linux-kernel - [RFC 0/1] i2c: omap: Add support for switching to slave mode

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Message-ID: <20160525141119.14486-1-rk@ti.com>
Date:	Wed, 25 May 2016 19:41:18 +0530
From:	Ravikumar Kattekola <rk@...com>
To:	<tony@...mide.com>, <wsa@...-dreams.de>,
	<linux-omap@...r.kernel.org>, <linux-i2c@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: [RFC 0/1] i2c: omap: Add support for switching to slave mode

I2C controller on most of the omap devices has both master and slave
capability but the i2c framework has been missing support for registering
a bus in slave mode for long.
Recently the i2c slave support has been added to i2c framework, the following
patch adds the required support for omap_i2c driver to register a controller
as a slave device and be deriven by an external/internal master.

The slave interface requires us to add following mandatory events

1. I2C_SLAVE_WRITE_REQUESTED
2. I2C_SLAVE_READ_REQUESTED
3. I2C_SLAVE_WRITE_RECEIVED
4. I2C_SLAVE_READ_PROCESSED

and 

5. I2C_SLAVE_STOP

The omap i2c controller (at least on dra7x devices)
doesn't have  start/stop (STT/STP) support for slave mode
so event  #5 is not implemented in the driver.

Refer to Documentation/i2c/slave-interface for more info on 
i2c-slave-interface and Documentation/i2c/slave-eeprom-backend for 
sample backend driver.

Tested on:
DRA75x EVM Rev G3 and DRA72x EVM Rev B1 connected over i2c3 using DCAN2 lines [JP3]

Ravikumar Kattekola (1):
  drivers: i2c: omap: Add slave support

 drivers/i2c/busses/i2c-omap.c | 144 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 144 insertions(+)

-- 
2.8.2.396.g5fe494c