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([2001:818:ea8e:7f00:2575:914:eedd:620e]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43d82a041d4sm198124305e9.0.2025.04.01.02.11.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Apr 2025 02:11:40 -0700 (PDT) Message-ID: <1f6116071b20846d07406a613d77fd45e5353690.camel@gmail.com> Subject: Re: [PATCH] iio: adc: ad7944: drop bits_per_word hack From: Nuno =?ISO-8859-1?Q?S=E1?= To: David Lechner , Jonathan Cameron , linux-iio@vger.kernel.org Cc: Michael Hennerich , Nuno =?ISO-8859-1?Q?S=E1?= , linux-kernel@vger.kernel.org Date: Tue, 01 Apr 2025 10:11:40 +0100 In-Reply-To: <20250331-iio-adc-ad7944-drop-bits_per_word-hack-v1-1-2b952e033340@baylibre.com> References: <20250331-iio-adc-ad7944-drop-bits_per_word-hack-v1-1-2b952e033340@baylibre.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.0 Precedence: bulk X-Mailing-List: linux-iio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Mon, 2025-03-31 at 14:29 -0500, David Lechner wrote: > Remove setting bits_per_word in SPI xfers without data. The shortcoming > that this was working around was fixed in the SPI controller driver, so > it is no longer necessary. And we don't need this to be cargo-culted to > new drivers. >=20 > Signed-off-by: David Lechner > --- Reviewed-by: Nuno S=C3=A1 > =C2=A0drivers/iio/adc/ad7944.c | 11 ----------- > =C2=A01 file changed, 11 deletions(-) >=20 > diff --git a/drivers/iio/adc/ad7944.c b/drivers/iio/adc/ad7944.c > index > 2f949fe5587318957f2e423029294ced0a6f803d..70f313545af2393a625ae2ec3c2cff2= e2915 > 3ffb 100644 > --- a/drivers/iio/adc/ad7944.c > +++ b/drivers/iio/adc/ad7944.c > @@ -189,11 +189,6 @@ static int ad7944_3wire_cs_mode_init_msg(struct devi= ce > *dev, struct ad7944_adc * > =C2=A0 =C2=A0=C2=A0 : adc->timing_spec- > >conv_ns; > =C2=A0 struct spi_transfer *xfers =3D adc->xfers; > =C2=A0 > - /* > - * NB: can get better performance from some SPI controllers if we use > - * the same bits_per_word in every transfer. > - */ > - xfers[0].bits_per_word =3D chan->scan_type.realbits; > =C2=A0 /* > =C2=A0 * CS is tied to CNV and we need a low to high transition to start > the > =C2=A0 * conversion, so place CNV low for t_QUIET to prepare for this. > @@ -208,7 +203,6 @@ static int ad7944_3wire_cs_mode_init_msg(struct devic= e > *dev, struct ad7944_adc * > =C2=A0 xfers[1].cs_off =3D 1; > =C2=A0 xfers[1].delay.value =3D t_conv_ns; > =C2=A0 xfers[1].delay.unit =3D SPI_DELAY_UNIT_NSECS; > - xfers[1].bits_per_word =3D chan->scan_type.realbits; > =C2=A0 > =C2=A0 /* Then we can read the data during the acquisition phase */ > =C2=A0 xfers[2].rx_buf =3D &adc->sample.raw; > @@ -227,11 +221,6 @@ static int ad7944_4wire_mode_init_msg(struct device = *dev, > struct ad7944_adc *adc > =C2=A0 =C2=A0=C2=A0 : adc->timing_spec- > >conv_ns; > =C2=A0 struct spi_transfer *xfers =3D adc->xfers; > =C2=A0 > - /* > - * NB: can get better performance from some SPI controllers if we use > - * the same bits_per_word in every transfer. > - */ > - xfers[0].bits_per_word =3D chan->scan_type.realbits; > =C2=A0 /* > =C2=A0 * CS has to be high for full conversion time to avoid triggering = the > =C2=A0 * busy indication. >=20 > --- > base-commit: f8ffc92ae9052e6615896052f0c5b808bfc17520 > change-id: 20250331-iio-adc-ad7944-drop-bits_per_word-hack-a71b2d51fa3f >=20 > Best regards,