[U-Boot] [PATCH 1/2] i2c: mvtwsi: Fix mvtwsi not working on sun6i and newer sunxi SoCs

[Heiko Schocher]

Hello Hans,

Am 14.01.2016 um 14:06 schrieb Hans de Goede:
> On sun6i and newer IFLG is a write-clear bit which is cleared by writing 1,
> rather then a normal r/w bit which is cleared by writing 0.
>
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
> ---
>   drivers/i2c/mvtwsi.c | 19 +++++++++++++++----
>   1 file changed, 15 insertions(+), 4 deletions(-)

Thanks!

Applied to u-boot-i2c.git with fixing 3 checkpatch
errors/warnings.

bye,
Heiko
>
> diff --git a/drivers/i2c/mvtwsi.c b/drivers/i2c/mvtwsi.c
> index f20d1b2..698bfc1 100644
> --- a/drivers/i2c/mvtwsi.c
> +++ b/drivers/i2c/mvtwsi.c
> @@ -73,6 +73,17 @@ struct  mvtwsi_registers {
>   #define	MVTWSI_CONTROL_INTEN	0x00000080
>
>   /*
> + * On sun6i and newer IFLG is a write-clear bit which is cleared by writing 1,
> + * on other platforms it is a normal r/w bit which is cleared by writing 0.
> + */
> +
> +#ifdef CONFIG_SUNXI_GEN_SUN6I
> +#define	MVTWSI_CONTROL_CLEAR_IFLG	0x00000008
> +#else
> +#define	MVTWSI_CONTROL_CLEAR_IFLG	0x00000000
> +#endif
> +
> +/*
>    * Status register values -- only those expected in normal master
>    * operation on non-10-bit-address devices; whatever status we don't
>    * expect in nominal conditions (bus errors, arbitration losses,
> @@ -189,7 +200,7 @@ static int twsi_start(struct i2c_adapter *adap, int expected_status)
>   	/* globally set TWSIEN in case it was not */
>   	twsi_control_flags |= MVTWSI_CONTROL_TWSIEN;
>   	/* assert START */
> -	writel(twsi_control_flags | MVTWSI_CONTROL_START, &twsi->control);
> +	writel(twsi_control_flags | MVTWSI_CONTROL_START | MVTWSI_CONTROL_CLEAR_IFLG, &twsi->control);
>   	/* wait for controller to process START */
>   	return twsi_wait(adap, expected_status);
>   }
> @@ -204,7 +215,7 @@ static int twsi_send(struct i2c_adapter *adap, u8 byte, int expected_status)
>   	/* put byte in data register for sending */
>   	writel(byte, &twsi->data);
>   	/* clear any pending interrupt -- that'll cause sending */
> -	writel(twsi_control_flags, &twsi->control);
> +        writel(twsi_control_flags | MVTWSI_CONTROL_CLEAR_IFLG, &twsi->control);
>   	/* wait for controller to receive byte and check ACK */
>   	return twsi_wait(adap, expected_status);
>   }
> @@ -224,7 +235,7 @@ static int twsi_recv(struct i2c_adapter *adap, u8 *byte)
>   	else
>   		expected_status = MVTWSI_STATUS_DATA_R_NAK;
>   	/* acknowledge *previous state* and launch receive */
> -	writel(twsi_control_flags, &twsi->control);
> +	writel(twsi_control_flags | MVTWSI_CONTROL_CLEAR_IFLG, &twsi->control);
>   	/* wait for controller to receive byte and assert ACK or NAK */
>   	status = twsi_wait(adap, expected_status);
>   	/* if we did receive expected byte then store it */
> @@ -246,7 +257,7 @@ static int twsi_stop(struct i2c_adapter *adap, int status)
>
>   	/* assert STOP */
>   	control = MVTWSI_CONTROL_TWSIEN | MVTWSI_CONTROL_STOP;
> -	writel(control, &twsi->control);
> +	writel(control | MVTWSI_CONTROL_CLEAR_IFLG, &twsi->control);
>   	/* wait for IDLE; IFLG won't rise so twsi_wait() is no use. */
>   	do {
>   		stop_status = readl(&twsi->status);
>

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