From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3AD901549E; Sat, 30 Sep 2023 15:03:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 27D8BC433C8; Sat, 30 Sep 2023 15:03:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696086217; bh=oc3yqphUC0dKNs9xjyNjFTM6qHopZJCOW0oefQNLdz0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=qa7XMf51NYuCrCQnq5UCARNc4TCNYjFGdQDqXPAPlmqSAM0jeT+u1YCk8fVWIXyPM PrVWbA5A56GV5Wvg1dlAe1b3D6ZnKKZF0F3ViFYtGqoBADD7Kc6hx9R84A+tDxs1R7 m3+GDNcXgwh2EsnctKxYSKCYsBNBLMqWrA+GM2diLDzxFVnXzPxRvCxW5U12u1cRnC EhnrBQNQWOwevne8mszK4ECdFxXt6rrCuLjDWFfOO/z0it/MfhFEgV9L8Pb9gLIAf9 x3FxYmQzfp3CYxEE6rnR8OcgLshLHq48UIDW4u9LhSOvBFGyoJPOZUKUzTBVWHIbks 4QCDgdxkDURPQ== Date: Sat, 30 Sep 2023 16:03:36 +0100 From: Jonathan Cameron To: David Lechner Cc: linux-iio@vger.kernel.org, devicetree@vger.kernel.org, linux-staging@lists.linux.dev, David Lechner , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Michael Hennerich , Nuno =?UTF-8?B?U8Oh?= , Axel Haslam , Philip Molloy , linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 14/27] staging: iio: resolver: ad2s1210: implement hysteresis as channel attr Message-ID: <20230930160336.6a67765a@jic23-huawei> In-Reply-To: <20230929-ad2s1210-mainline-v3-14-fa4364281745@baylibre.com> References: <20230929-ad2s1210-mainline-v3-0-fa4364281745@baylibre.com> <20230929-ad2s1210-mainline-v3-14-fa4364281745@baylibre.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 29 Sep 2023 12:23:19 -0500 David Lechner wrote: > From: David Lechner > > From: David Lechner > > The AD2S1210 resolver has a hysteresis feature that can be used to > prevent flicker in the LSB of the position register. This can be either > enabled or disabled. Disabling hysteresis is useful for increasing > precision by oversampling. > > Signed-off-by: David Lechner One trivial thing inline. Thanks, Jonathan > --- > > v3 changes: > * Refactored into more functions to reduce complexity of switch statements. > * Use early return instead of break in switch statements. > > drivers/staging/iio/resolver/ad2s1210.c | 86 +++++++++++++++++++++++++++++++-- > 1 file changed, 83 insertions(+), 3 deletions(-) > > diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c > index 0ec3598b600a..a82cb124a12f 100644 > --- a/drivers/staging/iio/resolver/ad2s1210.c > +++ b/drivers/staging/iio/resolver/ad2s1210.c > @@ -78,7 +78,6 @@ struct ad2s1210_state { > /** The external oscillator frequency in Hz. */ > unsigned long clkin_hz; > unsigned int fexcit; > - bool hysteresis; > u8 resolution; > /** For reading raw sample value via SPI. */ > __be16 sample __aligned(IIO_DMA_MINALIGN); > @@ -430,6 +429,35 @@ static int ad2s1210_single_conversion(struct ad2s1210_state *st, > return ret; > } > > +static int ad2s1210_get_hysteresis(struct ad2s1210_state *st, int *val) > +{ > + int ret; > + > + mutex_lock(&st->lock); > + ret = regmap_test_bits(st->regmap, AD2S1210_REG_CONTROL, > + AD2S1210_ENABLE_HYSTERESIS); > + mutex_unlock(&st->lock); > + > + if (ret < 0) > + return ret; > + > + *val = !!ret; regmap_test_bits() is documented as returning 1 or 0 anyway. So this !! isn't necessary.. > + return IIO_VAL_INT; > +} > + > +static int ad2s1210_set_hysteresis(struct ad2s1210_state *st, int val) > +{ > + int ret; > + > + mutex_lock(&st->lock); > + ret = regmap_update_bits(st->regmap, AD2S1210_REG_CONTROL, > + AD2S1210_ENABLE_HYSTERESIS, > + val ? AD2S1210_ENABLE_HYSTERESIS : 0); > + mutex_unlock(&st->lock); > + > + return ret; > +} > + > static const int ad2s1210_velocity_scale[] = { > 17089132, /* 8.192MHz / (2*pi * 2500 / 2^15) */ > 42722830, /* 8.192MHz / (2*pi * 1000 / 2^15) */ > @@ -462,7 +490,55 @@ static int ad2s1210_read_raw(struct iio_dev *indio_dev, > default: > return -EINVAL; > } > + case IIO_CHAN_INFO_HYSTERESIS: > + switch (chan->type) { > + case IIO_ANGL: > + return ad2s1210_get_hysteresis(st, val); > + default: > + return -EINVAL; > + } > + default: > + return -EINVAL; > + } > +} > + > +static int ad2s1210_read_avail(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + const int **vals, int *type, > + int *length, long mask) > +{ > + static const int hysteresis_available[] = { 0, 1 }; > + > + switch (mask) { > + case IIO_CHAN_INFO_HYSTERESIS: > + switch (chan->type) { > + case IIO_ANGL: > + *vals = hysteresis_available; > + *type = IIO_VAL_INT; > + *length = ARRAY_SIZE(hysteresis_available); > + return IIO_AVAIL_LIST; > + default: > + return -EINVAL; > + } > + default: > + return -EINVAL; > + } > +} > > +static int ad2s1210_write_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int val, int val2, long mask) > +{ > + struct ad2s1210_state *st = iio_priv(indio_dev); > + > + switch (mask) { > + case IIO_CHAN_INFO_HYSTERESIS: > + switch (chan->type) { > + case IIO_ANGL: > + return ad2s1210_set_hysteresis(st, val); > + default: > + return -EINVAL; > + } > default: > return -EINVAL; > } > @@ -503,7 +579,10 @@ static const struct iio_chan_spec ad2s1210_channels[] = { > .indexed = 1, > .channel = 0, > .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | > - BIT(IIO_CHAN_INFO_SCALE), > + BIT(IIO_CHAN_INFO_SCALE) | > + BIT(IIO_CHAN_INFO_HYSTERESIS), > + .info_mask_separate_available = > + BIT(IIO_CHAN_INFO_HYSTERESIS), > }, { > .type = IIO_ANGL_VEL, > .indexed = 1, > @@ -581,6 +660,8 @@ static int ad2s1210_debugfs_reg_access(struct iio_dev *indio_dev, > > static const struct iio_info ad2s1210_info = { > .read_raw = ad2s1210_read_raw, > + .read_avail = ad2s1210_read_avail, > + .write_raw = ad2s1210_write_raw, > .attrs = &ad2s1210_attribute_group, > .debugfs_reg_access = &ad2s1210_debugfs_reg_access, > }; > @@ -696,7 +777,6 @@ static int ad2s1210_probe(struct spi_device *spi) > > mutex_init(&st->lock); > st->sdev = spi; > - st->hysteresis = true; > st->resolution = 12; > st->fexcit = AD2S1210_DEF_EXCIT; > >