linux_dsm_epyc7002/Documentation/i2c/busses/i2c-ocores
Richard Röjfors dd14be4c27 i2c-ocores: Can add I2C devices to the bus
There is sometimes a need for the ocores driver to add devices to the
bus when installed.

i2c_register_board_info can not always be used, because the I2C devices
 are not known at an early state, they could for instance be connected
 on a I2C bus on a PCI device which has the Open Cores IP.

i2c_new_device can not be used in all cases either since the resulting
bus nummer might be unknown.

The solution is the pass a list of I2C devices in the platform data to
the Open Cores driver. This is useful for MFD drivers.

Signed-off-by: Richard Röjfors <richard.rojfors.ext@mocean-labs.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-06-13 10:39:28 +01:00

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Kernel driver i2c-ocores
Supported adapters:
* OpenCores.org I2C controller by Richard Herveille (see datasheet link)
Datasheet: http://www.opencores.org/projects.cgi/web/i2c/overview
Author: Peter Korsgaard <jacmet@sunsite.dk>
Description
-----------
i2c-ocores is an i2c bus driver for the OpenCores.org I2C controller
IP core by Richard Herveille.
Usage
-----
i2c-ocores uses the platform bus, so you need to provide a struct
platform_device with the base address and interrupt number. The
dev.platform_data of the device should also point to a struct
ocores_i2c_platform_data (see linux/i2c-ocores.h) describing the
distance between registers and the input clock speed.
There is also a possibility to attach a list of i2c_board_info which
the i2c-ocores driver will add to the bus upon creation.
E.G. something like:
static struct resource ocores_resources[] = {
[0] = {
.start = MYI2C_BASEADDR,
.end = MYI2C_BASEADDR + 8,
.flags = IORESOURCE_MEM,
},
[1] = {
.start = MYI2C_IRQ,
.end = MYI2C_IRQ,
.flags = IORESOURCE_IRQ,
},
};
/* optional board info */
struct i2c_board_info ocores_i2c_board_info[] = {
{
I2C_BOARD_INFO("tsc2003", 0x48),
.platform_data = &tsc2003_platform_data,
.irq = TSC_IRQ
},
{
I2C_BOARD_INFO("adv7180", 0x42 >> 1),
.irq = ADV_IRQ
}
};
static struct ocores_i2c_platform_data myi2c_data = {
.regstep = 2, /* two bytes between registers */
.clock_khz = 50000, /* input clock of 50MHz */
.devices = ocores_i2c_board_info, /* optional table of devices */
.num_devices = ARRAY_SIZE(ocores_i2c_board_info), /* table size */
};
static struct platform_device myi2c = {
.name = "ocores-i2c",
.dev = {
.platform_data = &myi2c_data,
},
.num_resources = ARRAY_SIZE(ocores_resources),
.resource = ocores_resources,
};