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Commit c1d15b68 authored by Gregory CLEMENT's avatar Gregory CLEMENT Committed by Wolfram Sang
Browse files

i2c: mv64xxx: Fix timing issue on Armada XP (errata FE-8471889) 



All the Armada XP (mv78230, mv78260 and mv78460) have a silicon issue
in the I2C controller which violate the i2c repeated start
timing. The I2C standard requires a minimum of 4.7us for the repeated
start condition whereas the I2C controller of the Armada XP this time
is 2.9us.

So this patch adds a 5us delay for the start case only if the
the compatible i2c-mv78230 is set.

Based on the initals patches from Zbigniew Bodek

Signed-off-by: default avatarGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: default avatarZbigniew Bodek <zbb@semihalf.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 930ab3d4

drivers/i2c/busses/i2c-mv64xxx.c

+13 −2
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/of_i2c.h>

#include <linux/clk.h>

#include <linux/err.h>

#include <linux/delay.h>



#define MV64XXX_I2C_ADDR_ADDR(val)			((val & 0x7f) << 1)

#define MV64XXX_I2C_BAUD_DIV_N(val)			(val & 0x7)
@@ -147,6 +148,8 @@ struct mv64xxx_i2c_data { 
	struct i2c_msg		*msg;

	struct i2c_adapter	adapter;

	bool			offload_enabled;

/* 5us delay in order to avoid repeated start timing violation */

	bool			errata_delay;

};



static struct mv64xxx_i2c_regs mv64xxx_i2c_regs_mv64xxx = {
@@ -440,6 +443,9 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data) 
			/* Setup for the next message */

			mv64xxx_i2c_prepare_for_io(drv_data, drv_data->msgs);

		}

		if (drv_data->errata_delay)

			udelay(5);



		/*

		 * We're never at the start of the message here, and by this

		 * time it's already too late to do any protocol mangling.
@@ -499,6 +505,9 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data) 
		writel(drv_data->cntl_bits | MV64XXX_I2C_REG_CONTROL_STOP,

			drv_data->reg_base + drv_data->reg_offsets.control);

		drv_data->block = 0;

		if (drv_data->errata_delay)

			udelay(5);



		wake_up(&drv_data->waitq);

		break;
@@ -766,10 +775,12 @@ mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data, 


	/*

	 * For controllers embedded in new SoCs activate the

	 * Transaction Generator support.

	 * Transaction Generator support and the errata fix.

	 */

	if (of_device_is_compatible(np, "marvell,mv78230-i2c"))

	if (of_device_is_compatible(np, "marvell,mv78230-i2c")) {

		drv_data->offload_enabled = true;

		drv_data->errata_delay = true;

	}



out:

	return rc;