xref: /openbmc/u-boot/include/i2c.h (revision 5794619e)
1 /*
2  * (C) Copyright 2001
3  * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
4  *
5  * See file CREDITS for list of people who contributed to this
6  * project.
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License as
10  * published by the Free Software Foundation; either version 2 of
11  * the License, or (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
21  * MA 02111-1307 USA
22  *
23  * The original I2C interface was
24  *   (C) 2000 by Paolo Scaffardi (arsenio@tin.it)
25  *   AIRVENT SAM s.p.a - RIMINI(ITALY)
26  * but has been changed substantially.
27  */
28 
29 #ifndef _I2C_H_
30 #define _I2C_H_
31 
32 /*
33  * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
34  *
35  * The implementation MUST NOT use static or global variables if the
36  * I2C routines are used to read SDRAM configuration information
37  * because this is done before the memories are initialized. Limited
38  * use of stack-based variables are OK (the initial stack size is
39  * limited).
40  *
41  * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
42  */
43 
44 /*
45  * Configuration items.
46  */
47 #define I2C_RXTX_LEN	128	/* maximum tx/rx buffer length */
48 
49 #if defined(CONFIG_I2C_MULTI_BUS)
50 #if !defined(CONFIG_SYS_MAX_I2C_BUS)
51 #define CONFIG_SYS_MAX_I2C_BUS		2
52 #endif
53 #define I2C_GET_BUS()		i2c_get_bus_num()
54 #define I2C_SET_BUS(a)		i2c_set_bus_num(a)
55 #else
56 #define CONFIG_SYS_MAX_I2C_BUS		1
57 #define I2C_GET_BUS()		0
58 #define I2C_SET_BUS(a)
59 #endif
60 
61 /* define the I2C bus number for RTC and DTT if not already done */
62 #if !defined(CONFIG_SYS_RTC_BUS_NUM)
63 #define CONFIG_SYS_RTC_BUS_NUM		0
64 #endif
65 #if !defined(CONFIG_SYS_DTT_BUS_NUM)
66 #define CONFIG_SYS_DTT_BUS_NUM		0
67 #endif
68 #if !defined(CONFIG_SYS_SPD_BUS_NUM)
69 #define CONFIG_SYS_SPD_BUS_NUM		0
70 #endif
71 
72 #ifndef I2C_SOFT_DECLARATIONS
73 # if defined(CONFIG_MPC8260)
74 #  define I2C_SOFT_DECLARATIONS volatile ioport_t *iop = ioport_addr((immap_t *)CONFIG_SYS_IMMR, I2C_PORT);
75 # elif defined(CONFIG_8xx)
76 #  define I2C_SOFT_DECLARATIONS	volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR;
77 
78 # elif (defined(CONFIG_AT91RM9200) || \
79 	defined(CONFIG_AT91SAM9260) ||  defined(CONFIG_AT91SAM9261) || \
80 	defined(CONFIG_AT91SAM9263)) && !defined(CONFIG_AT91_LEGACY)
81 #  define I2C_SOFT_DECLARATIONS	at91_pio_t *pio	= (at91_pio_t *) AT91_PIO_BASE;
82 # else
83 #  define I2C_SOFT_DECLARATIONS
84 # endif
85 #endif
86 
87 #ifdef CONFIG_8xx
88 /* Set default value for the I2C bus speed on 8xx. In the
89  * future, we'll define these in all 8xx board config files.
90  */
91 #ifndef	CONFIG_SYS_I2C_SPEED
92 #define	CONFIG_SYS_I2C_SPEED	50000
93 #endif
94 #endif
95 
96 /*
97  * Many boards/controllers/drivers don't support an I2C slave interface so
98  * provide a default slave address for them for use in common code.  A real
99  * value for CONFIG_SYS_I2C_SLAVE should be defined for any board which does
100  * support a slave interface.
101  */
102 #ifndef	CONFIG_SYS_I2C_SLAVE
103 #define	CONFIG_SYS_I2C_SLAVE	0xfe
104 #endif
105 
106 /*
107  * Initialization, must be called once on start up, may be called
108  * repeatedly to change the speed and slave addresses.
109  */
110 void i2c_init(int speed, int slaveaddr);
111 #ifdef CONFIG_SYS_I2C_INIT_BOARD
112 void i2c_init_board(void);
113 #endif
114 #ifdef CONFIG_SYS_I2C_BOARD_LATE_INIT
115 void i2c_board_late_init(void);
116 #endif
117 
118 #if defined(CONFIG_I2C_MUX)
119 
120 typedef struct _mux {
121 	uchar	chip;
122 	uchar	channel;
123 	char	*name;
124 	struct _mux	*next;
125 } I2C_MUX;
126 
127 typedef struct _mux_device {
128 	int	busid;
129 	I2C_MUX	*mux;	/* List of muxes, to reach the device */
130 	struct _mux_device	*next;
131 } I2C_MUX_DEVICE;
132 
133 I2C_MUX_DEVICE	*i2c_mux_search_device(int id);
134 I2C_MUX_DEVICE *i2c_mux_ident_muxstring (uchar *buf);
135 int i2x_mux_select_mux(int bus);
136 int i2c_mux_ident_muxstring_f (uchar *buf);
137 #endif
138 
139 /*
140  * Probe the given I2C chip address.  Returns 0 if a chip responded,
141  * not 0 on failure.
142  */
143 int i2c_probe(uchar chip);
144 
145 /*
146  * Read/Write interface:
147  *   chip:    I2C chip address, range 0..127
148  *   addr:    Memory (register) address within the chip
149  *   alen:    Number of bytes to use for addr (typically 1, 2 for larger
150  *              memories, 0 for register type devices with only one
151  *              register)
152  *   buffer:  Where to read/write the data
153  *   len:     How many bytes to read/write
154  *
155  *   Returns: 0 on success, not 0 on failure
156  */
157 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len);
158 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len);
159 
160 /*
161  * Utility routines to read/write registers.
162  */
163 static inline u8 i2c_reg_read(u8 addr, u8 reg)
164 {
165 	u8 buf;
166 
167 #ifdef CONFIG_8xx
168 	/* MPC8xx needs this.  Maybe one day we can get rid of it. */
169 	i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
170 #endif
171 
172 #ifdef DEBUG
173 	printf("%s: addr=0x%02x, reg=0x%02x\n", __func__, addr, reg);
174 #endif
175 
176 	i2c_read(addr, reg, 1, &buf, 1);
177 
178 	return buf;
179 }
180 
181 static inline void i2c_reg_write(u8 addr, u8 reg, u8 val)
182 {
183 #ifdef CONFIG_8xx
184 	/* MPC8xx needs this.  Maybe one day we can get rid of it. */
185 	i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
186 #endif
187 
188 #ifdef DEBUG
189 	printf("%s: addr=0x%02x, reg=0x%02x, val=0x%02x\n",
190 	       __func__, addr, reg, val);
191 #endif
192 
193 	i2c_write(addr, reg, 1, &val, 1);
194 }
195 
196 /*
197  * Functions for setting the current I2C bus and its speed
198  */
199 
200 /*
201  * i2c_set_bus_num:
202  *
203  *  Change the active I2C bus.  Subsequent read/write calls will
204  *  go to this one.
205  *
206  *	bus - bus index, zero based
207  *
208  *	Returns: 0 on success, not 0 on failure
209  *
210  */
211 int i2c_set_bus_num(unsigned int bus);
212 
213 /*
214  * i2c_get_bus_num:
215  *
216  *  Returns index of currently active I2C bus.  Zero-based.
217  */
218 
219 unsigned int i2c_get_bus_num(void);
220 
221 /*
222  * i2c_set_bus_speed:
223  *
224  *  Change the speed of the active I2C bus
225  *
226  *	speed - bus speed in Hz
227  *
228  *	Returns: 0 on success, not 0 on failure
229  *
230  */
231 int i2c_set_bus_speed(unsigned int);
232 
233 /*
234  * i2c_get_bus_speed:
235  *
236  *  Returns speed of currently active I2C bus in Hz
237  */
238 
239 unsigned int i2c_get_bus_speed(void);
240 
241 #endif	/* _I2C_H_ */
242