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git.ipfire.org Git - people/ms/u-boot.git/blob - drivers/i2c/fsl_i2c.c
2 * Copyright 2006 Freescale Semiconductor, Inc.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * Version 2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
22 #ifdef CONFIG_HARD_I2C
25 #include <i2c.h> /* Functional interface */
28 #include <asm/fsl_i2c.h> /* HW definitions */
30 #define I2C_TIMEOUT (CFG_HZ / 4)
32 #define I2C_READ_BIT 1
33 #define I2C_WRITE_BIT 0
35 DECLARE_GLOBAL_DATA_PTR
;
37 /* Initialize the bus pointer to whatever one the SPD EEPROM is on.
38 * Default is bus 0. This is necessary because the DDR initialization
39 * runs from ROM, and we can't switch buses because we can't modify
40 * the global variables.
42 #ifdef CFG_SPD_BUS_NUM
43 static unsigned int i2c_bus_num
__attribute__ ((section ("data"))) = CFG_SPD_BUS_NUM
;
45 static unsigned int i2c_bus_num
__attribute__ ((section ("data"))) = 0;
48 static unsigned int i2c_bus_speed
[2] = {CFG_I2C_SPEED
, CFG_I2C_SPEED
};
50 static const struct fsl_i2c
*i2c_dev
[2] = {
51 (struct fsl_i2c
*) (CFG_IMMR
+ CFG_I2C_OFFSET
),
52 #ifdef CFG_I2C2_OFFSET
53 (struct fsl_i2c
*) (CFG_IMMR
+ CFG_I2C2_OFFSET
)
57 /* I2C speed map for a DFSR value of 1 */
60 * Map I2C frequency dividers to FDR and DFSR values
62 * This structure is used to define the elements of a table that maps I2C
63 * frequency divider (I2C clock rate divided by I2C bus speed) to a value to be
64 * programmed into the Frequency Divider Ratio (FDR) and Digital Filter
65 * Sampling Rate (DFSR) registers.
67 * The actual table should be defined in the board file, and it must be called
68 * fsl_i2c_speed_map[].
70 * The last entry of the table must have a value of {-1, X}, where X is same
71 * FDR/DFSR values as the second-to-last entry. This guarantees that any
72 * search through the array will always find a match.
74 * The values of the divider must be in increasing numerical order, i.e.
75 * fsl_i2c_speed_map[x+1].divider > fsl_i2c_speed_map[x].divider.
77 * For this table, the values are based on a value of 1 for the DFSR
78 * register. See the application note AN2919 "Determining the I2C Frequency
79 * Divider Ratio for SCL"
82 unsigned short divider
;
85 } fsl_i2c_speed_map
[] = {
86 {160, 1, 32}, {192, 1, 33}, {224, 1, 34}, {256, 1, 35},
87 {288, 1, 0}, {320, 1, 1}, {352, 6, 1}, {384, 1, 2}, {416, 6, 2},
88 {448, 1, 38}, {480, 1, 3}, {512, 1, 39}, {544, 11, 3}, {576, 1, 4},
89 {608, 22, 3}, {640, 1, 5}, {672, 32, 3}, {704, 11, 5}, {736, 43, 3},
90 {768, 1, 6}, {800, 54, 3}, {832, 11, 6}, {896, 1, 42}, {960, 1, 7},
91 {1024, 1, 43}, {1088, 22, 7}, {1152, 1, 8}, {1216, 43, 7}, {1280, 1, 9},
92 {1408, 22, 9}, {1536, 1, 10}, {1664, 22, 10}, {1792, 1, 46},
93 {1920, 1, 11}, {2048, 1, 47}, {2176, 43, 11}, {2304, 1, 12},
94 {2560, 1, 13}, {2816, 43, 13}, {3072, 1, 14}, {3328, 43, 14},
95 {3584, 1, 50}, {3840, 1, 15}, {4096, 1, 51}, {4608, 1, 16},
96 {5120, 1, 17}, {6144, 1, 18}, {7168, 1, 54}, {7680, 1, 19},
97 {8192, 1, 55}, {9216, 1, 20}, {10240, 1, 21}, {12288, 1, 22},
98 {14336, 1, 58}, {15360, 1, 23}, {16384, 1, 59}, {18432, 1, 24},
99 {20480, 1, 25}, {24576, 1, 26}, {28672, 1, 62}, {30720, 1, 27},
100 {32768, 1, 63}, {36864, 1, 28}, {40960, 1, 29}, {49152, 1, 30},
101 {61440, 1, 31}, {-1, 1, 31}
105 * Set the I2C bus speed for a given I2C device
107 * @param dev: the I2C device
108 * @i2c_clk: I2C bus clock frequency
109 * @speed: the desired speed of the bus
111 * The I2C device must be stopped before calling this function.
113 * The return value is the actual bus speed that is set.
115 static unsigned int set_i2c_bus_speed(const struct fsl_i2c
*dev
,
116 unsigned int i2c_clk
, unsigned int speed
)
118 unsigned short divider
= min(i2c_clk
/ speed
, (unsigned short) -1);
122 * We want to choose an FDR/DFSR that generates an I2C bus speed that
123 * is equal to or lower than the requested speed. That means that we
124 * want the first divider that is equal to or greater than the
125 * calculated divider.
128 for (i
= 0; i
< ARRAY_SIZE(fsl_i2c_speed_map
); i
++)
129 if (fsl_i2c_speed_map
[i
].divider
>= divider
) {
131 dfsr
= fsl_i2c_speed_map
[i
].dfsr
;
132 fdr
= fsl_i2c_speed_map
[i
].fdr
;
133 speed
= i2c_clk
/ fsl_i2c_speed_map
[i
].divider
;
134 writeb(fdr
, &dev
->fdr
); /* set bus speed */
135 writeb(dfsr
, &dev
->dfsrr
); /* set default filter */
143 i2c_init(int speed
, int slaveadd
)
147 dev
= (struct fsl_i2c
*) (CFG_IMMR
+ CFG_I2C_OFFSET
);
149 writeb(0, &dev
->cr
); /* stop I2C controller */
150 udelay(5); /* let it shutdown in peace */
151 i2c_bus_speed
[0] = set_i2c_bus_speed(dev
, gd
->i2c1_clk
, speed
);
152 writeb(slaveadd
<< 1, &dev
->adr
); /* write slave address */
153 writeb(0x0, &dev
->sr
); /* clear status register */
154 writeb(I2C_CR_MEN
, &dev
->cr
); /* start I2C controller */
156 #ifdef CFG_I2C2_OFFSET
157 dev
= (struct fsl_i2c
*) (CFG_IMMR
+ CFG_I2C2_OFFSET
);
159 writeb(0, &dev
->cr
); /* stop I2C controller */
160 udelay(5); /* let it shutdown in peace */
161 i2c_bus_speed
[1] = set_i2c_bus_speed(dev
, gd
->i2c2_clk
, speed
);
162 writeb(slaveadd
<< 1, &dev
->adr
); /* write slave address */
163 writeb(0x0, &dev
->sr
); /* clear status register */
164 writeb(I2C_CR_MEN
, &dev
->cr
); /* start I2C controller */
168 static __inline__
int
171 ulong timeval
= get_timer(0);
173 while (readb(&i2c_dev
[i2c_bus_num
]->sr
) & I2C_SR_MBB
) {
174 if (get_timer(timeval
) > I2C_TIMEOUT
) {
182 static __inline__
int
186 ulong timeval
= get_timer(0);
189 csr
= readb(&i2c_dev
[i2c_bus_num
]->sr
);
190 if (!(csr
& I2C_SR_MIF
))
193 writeb(0x0, &i2c_dev
[i2c_bus_num
]->sr
);
195 if (csr
& I2C_SR_MAL
) {
196 debug("i2c_wait: MAL\n");
200 if (!(csr
& I2C_SR_MCF
)) {
201 debug("i2c_wait: unfinished\n");
205 if (write
== I2C_WRITE_BIT
&& (csr
& I2C_SR_RXAK
)) {
206 debug("i2c_wait: No RXACK\n");
211 } while (get_timer (timeval
) < I2C_TIMEOUT
);
213 debug("i2c_wait: timed out\n");
217 static __inline__
int
218 i2c_write_addr (u8 dev
, u8 dir
, int rsta
)
220 writeb(I2C_CR_MEN
| I2C_CR_MSTA
| I2C_CR_MTX
221 | (rsta
? I2C_CR_RSTA
: 0),
222 &i2c_dev
[i2c_bus_num
]->cr
);
224 writeb((dev
<< 1) | dir
, &i2c_dev
[i2c_bus_num
]->dr
);
226 if (i2c_wait(I2C_WRITE_BIT
) < 0)
232 static __inline__
int
233 __i2c_write(u8
*data
, int length
)
237 writeb(I2C_CR_MEN
| I2C_CR_MSTA
| I2C_CR_MTX
,
238 &i2c_dev
[i2c_bus_num
]->cr
);
240 for (i
= 0; i
< length
; i
++) {
241 writeb(data
[i
], &i2c_dev
[i2c_bus_num
]->dr
);
243 if (i2c_wait(I2C_WRITE_BIT
) < 0)
250 static __inline__
int
251 __i2c_read(u8
*data
, int length
)
255 writeb(I2C_CR_MEN
| I2C_CR_MSTA
| ((length
== 1) ? I2C_CR_TXAK
: 0),
256 &i2c_dev
[i2c_bus_num
]->cr
);
259 readb(&i2c_dev
[i2c_bus_num
]->dr
);
261 for (i
= 0; i
< length
; i
++) {
262 if (i2c_wait(I2C_READ_BIT
) < 0)
265 /* Generate ack on last next to last byte */
267 writeb(I2C_CR_MEN
| I2C_CR_MSTA
| I2C_CR_TXAK
,
268 &i2c_dev
[i2c_bus_num
]->cr
);
270 /* Generate stop on last byte */
272 writeb(I2C_CR_MEN
| I2C_CR_TXAK
, &i2c_dev
[i2c_bus_num
]->cr
);
274 data
[i
] = readb(&i2c_dev
[i2c_bus_num
]->dr
);
281 i2c_read(u8 dev
, uint addr
, int alen
, u8
*data
, int length
)
283 int i
= -1; /* signal error */
286 if (i2c_wait4bus() >= 0
287 && i2c_write_addr(dev
, I2C_WRITE_BIT
, 0) != 0
288 && __i2c_write(&a
[4 - alen
], alen
) == alen
)
289 i
= 0; /* No error so far */
292 && i2c_write_addr(dev
, I2C_READ_BIT
, 1) != 0)
293 i
= __i2c_read(data
, length
);
295 writeb(I2C_CR_MEN
, &i2c_dev
[i2c_bus_num
]->cr
);
304 i2c_write(u8 dev
, uint addr
, int alen
, u8
*data
, int length
)
306 int i
= -1; /* signal error */
309 if (i2c_wait4bus() >= 0
310 && i2c_write_addr(dev
, I2C_WRITE_BIT
, 0) != 0
311 && __i2c_write(&a
[4 - alen
], alen
) == alen
) {
312 i
= __i2c_write(data
, length
);
315 writeb(I2C_CR_MEN
, &i2c_dev
[i2c_bus_num
]->cr
);
324 i2c_probe(uchar chip
)
326 /* For unknow reason the controller will ACK when
327 * probing for a slave with the same address, so skip
330 if (chip
== (readb(&i2c_dev
[i2c_bus_num
]->adr
) >> 1))
333 return i2c_read(chip
, 0, 0, NULL
, 0);
337 i2c_reg_read(uchar i2c_addr
, uchar reg
)
341 i2c_read(i2c_addr
, reg
, 1, buf
, 1);
347 i2c_reg_write(uchar i2c_addr
, uchar reg
, uchar val
)
349 i2c_write(i2c_addr
, reg
, 1, &val
, 1);
352 int i2c_set_bus_num(unsigned int bus
)
354 #ifdef CFG_I2C2_OFFSET
367 int i2c_set_bus_speed(unsigned int speed
)
369 unsigned int i2c_clk
= (i2c_bus_num
== 1) ? gd
->i2c2_clk
: gd
->i2c1_clk
;
371 writeb(0, &i2c_dev
[i2c_bus_num
]->cr
); /* stop controller */
372 i2c_bus_speed
[i2c_bus_num
] =
373 set_i2c_bus_speed(i2c_dev
[i2c_bus_num
], i2c_clk
, speed
);
374 writeb(I2C_CR_MEN
, &i2c_dev
[i2c_bus_num
]->cr
); /* start controller */
379 unsigned int i2c_get_bus_num(void)
384 unsigned int i2c_get_bus_speed(void)
386 return i2c_bus_speed
[i2c_bus_num
];
389 #endif /* CONFIG_HARD_I2C */
390 #endif /* CONFIG_FSL_I2C */