[PATCH 2/2] i2c: mv64xxx: Fix bus hang on A0 version of the Armada XP SoCs

[Jason Cooper]

Wolfram,

On Thu, Jan 02, 2014 at 05:01:16PM +0100, Gregory CLEMENT wrote:
> The first variants of Armada XP SoCs (A0 stepping) have issues related
> to the i2c controller which prevent to use the offload mechanism and
> lead to a kernel hang during boot.
> 
> The driver now check the revision of the SoC. If the revision is not
> more recent than the A0 or if the driver can't get the SoC revision
> then it disables the offload mechanism.
> 
> Cc: stable at vger.kernel.org
> Signed-off-by: Gregory CLEMENT <gregory.clement at free-electrons.com>
> ---
>  drivers/i2c/busses/i2c-mv64xxx.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
> index 8be7e42aa4de..089a3663ad86 100644
> --- a/drivers/i2c/busses/i2c-mv64xxx.c
> +++ b/drivers/i2c/busses/i2c-mv64xxx.c
> @@ -24,6 +24,7 @@
>  #include <linux/clk.h>
>  #include <linux/err.h>
>  #include <linux/delay.h>
> +#include <linux/mvebu-soc-id.h>
>  
>  #define MV64XXX_I2C_ADDR_ADDR(val)			((val & 0x7f) << 1)
>  #define MV64XXX_I2C_BAUD_DIV_N(val)			(val & 0x7)
> @@ -779,8 +780,16 @@ mv64xxx_of_config(struct mv64xxx_i2c_data *drv_data,
>  	 * Transaction Generator support and the errata fix.
>  	 */
>  	if (of_device_is_compatible(np, "marvell,mv78230-i2c")) {
> -		drv_data->offload_enabled = true;
> +		u32 dev, rev;
> +
>  		drv_data->errata_delay = true;
> +		/*
> +		 * Only revison more recent than A0 support offload
> +		 * mechanism. In case we can't get the SoC revision
> +		 * weplay safe and we don't enable it
> +		 */
> +		if (!mvebu_get_soc_id(&rev, &dev) && (dev > MV78XX0_A0_REV))
> +			drv_data->offload_enabled = true;

Since this depends on arch-specific code in the previous patch, I'd like
to keep the two of them together in a topic branch.  Would you prefer to
take both with my Ack, or vice-versa?  I'm fine either way.

thx,

Jason.