linux-kernel - Re: [PATCH v3 04/24] drm/rockchip: dw-mipi-dsi: fix command header writes

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Date:   Mon, 30 Jan 2017 10:43:06 -0500
From:   Sean Paul <seanpaul@...omium.org>
To:     John Keeping <john@...anate.com>
Cc:     Mark Yao <mark.yao@...k-chips.com>, linux-kernel@...r.kernel.org,
        dri-devel@...ts.freedesktop.org,
        linux-rockchip@...ts.infradead.org,
        Chris Zhong <zyw@...k-chips.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3 04/24] drm/rockchip: dw-mipi-dsi: fix command header
 writes

On Sun, Jan 29, 2017 at 01:24:24PM +0000, John Keeping wrote:
> In a couple of places here we use "val" for the value that is about to
> be written to a register but then reuse the same variable for the value
> of a status register before we get around to writing it.  Rename the
> value to be written to so that we write the value we intend to and not
> what we have just read from the status register.
> 

Oh my.

Reviewed-by: Sean Paul <seanpaul@...omium.org>

> Signed-off-by: John Keeping <john@...anate.com>
> Tested-by: Chris Zhong <zyw@...k-chips.com>
> Reviewed-by: Chris Zhong <zyw@...k-chips.com>
> ---
> Unchanged in v3
> Unchanged in v2
> 
>  drivers/gpu/drm/rockchip/dw-mipi-dsi.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> index bd92e58b64f3..4cbbbcb619b7 100644
> --- a/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi.c
> @@ -542,9 +542,10 @@ static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host,
>  	return 0;
>  }
>  
> -static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32 val)
> +static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32 hdr_val)
>  {
>  	int ret;
> +	u32 val;
>  
>  	ret = readx_poll_timeout(readl, dsi->base + DSI_CMD_PKT_STATUS,
>  				 val, !(val & GEN_CMD_FULL), 1000,
> @@ -554,7 +555,7 @@ static int dw_mipi_dsi_gen_pkt_hdr_write(struct dw_mipi_dsi *dsi, u32 val)
>  		return ret;
>  	}
>  
> -	dsi_write(dsi, DSI_GEN_HDR, val);
> +	dsi_write(dsi, DSI_GEN_HDR, hdr_val);
>  
>  	ret = readx_poll_timeout(readl, dsi->base + DSI_CMD_PKT_STATUS,
>  				 val, val & (GEN_CMD_EMPTY | GEN_PLD_W_EMPTY),
> @@ -587,8 +588,9 @@ static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
>  {
>  	const u32 *tx_buf = msg->tx_buf;
>  	int len = msg->tx_len, pld_data_bytes = sizeof(*tx_buf), ret;
> -	u32 val = GEN_HDATA(msg->tx_len) | GEN_HTYPE(msg->type);
> +	u32 hdr_val = GEN_HDATA(msg->tx_len) | GEN_HTYPE(msg->type);
>  	u32 remainder = 0;
> +	u32 val;
>  
>  	if (msg->tx_len < 3) {
>  		dev_err(dsi->dev, "wrong tx buf length %zu for long write\n",
> @@ -617,7 +619,7 @@ static int dw_mipi_dsi_dcs_long_write(struct dw_mipi_dsi *dsi,
>  		}
>  	}
>  
> -	return dw_mipi_dsi_gen_pkt_hdr_write(dsi, val);
> +	return dw_mipi_dsi_gen_pkt_hdr_write(dsi, hdr_val);
>  }
>  
>  static ssize_t dw_mipi_dsi_host_transfer(struct mipi_dsi_host *host,
> -- 
> 2.11.0.197.gb556de5.dirty
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Sean Paul, Software Engineer, Google / Chromium OS

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