xref: /openbmc/u-boot/drivers/i2c/davinci_i2c.c (revision 0b304a24) 
1 /*
2  * TI DaVinci (TMS320DM644x) I2C driver.
3  *
4  * (C) Copyright 2012-2014
5  *     Texas Instruments Incorporated, <www.ti.com>
6  * (C) Copyright 2007 Sergey Kubushyn <ksi@koi8.net>
7  * --------------------------------------------------------
8  *
9  * SPDX-License-Identifier:	GPL-2.0+
10  */
11 
12 #include <common.h>
13 #include <i2c.h>
14 #include <asm/arch/hardware.h>
15 #include <asm/arch/i2c_defs.h>
16 #include <asm/io.h>
17 #include "davinci_i2c.h"
18 
19 #define CHECK_NACK() \
20 	do {\
21 		if (tmp & (I2C_TIMEOUT | I2C_STAT_NACK)) {\
22 			REG(&(i2c_base->i2c_con)) = 0;\
23 			return 1;\
24 		} \
25 	} while (0)
26 
27 static struct i2c_regs *davinci_get_base(struct i2c_adapter *adap);
28 
29 static int wait_for_bus(struct i2c_adapter *adap)
30 {
31 	struct i2c_regs *i2c_base = davinci_get_base(adap);
32 	int	stat, timeout;
33 
34 	REG(&(i2c_base->i2c_stat)) = 0xffff;
35 
36 	for (timeout = 0; timeout < 10; timeout++) {
37 		stat = REG(&(i2c_base->i2c_stat));
38 		if (!((stat) & I2C_STAT_BB)) {
39 			REG(&(i2c_base->i2c_stat)) = 0xffff;
40 			return 0;
41 		}
42 
43 		REG(&(i2c_base->i2c_stat)) = stat;
44 		udelay(50000);
45 	}
46 
47 	REG(&(i2c_base->i2c_stat)) = 0xffff;
48 	return 1;
49 }
50 
51 
52 static int poll_i2c_irq(struct i2c_adapter *adap, int mask)
53 {
54 	struct i2c_regs *i2c_base = davinci_get_base(adap);
55 	int	stat, timeout;
56 
57 	for (timeout = 0; timeout < 10; timeout++) {
58 		udelay(1000);
59 		stat = REG(&(i2c_base->i2c_stat));
60 		if (stat & mask)
61 			return stat;
62 	}
63 
64 	REG(&(i2c_base->i2c_stat)) = 0xffff;
65 	return stat | I2C_TIMEOUT;
66 }
67 
68 static void flush_rx(struct i2c_adapter *adap)
69 {
70 	struct i2c_regs *i2c_base = davinci_get_base(adap);
71 
72 	while (1) {
73 		if (!(REG(&(i2c_base->i2c_stat)) & I2C_STAT_RRDY))
74 			break;
75 
76 		REG(&(i2c_base->i2c_drr));
77 		REG(&(i2c_base->i2c_stat)) = I2C_STAT_RRDY;
78 		udelay(1000);
79 	}
80 }
81 
82 static uint davinci_i2c_setspeed(struct i2c_adapter *adap, uint speed)
83 {
84 	struct i2c_regs *i2c_base = davinci_get_base(adap);
85 	uint32_t	div, psc;
86 
87 	psc = 2;
88 	/* SCLL + SCLH */
89 	div = (CONFIG_SYS_HZ_CLOCK / ((psc + 1) * speed)) - 10;
90 	REG(&(i2c_base->i2c_psc)) = psc; /* 27MHz / (2 + 1) = 9MHz */
91 	REG(&(i2c_base->i2c_scll)) = (div * 50) / 100; /* 50% Duty */
92 	REG(&(i2c_base->i2c_sclh)) = div - REG(&(i2c_base->i2c_scll));
93 
94 	adap->speed	= speed;
95 	return 0;
96 }
97 
98 static void davinci_i2c_init(struct i2c_adapter *adap, int speed, int slaveadd)
99 {
100 	struct i2c_regs *i2c_base = davinci_get_base(adap);
101 
102 	if (REG(&(i2c_base->i2c_con)) & I2C_CON_EN) {
103 		REG(&(i2c_base->i2c_con)) = 0;
104 		udelay(50000);
105 	}
106 
107 	davinci_i2c_setspeed(adap, speed);
108 
109 	REG(&(i2c_base->i2c_oa)) = slaveadd;
110 	REG(&(i2c_base->i2c_cnt)) = 0;
111 
112 	/* Interrupts must be enabled or I2C module won't work */
113 	REG(&(i2c_base->i2c_ie)) = I2C_IE_SCD_IE | I2C_IE_XRDY_IE |
114 		I2C_IE_RRDY_IE | I2C_IE_ARDY_IE | I2C_IE_NACK_IE;
115 
116 	/* Now enable I2C controller (get it out of reset) */
117 	REG(&(i2c_base->i2c_con)) = I2C_CON_EN;
118 
119 	udelay(1000);
120 }
121 
122 static int davinci_i2c_probe(struct i2c_adapter *adap, uint8_t chip)
123 {
124 	struct i2c_regs *i2c_base = davinci_get_base(adap);
125 	int	rc = 1;
126 
127 	if (chip == REG(&(i2c_base->i2c_oa)))
128 		return rc;
129 
130 	REG(&(i2c_base->i2c_con)) = 0;
131 	if (wait_for_bus(adap))
132 		return 1;
133 
134 	/* try to read one byte from current (or only) address */
135 	REG(&(i2c_base->i2c_cnt)) = 1;
136 	REG(&(i2c_base->i2c_sa))  = chip;
137 	REG(&(i2c_base->i2c_con)) = (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT |
138 				     I2C_CON_STP);
139 	udelay(50000);
140 
141 	if (!(REG(&(i2c_base->i2c_stat)) & I2C_STAT_NACK)) {
142 		rc = 0;
143 		flush_rx(adap);
144 		REG(&(i2c_base->i2c_stat)) = 0xffff;
145 	} else {
146 		REG(&(i2c_base->i2c_stat)) = 0xffff;
147 		REG(&(i2c_base->i2c_con)) |= I2C_CON_STP;
148 		udelay(20000);
149 		if (wait_for_bus(adap))
150 			return 1;
151 	}
152 
153 	flush_rx(adap);
154 	REG(&(i2c_base->i2c_stat)) = 0xffff;
155 	REG(&(i2c_base->i2c_cnt)) = 0;
156 	return rc;
157 }
158 
159 static int davinci_i2c_read(struct i2c_adapter *adap, uint8_t chip,
160 				uint32_t addr, int alen, uint8_t *buf, int len)
161 {
162 	struct i2c_regs *i2c_base = davinci_get_base(adap);
163 	uint32_t	tmp;
164 	int		i;
165 
166 	if ((alen < 0) || (alen > 2)) {
167 		printf("%s(): bogus address length %x\n", __func__, alen);
168 		return 1;
169 	}
170 
171 	if (wait_for_bus(adap))
172 		return 1;
173 
174 	if (alen != 0) {
175 		/* Start address phase */
176 		tmp = I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX;
177 		REG(&(i2c_base->i2c_cnt)) = alen;
178 		REG(&(i2c_base->i2c_sa)) = chip;
179 		REG(&(i2c_base->i2c_con)) = tmp;
180 
181 		tmp = poll_i2c_irq(adap, I2C_STAT_XRDY | I2C_STAT_NACK);
182 
183 		CHECK_NACK();
184 
185 		switch (alen) {
186 		case 2:
187 			/* Send address MSByte */
188 			if (tmp & I2C_STAT_XRDY) {
189 				REG(&(i2c_base->i2c_dxr)) = (addr >> 8) & 0xff;
190 			} else {
191 				REG(&(i2c_base->i2c_con)) = 0;
192 				return 1;
193 			}
194 
195 			tmp = poll_i2c_irq(adap, I2C_STAT_XRDY | I2C_STAT_NACK);
196 
197 			CHECK_NACK();
198 			/* No break, fall through */
199 		case 1:
200 			/* Send address LSByte */
201 			if (tmp & I2C_STAT_XRDY) {
202 				REG(&(i2c_base->i2c_dxr)) = addr & 0xff;
203 			} else {
204 				REG(&(i2c_base->i2c_con)) = 0;
205 				return 1;
206 			}
207 
208 			tmp = poll_i2c_irq(adap, I2C_STAT_XRDY |
209 					   I2C_STAT_NACK | I2C_STAT_ARDY);
210 
211 			CHECK_NACK();
212 
213 			if (!(tmp & I2C_STAT_ARDY)) {
214 				REG(&(i2c_base->i2c_con)) = 0;
215 				return 1;
216 			}
217 		}
218 	}
219 
220 	/* Address phase is over, now read 'len' bytes and stop */
221 	tmp = I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP;
222 	REG(&(i2c_base->i2c_cnt)) = len & 0xffff;
223 	REG(&(i2c_base->i2c_sa)) = chip;
224 	REG(&(i2c_base->i2c_con)) = tmp;
225 
226 	for (i = 0; i < len; i++) {
227 		tmp = poll_i2c_irq(adap, I2C_STAT_RRDY | I2C_STAT_NACK |
228 				   I2C_STAT_ROVR);
229 
230 		CHECK_NACK();
231 
232 		if (tmp & I2C_STAT_RRDY) {
233 			buf[i] = REG(&(i2c_base->i2c_drr));
234 		} else {
235 			REG(&(i2c_base->i2c_con)) = 0;
236 			return 1;
237 		}
238 	}
239 
240 	tmp = poll_i2c_irq(adap, I2C_STAT_SCD | I2C_STAT_NACK);
241 
242 	CHECK_NACK();
243 
244 	if (!(tmp & I2C_STAT_SCD)) {
245 		REG(&(i2c_base->i2c_con)) = 0;
246 		return 1;
247 	}
248 
249 	flush_rx(adap);
250 	REG(&(i2c_base->i2c_stat)) = 0xffff;
251 	REG(&(i2c_base->i2c_cnt)) = 0;
252 	REG(&(i2c_base->i2c_con)) = 0;
253 
254 	return 0;
255 }
256 
257 static int davinci_i2c_write(struct i2c_adapter *adap, uint8_t chip,
258 				uint32_t addr, int alen, uint8_t *buf, int len)
259 {
260 	struct i2c_regs *i2c_base = davinci_get_base(adap);
261 	uint32_t	tmp;
262 	int		i;
263 
264 	if ((alen < 0) || (alen > 2)) {
265 		printf("%s(): bogus address length %x\n", __func__, alen);
266 		return 1;
267 	}
268 	if (len < 0) {
269 		printf("%s(): bogus length %x\n", __func__, len);
270 		return 1;
271 	}
272 
273 	if (wait_for_bus(adap))
274 		return 1;
275 
276 	/* Start address phase */
277 	tmp = I2C_CON_EN | I2C_CON_MST | I2C_CON_STT |
278 		I2C_CON_TRX | I2C_CON_STP;
279 	REG(&(i2c_base->i2c_cnt)) = (alen == 0) ?
280 		len & 0xffff : (len & 0xffff) + alen;
281 	REG(&(i2c_base->i2c_sa)) = chip;
282 	REG(&(i2c_base->i2c_con)) = tmp;
283 
284 	switch (alen) {
285 	case 2:
286 		/* Send address MSByte */
287 		tmp = poll_i2c_irq(adap, I2C_STAT_XRDY | I2C_STAT_NACK);
288 
289 		CHECK_NACK();
290 
291 		if (tmp & I2C_STAT_XRDY) {
292 			REG(&(i2c_base->i2c_dxr)) = (addr >> 8) & 0xff;
293 		} else {
294 			REG(&(i2c_base->i2c_con)) = 0;
295 			return 1;
296 		}
297 		/* No break, fall through */
298 	case 1:
299 		/* Send address LSByte */
300 		tmp = poll_i2c_irq(adap, I2C_STAT_XRDY | I2C_STAT_NACK);
301 
302 		CHECK_NACK();
303 
304 		if (tmp & I2C_STAT_XRDY) {
305 			REG(&(i2c_base->i2c_dxr)) = addr & 0xff;
306 		} else {
307 			REG(&(i2c_base->i2c_con)) = 0;
308 			return 1;
309 		}
310 	}
311 
312 	for (i = 0; i < len; i++) {
313 		tmp = poll_i2c_irq(adap, I2C_STAT_XRDY | I2C_STAT_NACK);
314 
315 		CHECK_NACK();
316 
317 		if (tmp & I2C_STAT_XRDY)
318 			REG(&(i2c_base->i2c_dxr)) = buf[i];
319 		else
320 			return 1;
321 	}
322 
323 	tmp = poll_i2c_irq(adap, I2C_STAT_SCD | I2C_STAT_NACK);
324 
325 	CHECK_NACK();
326 
327 	if (!(tmp & I2C_STAT_SCD)) {
328 		REG(&(i2c_base->i2c_con)) = 0;
329 		return 1;
330 	}
331 
332 	flush_rx(adap);
333 	REG(&(i2c_base->i2c_stat)) = 0xffff;
334 	REG(&(i2c_base->i2c_cnt)) = 0;
335 	REG(&(i2c_base->i2c_con)) = 0;
336 
337 	return 0;
338 }
339 
340 static struct i2c_regs *davinci_get_base(struct i2c_adapter *adap)
341 {
342 	switch (adap->hwadapnr) {
343 #if I2C_BUS_MAX >= 3
344 	case 2:
345 		return (struct i2c_regs *)I2C2_BASE;
346 #endif
347 #if I2C_BUS_MAX >= 2
348 	case 1:
349 		return (struct i2c_regs *)I2C1_BASE;
350 #endif
351 	case 0:
352 		return (struct i2c_regs *)I2C_BASE;
353 
354 	default:
355 		printf("wrong hwadapnr: %d\n", adap->hwadapnr);
356 	}
357 
358 	return NULL;
359 }
360 
361 U_BOOT_I2C_ADAP_COMPLETE(davinci_0, davinci_i2c_init, davinci_i2c_probe,
362 			 davinci_i2c_read, davinci_i2c_write,
363 			 davinci_i2c_setspeed,
364 			 CONFIG_SYS_DAVINCI_I2C_SPEED,
365 			 CONFIG_SYS_DAVINCI_I2C_SLAVE,
366 			 0)
367 
368 #if I2C_BUS_MAX >= 2
369 U_BOOT_I2C_ADAP_COMPLETE(davinci_1, davinci_i2c_init, davinci_i2c_probe,
370 			 davinci_i2c_read, davinci_i2c_write,
371 			 davinci_i2c_setspeed,
372 			 CONFIG_SYS_DAVINCI_I2C_SPEED1,
373 			 CONFIG_SYS_DAVINCI_I2C_SLAVE1,
374 			 1)
375 #endif
376 
377 #if I2C_BUS_MAX >= 3
378 U_BOOT_I2C_ADAP_COMPLETE(davinci_2, davinci_i2c_init, davinci_i2c_probe,
379 			 davinci_i2c_read, davinci_i2c_write,
380 			 davinci_i2c_setspeed,
381 			 CONFIG_SYS_DAVINCI_I2C_SPEED2,
382 			 CONFIG_SYS_DAVINCI_I2C_SLAVE2,
383 			 2)
384 #endif
385