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| author | Felix Held <felix-coreboot@felixheld.de> | 2022-03-08 17:48:59 +0100 |
|---|---|---|
| committer | Felix Held <felix-coreboot@felixheld.de> | 2022-04-27 16:07:29 +0000 |
| commit | 8fbf88fd8cbcd76274a2f418f08a80fc4d93fe13 (patch) | |
| tree | 4ac4b95a3fbf249d229b6290c5e896e8c3259a35 /src/include | |
| parent | 66538e08770794b4bf7baadc53f167a405b870bc (diff) | |
include/device/i2c_simple: add i2c_2ba_read_bytes function
To read data from an I2C EEPROM that uses 2 byte offsets or any other
I2C device that uses 2 byte offsets, first the two offset bytes are sent
to the device and then the data bytes are read from it. The main
difference to the existing i2c_read_bytes is that that function will
only send one offset byte to the I2C device.
TEST=Reading the contents of an EEPROM on the AMD Chausie board works
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I224e434bb2654aabef6302c1525112e44c4b21fa
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63791
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Fred Reitberger <reitbergerfred@gmail.com>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Diffstat (limited to 'src/include')
| -rw-r--r-- | src/include/device/i2c_simple.h | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/src/include/device/i2c_simple.h b/src/include/device/i2c_simple.h index 8f389b3107..9f3af1130e 100644 --- a/src/include/device/i2c_simple.h +++ b/src/include/device/i2c_simple.h @@ -142,4 +142,32 @@ static inline int i2c_writeb(unsigned int bus, uint8_t slave, uint8_t reg, return i2c_transfer(bus, &seg, 1); } +/** + * Read multi-bytes from an I2C device with two bytes register address/offset + * with two segments in one frame + * + * [start][slave addr][w][register high addr][register low addr] + * [start][slave addr][r][data...][stop] + */ +static inline int i2c_2ba_read_bytes(unsigned int bus, uint8_t slave, uint16_t offset, + uint8_t *data, int len) +{ + struct i2c_msg seg[2]; + uint8_t eeprom_offset[2]; + + eeprom_offset[0] = offset >> 8; + eeprom_offset[1] = offset & 0xff; + + seg[0].flags = 0; + seg[0].slave = slave; + seg[0].buf = eeprom_offset; + seg[0].len = sizeof(eeprom_offset); + seg[1].flags = I2C_M_RD; + seg[1].slave = slave; + seg[1].buf = data; + seg[1].len = len; + + return i2c_transfer(bus, seg, ARRAY_SIZE(seg)); +} + #endif /* _DEVICE_I2C_SIMPLE_H_ */ |