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([2001:818:ea8e:7f00:2575:914:eedd:620e]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-437c749956fsm207578905e9.4.2025.01.20.07.52.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Jan 2025 07:52:19 -0800 (PST) Message-ID: Subject: Re: [PATCH v2] iio: adc: ad7124: Micro-optimize channel disabling From: Nuno =?ISO-8859-1?Q?S=E1?= To: Uwe =?ISO-8859-1?Q?Kleine-K=F6nig?= , Lars-Peter Clausen , Michael Hennerich , Jonathan Cameron Cc: linux-iio@vger.kernel.org Date: Mon, 20 Jan 2025 15:52:20 +0000 In-Reply-To: <20250120140708.1093655-2-u.kleine-koenig@baylibre.com> References: <20250120140708.1093655-2-u.kleine-koenig@baylibre.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.54.3 Precedence: bulk X-Mailing-List: linux-iio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Mon, 2025-01-20 at 15:07 +0100, Uwe Kleine-K=C3=B6nig wrote: > The key objective in ad7124_disable_one() is clearing the > AD7124_CHANNEL_EN_MSK bit in the channel register. However there is no > advantage to keep the other bits in that register because when the > channel is used next time, all fields are rewritten anyhow. So instead > of using ad7124_spi_write_mask() (which is a register read plus a > register write) use a simple register write clearing the complete > register. >=20 > Also do the same in the .disable_all() callback by using the > .disable_one() callback there. >=20 > Signed-off-by: Uwe Kleine-K=C3=B6nig > --- Reviewed-by: Nuno Sa > Hello, >=20 > in (implicit) v1 I only adapted ad7124_disable_one() which resulted in > the very legitimate question why this wasn't done for .disable_all(). I > haven't checked because I wrongly assumed that .disable_all() used > .disable_one(). This v2 now makes the latter true and so .disable_all() > now also benefits from the micro optimisation. >=20 > Best regards > Uwe >=20 > =C2=A0drivers/iio/adc/ad7124.c | 17 +++++++++-------- > =C2=A01 file changed, 9 insertions(+), 8 deletions(-) >=20 > diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c > index 6ae27cdd3250..2fdeb3247952 100644 > --- a/drivers/iio/adc/ad7124.c > +++ b/drivers/iio/adc/ad7124.c > @@ -540,6 +540,14 @@ static int ad7124_append_status(struct ad_sigma_delt= a > *sd, bool append) > =C2=A0 return 0; > =C2=A0} > =C2=A0 > +static int ad7124_disable_one(struct ad_sigma_delta *sd, unsigned int ch= an) > +{ > + struct ad7124_state *st =3D container_of(sd, struct ad7124_state, sd); > + > + /* The relevant thing here is that AD7124_CHANNEL_EN_MSK is cleared. > */ > + return ad_sd_write_reg(&st->sd, AD7124_CHANNEL(chan), 2, 0); > +} > + > =C2=A0static int ad7124_disable_all(struct ad_sigma_delta *sd) > =C2=A0{ > =C2=A0 struct ad7124_state *st =3D container_of(sd, struct ad7124_state, = sd); > @@ -547,7 +555,7 @@ static int ad7124_disable_all(struct ad_sigma_delta *= sd) > =C2=A0 int i; > =C2=A0 > =C2=A0 for (i =3D 0; i < st->num_channels; i++) { > - ret =3D ad7124_spi_write_mask(st, AD7124_CHANNEL(i), > AD7124_CHANNEL_EN_MSK, 0, 2); > + ret =3D ad7124_disable_one(sd, i); > =C2=A0 if (ret < 0) > =C2=A0 return ret; > =C2=A0 } > @@ -555,13 +563,6 @@ static int ad7124_disable_all(struct ad_sigma_delta = *sd) > =C2=A0 return 0; > =C2=A0} > =C2=A0 > -static int ad7124_disable_one(struct ad_sigma_delta *sd, unsigned int ch= an) > -{ > - struct ad7124_state *st =3D container_of(sd, struct ad7124_state, sd); > - > - return ad7124_spi_write_mask(st, AD7124_CHANNEL(chan), > AD7124_CHANNEL_EN_MSK, 0, 2); > -} > - > =C2=A0static const struct ad_sigma_delta_info ad7124_sigma_delta_info =3D= { > =C2=A0 .set_channel =3D ad7124_set_channel, > =C2=A0 .append_status =3D ad7124_append_status, >=20 > base-commit: b323d8e7bc03d27dec646bfdccb7d1a92411f189