xref: /openbmc/u-boot/drivers/i2c/i2c_core.c (revision 282ce645)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2009 Sergey Kubushyn <ksi@koi8.net>
4  *
5  * (C) Copyright 2012
6  * Heiko Schocher, DENX Software Engineering, hs@denx.de.
7  *
8  * Multibus/multiadapter I2C core functions (wrappers)
9  */
10 #include <common.h>
11 #include <i2c.h>
12 
13 struct i2c_adapter *i2c_get_adapter(int index)
14 {
15 	struct i2c_adapter *i2c_adap_p = ll_entry_start(struct i2c_adapter,
16 						i2c);
17 	int max = ll_entry_count(struct i2c_adapter, i2c);
18 	int i;
19 
20 	if (index >= max) {
21 		printf("Error, wrong i2c adapter %d max %d possible\n",
22 		       index, max);
23 		return i2c_adap_p;
24 	}
25 	if (index == 0)
26 		return i2c_adap_p;
27 
28 	for (i = 0; i < index; i++)
29 		i2c_adap_p++;
30 
31 	return i2c_adap_p;
32 }
33 
34 #if !defined(CONFIG_SYS_I2C_DIRECT_BUS)
35 struct i2c_bus_hose i2c_bus[CONFIG_SYS_NUM_I2C_BUSES] =
36 			CONFIG_SYS_I2C_BUSES;
37 #endif
38 
39 DECLARE_GLOBAL_DATA_PTR;
40 
41 #ifndef CONFIG_SYS_I2C_DIRECT_BUS
42 /*
43  * i2c_mux_set()
44  * -------------
45  *
46  * This turns on the given channel on I2C multiplexer chip connected to
47  * a given I2C adapter directly or via other multiplexers. In the latter
48  * case the entire multiplexer chain must be initialized first starting
49  * with the one connected directly to the adapter. When disabling a chain
50  * muxes must be programmed in reverse order, starting with the one
51  * farthest from the adapter.
52  *
53  * mux_id is the multiplexer chip type from defined in i2c.h. So far only
54  * NXP (Philips) PCA954x multiplexers are supported. Switches are NOT
55  * supported (anybody uses them?)
56  */
57 
58 static int i2c_mux_set(struct i2c_adapter *adap, int mux_id, int chip,
59 			int channel)
60 {
61 	uint8_t	buf;
62 	int ret;
63 
64 	/* channel < 0 - turn off the mux */
65 	if (channel < 0) {
66 		buf = 0;
67 		ret = adap->write(adap, chip, 0, 0, &buf, 1);
68 		if (ret)
69 			printf("%s: Could not turn off the mux.\n", __func__);
70 		return ret;
71 	}
72 
73 	switch (mux_id) {
74 	case I2C_MUX_PCA9540_ID:
75 	case I2C_MUX_PCA9542_ID:
76 		if (channel > 1)
77 			return -1;
78 		buf = (uint8_t)((channel & 0x01) | (1 << 2));
79 		break;
80 	case I2C_MUX_PCA9544_ID:
81 		if (channel > 3)
82 			return -1;
83 		buf = (uint8_t)((channel & 0x03) | (1 << 2));
84 		break;
85 	case I2C_MUX_PCA9547_ID:
86 		if (channel > 7)
87 			return -1;
88 		buf = (uint8_t)((channel & 0x07) | (1 << 3));
89 		break;
90 	case I2C_MUX_PCA9548_ID:
91 		if (channel > 7)
92 			return -1;
93 		buf = (uint8_t)(0x01 << channel);
94 		break;
95 	default:
96 		printf("%s: wrong mux id: %d\n", __func__, mux_id);
97 		return -1;
98 	}
99 
100 	ret = adap->write(adap, chip, 0, 0, &buf, 1);
101 	if (ret)
102 		printf("%s: could not set mux: id: %d chip: %x channel: %d\n",
103 		       __func__, mux_id, chip, channel);
104 	return ret;
105 }
106 
107 static int i2c_mux_set_all(void)
108 {
109 	struct i2c_bus_hose *i2c_bus_tmp = &i2c_bus[I2C_BUS];
110 	int i;
111 
112 	/* Connect requested bus if behind muxes */
113 	if (i2c_bus_tmp->next_hop[0].chip != 0) {
114 		/* Set all muxes along the path to that bus */
115 		for (i = 0; i < CONFIG_SYS_I2C_MAX_HOPS; i++) {
116 			int	ret;
117 
118 			if (i2c_bus_tmp->next_hop[i].chip == 0)
119 				break;
120 
121 			ret = i2c_mux_set(I2C_ADAP,
122 					i2c_bus_tmp->next_hop[i].mux.id,
123 					i2c_bus_tmp->next_hop[i].chip,
124 					i2c_bus_tmp->next_hop[i].channel);
125 			if (ret != 0)
126 				return ret;
127 		}
128 	}
129 	return 0;
130 }
131 
132 static int i2c_mux_disconnect_all(void)
133 {
134 	struct	i2c_bus_hose *i2c_bus_tmp = &i2c_bus[I2C_BUS];
135 	int	i;
136 	uint8_t	buf = 0;
137 
138 	if (I2C_ADAP->init_done == 0)
139 		return 0;
140 
141 	/* Disconnect current bus (turn off muxes if any) */
142 	if ((i2c_bus_tmp->next_hop[0].chip != 0) &&
143 	    (I2C_ADAP->init_done != 0)) {
144 		i = CONFIG_SYS_I2C_MAX_HOPS;
145 		do {
146 			uint8_t	chip;
147 			int ret;
148 
149 			chip = i2c_bus_tmp->next_hop[--i].chip;
150 			if (chip == 0)
151 				continue;
152 
153 			ret = I2C_ADAP->write(I2C_ADAP, chip, 0, 0, &buf, 1);
154 			if (ret != 0) {
155 				printf("i2c: mux disconnect error\n");
156 				return ret;
157 			}
158 		} while (i > 0);
159 	}
160 
161 	return 0;
162 }
163 #endif
164 
165 /*
166  * i2c_init_bus():
167  * ---------------
168  *
169  * Initializes one bus. Will initialize the parent adapter. No current bus
170  * changes, no mux (if any) setup.
171  */
172 static void i2c_init_bus(unsigned int bus_no, int speed, int slaveaddr)
173 {
174 	if (bus_no >= CONFIG_SYS_NUM_I2C_BUSES)
175 		return;
176 
177 	I2C_ADAP->init(I2C_ADAP, speed, slaveaddr);
178 
179 	if (gd->flags & GD_FLG_RELOC) {
180 		I2C_ADAP->init_done = 1;
181 		I2C_ADAP->speed = speed;
182 		I2C_ADAP->slaveaddr = slaveaddr;
183 	}
184 }
185 
186 /* implement possible board specific board init */
187 __weak void i2c_init_board(void)
188 {
189 }
190 
191 /* implement possible for i2c specific early i2c init */
192 __weak void i2c_early_init_f(void)
193 {
194 }
195 
196 /*
197  * i2c_init_all():
198  *
199  * not longer needed, will deleted. Actual init the SPD_BUS
200  * for compatibility.
201  * i2c_adap[] must be initialized beforehead with function pointers and
202  * data, including speed and slaveaddr.
203  */
204 void i2c_init_all(void)
205 {
206 	i2c_init_board();
207 	i2c_set_bus_num(CONFIG_SYS_SPD_BUS_NUM);
208 	return;
209 }
210 
211 /*
212  * i2c_get_bus_num():
213  * ------------------
214  *
215  *  Returns index of currently active I2C bus.  Zero-based.
216  */
217 unsigned int i2c_get_bus_num(void)
218 {
219 	return gd->cur_i2c_bus;
220 }
221 
222 /*
223  * i2c_set_bus_num():
224  * ------------------
225  *
226  *  Change the active I2C bus. Subsequent read/write calls will
227  *  go to this one. Sets all of the muxes in a proper condition
228  *  if that bus is behind muxes.
229  *  If previously selected bus is behind the muxes turns off all the
230  *  muxes along the path to that bus.
231  *
232  *	bus - bus index, zero based
233  *
234  *	Returns: 0 on success, not 0 on failure
235  */
236 int i2c_set_bus_num(unsigned int bus)
237 {
238 	int max;
239 
240 	if ((bus == I2C_BUS) && (I2C_ADAP->init_done > 0))
241 		return 0;
242 
243 #ifndef CONFIG_SYS_I2C_DIRECT_BUS
244 	if (bus >= CONFIG_SYS_NUM_I2C_BUSES)
245 		return -1;
246 #endif
247 
248 	max = ll_entry_count(struct i2c_adapter, i2c);
249 	if (I2C_ADAPTER(bus) >= max) {
250 		printf("Error, wrong i2c adapter %d max %d possible\n",
251 		       I2C_ADAPTER(bus), max);
252 		return -2;
253 	}
254 
255 #ifndef CONFIG_SYS_I2C_DIRECT_BUS
256 	i2c_mux_disconnect_all();
257 #endif
258 
259 	gd->cur_i2c_bus = bus;
260 	if (I2C_ADAP->init_done == 0)
261 		i2c_init_bus(bus, I2C_ADAP->speed, I2C_ADAP->slaveaddr);
262 
263 #ifndef CONFIG_SYS_I2C_DIRECT_BUS
264 	i2c_mux_set_all();
265 #endif
266 	return 0;
267 }
268 
269 /*
270  * Probe the given I2C chip address.  Returns 0 if a chip responded,
271  * not 0 on failure.
272  */
273 int i2c_probe(uint8_t chip)
274 {
275 	return I2C_ADAP->probe(I2C_ADAP, chip);
276 }
277 
278 /*
279  * Read/Write interface:
280  *   chip:    I2C chip address, range 0..127
281  *   addr:    Memory (register) address within the chip
282  *   alen:    Number of bytes to use for addr (typically 1, 2 for larger
283  *              memories, 0 for register type devices with only one
284  *              register)
285  *   buffer:  Where to read/write the data
286  *   len:     How many bytes to read/write
287  *
288  *   Returns: 0 on success, not 0 on failure
289  */
290 int i2c_read(uint8_t chip, unsigned int addr, int alen,
291 				uint8_t *buffer, int len)
292 {
293 	return I2C_ADAP->read(I2C_ADAP, chip, addr, alen, buffer, len);
294 }
295 
296 int i2c_write(uint8_t chip, unsigned int addr, int alen,
297 				uint8_t *buffer, int len)
298 {
299 	return I2C_ADAP->write(I2C_ADAP, chip, addr, alen, buffer, len);
300 }
301 
302 unsigned int i2c_set_bus_speed(unsigned int speed)
303 {
304 	unsigned int ret;
305 
306 	if (I2C_ADAP->set_bus_speed == NULL)
307 		return 0;
308 	ret = I2C_ADAP->set_bus_speed(I2C_ADAP, speed);
309 	if (gd->flags & GD_FLG_RELOC)
310 		I2C_ADAP->speed = (ret == 0) ? speed : 0;
311 
312 	return ret;
313 }
314 
315 unsigned int i2c_get_bus_speed(void)
316 {
317 	struct i2c_adapter *cur = I2C_ADAP;
318 	return cur->speed;
319 }
320 
321 uint8_t i2c_reg_read(uint8_t addr, uint8_t reg)
322 {
323 	uint8_t buf;
324 
325 	i2c_read(addr, reg, 1, &buf, 1);
326 
327 #ifdef DEBUG
328 	printf("%s: bus=%d addr=0x%02x, reg=0x%02x, val=0x%02x\n",
329 	       __func__, i2c_get_bus_num(), addr, reg, buf);
330 #endif
331 
332 	return buf;
333 }
334 
335 void i2c_reg_write(uint8_t addr, uint8_t reg, uint8_t val)
336 {
337 #ifdef DEBUG
338 	printf("%s: bus=%d addr=0x%02x, reg=0x%02x, val=0x%02x\n",
339 	       __func__, i2c_get_bus_num(), addr, reg, val);
340 #endif
341 
342 	i2c_write(addr, reg, 1, &val, 1);
343 }
344 
345 __weak void i2c_init(int speed, int slaveaddr)
346 {
347 	i2c_init_bus(i2c_get_bus_num(), speed, slaveaddr);
348 }
349