xref: /kernel/linux/linux-6.6/Documentation/i2c/busses/i2c-ocores.rst

========================
Kernel driver i2c-ocores
========================

Supported adapters:
  * OpenCores.org I2C controller by Richard Herveille (see datasheet link)
    https://opencores.org/project/i2c/overview

Author: Peter Korsgaard <peter@korsgaard.com>

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/platform_data/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,
  };