Messages in this thread | | | Subject | Re: [PATCH v2 07/15] drm/bridge: tc358767: Simplify AUX data write | From | Tomi Valkeinen <> | Date | Fri, 22 Mar 2019 12:51:31 +0200 |
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On 22/03/2019 05:28, Andrey Smirnov wrote: > Simplify AUX data write by dropping index arithmetic and shifting and > replacing it with a call to a helper function that does three things: > > 1. Copies user-provided data into a write buffer > 2. Optionally fixes the endianness of the write buffer (not needed > on LE hosts) > 3. Transfers contenst of the write buffer to up to 4 32-bit > registers on the chip > > Note that separate data endianness fix: > > tmp = (tmp << 8) | buf[i]; > > that was reserved for DP_AUX_I2C_WRITE looks really strange, since it > will place data differently depending on the passed user-data > size. E.g. for a write of 1 byte, data transferred to the chip would > look like: > > [byte0] [dummy1] [dummy2] [dummy3] > > whereas for a write of 4 bytes we'd get: > > [byte3] [byte2] [byte1] [byte0] > > Since there's no indication in the datasheet that I2C write buffer > should be treated differently than AUX write buffer and no comment in > the original code explaining why it was done this way, that special > I2C write buffer transformation was dropped in this patch. > > 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: 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 | 58 +++++++++++++++++++------------ > 1 file changed, 36 insertions(+), 22 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c > index 81c10a5d8106..21374565585d 100644 > --- a/drivers/gpu/drm/bridge/tc358767.c > +++ b/drivers/gpu/drm/bridge/tc358767.c > @@ -307,6 +307,31 @@ static int tc_aux_get_status(struct tc_data *tc, u8 *reply) > return 0; > } > > +static int tc_aux_write_data(struct tc_data *tc, const void *data, > + size_t size) > +{ > + u32 auxwdata[DP_AUX_MAX_PAYLOAD_BYTES / sizeof(u32)] = { 0 }; > + int ret, i, count = DIV_ROUND_UP(size, 4);
Should 4 there be sizeof(u32)?
> + > + memcpy(auxwdata, data, size); > + > + for (i = 0; i < count; i++) { > + ret = regmap_write(tc->regmap, DP0_AUXWDATA(i), > + /* > + * Our regmap is configured as LE > + * for register data, so we need > + * undo any byte swapping that will > + * happened to preserve original > + * byte order. > + */ > + cpu_to_le32(auxwdata[i]));
Can regmap_bulk_write or regmap_raw_write be used here?
Tomi
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