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    SubjectRe: [PATCH v3 06/15] drm/bridge: tc358767: Simplify AUX data read
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    Date
    On 05.06.2019 09:04, Andrey Smirnov wrote:
    > Simplify AUX data read by removing index arithmetic and shifting with
    > a helper functions that does three things:
    >
    > 1. Fetch data from up to 4 32-bit registers from the chip
    > 2. Optionally fix data endianness (not needed on LE hosts)
    > 3. Copy read data into user provided array.
    >
    > Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
    > Cc: Archit Taneja <architt@codeaurora.org>
    > Cc: Andrzej Hajda <a.hajda@samsung.com>
    > Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
    > Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
    > Cc: Andrey Gusakov <andrey.gusakov@cogentembedded.com>
    > Cc: Philipp Zabel <p.zabel@pengutronix.de>
    > Cc: Cory Tusar <cory.tusar@zii.aero>
    > Cc: Chris Healy <cphealy@gmail.com>
    > Cc: Lucas Stach <l.stach@pengutronix.de>
    > Cc: dri-devel@lists.freedesktop.org
    > Cc: linux-kernel@vger.kernel.org
    > ---
    > drivers/gpu/drm/bridge/tc358767.c | 40 +++++++++++++++++++++----------
    > 1 file changed, 27 insertions(+), 13 deletions(-)
    >
    > diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
    > index e197ce0fb166..da47d81e7109 100644
    > --- a/drivers/gpu/drm/bridge/tc358767.c
    > +++ b/drivers/gpu/drm/bridge/tc358767.c
    > @@ -321,6 +321,29 @@ static int tc_aux_get_status(struct tc_data *tc, u8 *reply)
    > return 0;
    > }
    >
    > +static int tc_aux_read_data(struct tc_data *tc, void *data, size_t size)
    > +{
    > + u32 auxrdata[DP_AUX_MAX_PAYLOAD_BYTES / sizeof(u32)];
    > + int ret, i, count = DIV_ROUND_UP(size, sizeof(u32));
    > +
    > + ret = regmap_bulk_read(tc->regmap, DP0_AUXRDATA(0), auxrdata, count);
    > + if (ret)
    > + return ret;
    > +
    > + for (i = 0; i < count; i++) {
    > + /*
    > + * Our regmap is configured as LE for register data,
    > + * so we need undo any byte swapping that might have
    > + * happened to preserve original byte order.
    > + */
    > + le32_to_cpus(&auxrdata[i]);
    > + }
    > +
    > + memcpy(data, auxrdata, size);
    > +
    > + return size;
    > +}
    > +


    Hmm, cannot we just use regmap_raw_read?

    Beside this:

    Reviewed-by: Andrzej Hajda <a.hajda@samsung.com>

     --
    Regards
    Andrzej



    > static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
    > struct drm_dp_aux_msg *msg)
    > {
    > @@ -379,19 +402,10 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
    > if (ret)
    > return ret;
    >
    > - if (request == DP_AUX_I2C_READ || request == DP_AUX_NATIVE_READ) {
    > - /* Read data */
    > - while (i < size) {
    > - if ((i % 4) == 0) {
    > - ret = regmap_read(tc->regmap,
    > - DP0_AUXRDATA(i >> 2), &tmp);
    > - if (ret)
    > - return ret;
    > - }
    > - buf[i] = tmp & 0xff;
    > - tmp = tmp >> 8;
    > - i++;
    > - }
    > + switch (request) {
    > + case DP_AUX_NATIVE_READ:
    > + case DP_AUX_I2C_READ:
    > + return tc_aux_read_data(tc, msg->buffer, size);
    > }
    >
    > return size;


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