device/i2c_bus: Add i2c_dev_read_at16()

i2c_dev_read_at16() sends a 16-bit offset to the I2C chip (for larger
EEPROM parts), then reads bytes up to a given length into a buffer.

Change-Id: I7516f3e5d9aca362c2b340aa5627d91510c09412
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/29478
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
This commit is contained in:
Nico Huber 2017-11-01 13:15:33 +01:00 committed by Patrick Georgi
parent 9529530766
commit 9734af6697
2 changed files with 45 additions and 0 deletions

View File

@ -16,6 +16,7 @@
#include <console/console.h> #include <console/console.h>
#include <device/smbus.h> #include <device/smbus.h>
#include <device/i2c_bus.h> #include <device/i2c_bus.h>
#include <commonlib/endian.h>
struct bus *i2c_link(struct device *const dev) struct bus *i2c_link(struct device *const dev)
{ {
@ -159,3 +160,39 @@ int i2c_dev_writeb_at(struct device *const dev,
return -1; return -1;
} }
} }
int i2c_dev_read_at16(struct device *const dev,
uint8_t *const buf, const size_t len, uint16_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 = (uint8_t *)&off,
.len = sizeof(off),
},
{
.flags = I2C_M_RD,
.slave = dev->path.i2c.device,
.buf = buf,
.len = len,
},
};
write_be16(&off, off);
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;
}
}

View File

@ -89,4 +89,12 @@ int i2c_dev_readb_at(struct device *, uint8_t off);
*/ */
int i2c_dev_writeb_at(struct device *, uint8_t off, uint8_t val); int i2c_dev_writeb_at(struct device *, uint8_t off, uint8_t val);
/*
* Sends the 16-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_at16(struct device *, uint8_t *buf, size_t len, uint16_t off);
#endif /* _DEVICE_I2C_BUS_H_ */ #endif /* _DEVICE_I2C_BUS_H_ */