Reinvent I2C ops

Do not use the global platform_i2c_transfer() function that can only be
implemented by a single driver. Instead, make a `struct device` aware
transfer() function the only interface function for I2C controller dri-
vers to implement.

To not force the slave device drivers to be implemented either above
generic I2C or specialized SMBus operations, we support SMBus control-
lers in the slave device interface too.

We start with four simple slave functions: i2c_readb(), i2c_writeb(),
i2c_readb_at() and i2c_writeb_at(). They are all compatible to respec-
tive SMBus functions. But we keep aliases because it would be weird to
force e.g. an I2C EEPROM driver to call smbus_read_byte().

Change-Id: I98386f91bf4799ba3df84ec8bc0f64edd4142818
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/20846
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/soc/intel/common/block/i2c/lpss_i2c.h b/src/soc/intel/common/block/i2c/lpss_i2c.h
index 2cb3d5ed52..72341621c0 100644
--- a/src/soc/intel/common/block/i2c/lpss_i2c.h
+++ b/src/soc/intel/common/block/i2c/lpss_i2c.h
@@ -89,3 +89,11 @@ int lpss_i2c_gen_speed_config(struct lpss_i2c_regs *regs,
 					enum i2c_speed speed,
 					const struct lpss_i2c_bus_config *bcfg,
 					struct lpss_i2c_speed_config *config);
+
+/*
+ * Process given I2C segments in a single transfer
+ * Return value:
+ * -1 = failure
+ *  0 = success
+ */
+int lpss_i2c_transfer(unsigned int bus, const struct i2c_msg *, size_t count);