xref: /openbmc/linux/drivers/tty/serial/max310x.c (revision bc000245)
1 /*
2  *  Maxim (Dallas) MAX3107/8/9, MAX14830 serial driver
3  *
4  *  Copyright (C) 2012-2013 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/module.h>
17 #include <linux/delay.h>
18 #include <linux/device.h>
19 #include <linux/bitops.h>
20 #include <linux/serial_core.h>
21 #include <linux/serial.h>
22 #include <linux/tty.h>
23 #include <linux/tty_flip.h>
24 #include <linux/regmap.h>
25 #include <linux/gpio.h>
26 #include <linux/spi/spi.h>
27 
28 #include <linux/platform_data/max310x.h>
29 
30 #define MAX310X_NAME			"max310x"
31 #define MAX310X_MAJOR			204
32 #define MAX310X_MINOR			209
33 
34 /* MAX310X register definitions */
35 #define MAX310X_RHR_REG			(0x00) /* RX FIFO */
36 #define MAX310X_THR_REG			(0x00) /* TX FIFO */
37 #define MAX310X_IRQEN_REG		(0x01) /* IRQ enable */
38 #define MAX310X_IRQSTS_REG		(0x02) /* IRQ status */
39 #define MAX310X_LSR_IRQEN_REG		(0x03) /* LSR IRQ enable */
40 #define MAX310X_LSR_IRQSTS_REG		(0x04) /* LSR IRQ status */
41 #define MAX310X_REG_05			(0x05)
42 #define MAX310X_SPCHR_IRQEN_REG		MAX310X_REG_05 /* Special char IRQ en */
43 #define MAX310X_SPCHR_IRQSTS_REG	(0x06) /* Special char IRQ status */
44 #define MAX310X_STS_IRQEN_REG		(0x07) /* Status IRQ enable */
45 #define MAX310X_STS_IRQSTS_REG		(0x08) /* Status IRQ status */
46 #define MAX310X_MODE1_REG		(0x09) /* MODE1 */
47 #define MAX310X_MODE2_REG		(0x0a) /* MODE2 */
48 #define MAX310X_LCR_REG			(0x0b) /* LCR */
49 #define MAX310X_RXTO_REG		(0x0c) /* RX timeout */
50 #define MAX310X_HDPIXDELAY_REG		(0x0d) /* Auto transceiver delays */
51 #define MAX310X_IRDA_REG		(0x0e) /* IRDA settings */
52 #define MAX310X_FLOWLVL_REG		(0x0f) /* Flow control levels */
53 #define MAX310X_FIFOTRIGLVL_REG		(0x10) /* FIFO IRQ trigger levels */
54 #define MAX310X_TXFIFOLVL_REG		(0x11) /* TX FIFO level */
55 #define MAX310X_RXFIFOLVL_REG		(0x12) /* RX FIFO level */
56 #define MAX310X_FLOWCTRL_REG		(0x13) /* Flow control */
57 #define MAX310X_XON1_REG		(0x14) /* XON1 character */
58 #define MAX310X_XON2_REG		(0x15) /* XON2 character */
59 #define MAX310X_XOFF1_REG		(0x16) /* XOFF1 character */
60 #define MAX310X_XOFF2_REG		(0x17) /* XOFF2 character */
61 #define MAX310X_GPIOCFG_REG		(0x18) /* GPIO config */
62 #define MAX310X_GPIODATA_REG		(0x19) /* GPIO data */
63 #define MAX310X_PLLCFG_REG		(0x1a) /* PLL config */
64 #define MAX310X_BRGCFG_REG		(0x1b) /* Baud rate generator conf */
65 #define MAX310X_BRGDIVLSB_REG		(0x1c) /* Baud rate divisor LSB */
66 #define MAX310X_BRGDIVMSB_REG		(0x1d) /* Baud rate divisor MSB */
67 #define MAX310X_CLKSRC_REG		(0x1e) /* Clock source */
68 #define MAX310X_REG_1F			(0x1f)
69 
70 #define MAX310X_REVID_REG		MAX310X_REG_1F /* Revision ID */
71 
72 #define MAX310X_GLOBALIRQ_REG		MAX310X_REG_1F /* Global IRQ (RO) */
73 #define MAX310X_GLOBALCMD_REG		MAX310X_REG_1F /* Global Command (WO) */
74 
75 /* Extended registers */
76 #define MAX310X_REVID_EXTREG		MAX310X_REG_05 /* Revision ID */
77 
78 /* IRQ register bits */
79 #define MAX310X_IRQ_LSR_BIT		(1 << 0) /* LSR interrupt */
80 #define MAX310X_IRQ_SPCHR_BIT		(1 << 1) /* Special char interrupt */
81 #define MAX310X_IRQ_STS_BIT		(1 << 2) /* Status interrupt */
82 #define MAX310X_IRQ_RXFIFO_BIT		(1 << 3) /* RX FIFO interrupt */
83 #define MAX310X_IRQ_TXFIFO_BIT		(1 << 4) /* TX FIFO interrupt */
84 #define MAX310X_IRQ_TXEMPTY_BIT		(1 << 5) /* TX FIFO empty interrupt */
85 #define MAX310X_IRQ_RXEMPTY_BIT		(1 << 6) /* RX FIFO empty interrupt */
86 #define MAX310X_IRQ_CTS_BIT		(1 << 7) /* CTS interrupt */
87 
88 /* LSR register bits */
89 #define MAX310X_LSR_RXTO_BIT		(1 << 0) /* RX timeout */
90 #define MAX310X_LSR_RXOVR_BIT		(1 << 1) /* RX overrun */
91 #define MAX310X_LSR_RXPAR_BIT		(1 << 2) /* RX parity error */
92 #define MAX310X_LSR_FRERR_BIT		(1 << 3) /* Frame error */
93 #define MAX310X_LSR_RXBRK_BIT		(1 << 4) /* RX break */
94 #define MAX310X_LSR_RXNOISE_BIT		(1 << 5) /* RX noise */
95 #define MAX310X_LSR_CTS_BIT		(1 << 7) /* CTS pin state */
96 
97 /* Special character register bits */
98 #define MAX310X_SPCHR_XON1_BIT		(1 << 0) /* XON1 character */
99 #define MAX310X_SPCHR_XON2_BIT		(1 << 1) /* XON2 character */
100 #define MAX310X_SPCHR_XOFF1_BIT		(1 << 2) /* XOFF1 character */
101 #define MAX310X_SPCHR_XOFF2_BIT		(1 << 3) /* XOFF2 character */
102 #define MAX310X_SPCHR_BREAK_BIT		(1 << 4) /* RX break */
103 #define MAX310X_SPCHR_MULTIDROP_BIT	(1 << 5) /* 9-bit multidrop addr char */
104 
105 /* Status register bits */
106 #define MAX310X_STS_GPIO0_BIT		(1 << 0) /* GPIO 0 interrupt */
107 #define MAX310X_STS_GPIO1_BIT		(1 << 1) /* GPIO 1 interrupt */
108 #define MAX310X_STS_GPIO2_BIT		(1 << 2) /* GPIO 2 interrupt */
109 #define MAX310X_STS_GPIO3_BIT		(1 << 3) /* GPIO 3 interrupt */
110 #define MAX310X_STS_CLKREADY_BIT	(1 << 5) /* Clock ready */
111 #define MAX310X_STS_SLEEP_BIT		(1 << 6) /* Sleep interrupt */
112 
113 /* MODE1 register bits */
114 #define MAX310X_MODE1_RXDIS_BIT		(1 << 0) /* RX disable */
115 #define MAX310X_MODE1_TXDIS_BIT		(1 << 1) /* TX disable */
116 #define MAX310X_MODE1_TXHIZ_BIT		(1 << 2) /* TX pin three-state */
117 #define MAX310X_MODE1_RTSHIZ_BIT	(1 << 3) /* RTS pin three-state */
118 #define MAX310X_MODE1_TRNSCVCTRL_BIT	(1 << 4) /* Transceiver ctrl enable */
119 #define MAX310X_MODE1_FORCESLEEP_BIT	(1 << 5) /* Force sleep mode */
120 #define MAX310X_MODE1_AUTOSLEEP_BIT	(1 << 6) /* Auto sleep enable */
121 #define MAX310X_MODE1_IRQSEL_BIT	(1 << 7) /* IRQ pin enable */
122 
123 /* MODE2 register bits */
124 #define MAX310X_MODE2_RST_BIT		(1 << 0) /* Chip reset */
125 #define MAX310X_MODE2_FIFORST_BIT	(1 << 1) /* FIFO reset */
126 #define MAX310X_MODE2_RXTRIGINV_BIT	(1 << 2) /* RX FIFO INT invert */
127 #define MAX310X_MODE2_RXEMPTINV_BIT	(1 << 3) /* RX FIFO empty INT invert */
128 #define MAX310X_MODE2_SPCHR_BIT		(1 << 4) /* Special chr detect enable */
129 #define MAX310X_MODE2_LOOPBACK_BIT	(1 << 5) /* Internal loopback enable */
130 #define MAX310X_MODE2_MULTIDROP_BIT	(1 << 6) /* 9-bit multidrop enable */
131 #define MAX310X_MODE2_ECHOSUPR_BIT	(1 << 7) /* ECHO suppression enable */
132 
133 /* LCR register bits */
134 #define MAX310X_LCR_LENGTH0_BIT		(1 << 0) /* Word length bit 0 */
135 #define MAX310X_LCR_LENGTH1_BIT		(1 << 1) /* Word length bit 1
136 						  *
137 						  * Word length bits table:
138 						  * 00 -> 5 bit words
139 						  * 01 -> 6 bit words
140 						  * 10 -> 7 bit words
141 						  * 11 -> 8 bit words
142 						  */
143 #define MAX310X_LCR_STOPLEN_BIT		(1 << 2) /* STOP length bit
144 						  *
145 						  * STOP length bit table:
146 						  * 0 -> 1 stop bit
147 						  * 1 -> 1-1.5 stop bits if
148 						  *      word length is 5,
149 						  *      2 stop bits otherwise
150 						  */
151 #define MAX310X_LCR_PARITY_BIT		(1 << 3) /* Parity bit enable */
152 #define MAX310X_LCR_EVENPARITY_BIT	(1 << 4) /* Even parity bit enable */
153 #define MAX310X_LCR_FORCEPARITY_BIT	(1 << 5) /* 9-bit multidrop parity */
154 #define MAX310X_LCR_TXBREAK_BIT		(1 << 6) /* TX break enable */
155 #define MAX310X_LCR_RTS_BIT		(1 << 7) /* RTS pin control */
156 #define MAX310X_LCR_WORD_LEN_5		(0x00)
157 #define MAX310X_LCR_WORD_LEN_6		(0x01)
158 #define MAX310X_LCR_WORD_LEN_7		(0x02)
159 #define MAX310X_LCR_WORD_LEN_8		(0x03)
160 
161 /* IRDA register bits */
162 #define MAX310X_IRDA_IRDAEN_BIT		(1 << 0) /* IRDA mode enable */
163 #define MAX310X_IRDA_SIR_BIT		(1 << 1) /* SIR mode enable */
164 #define MAX310X_IRDA_SHORTIR_BIT	(1 << 2) /* Short SIR mode enable */
165 #define MAX310X_IRDA_MIR_BIT		(1 << 3) /* MIR mode enable */
166 #define MAX310X_IRDA_RXINV_BIT		(1 << 4) /* RX logic inversion enable */
167 #define MAX310X_IRDA_TXINV_BIT		(1 << 5) /* TX logic inversion enable */
168 
169 /* Flow control trigger level register masks */
170 #define MAX310X_FLOWLVL_HALT_MASK	(0x000f) /* Flow control halt level */
171 #define MAX310X_FLOWLVL_RES_MASK	(0x00f0) /* Flow control resume level */
172 #define MAX310X_FLOWLVL_HALT(words)	((words / 8) & 0x0f)
173 #define MAX310X_FLOWLVL_RES(words)	(((words / 8) & 0x0f) << 4)
174 
175 /* FIFO interrupt trigger level register masks */
176 #define MAX310X_FIFOTRIGLVL_TX_MASK	(0x0f) /* TX FIFO trigger level */
177 #define MAX310X_FIFOTRIGLVL_RX_MASK	(0xf0) /* RX FIFO trigger level */
178 #define MAX310X_FIFOTRIGLVL_TX(words)	((words / 8) & 0x0f)
179 #define MAX310X_FIFOTRIGLVL_RX(words)	(((words / 8) & 0x0f) << 4)
180 
181 /* Flow control register bits */
182 #define MAX310X_FLOWCTRL_AUTORTS_BIT	(1 << 0) /* Auto RTS flow ctrl enable */
183 #define MAX310X_FLOWCTRL_AUTOCTS_BIT	(1 << 1) /* Auto CTS flow ctrl enable */
184 #define MAX310X_FLOWCTRL_GPIADDR_BIT	(1 << 2) /* Enables that GPIO inputs
185 						  * are used in conjunction with
186 						  * XOFF2 for definition of
187 						  * special character */
188 #define MAX310X_FLOWCTRL_SWFLOWEN_BIT	(1 << 3) /* Auto SW flow ctrl enable */
189 #define MAX310X_FLOWCTRL_SWFLOW0_BIT	(1 << 4) /* SWFLOW bit 0 */
190 #define MAX310X_FLOWCTRL_SWFLOW1_BIT	(1 << 5) /* SWFLOW bit 1
191 						  *
192 						  * SWFLOW bits 1 & 0 table:
193 						  * 00 -> no transmitter flow
194 						  *       control
195 						  * 01 -> receiver compares
196 						  *       XON2 and XOFF2
197 						  *       and controls
198 						  *       transmitter
199 						  * 10 -> receiver compares
200 						  *       XON1 and XOFF1
201 						  *       and controls
202 						  *       transmitter
203 						  * 11 -> receiver compares
204 						  *       XON1, XON2, XOFF1 and
205 						  *       XOFF2 and controls
206 						  *       transmitter
207 						  */
208 #define MAX310X_FLOWCTRL_SWFLOW2_BIT	(1 << 6) /* SWFLOW bit 2 */
209 #define MAX310X_FLOWCTRL_SWFLOW3_BIT	(1 << 7) /* SWFLOW bit 3
210 						  *
211 						  * SWFLOW bits 3 & 2 table:
212 						  * 00 -> no received flow
213 						  *       control
214 						  * 01 -> transmitter generates
215 						  *       XON2 and XOFF2
216 						  * 10 -> transmitter generates
217 						  *       XON1 and XOFF1
218 						  * 11 -> transmitter generates
219 						  *       XON1, XON2, XOFF1 and
220 						  *       XOFF2
221 						  */
222 
223 /* GPIO configuration register bits */
224 #define MAX310X_GPIOCFG_GP0OUT_BIT	(1 << 0) /* GPIO 0 output enable */
225 #define MAX310X_GPIOCFG_GP1OUT_BIT	(1 << 1) /* GPIO 1 output enable */
226 #define MAX310X_GPIOCFG_GP2OUT_BIT	(1 << 2) /* GPIO 2 output enable */
227 #define MAX310X_GPIOCFG_GP3OUT_BIT	(1 << 3) /* GPIO 3 output enable */
228 #define MAX310X_GPIOCFG_GP0OD_BIT	(1 << 4) /* GPIO 0 open-drain enable */
229 #define MAX310X_GPIOCFG_GP1OD_BIT	(1 << 5) /* GPIO 1 open-drain enable */
230 #define MAX310X_GPIOCFG_GP2OD_BIT	(1 << 6) /* GPIO 2 open-drain enable */
231 #define MAX310X_GPIOCFG_GP3OD_BIT	(1 << 7) /* GPIO 3 open-drain enable */
232 
233 /* GPIO DATA register bits */
234 #define MAX310X_GPIODATA_GP0OUT_BIT	(1 << 0) /* GPIO 0 output value */
235 #define MAX310X_GPIODATA_GP1OUT_BIT	(1 << 1) /* GPIO 1 output value */
236 #define MAX310X_GPIODATA_GP2OUT_BIT	(1 << 2) /* GPIO 2 output value */
237 #define MAX310X_GPIODATA_GP3OUT_BIT	(1 << 3) /* GPIO 3 output value */
238 #define MAX310X_GPIODATA_GP0IN_BIT	(1 << 4) /* GPIO 0 input value */
239 #define MAX310X_GPIODATA_GP1IN_BIT	(1 << 5) /* GPIO 1 input value */
240 #define MAX310X_GPIODATA_GP2IN_BIT	(1 << 6) /* GPIO 2 input value */
241 #define MAX310X_GPIODATA_GP3IN_BIT	(1 << 7) /* GPIO 3 input value */
242 
243 /* PLL configuration register masks */
244 #define MAX310X_PLLCFG_PREDIV_MASK	(0x3f) /* PLL predivision value */
245 #define MAX310X_PLLCFG_PLLFACTOR_MASK	(0xc0) /* PLL multiplication factor */
246 
247 /* Baud rate generator configuration register bits */
248 #define MAX310X_BRGCFG_2XMODE_BIT	(1 << 4) /* Double baud rate */
249 #define MAX310X_BRGCFG_4XMODE_BIT	(1 << 5) /* Quadruple baud rate */
250 
251 /* Clock source register bits */
252 #define MAX310X_CLKSRC_CRYST_BIT	(1 << 1) /* Crystal osc enable */
253 #define MAX310X_CLKSRC_PLL_BIT		(1 << 2) /* PLL enable */
254 #define MAX310X_CLKSRC_PLLBYP_BIT	(1 << 3) /* PLL bypass */
255 #define MAX310X_CLKSRC_EXTCLK_BIT	(1 << 4) /* External clock enable */
256 #define MAX310X_CLKSRC_CLK2RTS_BIT	(1 << 7) /* Baud clk to RTS pin */
257 
258 /* Global commands */
259 #define MAX310X_EXTREG_ENBL		(0xce)
260 #define MAX310X_EXTREG_DSBL		(0xcd)
261 
262 /* Misc definitions */
263 #define MAX310X_FIFO_SIZE		(128)
264 #define MAX310x_REV_MASK		(0xfc)
265 
266 /* MAX3107 specific */
267 #define MAX3107_REV_ID			(0xa0)
268 
269 /* MAX3109 specific */
270 #define MAX3109_REV_ID			(0xc0)
271 
272 /* MAX14830 specific */
273 #define MAX14830_BRGCFG_CLKDIS_BIT	(1 << 6) /* Clock Disable */
274 #define MAX14830_REV_ID			(0xb0)
275 
276 struct max310x_devtype {
277 	char	name[9];
278 	int	nr;
279 	int	(*detect)(struct device *);
280 	void	(*power)(struct uart_port *, int);
281 };
282 
283 struct max310x_one {
284 	struct uart_port	port;
285 	struct work_struct	tx_work;
286 };
287 
288 struct max310x_port {
289 	struct uart_driver	uart;
290 	struct max310x_devtype	*devtype;
291 	struct regmap		*regmap;
292 	struct regmap_config	regcfg;
293 	struct mutex		mutex;
294 	struct max310x_pdata	*pdata;
295 	int			gpio_used;
296 #ifdef CONFIG_GPIOLIB
297 	struct gpio_chip	gpio;
298 #endif
299 	struct max310x_one	p[0];
300 };
301 
302 static u8 max310x_port_read(struct uart_port *port, u8 reg)
303 {
304 	struct max310x_port *s = dev_get_drvdata(port->dev);
305 	unsigned int val = 0;
306 
307 	regmap_read(s->regmap, port->iobase + reg, &val);
308 
309 	return val;
310 }
311 
312 static void max310x_port_write(struct uart_port *port, u8 reg, u8 val)
313 {
314 	struct max310x_port *s = dev_get_drvdata(port->dev);
315 
316 	regmap_write(s->regmap, port->iobase + reg, val);
317 }
318 
319 static void max310x_port_update(struct uart_port *port, u8 reg, u8 mask, u8 val)
320 {
321 	struct max310x_port *s = dev_get_drvdata(port->dev);
322 
323 	regmap_update_bits(s->regmap, port->iobase + reg, mask, val);
324 }
325 
326 static int max3107_detect(struct device *dev)
327 {
328 	struct max310x_port *s = dev_get_drvdata(dev);
329 	unsigned int val = 0;
330 	int ret;
331 
332 	ret = regmap_read(s->regmap, MAX310X_REVID_REG, &val);
333 	if (ret)
334 		return ret;
335 
336 	if (((val & MAX310x_REV_MASK) != MAX3107_REV_ID)) {
337 		dev_err(dev,
338 			"%s ID 0x%02x does not match\n", s->devtype->name, val);
339 		return -ENODEV;
340 	}
341 
342 	return 0;
343 }
344 
345 static int max3108_detect(struct device *dev)
346 {
347 	struct max310x_port *s = dev_get_drvdata(dev);
348 	unsigned int val = 0;
349 	int ret;
350 
351 	/* MAX3108 have not REV ID register, we just check default value
352 	 * from clocksource register to make sure everything works.
353 	 */
354 	ret = regmap_read(s->regmap, MAX310X_CLKSRC_REG, &val);
355 	if (ret)
356 		return ret;
357 
358 	if (val != (MAX310X_CLKSRC_EXTCLK_BIT | MAX310X_CLKSRC_PLLBYP_BIT)) {
359 		dev_err(dev, "%s not present\n", s->devtype->name);
360 		return -ENODEV;
361 	}
362 
363 	return 0;
364 }
365 
366 static int max3109_detect(struct device *dev)
367 {
368 	struct max310x_port *s = dev_get_drvdata(dev);
369 	unsigned int val = 0;
370 	int ret;
371 
372 	ret = regmap_read(s->regmap, MAX310X_REVID_REG, &val);
373 	if (ret)
374 		return ret;
375 
376 	if (((val & MAX310x_REV_MASK) != MAX3109_REV_ID)) {
377 		dev_err(dev,
378 			"%s ID 0x%02x does not match\n", s->devtype->name, val);
379 		return -ENODEV;
380 	}
381 
382 	return 0;
383 }
384 
385 static void max310x_power(struct uart_port *port, int on)
386 {
387 	max310x_port_update(port, MAX310X_MODE1_REG,
388 			    MAX310X_MODE1_FORCESLEEP_BIT,
389 			    on ? 0 : MAX310X_MODE1_FORCESLEEP_BIT);
390 	if (on)
391 		msleep(50);
392 }
393 
394 static int max14830_detect(struct device *dev)
395 {
396 	struct max310x_port *s = dev_get_drvdata(dev);
397 	unsigned int val = 0;
398 	int ret;
399 
400 	ret = regmap_write(s->regmap, MAX310X_GLOBALCMD_REG,
401 			   MAX310X_EXTREG_ENBL);
402 	if (ret)
403 		return ret;
404 
405 	regmap_read(s->regmap, MAX310X_REVID_EXTREG, &val);
406 	regmap_write(s->regmap, MAX310X_GLOBALCMD_REG, MAX310X_EXTREG_DSBL);
407 	if (((val & MAX310x_REV_MASK) != MAX14830_REV_ID)) {
408 		dev_err(dev,
409 			"%s ID 0x%02x does not match\n", s->devtype->name, val);
410 		return -ENODEV;
411 	}
412 
413 	return 0;
414 }
415 
416 static void max14830_power(struct uart_port *port, int on)
417 {
418 	max310x_port_update(port, MAX310X_BRGCFG_REG,
419 			    MAX14830_BRGCFG_CLKDIS_BIT,
420 			    on ? 0 : MAX14830_BRGCFG_CLKDIS_BIT);
421 	if (on)
422 		msleep(50);
423 }
424 
425 static const struct max310x_devtype max3107_devtype = {
426 	.name	= "MAX3107",
427 	.nr	= 1,
428 	.detect	= max3107_detect,
429 	.power	= max310x_power,
430 };
431 
432 static const struct max310x_devtype max3108_devtype = {
433 	.name	= "MAX3108",
434 	.nr	= 1,
435 	.detect	= max3108_detect,
436 	.power	= max310x_power,
437 };
438 
439 static const struct max310x_devtype max3109_devtype = {
440 	.name	= "MAX3109",
441 	.nr	= 2,
442 	.detect	= max3109_detect,
443 	.power	= max310x_power,
444 };
445 
446 static const struct max310x_devtype max14830_devtype = {
447 	.name	= "MAX14830",
448 	.nr	= 4,
449 	.detect	= max14830_detect,
450 	.power	= max14830_power,
451 };
452 
453 static bool max310x_reg_writeable(struct device *dev, unsigned int reg)
454 {
455 	switch (reg & 0x1f) {
456 	case MAX310X_IRQSTS_REG:
457 	case MAX310X_LSR_IRQSTS_REG:
458 	case MAX310X_SPCHR_IRQSTS_REG:
459 	case MAX310X_STS_IRQSTS_REG:
460 	case MAX310X_TXFIFOLVL_REG:
461 	case MAX310X_RXFIFOLVL_REG:
462 		return false;
463 	default:
464 		break;
465 	}
466 
467 	return true;
468 }
469 
470 static bool max310x_reg_volatile(struct device *dev, unsigned int reg)
471 {
472 	switch (reg & 0x1f) {
473 	case MAX310X_RHR_REG:
474 	case MAX310X_IRQSTS_REG:
475 	case MAX310X_LSR_IRQSTS_REG:
476 	case MAX310X_SPCHR_IRQSTS_REG:
477 	case MAX310X_STS_IRQSTS_REG:
478 	case MAX310X_TXFIFOLVL_REG:
479 	case MAX310X_RXFIFOLVL_REG:
480 	case MAX310X_GPIODATA_REG:
481 	case MAX310X_BRGDIVLSB_REG:
482 	case MAX310X_REG_05:
483 	case MAX310X_REG_1F:
484 		return true;
485 	default:
486 		break;
487 	}
488 
489 	return false;
490 }
491 
492 static bool max310x_reg_precious(struct device *dev, unsigned int reg)
493 {
494 	switch (reg & 0x1f) {
495 	case MAX310X_RHR_REG:
496 	case MAX310X_IRQSTS_REG:
497 	case MAX310X_SPCHR_IRQSTS_REG:
498 	case MAX310X_STS_IRQSTS_REG:
499 		return true;
500 	default:
501 		break;
502 	}
503 
504 	return false;
505 }
506 
507 static void max310x_set_baud(struct uart_port *port, int baud)
508 {
509 	unsigned int mode = 0, div = port->uartclk / baud;
510 
511 	if (!(div / 16)) {
512 		/* Mode x2 */
513 		mode = MAX310X_BRGCFG_2XMODE_BIT;
514 		div = (port->uartclk * 2) / baud;
515 	}
516 
517 	if (!(div / 16)) {
518 		/* Mode x4 */
519 		mode = MAX310X_BRGCFG_4XMODE_BIT;
520 		div = (port->uartclk * 4) / baud;
521 	}
522 
523 	max310x_port_write(port, MAX310X_BRGDIVMSB_REG, (div / 16) >> 8);
524 	max310x_port_write(port, MAX310X_BRGDIVLSB_REG, div / 16);
525 	max310x_port_write(port, MAX310X_BRGCFG_REG, (div % 16) | mode);
526 }
527 
528 static int max310x_update_best_err(unsigned long f, long *besterr)
529 {
530 	/* Use baudrate 115200 for calculate error */
531 	long err = f % (115200 * 16);
532 
533 	if ((*besterr < 0) || (*besterr > err)) {
534 		*besterr = err;
535 		return 0;
536 	}
537 
538 	return 1;
539 }
540 
541 static int max310x_set_ref_clk(struct max310x_port *s)
542 {
543 	unsigned int div, clksrc, pllcfg = 0;
544 	long besterr = -1;
545 	unsigned long fdiv, fmul, bestfreq = s->pdata->frequency;
546 
547 	/* First, update error without PLL */
548 	max310x_update_best_err(s->pdata->frequency, &besterr);
549 
550 	/* Try all possible PLL dividers */
551 	for (div = 1; (div <= 63) && besterr; div++) {
552 		fdiv = DIV_ROUND_CLOSEST(s->pdata->frequency, div);
553 
554 		/* Try multiplier 6 */
555 		fmul = fdiv * 6;
556 		if ((fdiv >= 500000) && (fdiv <= 800000))
557 			if (!max310x_update_best_err(fmul, &besterr)) {
558 				pllcfg = (0 << 6) | div;
559 				bestfreq = fmul;
560 			}
561 		/* Try multiplier 48 */
562 		fmul = fdiv * 48;
563 		if ((fdiv >= 850000) && (fdiv <= 1200000))
564 			if (!max310x_update_best_err(fmul, &besterr)) {
565 				pllcfg = (1 << 6) | div;
566 				bestfreq = fmul;
567 			}
568 		/* Try multiplier 96 */
569 		fmul = fdiv * 96;
570 		if ((fdiv >= 425000) && (fdiv <= 1000000))
571 			if (!max310x_update_best_err(fmul, &besterr)) {
572 				pllcfg = (2 << 6) | div;
573 				bestfreq = fmul;
574 			}
575 		/* Try multiplier 144 */
576 		fmul = fdiv * 144;
577 		if ((fdiv >= 390000) && (fdiv <= 667000))
578 			if (!max310x_update_best_err(fmul, &besterr)) {
579 				pllcfg = (3 << 6) | div;
580 				bestfreq = fmul;
581 			}
582 	}
583 
584 	/* Configure clock source */
585 	if (s->pdata->driver_flags & MAX310X_EXT_CLK)
586 		clksrc = MAX310X_CLKSRC_EXTCLK_BIT;
587 	else
588 		clksrc = MAX310X_CLKSRC_CRYST_BIT;
589 
590 	/* Configure PLL */
591 	if (pllcfg) {
592 		clksrc |= MAX310X_CLKSRC_PLL_BIT;
593 		regmap_write(s->regmap, MAX310X_PLLCFG_REG, pllcfg);
594 	} else
595 		clksrc |= MAX310X_CLKSRC_PLLBYP_BIT;
596 
597 	regmap_write(s->regmap, MAX310X_CLKSRC_REG, clksrc);
598 
599 	/* Wait for crystal */
600 	if (pllcfg && !(s->pdata->driver_flags & MAX310X_EXT_CLK))
601 		msleep(10);
602 
603 	return (int)bestfreq;
604 }
605 
606 static void max310x_handle_rx(struct uart_port *port, unsigned int rxlen)
607 {
608 	unsigned int sts, ch, flag;
609 
610 	if (unlikely(rxlen >= port->fifosize)) {
611 		dev_warn_ratelimited(port->dev,
612 				     "Port %i: Possible RX FIFO overrun\n",
613 				     port->line);
614 		port->icount.buf_overrun++;
615 		/* Ensure sanity of RX level */
616 		rxlen = port->fifosize;
617 	}
618 
619 	while (rxlen--) {
620 		ch = max310x_port_read(port, MAX310X_RHR_REG);
621 		sts = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG);
622 
623 		sts &= MAX310X_LSR_RXPAR_BIT | MAX310X_LSR_FRERR_BIT |
624 		       MAX310X_LSR_RXOVR_BIT | MAX310X_LSR_RXBRK_BIT;
625 
626 		port->icount.rx++;
627 		flag = TTY_NORMAL;
628 
629 		if (unlikely(sts)) {
630 			if (sts & MAX310X_LSR_RXBRK_BIT) {
631 				port->icount.brk++;
632 				if (uart_handle_break(port))
633 					continue;
634 			} else if (sts & MAX310X_LSR_RXPAR_BIT)
635 				port->icount.parity++;
636 			else if (sts & MAX310X_LSR_FRERR_BIT)
637 				port->icount.frame++;
638 			else if (sts & MAX310X_LSR_RXOVR_BIT)
639 				port->icount.overrun++;
640 
641 			sts &= port->read_status_mask;
642 			if (sts & MAX310X_LSR_RXBRK_BIT)
643 				flag = TTY_BREAK;
644 			else if (sts & MAX310X_LSR_RXPAR_BIT)
645 				flag = TTY_PARITY;
646 			else if (sts & MAX310X_LSR_FRERR_BIT)
647 				flag = TTY_FRAME;
648 			else if (sts & MAX310X_LSR_RXOVR_BIT)
649 				flag = TTY_OVERRUN;
650 		}
651 
652 		if (uart_handle_sysrq_char(port, ch))
653 			continue;
654 
655 		if (sts & port->ignore_status_mask)
656 			continue;
657 
658 		uart_insert_char(port, sts, MAX310X_LSR_RXOVR_BIT, ch, flag);
659 	}
660 
661 	tty_flip_buffer_push(&port->state->port);
662 }
663 
664 static void max310x_handle_tx(struct uart_port *port)
665 {
666 	struct circ_buf *xmit = &port->state->xmit;
667 	unsigned int txlen, to_send;
668 
669 	if (unlikely(port->x_char)) {
670 		max310x_port_write(port, MAX310X_THR_REG, port->x_char);
671 		port->icount.tx++;
672 		port->x_char = 0;
673 		return;
674 	}
675 
676 	if (uart_circ_empty(xmit) || uart_tx_stopped(port))
677 		return;
678 
679 	/* Get length of data pending in circular buffer */
680 	to_send = uart_circ_chars_pending(xmit);
681 	if (likely(to_send)) {
682 		/* Limit to size of TX FIFO */
683 		txlen = max310x_port_read(port, MAX310X_TXFIFOLVL_REG);
684 		txlen = port->fifosize - txlen;
685 		to_send = (to_send > txlen) ? txlen : to_send;
686 
687 		/* Add data to send */
688 		port->icount.tx += to_send;
689 		while (to_send--) {
690 			max310x_port_write(port, MAX310X_THR_REG,
691 					   xmit->buf[xmit->tail]);
692 			xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
693 		}
694 	}
695 
696 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
697 		uart_write_wakeup(port);
698 }
699 
700 static void max310x_port_irq(struct max310x_port *s, int portno)
701 {
702 	struct uart_port *port = &s->p[portno].port;
703 
704 	do {
705 		unsigned int ists, lsr, rxlen;
706 
707 		/* Read IRQ status & RX FIFO level */
708 		ists = max310x_port_read(port, MAX310X_IRQSTS_REG);
709 		rxlen = max310x_port_read(port, MAX310X_RXFIFOLVL_REG);
710 		if (!ists && !rxlen)
711 			break;
712 
713 		if (ists & MAX310X_IRQ_CTS_BIT) {
714 			lsr = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG);
715 			uart_handle_cts_change(port,
716 					       !!(lsr & MAX310X_LSR_CTS_BIT));
717 		}
718 		if (rxlen)
719 			max310x_handle_rx(port, rxlen);
720 		if (ists & MAX310X_IRQ_TXEMPTY_BIT) {
721 			mutex_lock(&s->mutex);
722 			max310x_handle_tx(port);
723 			mutex_unlock(&s->mutex);
724 		}
725 	} while (1);
726 }
727 
728 static irqreturn_t max310x_ist(int irq, void *dev_id)
729 {
730 	struct max310x_port *s = (struct max310x_port *)dev_id;
731 
732 	if (s->uart.nr > 1) {
733 		do {
734 			unsigned int val = ~0;
735 
736 			WARN_ON_ONCE(regmap_read(s->regmap,
737 						 MAX310X_GLOBALIRQ_REG, &val));
738 			val = ((1 << s->uart.nr) - 1) & ~val;
739 			if (!val)
740 				break;
741 			max310x_port_irq(s, fls(val) - 1);
742 		} while (1);
743 	} else
744 		max310x_port_irq(s, 0);
745 
746 	return IRQ_HANDLED;
747 }
748 
749 static void max310x_wq_proc(struct work_struct *ws)
750 {
751 	struct max310x_one *one = container_of(ws, struct max310x_one, tx_work);
752 	struct max310x_port *s = dev_get_drvdata(one->port.dev);
753 
754 	mutex_lock(&s->mutex);
755 	max310x_handle_tx(&one->port);
756 	mutex_unlock(&s->mutex);
757 }
758 
759 static void max310x_start_tx(struct uart_port *port)
760 {
761 	struct max310x_one *one = container_of(port, struct max310x_one, port);
762 
763 	if (!work_pending(&one->tx_work))
764 		schedule_work(&one->tx_work);
765 }
766 
767 static unsigned int max310x_tx_empty(struct uart_port *port)
768 {
769 	unsigned int lvl, sts;
770 
771 	lvl = max310x_port_read(port, MAX310X_TXFIFOLVL_REG);
772 	sts = max310x_port_read(port, MAX310X_IRQSTS_REG);
773 
774 	return ((sts & MAX310X_IRQ_TXEMPTY_BIT) && !lvl) ? TIOCSER_TEMT : 0;
775 }
776 
777 static unsigned int max310x_get_mctrl(struct uart_port *port)
778 {
779 	/* DCD and DSR are not wired and CTS/RTS is handled automatically
780 	 * so just indicate DSR and CAR asserted
781 	 */
782 	return TIOCM_DSR | TIOCM_CAR;
783 }
784 
785 static void max310x_set_mctrl(struct uart_port *port, unsigned int mctrl)
786 {
787 	/* DCD and DSR are not wired and CTS/RTS is hadnled automatically
788 	 * so do nothing
789 	 */
790 }
791 
792 static void max310x_break_ctl(struct uart_port *port, int break_state)
793 {
794 	max310x_port_update(port, MAX310X_LCR_REG,
795 			    MAX310X_LCR_TXBREAK_BIT,
796 			    break_state ? MAX310X_LCR_TXBREAK_BIT : 0);
797 }
798 
799 static void max310x_set_termios(struct uart_port *port,
800 				struct ktermios *termios,
801 				struct ktermios *old)
802 {
803 	unsigned int lcr, flow = 0;
804 	int baud;
805 
806 	/* Mask termios capabilities we don't support */
807 	termios->c_cflag &= ~CMSPAR;
808 
809 	/* Word size */
810 	switch (termios->c_cflag & CSIZE) {
811 	case CS5:
812 		lcr = MAX310X_LCR_WORD_LEN_5;
813 		break;
814 	case CS6:
815 		lcr = MAX310X_LCR_WORD_LEN_6;
816 		break;
817 	case CS7:
818 		lcr = MAX310X_LCR_WORD_LEN_7;
819 		break;
820 	case CS8:
821 	default:
822 		lcr = MAX310X_LCR_WORD_LEN_8;
823 		break;
824 	}
825 
826 	/* Parity */
827 	if (termios->c_cflag & PARENB) {
828 		lcr |= MAX310X_LCR_PARITY_BIT;
829 		if (!(termios->c_cflag & PARODD))
830 			lcr |= MAX310X_LCR_EVENPARITY_BIT;
831 	}
832 
833 	/* Stop bits */
834 	if (termios->c_cflag & CSTOPB)
835 		lcr |= MAX310X_LCR_STOPLEN_BIT; /* 2 stops */
836 
837 	/* Update LCR register */
838 	max310x_port_write(port, MAX310X_LCR_REG, lcr);
839 
840 	/* Set read status mask */
841 	port->read_status_mask = MAX310X_LSR_RXOVR_BIT;
842 	if (termios->c_iflag & INPCK)
843 		port->read_status_mask |= MAX310X_LSR_RXPAR_BIT |
844 					  MAX310X_LSR_FRERR_BIT;
845 	if (termios->c_iflag & (BRKINT | PARMRK))
846 		port->read_status_mask |= MAX310X_LSR_RXBRK_BIT;
847 
848 	/* Set status ignore mask */
849 	port->ignore_status_mask = 0;
850 	if (termios->c_iflag & IGNBRK)
851 		port->ignore_status_mask |= MAX310X_LSR_RXBRK_BIT;
852 	if (!(termios->c_cflag & CREAD))
853 		port->ignore_status_mask |= MAX310X_LSR_RXPAR_BIT |
854 					    MAX310X_LSR_RXOVR_BIT |
855 					    MAX310X_LSR_FRERR_BIT |
856 					    MAX310X_LSR_RXBRK_BIT;
857 
858 	/* Configure flow control */
859 	max310x_port_write(port, MAX310X_XON1_REG, termios->c_cc[VSTART]);
860 	max310x_port_write(port, MAX310X_XOFF1_REG, termios->c_cc[VSTOP]);
861 	if (termios->c_cflag & CRTSCTS)
862 		flow |= MAX310X_FLOWCTRL_AUTOCTS_BIT |
863 			MAX310X_FLOWCTRL_AUTORTS_BIT;
864 	if (termios->c_iflag & IXON)
865 		flow |= MAX310X_FLOWCTRL_SWFLOW3_BIT |
866 			MAX310X_FLOWCTRL_SWFLOWEN_BIT;
867 	if (termios->c_iflag & IXOFF)
868 		flow |= MAX310X_FLOWCTRL_SWFLOW1_BIT |
869 			MAX310X_FLOWCTRL_SWFLOWEN_BIT;
870 	max310x_port_write(port, MAX310X_FLOWCTRL_REG, flow);
871 
872 	/* Get baud rate generator configuration */
873 	baud = uart_get_baud_rate(port, termios, old,
874 				  port->uartclk / 16 / 0xffff,
875 				  port->uartclk / 4);
876 
877 	/* Setup baudrate generator */
878 	max310x_set_baud(port, baud);
879 
880 	/* Update timeout according to new baud rate */
881 	uart_update_timeout(port, termios->c_cflag, baud);
882 }
883 
884 static int max310x_startup(struct uart_port *port)
885 {
886 	unsigned int val, line = port->line;
887 	struct max310x_port *s = dev_get_drvdata(port->dev);
888 
889 	s->devtype->power(port, 1);
890 
891 	/* Configure baud rate, 9600 as default */
892 	max310x_set_baud(port, 9600);
893 
894 	/* Configure LCR register, 8N1 mode by default */
895 	max310x_port_write(port, MAX310X_LCR_REG, MAX310X_LCR_WORD_LEN_8);
896 
897 	/* Configure MODE1 register */
898 	max310x_port_update(port, MAX310X_MODE1_REG,
899 			    MAX310X_MODE1_TRNSCVCTRL_BIT,
900 			    (s->pdata->uart_flags[line] & MAX310X_AUTO_DIR_CTRL)
901 			    ? MAX310X_MODE1_TRNSCVCTRL_BIT : 0);
902 
903 	/* Configure MODE2 register */
904 	val = MAX310X_MODE2_RXEMPTINV_BIT;
905 	if (s->pdata->uart_flags[line] & MAX310X_LOOPBACK)
906 		val |= MAX310X_MODE2_LOOPBACK_BIT;
907 	if (s->pdata->uart_flags[line] & MAX310X_ECHO_SUPRESS)
908 		val |= MAX310X_MODE2_ECHOSUPR_BIT;
909 
910 	/* Reset FIFOs */
911 	val |= MAX310X_MODE2_FIFORST_BIT;
912 	max310x_port_write(port, MAX310X_MODE2_REG, val);
913 	max310x_port_update(port, MAX310X_MODE2_REG,
914 			    MAX310X_MODE2_FIFORST_BIT, 0);
915 
916 	/* Configure flow control levels */
917 	/* Flow control halt level 96, resume level 48 */
918 	max310x_port_write(port, MAX310X_FLOWLVL_REG,
919 			   MAX310X_FLOWLVL_RES(48) | MAX310X_FLOWLVL_HALT(96));
920 
921 	/* Clear IRQ status register */
922 	max310x_port_read(port, MAX310X_IRQSTS_REG);
923 
924 	/* Enable RX, TX, CTS change interrupts */
925 	val = MAX310X_IRQ_RXEMPTY_BIT | MAX310X_IRQ_TXEMPTY_BIT;
926 	max310x_port_write(port, MAX310X_IRQEN_REG, val | MAX310X_IRQ_CTS_BIT);
927 
928 	return 0;
929 }
930 
931 static void max310x_shutdown(struct uart_port *port)
932 {
933 	struct max310x_port *s = dev_get_drvdata(port->dev);
934 
935 	/* Disable all interrupts */
936 	max310x_port_write(port, MAX310X_IRQEN_REG, 0);
937 
938 	s->devtype->power(port, 0);
939 }
940 
941 static const char *max310x_type(struct uart_port *port)
942 {
943 	struct max310x_port *s = dev_get_drvdata(port->dev);
944 
945 	return (port->type == PORT_MAX310X) ? s->devtype->name : NULL;
946 }
947 
948 static int max310x_request_port(struct uart_port *port)
949 {
950 	/* Do nothing */
951 	return 0;
952 }
953 
954 static void max310x_config_port(struct uart_port *port, int flags)
955 {
956 	if (flags & UART_CONFIG_TYPE)
957 		port->type = PORT_MAX310X;
958 }
959 
960 static int max310x_verify_port(struct uart_port *port, struct serial_struct *s)
961 {
962 	if ((s->type != PORT_UNKNOWN) && (s->type != PORT_MAX310X))
963 		return -EINVAL;
964 	if (s->irq != port->irq)
965 		return -EINVAL;
966 
967 	return 0;
968 }
969 
970 static void max310x_null_void(struct uart_port *port)
971 {
972 	/* Do nothing */
973 }
974 
975 static const struct uart_ops max310x_ops = {
976 	.tx_empty	= max310x_tx_empty,
977 	.set_mctrl	= max310x_set_mctrl,
978 	.get_mctrl	= max310x_get_mctrl,
979 	.stop_tx	= max310x_null_void,
980 	.start_tx	= max310x_start_tx,
981 	.stop_rx	= max310x_null_void,
982 	.enable_ms	= max310x_null_void,
983 	.break_ctl	= max310x_break_ctl,
984 	.startup	= max310x_startup,
985 	.shutdown	= max310x_shutdown,
986 	.set_termios	= max310x_set_termios,
987 	.type		= max310x_type,
988 	.request_port	= max310x_request_port,
989 	.release_port	= max310x_null_void,
990 	.config_port	= max310x_config_port,
991 	.verify_port	= max310x_verify_port,
992 };
993 
994 static int __maybe_unused max310x_suspend(struct device *dev)
995 {
996 	struct max310x_port *s = dev_get_drvdata(dev);
997 	int i;
998 
999 	for (i = 0; i < s->uart.nr; i++) {
1000 		uart_suspend_port(&s->uart, &s->p[i].port);
1001 		s->devtype->power(&s->p[i].port, 0);
1002 	}
1003 
1004 	return 0;
1005 }
1006 
1007 static int __maybe_unused max310x_resume(struct device *dev)
1008 {
1009 	struct max310x_port *s = dev_get_drvdata(dev);
1010 	int i;
1011 
1012 	for (i = 0; i < s->uart.nr; i++) {
1013 		s->devtype->power(&s->p[i].port, 1);
1014 		uart_resume_port(&s->uart, &s->p[i].port);
1015 	}
1016 
1017 	return 0;
1018 }
1019 
1020 #ifdef CONFIG_GPIOLIB
1021 static int max310x_gpio_get(struct gpio_chip *chip, unsigned offset)
1022 {
1023 	unsigned int val;
1024 	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
1025 	struct uart_port *port = &s->p[offset / 4].port;
1026 
1027 	val = max310x_port_read(port, MAX310X_GPIODATA_REG);
1028 
1029 	return !!((val >> 4) & (1 << (offset % 4)));
1030 }
1031 
1032 static void max310x_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
1033 {
1034 	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
1035 	struct uart_port *port = &s->p[offset / 4].port;
1036 
1037 	max310x_port_update(port, MAX310X_GPIODATA_REG, 1 << (offset % 4),
1038 			    value ? 1 << (offset % 4) : 0);
1039 }
1040 
1041 static int max310x_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
1042 {
1043 	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
1044 	struct uart_port *port = &s->p[offset / 4].port;
1045 
1046 	max310x_port_update(port, MAX310X_GPIOCFG_REG, 1 << (offset % 4), 0);
1047 
1048 	return 0;
1049 }
1050 
1051 static int max310x_gpio_direction_output(struct gpio_chip *chip,
1052 					 unsigned offset, int value)
1053 {
1054 	struct max310x_port *s = container_of(chip, struct max310x_port, gpio);
1055 	struct uart_port *port = &s->p[offset / 4].port;
1056 
1057 	max310x_port_update(port, MAX310X_GPIODATA_REG, 1 << (offset % 4),
1058 			    value ? 1 << (offset % 4) : 0);
1059 	max310x_port_update(port, MAX310X_GPIOCFG_REG, 1 << (offset % 4),
1060 			    1 << (offset % 4));
1061 
1062 	return 0;
1063 }
1064 #endif
1065 
1066 static int max310x_probe(struct device *dev, int is_spi,
1067 			 struct max310x_devtype *devtype, int irq)
1068 {
1069 	struct max310x_port *s;
1070 	struct max310x_pdata *pdata = dev_get_platdata(dev);
1071 	int i, ret, uartclk;
1072 
1073 	/* Check for IRQ */
1074 	if (irq <= 0) {
1075 		dev_err(dev, "No IRQ specified\n");
1076 		return -ENOTSUPP;
1077 	}
1078 
1079 	if (!pdata) {
1080 		dev_err(dev, "No platform data supplied\n");
1081 		return -EINVAL;
1082 	}
1083 
1084 	/* Alloc port structure */
1085 	s = devm_kzalloc(dev, sizeof(*s) +
1086 			 sizeof(struct max310x_one) * devtype->nr, GFP_KERNEL);
1087 	if (!s) {
1088 		dev_err(dev, "Error allocating port structure\n");
1089 		return -ENOMEM;
1090 	}
1091 
1092 	/* Check input frequency */
1093 	if ((pdata->driver_flags & MAX310X_EXT_CLK) &&
1094 	   ((pdata->frequency < 500000) || (pdata->frequency > 35000000)))
1095 		goto err_freq;
1096 	/* Check frequency for quartz */
1097 	if (!(pdata->driver_flags & MAX310X_EXT_CLK) &&
1098 	   ((pdata->frequency < 1000000) || (pdata->frequency > 4000000)))
1099 		goto err_freq;
1100 
1101 	s->pdata = pdata;
1102 	s->devtype = devtype;
1103 	dev_set_drvdata(dev, s);
1104 
1105 	mutex_init(&s->mutex);
1106 
1107 	/* Setup regmap */
1108 	s->regcfg.reg_bits		= 8;
1109 	s->regcfg.val_bits		= 8;
1110 	s->regcfg.read_flag_mask	= 0x00;
1111 	s->regcfg.write_flag_mask	= 0x80;
1112 	s->regcfg.cache_type		= REGCACHE_RBTREE;
1113 	s->regcfg.writeable_reg		= max310x_reg_writeable;
1114 	s->regcfg.volatile_reg		= max310x_reg_volatile;
1115 	s->regcfg.precious_reg		= max310x_reg_precious;
1116 	s->regcfg.max_register		= devtype->nr * 0x20 - 1;
1117 
1118 	if (IS_ENABLED(CONFIG_SPI_MASTER) && is_spi) {
1119 		struct spi_device *spi = to_spi_device(dev);
1120 
1121 		s->regmap = devm_regmap_init_spi(spi, &s->regcfg);
1122 	} else
1123 		return -ENOTSUPP;
1124 
1125 	if (IS_ERR(s->regmap)) {
1126 		dev_err(dev, "Failed to initialize register map\n");
1127 		return PTR_ERR(s->regmap);
1128 	}
1129 
1130 	/* Board specific configure */
1131 	if (s->pdata->init)
1132 		s->pdata->init();
1133 
1134 	/* Check device to ensure we are talking to what we expect */
1135 	ret = devtype->detect(dev);
1136 	if (ret)
1137 		return ret;
1138 
1139 	for (i = 0; i < devtype->nr; i++) {
1140 		unsigned int offs = i << 5;
1141 
1142 		/* Reset port */
1143 		regmap_write(s->regmap, MAX310X_MODE2_REG + offs,
1144 			     MAX310X_MODE2_RST_BIT);
1145 		/* Clear port reset */
1146 		regmap_write(s->regmap, MAX310X_MODE2_REG + offs, 0);
1147 
1148 		/* Wait for port startup */
1149 		do {
1150 			regmap_read(s->regmap,
1151 				    MAX310X_BRGDIVLSB_REG + offs, &ret);
1152 		} while (ret != 0x01);
1153 
1154 		regmap_update_bits(s->regmap, MAX310X_MODE1_REG + offs,
1155 				   MAX310X_MODE1_AUTOSLEEP_BIT,
1156 				   MAX310X_MODE1_AUTOSLEEP_BIT);
1157 	}
1158 
1159 	uartclk = max310x_set_ref_clk(s);
1160 	dev_dbg(dev, "Reference clock set to %i Hz\n", uartclk);
1161 
1162 	/* Register UART driver */
1163 	s->uart.owner		= THIS_MODULE;
1164 	s->uart.dev_name	= "ttyMAX";
1165 	s->uart.major		= MAX310X_MAJOR;
1166 	s->uart.minor		= MAX310X_MINOR;
1167 	s->uart.nr		= devtype->nr;
1168 	ret = uart_register_driver(&s->uart);
1169 	if (ret) {
1170 		dev_err(dev, "Registering UART driver failed\n");
1171 		return ret;
1172 	}
1173 
1174 	for (i = 0; i < devtype->nr; i++) {
1175 		/* Initialize port data */
1176 		s->p[i].port.line	= i;
1177 		s->p[i].port.dev	= dev;
1178 		s->p[i].port.irq	= irq;
1179 		s->p[i].port.type	= PORT_MAX310X;
1180 		s->p[i].port.fifosize	= MAX310X_FIFO_SIZE;
1181 		s->p[i].port.flags	= UPF_SKIP_TEST | UPF_FIXED_TYPE |
1182 					  UPF_LOW_LATENCY;
1183 		s->p[i].port.iotype	= UPIO_PORT;
1184 		s->p[i].port.iobase	= i * 0x20;
1185 		s->p[i].port.membase	= (void __iomem *)~0;
1186 		s->p[i].port.uartclk	= uartclk;
1187 		s->p[i].port.ops	= &max310x_ops;
1188 		/* Disable all interrupts */
1189 		max310x_port_write(&s->p[i].port, MAX310X_IRQEN_REG, 0);
1190 		/* Clear IRQ status register */
1191 		max310x_port_read(&s->p[i].port, MAX310X_IRQSTS_REG);
1192 		/* Enable IRQ pin */
1193 		max310x_port_update(&s->p[i].port, MAX310X_MODE1_REG,
1194 				    MAX310X_MODE1_IRQSEL_BIT,
1195 				    MAX310X_MODE1_IRQSEL_BIT);
1196 		/* Initialize queue for start TX */
1197 		INIT_WORK(&s->p[i].tx_work, max310x_wq_proc);
1198 		/* Register port */
1199 		uart_add_one_port(&s->uart, &s->p[i].port);
1200 		/* Go to suspend mode */
1201 		devtype->power(&s->p[i].port, 0);
1202 	}
1203 
1204 #ifdef CONFIG_GPIOLIB
1205 	/* Setup GPIO cotroller */
1206 	if (s->pdata->gpio_base) {
1207 		s->gpio.owner		= THIS_MODULE;
1208 		s->gpio.dev		= dev;
1209 		s->gpio.label		= dev_name(dev);
1210 		s->gpio.direction_input	= max310x_gpio_direction_input;
1211 		s->gpio.get		= max310x_gpio_get;
1212 		s->gpio.direction_output= max310x_gpio_direction_output;
1213 		s->gpio.set		= max310x_gpio_set;
1214 		s->gpio.base		= s->pdata->gpio_base;
1215 		s->gpio.ngpio		= devtype->nr * 4;
1216 		s->gpio.can_sleep	= 1;
1217 		if (!gpiochip_add(&s->gpio))
1218 			s->gpio_used = 1;
1219 	} else
1220 		dev_info(dev, "GPIO support not enabled\n");
1221 #endif
1222 
1223 	/* Setup interrupt */
1224 	ret = devm_request_threaded_irq(dev, irq, NULL, max310x_ist,
1225 					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
1226 					dev_name(dev), s);
1227 	if (ret) {
1228 		dev_err(dev, "Unable to reguest IRQ %i\n", irq);
1229 #ifdef CONFIG_GPIOLIB
1230 		if (s->gpio_used)
1231 			WARN_ON(gpiochip_remove(&s->gpio));
1232 #endif
1233 	}
1234 
1235 	return ret;
1236 
1237 err_freq:
1238 	dev_err(dev, "Frequency parameter incorrect\n");
1239 	return -EINVAL;
1240 }
1241 
1242 static int max310x_remove(struct device *dev)
1243 {
1244 	struct max310x_port *s = dev_get_drvdata(dev);
1245 	int i, ret = 0;
1246 
1247 	for (i = 0; i < s->uart.nr; i++) {
1248 		cancel_work_sync(&s->p[i].tx_work);
1249 		uart_remove_one_port(&s->uart, &s->p[i].port);
1250 		s->devtype->power(&s->p[i].port, 0);
1251 	}
1252 
1253 	uart_unregister_driver(&s->uart);
1254 
1255 #ifdef CONFIG_GPIOLIB
1256 	if (s->gpio_used)
1257 		ret = gpiochip_remove(&s->gpio);
1258 #endif
1259 
1260 	if (s->pdata->exit)
1261 		s->pdata->exit();
1262 
1263 	return ret;
1264 }
1265 
1266 #ifdef CONFIG_SPI_MASTER
1267 static int max310x_spi_probe(struct spi_device *spi)
1268 {
1269 	struct max310x_devtype *devtype =
1270 		(struct max310x_devtype *)spi_get_device_id(spi)->driver_data;
1271 	int ret;
1272 
1273 	/* Setup SPI bus */
1274 	spi->bits_per_word	= 8;
1275 	spi->mode		= spi->mode ? : SPI_MODE_0;
1276 	spi->max_speed_hz	= spi->max_speed_hz ? : 26000000;
1277 	ret = spi_setup(spi);
1278 	if (ret) {
1279 		dev_err(&spi->dev, "SPI setup failed\n");
1280 		return ret;
1281 	}
1282 
1283 	return max310x_probe(&spi->dev, 1, devtype, spi->irq);
1284 }
1285 
1286 static int max310x_spi_remove(struct spi_device *spi)
1287 {
1288 	return max310x_remove(&spi->dev);
1289 }
1290 
1291 static SIMPLE_DEV_PM_OPS(max310x_pm_ops, max310x_suspend, max310x_resume);
1292 
1293 static const struct spi_device_id max310x_id_table[] = {
1294 	{ "max3107",	(kernel_ulong_t)&max3107_devtype, },
1295 	{ "max3108",	(kernel_ulong_t)&max3108_devtype, },
1296 	{ "max3109",	(kernel_ulong_t)&max3109_devtype, },
1297 	{ "max14830",	(kernel_ulong_t)&max14830_devtype, },
1298 	{ }
1299 };
1300 MODULE_DEVICE_TABLE(spi, max310x_id_table);
1301 
1302 static struct spi_driver max310x_uart_driver = {
1303 	.driver = {
1304 		.name	= MAX310X_NAME,
1305 		.owner	= THIS_MODULE,
1306 		.pm	= &max310x_pm_ops,
1307 	},
1308 	.probe		= max310x_spi_probe,
1309 	.remove		= max310x_spi_remove,
1310 	.id_table	= max310x_id_table,
1311 };
1312 module_spi_driver(max310x_uart_driver);
1313 #endif
1314 
1315 MODULE_LICENSE("GPL");
1316 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
1317 MODULE_DESCRIPTION("MAX310X serial driver");
1318