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Reinvent I2C ops

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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>
This commit is contained in:
Nico Huber
2017-08-01 17:09:35 +02:00
committed by Martin Roth
parent 0f2dd1eff9
commit 581738642f
9 changed files with 267 additions and 112 deletions
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83
src/device/i2c.c
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@@ -13,92 +13,9 @@
* GNU General Public License for more details.
*/
#include <device/device.h>
#include <device/i2c_bus.h>
#include <device/i2c_simple.h>
#include <stdint.h>
#if ENV_RAMSTAGE
/* Return I2C operations for a bus */
static inline const struct i2c_bus_operations *ops_i2c_bus(struct bus *bus)
{
if (bus && bus->dev && bus->dev->ops)
return bus->dev->ops->ops_i2c_bus;
return NULL;
}
int i2c_dev_find_bus(struct device *dev)
{
const struct i2c_bus_operations *ops;
struct bus *pbus;
if (!dev)
return -1;
/* Locate parent bus with I2C controller ops */
pbus = dev->bus;
while (pbus && pbus->dev && !ops_i2c_bus(pbus))
if (pbus->dev->bus != pbus)
pbus = pbus->dev->bus;
/* Check if this I2C controller ops implements dev_to_bus() */
ops = ops_i2c_bus(pbus);
if (!ops || !ops->dev_to_bus)
return -1;
/* Use controller ops to determine the bus number */
return ops->dev_to_bus(pbus->dev);
}
int i2c_dev_transfer(struct device *dev, struct i2c_msg *segments, int count)
{
int bus = i2c_dev_find_bus(dev);
if (bus < 0)
return -1;
return i2c_transfer(bus, segments, count);
}
int i2c_dev_readb(struct device *dev, uint8_t reg, uint8_t *data)
{
int bus = i2c_dev_find_bus(dev);
if (bus < 0)
return -1;
return i2c_readb(bus, dev->path.i2c.device, reg, data);
}
int i2c_dev_writeb(struct device *dev, uint8_t reg, uint8_t data)
{
int bus = i2c_dev_find_bus(dev);
if (bus < 0)
return -1;
return i2c_writeb(bus, dev->path.i2c.device, reg, data);
}
int i2c_dev_read_bytes(struct device *dev, uint8_t reg, uint8_t *data, int len)
{
int bus = i2c_dev_find_bus(dev);
if (bus < 0)
return -1;
return i2c_read_bytes(bus, dev->path.i2c.device, reg, data, len);
}
int i2c_dev_read_raw(struct device *dev, uint8_t *data, int len)
{
int bus = i2c_dev_find_bus(dev);
if (bus < 0)
return -1;
return i2c_read_raw(bus, dev->path.i2c.device, data, len);
}
int i2c_dev_write_raw(struct device *dev, uint8_t *data, int len)
{
int bus = i2c_dev_find_bus(dev);
if (bus < 0)
return -1;
return i2c_write_raw(bus, dev->path.i2c.device, data, len);
}
#endif
int i2c_read_field(unsigned bus, uint8_t chip, uint8_t reg, uint8_t *data,
uint8_t mask, uint8_t shift)
{