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From: Sascha Hauer <s.hauer@pengutronix.de>
To: Bastian Stender <bst@pengutronix.de>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH 1/2] i2c: mv64xxx: add software delays
Date: Fri, 24 Feb 2017 08:24:04 +0100	[thread overview]
Message-ID: <20170224072404.kuheslpettjdnuny@pengutronix.de> (raw)
In-Reply-To: <20170223163450.6611-1-bst@pengutronix.de>

On Thu, Feb 23, 2017 at 05:34:49PM +0100, Bastian Stender wrote:
> As stated in Marvell's Functional Specifications in MV-S107021-U0 Rev. A
> on page 420 ff. software delays are needed. "SW delay represent a delay
> of at least 2 internal clock cycles". These delays are hereby
> implemented.
> 
> The original kernel driver compensates the needed software delays with
> the time the interrupts take.
> 
> Signed-off-by: Bastian Stender <bst@pengutronix.de>

Applied, thanks

Sascha

> ---
>  drivers/i2c/busses/i2c-mv64xxx.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
> index 9b9e6c953f..45d5a2b6dc 100644
> --- a/drivers/i2c/busses/i2c-mv64xxx.c
> +++ b/drivers/i2c/busses/i2c-mv64xxx.c
> @@ -270,6 +270,7 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
>  		}
>  		/* FALLTHRU */
>  	case STATUS_MAST_RD_DATA_ACK: /* 0x50 */
> +		udelay(2);
>  		if (status != STATUS_MAST_RD_DATA_ACK)
>  			drv_data->action = ACTION_CONTINUE;
>  		else {
> @@ -280,6 +281,7 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
>  
>  		if (drv_data->bytes_left == 1)
>  			drv_data->cntl_bits &= ~REG_CONTROL_ACK;
> +			udelay(2);
>  		break;
>  
>  	case STATUS_MAST_RD_DATA_NO_ACK: /* 0x58 */
> @@ -318,6 +320,8 @@ static void mv64xxx_i2c_send_start(struct mv64xxx_i2c_data *drv_data)
>  	mv64xxx_i2c_prepare_for_io(drv_data, drv_data->msgs);
>  	mv64xxx_write(drv_data, drv_data->cntl_bits | REG_CONTROL_START,
>  		drv_data->reg_offsets.control);
> +
> +	udelay(2);
>  }
>  
>  static void
> @@ -333,7 +337,7 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
>  		mv64xxx_i2c_send_start(drv_data);
>  
>  		if (drv_data->errata_delay)
> -			udelay(5);
> +			udelay(3);
>  
>  		/*
>  		 * We're never at the start of the message here, and by this
> @@ -349,6 +353,7 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
>  		break;
>  
>  	case ACTION_SEND_ADDR_1:
> +		udelay(2);
>  		mv64xxx_write(drv_data, drv_data->addr1,
>  			drv_data->reg_offsets.data);
>  		mv64xxx_write(drv_data, drv_data->cntl_bits,
> @@ -360,9 +365,11 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
>  			drv_data->reg_offsets.data);
>  		mv64xxx_write(drv_data, drv_data->cntl_bits,
>  			drv_data->reg_offsets.control);
> +		udelay(2);
>  		break;
>  
>  	case ACTION_SEND_DATA:
> +		udelay(2);
>  		mv64xxx_write(drv_data, drv_data->msg->buf[drv_data->byte_posn++],
>  			drv_data->reg_offsets.data);
>  		mv64xxx_write(drv_data, drv_data->cntl_bits,
> @@ -383,8 +390,9 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
>  		mv64xxx_write(drv_data, drv_data->cntl_bits | REG_CONTROL_STOP,
>  			drv_data->reg_offsets.control);
>  		drv_data->block = false;
> +		udelay(2);
>  		if (drv_data->errata_delay)
> -			udelay(5);
> +			udelay(3);
>  
>  		break;
>  
> -- 
> 2.11.0
> 
> 
> _______________________________________________
> barebox mailing list
> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox
> 

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      parent reply	other threads:[~2017-02-24  7:24 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-23 16:34 Bastian Stender
2017-02-23 16:34 ` [PATCH 2/2] i2c: mv64xxx: simplify mv64xxx_i2c_wait_for_completion Bastian Stender
2017-02-24  7:24 ` Sascha Hauer [this message]

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