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2016-06-09device: i2c: Add support for I2C bus operationsDuncan Laurie
In order to support doing bus operations on an I2C device that is described in the devicetree there needs to be some linkage of the device and the existing opaque I2C controller bus number. This is provided in a similar fashion to the existing SMBUS operations but modified to fit within the existing I2C infrastructure. Variants of the existing I2C helper functions are provided that will obtain the bus number that corresponds to this device by looking for the SOC-provided I2C bus operation structure to provide a function that will make that translation. For example an SOC using a PCI I2C controller at 0:15.0 could use: soc/intel/.../i2c.c: static int i2c_dev_to_bus(struct device *dev) { if (dev->path.pci.devfn == PCI_DEVFN(0x15, 0)) return 0; return -1; } static struct i2c_bus_operation i2c_bus_ops = { .dev_to_bus = &i2c_dev_to_bus } static struct device_operations i2c_dev_ops = { .ops_i2c_bus = &i2c_bus_ops ... } With an I2C device on that bus at address 0x1a described in the tree: devicetree.cb: device pci 15.0 on # I2C0 chip drivers/i2c/sample device i2c 1a.0 on end end end That driver can then do I2C transactions with the device object without needing to know that the SOC-specific bus number that this I2C device lives on is "0". For example it could read a version value from register address 0 with a byte transaction: drivers/i2c/sample/sample.c: static void i2c_sample_enable(struct device *dev) { uint8_t ver; if (!i2c_dev_readb(dev, 0x00, &ver)) printk(BIOS_INFO, "I2C %s version 0x02x\n", dev_path(dev), ver); } Change-Id: I6c41c8e0d10caabe01cc41da96382074de40e91e Signed-off-by: Duncan Laurie <dlaurie@chromium.org> Reviewed-on: https://review.coreboot.org/15100 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin <adurbin@chromium.org>
2016-03-21device: Add i2c read/write register field APIYidi Lin
i2c_read_field() - read the value from the specific register field i2c_write_field() - write the value to the specific register field BRANCH=none BUG=none TEST=none Change-Id: I2098715b4583c1936c93b3ff45ec330910964304 Signed-off-by: Patrick Georgi <pgeorgi@chromium.org> Original-Commit-Id: 0817fc76d07491b39c066f1393a6435f0831b50c Original-Change-Id: I92c187a89d10cfcecf3dfd9291e0bc015459c393 Original-Signed-off-by: Yidi Lin <yidi.lin@mediatek.com> Original-Reviewed-on: https://chromium-review.googlesource.com/332712 Original-Reviewed-by: Julius Werner <jwerner@chromium.org> Reviewed-on: https://review.coreboot.org/14105 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org> Reviewed-by: Martin Roth <martinroth@google.com>