Duncan Laurie (dlaurie@chromium.org) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/15100
-gerrit
commit c83513647005ac67a2a9e1e43145dfdb5cd0f8e3 Author: Duncan Laurie dlaurie@chromium.org Date: Tue Jun 7 15:38:14 2016 -0700
device: i2c: Add support for I2C bus operations
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 --- src/device/i2c.c | 83 +++++++++++++++++++++++++++++++++++++++++++++ src/include/device/device.h | 2 ++ src/include/device/i2c.h | 22 ++++++++++++ 3 files changed, 107 insertions(+)
diff --git a/src/device/i2c.c b/src/device/i2c.c index 53bfdf0..d4670a0 100644 --- a/src/device/i2c.c +++ b/src/device/i2c.c @@ -13,7 +13,90 @@ * GNU General Public License for more details. */
+#include <device/device.h> #include <device/i2c.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_seg *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) diff --git a/src/include/device/device.h b/src/include/device/device.h index 00ff3d9..95fabf4 100644 --- a/src/include/device/device.h +++ b/src/include/device/device.h @@ -20,6 +20,7 @@ struct device; typedef struct device * device_t; struct pci_operations; struct pci_bus_operations; +struct i2c_bus_operations; struct smbus_bus_operations; struct pnp_mode_ops;
@@ -62,6 +63,7 @@ struct device_operations { const char *(*acpi_name)(device_t dev); #endif const struct pci_operations *ops_pci; + const struct i2c_bus_operations *ops_i2c_bus; const struct smbus_bus_operations *ops_smbus_bus; const struct pci_bus_operations * (*ops_pci_bus)(device_t dev); const struct pnp_mode_ops *ops_pnp_mode; diff --git a/src/include/device/i2c.h b/src/include/device/i2c.h index c8c7b22..d8a793c 100644 --- a/src/include/device/i2c.h +++ b/src/include/device/i2c.h @@ -168,4 +168,26 @@ static inline int i2c_writeb(unsigned bus, uint8_t chip, uint8_t reg, return i2c_transfer(bus, &seg, 1); }
+/* I2C bus operation for ramstage drivers */ +struct device; +struct i2c_bus_operations { + /* + * This is an SOC specific method that can be provided to translate the + * 'struct device' for an I2C controller into a unique I2C bus number. + * Returns -1 if the bus number for this device cannot be determined. + */ + int (*dev_to_bus)(struct device *dev); +}; + +/* Return I2C bus number for provided device, -1 if not found */ +int i2c_dev_find_bus(struct device *dev); + +/* Variants of I2C helper functions that take a device instead of bus number */ +int i2c_dev_transfer(struct device *dev, struct i2c_seg *segments, int count); +int i2c_dev_readb(struct device *dev, uint8_t reg, uint8_t *data); +int i2c_dev_writeb(struct device *dev, uint8_t reg, uint8_t data); +int i2c_dev_read_bytes(struct device *dev, uint8_t reg, uint8_t *data, int len); +int i2c_dev_read_raw(struct device *dev, uint8_t *data, int len); +int i2c_dev_write_raw(struct device *dev, uint8_t *data, int len); + #endif /* _DEVICE_I2C_H_ */