linux-kernel - Re: [PATCH v7 2/3] drm/bridge: ti-sn65dsi86: Use regmap_bulk

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Date:   Wed, 27 Oct 2021 10:29:08 +0200
From:   Robert Foss <robert.foss@...aro.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>, Lee Jones <lee.jones@...aro.org>,
        linux-pwm@...r.kernel.org,
        linux-kernel <linux-kernel@...r.kernel.org>,
        MSM <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH v7 2/3] drm/bridge: ti-sn65dsi86: Use regmap_bulk_write API

Hey Bjorn,

On Mon, 25 Oct 2021 at 19:07, Bjorn Andersson
<bjorn.andersson@...aro.org> wrote:
>
> The multi-register u16 write operation can use regmap_bulk_write()
> instead of two separate regmap_write() calls.
>
> It's uncertain if this has any effect on the actual updates of the
> underlying registers, but this at least gives the hardware the
> opportunity and saves us one transation on the bus.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>

Did you miss including Dougs R-B from v6? As far as I can tell nothing
else changed between v6 & v7.

> ---
>
> Changes since v6:
> - None
>
>  drivers/gpu/drm/bridge/ti-sn65dsi86.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> index 6154bed0af5b..5b59d8dd3acd 100644
> --- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> +++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
> @@ -193,8 +193,9 @@ static const struct regmap_config ti_sn65dsi86_regmap_config = {
>  static void ti_sn65dsi86_write_u16(struct ti_sn65dsi86 *pdata,
>                                    unsigned int reg, u16 val)
>  {
> -       regmap_write(pdata->regmap, reg, val & 0xFF);
> -       regmap_write(pdata->regmap, reg + 1, val >> 8);
> +       u8 buf[2] = { val & 0xff, val >> 8 };
> +
> +       regmap_bulk_write(pdata->regmap, reg, buf, ARRAY_SIZE(buf));
>  }
>
>  static u32 ti_sn_bridge_get_dsi_freq(struct ti_sn65dsi86 *pdata)
> --
> 2.29.2
>