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SubjectRe: [PATCH v3 06/15] drm/bridge: tc358767: Simplify AUX data read
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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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