&sc16is750_devtype, },
1255 	{ "sc16is752",	(kernel_ulong_t)&sc16is752_devtype, },
1256 	{ "sc16is760",	(kernel_ulong_t)&sc16is760_devtype, },
1257 	{ "sc16is762",	(kernel_ulong_t)&sc16is762_devtype, },
1258 	{ }
1259 };
1260 MODULE_DEVICE_TABLE(i2c, sc16is7xx_i2c_id_table);
1261 
1262 static struct i2c_driver sc16is7xx_i2c_uart_driver = {
1263 	.driver = {
1264 		.name		= SC16IS7XX_NAME,
1265 		.owner		= THIS_MODULE,
1266 		.of_match_table	= of_match_ptr(sc16is7xx_dt_ids),
1267 	},
1268 	.probe		= sc16is7xx_i2c_probe,
1269 	.remove		= sc16is7xx_i2c_remove,
1270 	.id_table	= sc16is7xx_i2c_id_table,
1271 };
1272 module_i2c_driver(sc16is7xx_i2c_uart_driver);
1273 MODULE_ALIAS("i2c:sc16is7xx");
1274 
1275 MODULE_LICENSE("GPL");
1276 MODULE_AUTHOR("Jon Ringle <jringle@gridpoint.com>");
1277 MODULE_DESCRIPTION("SC16IS7XX serial driver");
1278