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device/i2c_bus: Add routines to read and write multiple bytes 

Some devices require that several bytes are written with a single I2C
write command. Extend the i2c_bus interface functions and add both, read
and write for more than one byte at a defined byte offset.

Change-Id: I0eec2e1d4185170f02b4ab35aa6546dc69569303
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/67098
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Mario Scheithauer <mario.scheithauer@siemens.com>
This commit is contained in:
Werner Zeh 2022-08-26 13:17:52 +02:00 committed by Martin L Roth
parent 74a00b9cec
commit 63f72f0cd0
2 changed files with 84 additions and 0 deletions
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70
src/device/i2c_bus.c
View File

@ -183,3 +183,73 @@ int i2c_dev_read_at16(struct device *const dev, uint8_t *const buf, const size_t
return -1;
}
}
int i2c_dev_read_at(struct device *const dev, uint8_t *const buf, const size_t len,
uint8_t off)
{
struct device *const busdev = i2c_busdev(dev);
if (!busdev)
return -1;
if (busdev->ops->ops_i2c_bus) {
const struct i2c_msg msg[] = {
{
.flags = 0,
.slave = dev->path.i2c.device,
.buf = &off,
.len = sizeof(off),
},
{
.flags = I2C_M_RD,
.slave = dev->path.i2c.device,
.buf = buf,
.len = len,
},
};
const int ret = busdev->ops->ops_i2c_bus->transfer(busdev, msg,
ARRAY_SIZE(msg));
if (ret)
return ret;
else
return len;
} else {
printk(BIOS_ERR, "%s Missing ops_i2c_bus->transfer", dev_path(busdev));
return -1;
}
}
int i2c_dev_write_at(struct device *const dev, uint8_t *const buf, const size_t len,
uint8_t off)
{
struct device *const busdev = i2c_busdev(dev);
if (!busdev)
return -1;
if (busdev->ops->ops_i2c_bus) {
const struct i2c_msg msg[] = {
{
.flags = 0,
.slave = dev->path.i2c.device,
.buf = &off,
.len = sizeof(off),
},
{
.flags = I2C_M_NOSTART,
.slave = dev->path.i2c.device,
.buf = buf,
.len = len,
},
};
const int ret = busdev->ops->ops_i2c_bus->transfer(busdev, msg,
ARRAY_SIZE(msg));
if (ret)
return ret;
else
return len;
} else {
printk(BIOS_ERR, "%s Missing ops_i2c_bus->transfer", dev_path(busdev));
return -1;
}
}

14
src/include/device/i2c_bus.h
View File

@ -90,5 +90,19 @@ int i2c_dev_writeb_at(struct device *, uint8_t off, uint8_t val);
* value on error.
*/
int i2c_dev_read_at16(struct device *, uint8_t *buf, size_t len, uint16_t off);
/*
* Sends the 8-bit register offset `off` and reads `len` bytes into `buf`.
*
* Returns the number of bytes read on success, negative `enum cb_err`
* value on error.
*/
int i2c_dev_read_at(struct device *, uint8_t *buf, size_t len, uint8_t off);
/*
* Sends the 8-bit register offset `off` and writes `len` bytes from `buf`.
*
* Returns the number of bytes written on success, negative `enum cb_err`
* value on error.
*/
int i2c_dev_write_at(struct device *, uint8_t *buf, size_t len, uint8_t off);
#endif /* _DEVICE_I2C_BUS_H_ */