xref: /openbmc/linux/drivers/tty/serial/max310x.c (revision a8a28aff)
1 /*
2  *  Maxim (Dallas) MAX3107/8/9, MAX14830 serial driver
3  *
4  *  Copyright (C) 2012-2014 Alexander Shiyan <shc_work@mail.ru>
5  *
6  *  Based on max3100.c, by Christian Pellegrin <chripell@evolware.org>
7  *  Based on max3110.c, by Feng Tang <feng.tang@intel.com>
8  *  Based on max3107.c, by Aavamobile
9  *
10  *  This program is free software; you can redistribute it and/or modify
11  *  it under the terms of the GNU General Public License as published by
12  *  the Free Software Foundation; either version 2 of the License, or
13  *  (at your option) any later version.
14  */
15 
16 #include <linux/bitops.h>
17 #include <linux/clk.h>
18 #include <linux/delay.h>
19 #include <linux/device.h>
20 #include <linux/gpio.h>
21 #include <linux/module.h>
22 #include <linux/of.h>
23 #include <linux/of_device.h>
24 #include <linux/regmap.h>
25 #include <linux/serial_core.h>
26 #include <linux/serial.h>
27 #include <linux/tty.h>
28 #include <linux/tty_flip.h>
29 #include <linux/spi/spi.h>
30 #include <linux/uaccess.h>
31 
32 #define MAX310X_NAME			"max310x"
33 #define MAX310X_MAJOR			204
34 #define MAX310X_MINOR			209
35 
36 /* MAX310X register definitions */
37 #define MAX310X_RHR_REG			(0x00) /* RX FIFO */
38 #define MAX310X_THR_REG			(0x00) /* TX FIFO */
39 #define MAX310X_IRQEN_REG		(0x01) /* IRQ enable */
40 #define MAX310X_IRQSTS_REG		(0x02) /* IRQ status */
41 #define MAX310X_LSR_IRQEN_REG		(0x03) /* LSR IRQ enable */
42 #define MAX310X_LSR_IRQSTS_REG		(0x04) /* LSR IRQ status */
43 #define MAX310X_REG_05			(0x05)
44 #define MAX310X_SPCHR_IRQEN_REG		MAX310X_REG_05 /* Special char IRQ en */
45 #define MAX310X_SPCHR_IRQSTS_REG	(0x06) /* Special char IRQ status */
46 #define MAX310X_STS_IRQEN_REG		(0x07) /* Status IRQ enable */
47 #define MAX310X_STS_IRQSTS_REG		(0x08) /* Status IRQ status */
48 #define MAX310X_MODE1_REG		(0x09) /* MODE1 */
49 #define MAX310X_MODE2_REG		(0x0a) /* MODE2 */
50 #define MAX310X_LCR_REG			(0x0b) /* LCR */
51 #define MAX310X_RXTO_REG		(0x0c) /* RX timeout */
52 #define MAX310X_HDPIXDELAY_REG		(0x0d) /* Auto transceiver delays */
53 #define MAX310X_IRDA_REG		(0x0e) /* IRDA settings */
54 #define MAX310X_FLOWLVL_REG		(0x0f) /* Flow control levels */
55 #define MAX310X_FIFOTRIGLVL_REG		(0x10) /* FIFO IRQ trigger levels */
56 #define MAX310X_TXFIFOLVL_REG		(0x11) /* TX FIFO level */
57 #define MAX310X_RXFIFOLVL_REG		(0x12) /* RX FIFO level */
58 #define MAX310X_FLOWCTRL_REG		(0x13) /* Flow control */
59 #define MAX310X_XON1_REG		(0x14) /* XON1 character */
60 #define MAX310X_XON2_REG		(0x15) /* XON2 character */
61 #define MAX310X_XOFF1_REG		(0x16) /* XOFF1 character */
62 #define MAX310X_XOFF2_REG		(0x17) /* XOFF2 character */
63 #define MAX310X_GPIOCFG_REG		(0x18) /* GPIO config */
64 #define MAX310X_GPIODATA_REG		(0x19) /* GPIO data */
65 #define MAX310X_PLLCFG_REG		(0x1a) /* PLL config */
66 #define MAX310X_BRGCFG_REG		(0x1b) /* Baud rate generator conf */
67 #define MAX310X_BRGDIVLSB_REG		(0x1c) /* Baud rate divisor LSB */
68 #define MAX310X_BRGDIVMSB_REG		(0x1d) /* Baud rate divisor MSB */
69 #define MAX310X_CLKSRC_REG		(0x1e) /* Clock source */
70 #define MAX310X_REG_1F			(0x1f)
71 
72 #define MAX310X_REVID_REG		MAX310X_REG_1F /* Revision ID */
73 
74 #define MAX310X_GLOBALIRQ_REG		MAX310X_REG_1F /* Global IRQ (RO) */
75 #define MAX310X_GLOBALCMD_REG		MAX310X_REG_1F /* Global Command (WO) */
76 
77 /* Extended registers */
78 #define MAX310X_REVID_EXTREG		MAX310X_REG_05 /* Revision ID */
79 
80 /* IRQ register bits */
81 #define MAX310X_IRQ_LSR_BIT		(1 << 0) /* LSR interrupt */
82 #define MAX310X_IRQ_SPCHR_BIT		(1 << 1) /* Special char interrupt */
83 #define MAX310X_IRQ_STS_BIT		(1 << 2) /* Status interrupt */
84 #define MAX310X_IRQ_RXFIFO_BIT		(1 << 3) /* RX FIFO interrupt */
85 #define MAX310X_IRQ_TXFIFO_BIT		(1 << 4) /* TX FIFO interrupt */
86 #define MAX310X_IRQ_TXEMPTY_BIT		(1 << 5) /* TX FIFO empty interrupt */
87 #define MAX310X_IRQ_RXEMPTY_BIT		(1 << 6) /* RX FIFO empty interrupt */
88 #define MAX310X_IRQ_CTS_BIT		(1 << 7) /* CTS interrupt */
89 
90 /* LSR register bits */
91 #define MAX310X_LSR_RXTO_BIT		(1 << 0) /* RX timeout */
92 #define MAX310X_LSR_RXOVR_BIT		(1 << 1) /* RX overrun */
93 #define MAX310X_LSR_RXPAR_BIT		(1 << 2) /* RX parity error */
94 #define MAX310X_LSR_FRERR_BIT		(1 << 3) /* Frame error */
95 #define MAX310X_LSR_RXBRK_BIT		(1 << 4) /* RX break */
96 #define MAX310X_LSR_RXNOISE_BIT		(1 << 5) /* RX noise */
97 #define MAX310X_LSR_CTS_BIT		(1 << 7) /* CTS pin state */
98 
99 /* Special character register bits */
100 #define MAX310X_SPCHR_XON1_BIT		(1 << 0) /* XON1 character */
101 #define MAX310X_SPCHR_XON2_BIT		(1 << 1) /* XON2 character */
102 #define MAX310X_SPCHR_XOFF1_BIT		(1 << 2) /* XOFF1 character */
103 #define MAX310X_SPCHR_XOFF2_BIT		(1 << 3) /* XOFF2 character */
104 #define MAX310X_SPCHR_BREAK_BIT		(1 << 4) /* RX break */
105 #define MAX310X_SPCHR_MULTIDROP_BIT	(1 << 5) /* 9-bit multidrop addr char */
106 
107 /* Status register bits */
108 #define MAX310X_STS_GPIO0_BIT		(1 << 0) /* GPIO 0 interrupt */
109 #define MAX310X_STS_GPIO1_BIT		(1 << 1) /* GPIO 1 interrupt */
110 #define MAX310X_STS_GPIO2_BIT		(1 << 2) /* GPIO 2 interrupt */
111 #define MAX310X_STS_GPIO3_BIT		(1 << 3) /* GPIO 3 interrupt */
112 #define MAX310X_STS_CLKREADY_BIT	(1 << 5) /* Clock ready */
113 #define MAX310X_STS_SLEEP_BIT		(1 << 6) /* Sleep interrupt */
114 
115 /* MODE1 register bits */
116 #define MAX310X_MODE1_RXDIS_BIT		(1 << 0) /* RX disable */
117 #define MAX310X_MODE1_TXDIS_BIT		(1 << 1) /* TX disable */
118 #define MAX310X_MODE1_TXHIZ_BIT		(1 << 2) /* TX pin three-state */
119 #define MAX310X_MODE1_RTSHIZ_BIT	(1 << 3) /* RTS pin three-state */
120 #define MAX310X_MODE1_TRNSCVCTRL_BIT	(1 << 4) /* Transceiver ctrl enable */
121 #define MAX310X_MODE1_FORCESLEEP_BIT	(1 << 5) /* Force sleep mode */
122 #define MAX310X_MODE1_AUTOSLEEP_BIT	(1 << 6) /* Auto sleep enable */
123 #define MAX310X_MODE1_IRQSEL_BIT	(1 << 7) /* IRQ pin enable */
124 
125 /* MODE2 register bits */
126 #define MAX310X_MODE2_RST_BIT		(1 << 0) /* Chip reset */
127 #define MAX310X_MODE2_FIFORST_BIT	(1 << 1) /* FIFO reset */
128 #define MAX310X_MODE2_RXTRIGINV_BIT	(1 << 2) /* RX FIFO INT invert */
129 #define MAX310X_MODE2_RXEMPTINV_BIT	(1 << 3) /* RX FIFO empty INT invert */
130 #define MAX310X_MODE2_SPCHR_BIT		(1 << 4) /* Special chr detect enable */
131 #define MAX310X_MODE2_LOOPBACK_BIT	(1 << 5) /* Internal loopback enable */
132 #define MAX310X_MODE2_MULTIDROP_BIT	(1 << 6) /* 9-bit multidrop enable */
133 #define MAX310X_MODE2_ECHOSUPR_BIT	(1 << 7) /* ECHO suppression enable */
134 
135 /* LCR register bits */
136 #define MAX310X_LCR_LENGTH0_BIT		(1 << 0) /* Word length bit 0 */
137 #define MAX310X_LCR_LENGTH1_BIT		(1 << 1) /* Word length bit 1
138 						  *
139 						  * Word length bits table:
140 						  * 00 -> 5 bit words
141 						  * 01 -> 6 bit words
142 						  * 10 -> 7 bit words
143 						  * 11 -> 8 bit words
144 						  */
145 #define MAX310X_LCR_STOPLEN_BIT		(1 << 2) /* STOP length bit
146 						  *
147 						  * STOP length bit table:
148 						  * 0 -> 1 stop bit
149 						  * 1 -> 1-1.5 stop bits if
150 						  *      word length is 5,
151 						  *      2 stop bits otherwise
152 						  */
153 #define MAX310X_LCR_PARITY_BIT		(1 << 3) /* Parity bit enable */
154 #define MAX310X_LCR_EVENPARITY_BIT	(1 << 4) /* Even parity bit enable */
155 #define MAX310X_LCR_FORCEPARITY_BIT	(1 << 5) /* 9-bit multidrop parity */
156 #define MAX310X_LCR_TXBREAK_BIT		(1 << 6) /* TX break enable */
157 #define MAX310X_LCR_RTS_BIT		(1 << 7) /* RTS pin control */
158 #define MAX310X_LCR_WORD_LEN_5		(0x00)
159 #define MAX310X_LCR_WORD_LEN_6		(0x01)
160 #define MAX310X_LCR_WORD_LEN_7		(0x02)
161 #define MAX310X_LCR_WORD_LEN_8		(0x03)
162 
163 /* IRDA register bits */
164 #define MAX310X_IRDA_IRDAEN_BIT		(1 << 0) /* IRDA mode enable */
165 #define MAX310X_IRDA_SIR_BIT		(1 << 1) /* SIR mode enable */
166 
167 /* Flow control trigger level register masks */
168 #define MAX310X_FLOWLVL_HALT_MASK	(0x000f) /* Flow control halt level */
169 #define MAX310X_FLOWLVL_RES_MASK	(0x00f0) /* Flow control resume level */
170 #define MAX310X_FLOWLVL_HALT(words)	((words / 8) & 0x0f)
171 #define MAX310X_FLOWLVL_RES(words)	(((words / 8) & 0x0f) << 4)
172 
173 /* FIFO interrupt trigger level register masks */
174 #define MAX310X_FIFOTRIGLVL_TX_MASK	(0x0f) /* TX FIFO trigger level */
175 #define MAX310X_FIFOTRIGLVL_RX_MASK	(0xf0) /* RX FIFO trigger level */
176 #define MAX310X_FIFOTRIGLVL_TX(words)	((words / 8) & 0x0f)
177 #define MAX310X_FIFOTRIGLVL_RX(words)	(((words / 8) & 0x0f) << 4)
178 
179 /* Flow control register bits */
180 #define MAX310X_FLOWCTRL_AUTORTS_BIT	(1 << 0) /* Auto RTS flow ctrl enable */
181 #define MAX310X_FLOWCTRL_AUTOCTS_BIT	(1 << 1) /* Auto CTS flow ctrl enable */
182 #define MAX310X_FLOWCTRL_GPIADDR_BIT	(1 << 2) /* Enables that GPIO inputs
183 						  * are used in conjunction with
184 						  * XOFF2 for definition of
185 						  * special character */
186 #define MAX310X_FLOWCTRL_SWFLOWEN_BIT	(1 << 3) /* Auto SW flow ctrl enable */
187 #define MAX310X_FLOWCTRL_SWFLOW0_BIT	(1 << 4) /* SWFLOW bit 0 */
188 #define MAX310X_FLOWCTRL_SWFLOW1_BIT	(1 << 5) /* SWFLOW bit 1
189 						  *
190 						  * SWFLOW bits 1 & 0 table:
191 						  * 00 -> no transmitter flow
192 						  *       control
193 						  * 01 -> receiver compares
194 						  *       XON2 and XOFF2
195 						  *       and controls
196 						  *       transmitter
197 						  * 10 -> receiver compares
198 						  *       XON1 and XOFF1
199 						  *       and controls
200 						  *       transmitter
201 						  * 11 -> receiver compares
202 						  *       XON1, XON2, XOFF1 and
203 						  *       XOFF2 and controls
204 						  *       transmitter
205 						  */
206 #define MAX310X_FLOWCTRL_SWFLOW2_BIT	(1 << 6) /* SWFLOW bit 2 */
207 #define MAX310X_FLOWCTRL_SWFLOW3_BIT	(1 << 7) /* SWFLOW bit 3
208 						  *
209 						  * SWFLOW bits 3 & 2 table:
210 						  * 00 -> no received flow
211 						  *       control
212 						  * 01 -> transmitter generates
213 						  *       XON2 and XOFF2
214 						  * 10 -> transmitter generates
215 						  *       XON1 and XOFF1
216 						  * 11 -> transmitter generates
217 						  *       XON1, XON2, XOFF1 and
218 						  *       XOFF2
219 						  */
220 
221 /* PLL configuration register masks */
222 #define MAX310X_PLLCFG_PREDIV_MASK	(0x3f) /* PLL predivision value */
223 #define MAX310X_PLLCFG_PLLFACTOR_MASK	(0xc0) /* PLL multiplication factor */
224 
225 /* Baud rate generator configuration register bits */
226 #define MAX310X_BRGCFG_2XMODE_BIT	(1 << 4) /* Double baud rate */
227 #define MAX310X_BRGCFG_4XMODE_BIT	(1 << 5) /* Quadruple baud rate */
228 
229 /* Clock source register bits */
230 #define MAX310X_CLKSRC_CRYST_BIT	(1 << 1) /* Crystal osc enable */
231 #define MAX310X_CLKSRC_PLL_BIT		(1 << 2) /* PLL enable */
232 #define MAX310X_CLKSRC_PLLBYP_BIT	(1 << 3) /* PLL bypass */
233 #define MAX310X_CLKSRC_EXTCLK_BIT	(1 << 4) /* External clock enable */
234 #define MAX310X_CLKSRC_CLK2RTS_BIT	(1 << 7) /* Baud clk to RTS pin */
235 
236 /* Global commands */
237 #define MAX310X_EXTREG_ENBL		(0xce)
238 #define MAX310X_EXTREG_DSBL		(0xcd)
239 
240 /* Misc definitions */
241 #define MAX310X_FIFO_SIZE		(128)
242 #define MAX310x_REV_MASK		(0xfc)
243 
244 /* MAX3107 specific */
245 #define MAX3107_REV_ID			(0xa0)
246 
247 /* MAX3109 specific */
248 #define MAX3109_REV_ID			(0xc0)
249 
250 /* MAX14830 specific */
251 #define MAX14830_BRGCFG_CLKDIS_BIT	(1 << 6) /* Clock Disable */
252 #define MAX14830_REV_ID			(0xb0)
253 
254 struct max310x_devtype {
255 	char	name[9];
256 	int	nr;
257 	int	(*detect)(struct device *);
258 	void	(*power)(struct uart_port *, int);
259 };
260 
261 struct max310x_one {
262 	struct uart_port	port;
263 	struct work_struct	tx_work;
264 	struct work_struct	md_work;
265 };
266 
267 struct max310x_port {
268 	struct uart_driver	uart;
269 	struct max310x_devtype	*devtype;
270 	struct regmap		*regmap;
271 	struct mutex		mutex;
272 	struct clk		*clk;
273 #ifdef CONFIG_GPIOLIB
274 	struct gpio_chip	gpio;
275 #endif
276 	struct max310x_one	p[0];
277 };
278 
279 static u8 max310x_port_read(struct uart_port *port, u8 reg)
280 {
281 	struct max310x_port *s = dev_get_drvdata(port->dev);
282 	unsigned int val = 0;
283 
284 	regmap_read(s->regmap, port->iobase + reg, &val);
285 
286 	return val;
287 }
288 
289 static void max310x_port_write(struct uart_port *port, u8 reg, u8 val)
290 {
291 	struct max310x_port *s = dev_get_drvdata(port->dev);
292 
293 	regmap_write(s->regmap, port->iobase + reg, val);
294 }
295 
296 static void max310x_port_update(struct uart_port *port, u8 reg, u8 mask, u8 val)
297 {
298 	struct max310x_port *s = dev_get_drvdata(port->dev);
299 
300 	regmap_update_bits(s->regmap, port->iobase + reg, mask, val);
301 }
302 
303 static int max3107_detect(struct device *dev)
304 {
305 	struct max310x_port *s = dev_get_drvdata(dev);
306 	unsigned int val = 0;
307 	int ret;
308 
309 	ret = regmap_read(s->regmap, MAX310X_REVID_REG, &val);
310 	if (ret)
311 		return ret;
312 
313 	if (((val & MAX310x_REV_MASK) != MAX3107_REV_ID)) {
314 		dev_err(dev,
315 			"%s ID 0x%02x does not match\n", s->devtype->name, val);
316 		return -ENODEV;
317 	}
318 
319 	return 0;
320 }
321 
322 static int max3108_detect(struct device *dev)
323 {
324 	struct max310x_port *s = dev_get_drvdata(dev);
325 	unsigned int val = 0;
326 	int ret;
327 
328 	/* MAX3108 have not REV ID register, we just check default value
329 	 * from clocksource register to make sure everything works.
330 	 */
331 	ret = regmap_read(s->regmap, MAX310X_CLKSRC_REG, &val);
332 	if (ret)
333 		return ret;
334 
335 	if (val != (MAX310X_CLKSRC_EXTCLK_BIT | MAX310X_CLKSRC_PLLBYP_BIT)) {
336 		dev_err(dev, "%s not present\n", s->devtype->name);
337 		return -ENODEV;
338 	}
339 
340 	return 0;
341 }
342 
343 static int max3109_detect(struct device *dev)
344 {
345 	struct max310x_port *s = dev_get_drvdata(dev);
346 	unsigned int val = 0;
347 	int ret;
348 
349 	ret = regmap_read(s->regmap, MAX310X_REVID_REG, &val);
350 	if (ret)
351 		return ret;
352 
353 	if (((val & MAX310x_REV_MASK) != MAX3109_REV_ID)) {
354 		dev_err(dev,
355 			"%s ID 0x%02x does not match\n", s->devtype->name, val);
356 		return -ENODEV;
357 	}
358 
359 	return 0;
360 }
361 
362 static void max310x_power(struct uart_port *port, int on)
363 {
364 	max310x_port_update(port, MAX310X_MODE1_REG,
365 			    MAX310X_MODE1_FORCESLEEP_BIT,
366 			    on ? 0 : MAX310X_MODE1_FORCESLEEP_BIT);
367 	if (on)
368 		msleep(50);
369 }
370 
371 static int max14830_detect(struct device *dev)
372 {
373 	struct max310x_port *s = dev_get_drvdata(dev);
374 	unsigned int val = 0;
375 	int ret;
376 
377 	ret = regmap_write(s->regmap, MAX310X_GLOBALCMD_REG,
378 			   MAX310X_EXTREG_ENBL);
379 	if (ret)
380 		return ret;
381 
382 	regmap_read(s->regmap, MAX310X_REVID_EXTREG, &val);
383 	regmap_write(s->regmap, MAX310X_GLOBALCMD_REG, MAX310X_EXTREG_DSBL);
384 	if (((val & MAX310x_REV_MASK) != MAX14830_REV_ID)) {
385 		dev_err(dev,
386 			"%s ID 0x%02x does not match\n", s->devtype->name, val);
387 		return -ENODEV;
388 	}
389 
390 	return 0;
391 }
392 
393 static void max14830_power(struct uart_port *port, int on)
394 {
395 	max310x_port_update(port, MAX310X_BRGCFG_REG,
396 			    MAX14830_BRGCFG_CLKDIS_BIT,
397 			    on ? 0 : MAX14830_BRGCFG_CLKDIS_BIT);
398 	if (on)
399 		msleep(50);
400 }
401 
402 static const struct max310x_devtype max3107_devtype = {
403 	.name	= "MAX3107",
404 	.nr	= 1,
405 	.detect	= max3107_detect,
406 	.power	= max310x_power,
407 };
408 
409 static const struct max310x_devtype max3108_devtype = {
410 	.name	= "MAX3108",
411 	.nr	= 1,
412 	.detect	= max3108_detect,
413 	.power	= max310x_power,
414 };
415 
416 static const struct max310x_devtype max3109_devtype = {
417 	.name	= "MAX3109",
418 	.nr	= 2,
419 	.detect	= max3109_detect,
420 	.power	= max310x_power,
421 };
422 
423 static const struct max310x_devtype max14830_devtype = {
424 	.name	= "MAX14830",
425 	.nr	= 4,
426 	.detect	= max14830_detect,
427 	.power	= max14830_power,
428 };
429 
430 static bool max310x_reg_writeable(struct device *dev, unsigned int reg)
431 {
432 	switch (reg & 0x1f) {
433 	case MAX310X_IRQSTS_REG:
434 	case MAX310X_LSR_IRQSTS_REG:
435 	case MAX310X_SPCHR_IRQSTS_REG:
436 	case MAX310X_STS_IRQSTS_REG:
437 	case MAX310X_TXFIFOLVL_REG:
438 	case MAX310X_RXFIFOLVL_REG:
439 		return false;
440 	default:
441 		break;
442 	}
443 
444 	return true;
445 }
446 
447 static bool max310x_reg_volatile(struct device *dev, unsigned int reg)
448 {
449 	switch (reg & 0x1f) {
450 	case MAX310X_RHR_REG:
451 	case MAX310X_IRQSTS_REG:
452 	case MAX310X_LSR_IRQSTS_REG:
453 	case MAX310X_SPCHR_IRQSTS_REG:
454 	case MAX310X_STS_IRQSTS_REG:
455 	case MAX310X_TXFIFOLVL_REG:
456 	case MAX310X_RXFIFOLVL_REG:
457 	case MAX310X_GPIODATA_REG:
458 	case MAX310X_BRGDIVLSB_REG:
459 	case MAX310X_REG_05:
460 	case MAX310X_REG_1F:
461 		return true;
462 	default:
463 		break;
464 	}
465 
466 	return false;
467 }
468 
469 static bool max310x_reg_precious(struct device *dev, unsigned int reg)
470 {
471 	switch (reg & 0x1f) {
472 	case MAX310X_RHR_REG:
473 	case MAX310X_IRQSTS_REG:
474 	case MAX310X_SPCHR_IRQSTS_REG:
475 	case MAX310X_STS_IRQSTS_REG:
476 		return true;
477 	default:
478 		break;
479 	}
480 
481 	return false;
482 }
483 
484 static int max310x_set_baud(struct uart_port *port, int baud)
485 {
486 	unsigned int mode = 0, clk = port->uartclk, div = clk / baud;
487 
488 	/* Check for minimal value for divider */
489 	if (div < 16)
490 		div = 16;
491 
492 	if (clk % baud && (div / 16) < 0x8000) {
493 		/* Mode x2 */
494 		mode = MAX310X_BRGCFG_2XMODE_BIT;
495 		clk = port->uartclk * 2;
496 		div = clk / baud;
497 
498 		if (clk % baud && (div / 16) < 0x8000) {
499 			/* Mode x4 */
500 			mode = MAX310X_BRGCFG_4XMODE_BIT;
501 			clk = port->uartclk * 4;
502 			div = clk / baud;
503 		}
504 	}
505 
506 	max310x_port_write(port, MAX310X_BRGDIVMSB_REG, (div / 16) >> 8);
507 	max310x_port_write(port, MAX310X_BRGDIVLSB_REG, div / 16);
508 	max310x_port_write(port, MAX310X_BRGCFG_REG, (div % 16) | mode);
509 
510 	return DIV_ROUND_CLOSEST(clk, div);
511 }
512 
513 static int max310x_update_best_err(unsigned long f, long *besterr)
514 {
515 	/* Use baudrate 115200 for calculate error */
516 	long err = f % (115200 * 16);
517 
518 	if ((*besterr < 0) || (*besterr > err)) {
519 		*besterr = err;
520 		return 0;
521 	}
522 
523 	return 1;
524 }
525 
526 static int max310x_set_ref_clk(struct max310x_port *s, unsigned long freq,
527 			       bool xtal)
528 {
529 	unsigned int div, clksrc, pllcfg = 0;
530 	long besterr = -1;
531 	unsigned long fdiv, fmul, bestfreq = freq;
532 
533 	/* First, update error without PLL */
534 	max310x_update_best_err(freq, &besterr);
535 
536 	/* Try all possible PLL dividers */
537 	for (div = 1; (div <= 63) && besterr; div++) {
538 		fdiv = DIV_ROUND_CLOSEST(freq, div);
539 
540 		/* Try multiplier 6 */
541 		fmul = fdiv * 6;
542 		if ((fdiv >= 500000) && (fdiv <= 800000))
543 			if (!max310x_update_best_err(fmul, &besterr)) {
544 				pllcfg = (0 << 6) | div;
545 				bestfreq = fmul;
546 			}
547 		/* Try multiplier 48 */
548 		fmul = fdiv * 48;
549 		if ((fdiv >= 850000) && (fdiv <= 1200000))
550 			if (!max310x_update_best_err(fmul, &besterr)) {
551 				pllcfg = (1 << 6) | div;
552 				bestfreq = fmul;
553 			}
554 		/* Try multiplier 96 */
555 		fmul = fdiv * 96;
556 		if ((fdiv >= 425000) && (fdiv <= 1000000))
557 			if (!max310x_update_best_err(fmul, &besterr)) {
558 				pllcfg = (2 << 6) | div;
559 				bestfreq = fmul;
560 			}
561 		/* Try multiplier 144 */
562 		fmul = fdiv * 144;
563 		if ((fdiv >= 390000) && (fdiv <= 667000))
564 			if (!max310x_update_best_err(fmul, &besterr)) {
565 				pllcfg = (3 << 6) | div;
566 				bestfreq = fmul;
567 			}
568 	}
569 
570 	/* Configure clock source */
571 	clksrc = xtal ? MAX310X_CLKSRC_CRYST_BIT : MAX310X_CLKSRC_EXTCLK_BIT;
572 
573 	/* Configure PLL */
574 	if (pllcfg) {
575 		clksrc |= MAX310X_CLKSRC_PLL_BIT;
576 		regmap_write(s->regmap, MAX310X_PLLCFG_REG, pllcfg);
577 	} else
578 		clksrc |= MAX310X_CLKSRC_PLLBYP_BIT;
579 
580 	regmap_write(s->regmap, MAX310X_CLKSRC_REG, clksrc);
581 
582 	/* Wait for crystal */
583 	if (pllcfg && xtal)
584 		msleep(10);
585 
586 	return (int)bestfreq;
587 }
588 
589 static void max310x_handle_rx(struct uart_port *port, unsigned int rxlen)
590 {
591 	unsigned int sts, ch, flag;
592 
593 	if (unlikely(rxlen >= port->fifosize)) {
594 		dev_warn_ratelimited(port->dev,
595 				     "Port %i: Possible RX FIFO overrun\n",
596 				     port->line);
597 		port->icount.buf_overrun++;
598 		/* Ensure sanity of RX level */
599 		rxlen = port->fifosize;
600 	}
601 
602 	while (rxlen--) {
603 		ch = max310x_port_read(port, MAX310X_RHR_REG);
604 		sts = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG);
605 
606 		sts &= MAX310X_LSR_RXPAR_BIT | MAX310X_LSR_FRERR_BIT |
607 		       MAX310X_LSR_RXOVR_BIT | MAX310X_LSR_RXBRK_BIT;
608 
609 		port->icount.rx++;
610 		flag = TTY_NORMAL;
611 
612 		if (unlikely(sts)) {
613 			if (sts & MAX310X_LSR_RXBRK_BIT) {
614 				port->icount.brk++;
615 				if (uart_handle_break(port))
616 					continue;
617 			} else if (sts & MAX310X_LSR_RXPAR_BIT)
618 				port->icount.parity++;
619 			else if (sts & MAX310X_LSR_FRERR_BIT)
620 				port->icount.frame++;
621 			else if (sts & MAX310X_LSR_RXOVR_BIT)
622 				port->icount.overrun++;
623 
624 			sts &= port->read_status_mask;
625 			if (sts & MAX310X_LSR_RXBRK_BIT)
626 				flag = TTY_BREAK;
627 			else if (sts & MAX310X_LSR_RXPAR_BIT)
628 				flag = TTY_PARITY;
629 			else if (sts & MAX310X_LSR_FRERR_BIT)
630 				flag = TTY_FRAME;
631 			else if (sts & MAX310X_LSR_RXOVR_BIT)
632 				flag = TTY_OVERRUN;
633 		}
634 
635 		if (uart_handle_sysrq_char(port, ch))
636 			continue;
637 
638 		if (sts & port->ignore_status_mask)
639 			continue;
640 
641 		uart_insert_char(port, sts, MAX310X_LSR_RXOVR_BIT, ch, flag);
642 	}
643 
644 	tty_flip_buffer_push(&port->state->port);
645 }
646 
647 static void max310x_handle_tx(struct uart_port *port)
648 {
649 	struct circ_buf *xmit = &port->state->xmit;
650 	unsigned int txlen, to_send;
651 
652 	if (unlikely(port->x_char)) {
653 		max310x_port_write(port, MAX310X_THR_REG, port->x_char);
654 		port->icount.tx++;
655 		port->x_char = 0;
656 		return;
657 	}
658 
659 	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
660 		return;
661 
662 	/* Get length of data pending in circular buffer */
663 	to_send = uart_circ_chars_pending(xmit);
664 	if (likely(to_send)) {
665 		/* Limit to size of TX FIFO */
666 		txlen = max310x_port_read(port, MAX310X_TXFIFOLVL_REG);
667 		txlen = port->fifosize - txlen;
668 		to_send = (to_send > txlen) ? txlen : to_send;
669 
670 		/* Add data to send */
671 		port->icount.tx += to_send;
672 		while (to_send--) {
673 			max310x_port_write(port, MAX310X_THR_REG,
674 					   xmit->buf[xmit->tail]);
675 			xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
676 		}
677 	}
678 
679 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
680 		uart_write_wakeup(port);
681 }
682 
683 static void max310x_port_irq(struct max310x_port *s, int portno)
684 {
685 	struct uart_port *port = &s->p[portno].port;
686 
687 	do {
688 		unsigned int ists, lsr, rxlen;
689 
690 		/* Read IRQ status & RX FIFO level */
691 		ists = max310x_port_read(port, MAX310X_IRQSTS_REG);
692 		rxlen = max310x_port_read(port, MAX310X_RXFIFOLVL_REG);
693 		if (!ists && !rxlen)
694 			break;
695 
696 		if (ists & MAX310X_IRQ_CTS_BIT) {
697 			lsr = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG);
698 			uart_handle_cts_change(port,
699 					       !!(lsr & MAX310X_LSR_CTS_BIT));
700 		}
701 		if (rxlen)
702 			max310x_handle_rx(port, rxlen);
703 		if (ists & MAX310X_IRQ_TXEMPTY_BIT) {
704 			mutex_lock(&s->mutex);
705 			max310x_handle_tx(port);
706 			mutex_unlock(&s->mutex);
707 		}
708 	} while (1);
709 }
710 
711 static irqreturn_t max310x_ist(int irq, void *dev_id)
712 {
713 	struct max310x_port *s = (struct max310x_port *)dev_id;
714 
715 	if (s->uart.nr > 1) {
716 		do {
717 			unsigned int val = ~0;
718 
719 			WARN_ON_ONCE(regmap_read(s->regmap,
720 						 MAX310X_GLOBALIRQ_REG, &val));
721 			val = ((1 << s->uart.nr) - 1) & ~val;
722 			if (!val)
723 				break;
724 			max310x_port_irq(s, fls(val) - 1);
725 		} while (1);
726 	} else
727 		max310x_port_irq(s, 0);
728 
729 	return IRQ_HANDLED;
730 }
731 
732 static void max310x_wq_proc(struct work_struct *ws)
733 {
734 	struct max310x_one *one = container_of(ws, struct max310x_one, tx_work);
735 	struct max310x_port *s = dev_get_drvdata(one->port.dev);
736 
737 	mutex_lock(&s->mutex);
738 	max310x_handle_tx(&one->port);
739 	mutex_unlock(&s->mutex);
740 }
741 
742 static void max310x_start_tx(struct uart_port *port)
743 {
744 	struct max310x_one *one = container_of(port, struct max310x_one, port);
745 
746 	if (!work_pending(&one->tx_work))
747 		schedule_work(&one->tx_work);
748 }
749 
750 static unsigned int max310x_tx_empty(struct uart_port *port)
751 {
752 	unsigned int lvl, sts;
753 
754 	lvl = max310x_port_read(port, MAX310X_TXFIFOLVL_REG);
755 	sts = max310x_port_read(port, MAX310X_IRQSTS_REG);
756 
757 	return ((sts & MAX310X_IRQ_TXEMPTY_BIT) && !lvl) ? TIOCSER_TEMT : 0;
758 }
759 
760 static unsigned int max310x_get_mctrl(struct uart_port *port)
761 {
762 	/* DCD and DSR are not wired and CTS/RTS is handled automatically
763 	 * so just indicate DSR and CAR asserted
764 	 */
765 	return TIOCM_DSR | TIOCM_CAR;
766 }
767 
768 static void max310x_md_proc(struct work_struct *ws)
769 {
770 	struct max310x_one *one = container_of(ws, struct max310x_one, md_work);
771 
772 	max310x_port_update(&one->port, MAX310X_MODE2_REG,
773 			    MAX310X_MODE2_LOOPBACK_BIT,
774 			    (one->port.mctrl & TIOCM_LOOP) ?
775 			    MAX310X_MODE2_LOOPBACK_BIT : 0);
776 }
777 
778 static void max310x_set_mctrl(struct uart_port *port, unsigned int mctrl)
779 {
780 	struct max310x_one *one = container_of(port, struct max310x_one, port);
781 
782 	schedule_work(&one->md_work);
783 }
784 
785 static void max310x_break_ctl(struct uart_port *port, int break_state)
786 {
787 	max310x_port_update(port, MAX310X_LCR_REG,
788 			    MAX310X_LCR_TXBREAK_BIT,
789 			    break_state ? MAX310X_LCR_TXBREAK_BIT : 0);
790 }
791 
792 static void max310x_set_termios(struct uart_port *port,
793 				struct ktermios *termios,
794 				struct ktermios *old)
795 {
796 	unsigned int lcr, flow = 0;
797 	int baud;
798 
799 	/* Mask termios capabilities we don't support */
800 	termios->c_cflag &= ~CMSPAR;
801 
802 	/* Word size */
803 	switch (termios->c_cflag & CSIZE) {
804 	case CS5:
805 		lcr = MAX310X_LCR_WORD_LEN_5;
806 		break;
807 	case CS6:
808 		lcr = MAX310X_LCR_WORD_LEN_6;
809 		break;
810 	case CS7:
811 		lcr = MAX310X_LCR_WORD_LEN_7;
812 		break;
813 	case CS8:
814 	default:
815 		lcr = MAX310X_LCR_WORD_LEN_8;
816 		break;
817 	}
818 
819 	/* Parity */
820 	if (termios->c_cflag & PARENB) {
821 		lcr |= MAX310X_LCR_PARITY_BIT;
822 		if (!(termios->c_cflag & PARODD))
823 			lcr |= MAX310X_LCR_EVENPARITY_BIT;
824 	}
825 
826 	/* Stop bits */
827 	if (termios->c_cflag & CSTOPB)
828 		lcr |= MAX310X_LCR_STOPLEN_BIT; /* 2 stops */
829 
830 	/* Update LCR register */
831 	max310x_port_write(port, MAX310X_LCR_REG, lcr);
832 
833 	/* Set read status mask */
834 	port->read_status_mask = MAX310X_LSR_RXOVR_BIT;
835 	if (termios->c_iflag & INPCK)
836 		port->read_status_mask |= MAX310X_LSR_RXPAR_BIT |
837 					  MAX310X_LSR_FRERR_BIT;
838 	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
839 		port->read_status_mask |= MAX310X_LSR_RXBRK_BIT;
840 
841 	/* Set status ignore mask */
842 	port->ignore_status_mask = 0;
843 	if (termios->c_iflag & IGNBRK)
844 		port->ignore_status_mask |= MAX310X_LSR_RXBRK_BIT;
845 	if (!(termios->c_cflag & CREAD))
846 		port->ignore_status_mask |= MAX310X_LSR_RXPAR_BIT |
847 					    MAX310X_LSR_RXOVR_BIT |
848 					    MAX310X_LSR_FRERR_BIT |
849 					    MAX310X_LSR_RXBRK_BIT;
850 
851 	/* Configure flow control */
852 	max310x_port_write(port, MAX310X_XON1_REG, termios->c_cc[VSTART]);
853 	max310x_port_write(port, MAX310X_XOFF1_REG, termios->c_cc[VSTOP]);
854 	if (termios->c_cflag & CRTSCTS)
855 		flow |= MAX310X_FLOWCTRL_AUTOCTS_BIT |
856 			MAX310X_FLOWCTRL_AUTORTS_BIT;
857 	if (termios->c_iflag & IXON)
858 		flow |= MAX310X_FLOWCTRL_SWFLOW3_BIT |
859 			MAX310X_FLOWCTRL_SWFLOWEN_BIT;
860 	if (termios->c_iflag & IXOFF)
861 		flow |= MAX310X_FLOWCTRL_SWFLOW1_BIT |
862 			MAX310X_FLOWCTRL_SWFLOWEN_BIT;
863 	max310x_port_write(port, MAX310X_FLOWCTRL_REG, flow);
864 
865 	/* Get baud rate generator configuration */
866 	baud = uart_get_baud_rate(port, termios, old,
867 				  port->uartclk / 16 / 0xffff,
868 				  port->uartclk / 4);
869 
870 	/* Setup baudrate generator */
871 	baud = max310x_set_baud(port, baud);
872 
873 	/* Update timeout according to new baud rate */
874 	uart_update_timeout(port, termios->c_cflag, baud);
875 }
876 
877 static int max310x_ioctl(struct uart_port *port, unsigned int cmd,
878 			 unsigned long arg)
879 {
880 #if defined(TIOCSRS485) && defined(TIOCGRS485)
881 	struct serial_rs485 rs485;
882 	unsigned int val;
883 
884 	switch (cmd) {
885 	case TIOCSRS485:
886 		if (copy_from_user(&rs485, (void __user *)arg, sizeof(rs485)))
887 			return -EFAULT;
888 		if (rs485.delay_rts_before_send > 0x0f ||
889 		    rs485.delay_rts_after_send > 0x0f)
890 			return -ERANGE;
891 		val = (rs485.delay_rts_before_send << 4) |
892 		      rs485.delay_rts_after_send;
893 		max310x_port_write(port, MAX310X_HDPIXDELAY_REG, val);
894 		if (rs485.flags & SER_RS485_ENABLED) {
895 			max310x_port_update(port, MAX310X_MODE1_REG,
896 					    MAX310X_MODE1_TRNSCVCTRL_BIT,
897 					    MAX310X_MODE1_TRNSCVCTRL_BIT);
898 			max310x_port_update(port, MAX310X_MODE2_REG,
899 					    MAX310X_MODE2_ECHOSUPR_BIT,
900 					    MAX310X_MODE2_ECHOSUPR_BIT);
901 		} else {
902 			max310x_port_update(port, MAX310X_MODE1_REG,
903 					    MAX310X_MODE1_TRNSCVCTRL_BIT, 0);
904 			max310x_port_update(port, MAX310X_MODE2_REG,
905 					    MAX310X_MODE2_ECHOSUPR_BIT, 0);
906 		}
907 		return 0;
908 	case TIOCGRS485:
909 		memset(&rs485, 0, sizeof(rs485));
910 		val = max310x_port_read(port, MAX310X_MODE1_REG);
911 		rs485.flags = (val & MAX310X_MODE1_TRNSCVCTRL_BIT) ?
912 			      SER_RS485_ENABLED : 0;
913 		rs485.flags |= SER_RS485_RTS_ON_SEND;
914 		val = max310x_port_read(port, MAX310X_HDPIXDELAY_REG);
915 		rs485.delay_rts_before_send = val >> 4;
916 		rs485.delay_rts_after_send = val & 0x0f;
917 		if (copy_to_user((void __user *)arg, &rs485, sizeof(rs485)))
918 			return -EFAULT;
919 		return 0;
920 	default:
921 		break;
922 	}
923 #endif
924 
925 	return -ENOIOCTLCMD;
926 }
927 
928 static int max310x_startup(struct uart_port *port)
929 {
930 	struct max310x_port *s = dev_get_drvdata(port->dev);
931 	unsigned int val;
932 
933 	s->devtype->power(port, 1);
934 
935 	/* Configure MODE1 register */
936 	max310x_port_update(port, MAX310X_MODE1_REG,
937 			    MAX310X_MODE1_TRNSCVCTRL_BIT, 0);
938 
939 	/* Configure MODE2 register & Reset FIFOs*/
940 	val = MAX310X_MODE2_RXEMPTINV_BIT | MAX310X_MODE2_FIFORST_BIT;
941 	max310x_port_write(port, MAX310X_MODE2_REG, val);
942 	max310x_port_update(port, MAX310X_MODE2_REG,
943 			    MAX310X_MODE2_FIFORST_BIT, 0);
944 
945 	/* Configure flow control levels */
946 	/* Flow control halt level 96, resume level 48 */
947 	max310x_port_write(port, MAX310X_FLOWLVL_REG,
948 			   MAX310X_FLOWLVL_RES(48) | MAX310X_FLOWLVL_HALT(96));
949 
950 	/* Clear IRQ status register */
951 	max310x_port_read(port, MAX310X_IRQSTS_REG);
952 
953 	/* Enable RX, TX, CTS change interrupts */
954 	val = MAX310X_IRQ_RXEMPTY_BIT | MAX310X_IRQ_TXEMPTY_BIT;
955 	max310x_port_write(port, MAX310X_IRQEN_REG, val | MAX310X_IRQ_CTS_BIT);
956 
957 	return 0;
958 }
959 
960 static void max310x_shutdown(struct uart_port *port)
961 {
962 	struct max310x_port *s = dev_get_drvdata(port->dev);
963 
964 	/* Disable all interrupts */
965 	max310x_port_write(port, MAX310X_IRQEN_REG, 0);
966 
967 	s->devtype->power(port, 0);
968 }
969 
970 static const char *max310x_type(struct uart_port *port)
971 {
972 	struct max310x_port *s = dev_get_drvdata(port->dev);
973 
974 	return (port->type == PORT_MAX310X) ? s->devtype->name : NULL;
975 }
976 
977 static int max310x_request_port(struct uart_port *port)
978 {
979 	/* Do nothing */
980 	return 0;
981 }
982 
983 static void max310x_config_port(struct uart_port *port, int flags)
984 {
985 	if (flags & UART_CONFIG_TYPE)
986 		port->type = PORT_MAX310X;
987 }
988 
989 static int max310x_verify_port(struct uart_port *port, struct serial_struct *s)
990 {
991 	if ((s->type != PORT_UNKNOWN) && (s->type != PORT_MAX310X))
992 		return -EINVAL;
993 	if (s->irq != port->irq)
994 		return -EINVAL;
995 
996 	return 0;
997 }
998 
999 static void max310x_null_void(struct uart_port *port)
1000 {
1001 	/* Do nothing */
1002 }
1003 
1004 static const struct uart_ops max310x_ops = {
1005 	.tx_empty	= max310x_tx_empty,
1006 	.set_mctrl	= max310x_set_mctrl,
1007 	.get_mctrl	= max310x_get_mctrl,
1008 	.stop_tx	= max310x_null_void,
1009 	.start_tx	= max310x_start_tx,
1010 	.stop_rx	= max310x_null_void,
1011 	.enable_ms	= max310x_null_void,
1012 	.break_ctl	= max310x_break_ctl,
1013 	.startup	= max310x_startup,
1014 	.shutdown	= max310x_shutdown,
1015 	.set_termios	= max310x_set_termios,
1016 	.type		= max310x_type,
1017 	.request_port	= max310x_request_port,
1018 	.release_port	= max310x_null_void,
1019 	.config_port	= max310x_config_port,
1020 	.verify_port	= max310x_verify_port,
1021 	.ioctl		= max310x_ioctl,
1022 };
1023 
1024 static int __maybe_unused max310x_suspend(struct device *dev)
1025 {
1026 	struct max310x_port *s = dev_get_drvdata(dev);
1027 	int i;
1028 
1029 	for (i = 0; i < s->uart.nr; i++) {
1030 		uart_suspend_port(&s->uart, &s->p[i].port);
1031 		s->devtype->power(&s->p[i].port, 0);
1032 	}
1033 
1034 	return 0;
1035 }
1036 
1037 static int __maybe_unused max310x_resume(struct device *dev)
1038 {
1039 	struct max310x_port *s = dev_get_drvdata(dev);
1040 	int i;
1041 
1042 	for (i = 0; i < s->uart.nr; i++) {
1043 		s->devtype->power(&s->p[i].port, 1);
1044 		uart_resume_port(&s->uart, &s->p[i].port);
1045 	}
1046 
1047 	return 0;
1048 }
1049 
1050 static SIMPLE_DEV_PM_OPS(max310x_pm_ops, max310x_suspend, max310x_resume);
1051 
1052 #ifdef CONFIG_GPIOLIB
1053 static int max310x_gpio_get(struct gpio_chip *chip, unsigned offset)
1054 {
1055 	unsigned int val;
1056 	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
1057 	struct uart_port *port = &s->p[offset / 4].port;
1058 
1059 	val = max310x_port_read(port, MAX310X_GPIODATA_REG);
1060 
1061 	return !!((val >> 4) & (1 << (offset % 4)));
1062 }
1063 
1064 static void max310x_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
1065 {
1066 	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
1067 	struct uart_port *port = &s->p[offset / 4].port;
1068 
1069 	max310x_port_update(port, MAX310X_GPIODATA_REG, 1 << (offset % 4),
1070 			    value ? 1 << (offset % 4) : 0);
1071 }
1072 
1073 static int max310x_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
1074 {
1075 	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
1076 	struct uart_port *port = &s->p[offset / 4].port;
1077 
1078 	max310x_port_update(port, MAX310X_GPIOCFG_REG, 1 << (offset % 4), 0);
1079 
1080 	return 0;
1081 }
1082 
1083 static int max310x_gpio_direction_output(struct gpio_chip *chip,
1084 					 unsigned offset, int value)
1085 {
1086 	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
1087 	struct uart_port *port = &s->p[offset / 4].port;
1088 
1089 	max310x_port_update(port, MAX310X_GPIODATA_REG, 1 << (offset % 4),
1090 			    value ? 1 << (offset % 4) : 0);
1091 	max310x_port_update(port, MAX310X_GPIOCFG_REG, 1 << (offset % 4),
1092 			    1 << (offset % 4));
1093 
1094 	return 0;
1095 }
1096 #endif
1097 
1098 static int max310x_probe(struct device *dev, struct max310x_devtype *devtype,
1099 			 struct regmap *regmap, int irq, unsigned long flags)
1100 {
1101 	int i, ret, fmin, fmax, freq, uartclk;
1102 	struct clk *clk_osc, *clk_xtal;
1103 	struct max310x_port *s;
1104 	bool xtal = false;
1105 
1106 	if (IS_ERR(regmap))
1107 		return PTR_ERR(regmap);
1108 
1109 	/* Alloc port structure */
1110 	s = devm_kzalloc(dev, sizeof(*s) +
1111 			 sizeof(struct max310x_one) * devtype->nr, GFP_KERNEL);
1112 	if (!s) {
1113 		dev_err(dev, "Error allocating port structure\n");
1114 		return -ENOMEM;
1115 	}
1116 
1117 	clk_osc = devm_clk_get(dev, "osc");
1118 	clk_xtal = devm_clk_get(dev, "xtal");
1119 	if (!IS_ERR(clk_osc)) {
1120 		s->clk = clk_osc;
1121 		fmin = 500000;
1122 		fmax = 35000000;
1123 	} else if (!IS_ERR(clk_xtal)) {
1124 		s->clk = clk_xtal;
1125 		fmin = 1000000;
1126 		fmax = 4000000;
1127 		xtal = true;
1128 	} else if (PTR_ERR(clk_osc) == -EPROBE_DEFER ||
1129 		   PTR_ERR(clk_xtal) == -EPROBE_DEFER) {
1130 		return -EPROBE_DEFER;
1131 	} else {
1132 		dev_err(dev, "Cannot get clock\n");
1133 		return -EINVAL;
1134 	}
1135 
1136 	ret = clk_prepare_enable(s->clk);
1137 	if (ret)
1138 		return ret;
1139 
1140 	freq = clk_get_rate(s->clk);
1141 	/* Check frequency limits */
1142 	if (freq < fmin || freq > fmax) {
1143 		ret = -ERANGE;
1144 		goto out_clk;
1145 	}
1146 
1147 	s->regmap = regmap;
1148 	s->devtype = devtype;
1149 	dev_set_drvdata(dev, s);
1150 
1151 	/* Check device to ensure we are talking to what we expect */
1152 	ret = devtype->detect(dev);
1153 	if (ret)
1154 		goto out_clk;
1155 
1156 	for (i = 0; i < devtype->nr; i++) {
1157 		unsigned int offs = i << 5;
1158 
1159 		/* Reset port */
1160 		regmap_write(s->regmap, MAX310X_MODE2_REG + offs,
1161 			     MAX310X_MODE2_RST_BIT);
1162 		/* Clear port reset */
1163 		regmap_write(s->regmap, MAX310X_MODE2_REG + offs, 0);
1164 
1165 		/* Wait for port startup */
1166 		do {
1167 			regmap_read(s->regmap,
1168 				    MAX310X_BRGDIVLSB_REG + offs, &ret);
1169 		} while (ret != 0x01);
1170 
1171 		regmap_update_bits(s->regmap, MAX310X_MODE1_REG + offs,
1172 				   MAX310X_MODE1_AUTOSLEEP_BIT,
1173 				   MAX310X_MODE1_AUTOSLEEP_BIT);
1174 	}
1175 
1176 	uartclk = max310x_set_ref_clk(s, freq, xtal);
1177 	dev_dbg(dev, "Reference clock set to %i Hz\n", uartclk);
1178 
1179 	/* Register UART driver */
1180 	s->uart.owner		= THIS_MODULE;
1181 	s->uart.dev_name	= "ttyMAX";
1182 	s->uart.major		= MAX310X_MAJOR;
1183 	s->uart.minor		= MAX310X_MINOR;
1184 	s->uart.nr		= devtype->nr;
1185 	ret = uart_register_driver(&s->uart);
1186 	if (ret) {
1187 		dev_err(dev, "Registering UART driver failed\n");
1188 		goto out_clk;
1189 	}
1190 
1191 #ifdef CONFIG_GPIOLIB
1192 	/* Setup GPIO cotroller */
1193 	s->gpio.owner		= THIS_MODULE;
1194 	s->gpio.dev		= dev;
1195 	s->gpio.label		= dev_name(dev);
1196 	s->gpio.direction_input	= max310x_gpio_direction_input;
1197 	s->gpio.get		= max310x_gpio_get;
1198 	s->gpio.direction_output= max310x_gpio_direction_output;
1199 	s->gpio.set		= max310x_gpio_set;
1200 	s->gpio.base		= -1;
1201 	s->gpio.ngpio		= devtype->nr * 4;
1202 	s->gpio.can_sleep	= 1;
1203 	ret = gpiochip_add(&s->gpio);
1204 	if (ret)
1205 		goto out_uart;
1206 #endif
1207 
1208 	mutex_init(&s->mutex);
1209 
1210 	for (i = 0; i < devtype->nr; i++) {
1211 		/* Initialize port data */
1212 		s->p[i].port.line	= i;
1213 		s->p[i].port.dev	= dev;
1214 		s->p[i].port.irq	= irq;
1215 		s->p[i].port.type	= PORT_MAX310X;
1216 		s->p[i].port.fifosize	= MAX310X_FIFO_SIZE;
1217 		s->p[i].port.flags	= UPF_FIXED_TYPE | UPF_LOW_LATENCY;
1218 		s->p[i].port.iotype	= UPIO_PORT;
1219 		s->p[i].port.iobase	= i * 0x20;
1220 		s->p[i].port.membase	= (void __iomem *)~0;
1221 		s->p[i].port.uartclk	= uartclk;
1222 		s->p[i].port.ops	= &max310x_ops;
1223 		/* Disable all interrupts */
1224 		max310x_port_write(&s->p[i].port, MAX310X_IRQEN_REG, 0);
1225 		/* Clear IRQ status register */
1226 		max310x_port_read(&s->p[i].port, MAX310X_IRQSTS_REG);
1227 		/* Enable IRQ pin */
1228 		max310x_port_update(&s->p[i].port, MAX310X_MODE1_REG,
1229 				    MAX310X_MODE1_IRQSEL_BIT,
1230 				    MAX310X_MODE1_IRQSEL_BIT);
1231 		/* Initialize queue for start TX */
1232 		INIT_WORK(&s->p[i].tx_work, max310x_wq_proc);
1233 		/* Initialize queue for changing mode */
1234 		INIT_WORK(&s->p[i].md_work, max310x_md_proc);
1235 		/* Register port */
1236 		uart_add_one_port(&s->uart, &s->p[i].port);
1237 		/* Go to suspend mode */
1238 		devtype->power(&s->p[i].port, 0);
1239 	}
1240 
1241 	/* Setup interrupt */
1242 	ret = devm_request_threaded_irq(dev, irq, NULL, max310x_ist,
1243 					IRQF_ONESHOT | flags, dev_name(dev), s);
1244 	if (!ret)
1245 		return 0;
1246 
1247 	dev_err(dev, "Unable to reguest IRQ %i\n", irq);
1248 
1249 	mutex_destroy(&s->mutex);
1250 
1251 #ifdef CONFIG_GPIOLIB
1252 	WARN_ON(gpiochip_remove(&s->gpio));
1253 
1254 out_uart:
1255 #endif
1256 	uart_unregister_driver(&s->uart);
1257 
1258 out_clk:
1259 	clk_disable_unprepare(s->clk);
1260 
1261 	return ret;
1262 }
1263 
1264 static int max310x_remove(struct device *dev)
1265 {
1266 	struct max310x_port *s = dev_get_drvdata(dev);
1267 	int i, ret = 0;
1268 
1269 #ifdef CONFIG_GPIOLIB
1270 	ret = gpiochip_remove(&s->gpio);
1271 	if (ret)
1272 		return ret;
1273 #endif
1274 
1275 	for (i = 0; i < s->uart.nr; i++) {
1276 		cancel_work_sync(&s->p[i].tx_work);
1277 		cancel_work_sync(&s->p[i].md_work);
1278 		uart_remove_one_port(&s->uart, &s->p[i].port);
1279 		s->devtype->power(&s->p[i].port, 0);
1280 	}
1281 
1282 	mutex_destroy(&s->mutex);
1283 	uart_unregister_driver(&s->uart);
1284 	clk_disable_unprepare(s->clk);
1285 
1286 	return ret;
1287 }
1288 
1289 static const struct of_device_id __maybe_unused max310x_dt_ids[] = {
1290 	{ .compatible = "maxim,max3107",	.data = &max3107_devtype, },
1291 	{ .compatible = "maxim,max3108",	.data = &max3108_devtype, },
1292 	{ .compatible = "maxim,max3109",	.data = &max3109_devtype, },
1293 	{ .compatible = "maxim,max14830",	.data = &max14830_devtype },
1294 	{ }
1295 };
1296 MODULE_DEVICE_TABLE(of, max310x_dt_ids);
1297 
1298 static struct regmap_config regcfg = {
1299 	.reg_bits = 8,
1300 	.val_bits = 8,
1301 	.write_flag_mask = 0x80,
1302 	.cache_type = REGCACHE_RBTREE,
1303 	.writeable_reg = max310x_reg_writeable,
1304 	.volatile_reg = max310x_reg_volatile,
1305 	.precious_reg = max310x_reg_precious,
1306 };
1307 
1308 #ifdef CONFIG_SPI_MASTER
1309 static int max310x_spi_probe(struct spi_device *spi)
1310 {
1311 	struct max310x_devtype *devtype;
1312 	unsigned long flags = 0;
1313 	struct regmap *regmap;
1314 	int ret;
1315 
1316 	/* Setup SPI bus */
1317 	spi->bits_per_word	= 8;
1318 	spi->mode		= spi->mode ? : SPI_MODE_0;
1319 	spi->max_speed_hz	= spi->max_speed_hz ? : 26000000;
1320 	ret = spi_setup(spi);
1321 	if (ret)
1322 		return ret;
1323 
1324 	if (spi->dev.of_node) {
1325 		const struct of_device_id *of_id =
1326 			of_match_device(max310x_dt_ids, &spi->dev);
1327 
1328 		devtype = (struct max310x_devtype *)of_id->data;
1329 	} else {
1330 		const struct spi_device_id *id_entry = spi_get_device_id(spi);
1331 
1332 		devtype = (struct max310x_devtype *)id_entry->driver_data;
1333 		flags = IRQF_TRIGGER_FALLING;
1334 	}
1335 
1336 	regcfg.max_register = devtype->nr * 0x20 - 1;
1337 	regmap = devm_regmap_init_spi(spi, &regcfg);
1338 
1339 	return max310x_probe(&spi->dev, devtype, regmap, spi->irq, flags);
1340 }
1341 
1342 static int max310x_spi_remove(struct spi_device *spi)
1343 {
1344 	return max310x_remove(&spi->dev);
1345 }
1346 
1347 static const struct spi_device_id max310x_id_table[] = {
1348 	{ "max3107",	(kernel_ulong_t)&max3107_devtype, },
1349 	{ "max3108",	(kernel_ulong_t)&max3108_devtype, },
1350 	{ "max3109",	(kernel_ulong_t)&max3109_devtype, },
1351 	{ "max14830",	(kernel_ulong_t)&max14830_devtype, },
1352 	{ }
1353 };
1354 MODULE_DEVICE_TABLE(spi, max310x_id_table);
1355 
1356 static struct spi_driver max310x_uart_driver = {
1357 	.driver = {
1358 		.name		= MAX310X_NAME,
1359 		.owner		= THIS_MODULE,
1360 		.of_match_table	= of_match_ptr(max310x_dt_ids),
1361 		.pm		= &max310x_pm_ops,
1362 	},
1363 	.probe		= max310x_spi_probe,
1364 	.remove		= max310x_spi_remove,
1365 	.id_table	= max310x_id_table,
1366 };
1367 module_spi_driver(max310x_uart_driver);
1368 #endif
1369 
1370 MODULE_LICENSE("GPL");
1371 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
1372 MODULE_DESCRIPTION("MAX310X serial driver");
1373