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 9E47227442 for ; Tue, 10 Oct 2023 15:40:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RVjr6yXO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36A0AC433C8; Tue, 10 Oct 2023 15:40:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696952448; bh=Bns2XY9k0e9ThFmHo3x2+L8G5fFyPtlK1e6YKoRto9M=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=RVjr6yXORxZIobDS/hkTiOZX/wAlelhrNwLoRUciv7VDfByEpoJZrgYp1VzCJcRsR LB0POM2c3OyvHQviGCeuWG414/XCmUnmm44uzGEHqbp20mbwwT3Dt4Br68E/bqB4Rk 5+Hg3fnxcU/DdYLn/zHSRvKz8P2w1LLgs0mQnZ8PXjTvVGmnh8+/e/s0cU1oyK/Bbn b9y1vqTQtPTag5/mwQVujrOcLnVtsTw4TJQJU2/Sm2jw0CSpmVIUWrIxybXpc7Job8 DNaCLY08P2LakVd2rnu6kcqFp3veInA2ksGwhPRwrG8leFM20LvvHG468GMbZNZMQh zoPZK618+aEHg== Date: Tue, 10 Oct 2023 16:40:58 +0100 From: Jonathan Cameron To: David Lechner Cc: linux-iio@vger.kernel.org, linux-staging@lists.linux.dev, Michael Hennerich , Nuno =?UTF-8?B?U8Oh?= , Axel Haslam , Philip Molloy , linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 02/17] staging: iio: resolver: ad2s1210: implement hysteresis as channel attr Message-ID: <20231010164058.29ee52b4@jic23-huawei> In-Reply-To: <20231005-ad2s1210-mainline-v4-2-ec00746840fc@baylibre.com> References: <20231005-ad2s1210-mainline-v4-0-ec00746840fc@baylibre.com> <20231005-ad2s1210-mainline-v4-2-ec00746840fc@baylibre.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 5 Oct 2023 19:50:19 -0500 David Lechner wrote: > 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 Applied > --- > > v4 changes: > * Fixed hysteresis raw values when st->resolution != 16. > > 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 | 91 +++++++++++++++++++++++++++++++-- > 1 file changed, 88 insertions(+), 3 deletions(-) > > diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c > index 8fbde9517fe9..af063eb25e9c 100644 > --- a/drivers/staging/iio/resolver/ad2s1210.c > +++ b/drivers/staging/iio/resolver/ad2s1210.c > @@ -76,7 +76,8 @@ struct ad2s1210_state { > struct regmap *regmap; > /** The external oscillator frequency in Hz. */ > unsigned long clkin_hz; > - bool hysteresis; > + /** Available raw hysteresis values based on resolution. */ > + int hysteresis_available[2]; > u8 resolution; > /** For reading raw sample value via SPI. */ > __be16 sample __aligned(IIO_DMA_MINALIGN); > @@ -311,6 +312,7 @@ static ssize_t ad2s1210_store_resolution(struct device *dev, > goto error_ret; > > st->resolution = udata; > + st->hysteresis_available[1] = 1 << (16 - st->resolution); > ret = len; > > error_ret: > @@ -447,6 +449,35 @@ 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 << (16 - st->resolution); > + 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) */ > @@ -479,7 +510,55 @@ 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) > +{ > + struct ad2s1210_state *st = iio_priv(indio_dev); > + > + switch (mask) { > + case IIO_CHAN_INFO_HYSTERESIS: > + switch (chan->type) { > + case IIO_ANGL: > + *vals = st->hysteresis_available; > + *type = IIO_VAL_INT; > + *length = ARRAY_SIZE(st->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; > } > @@ -520,7 +599,10 @@ 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, > @@ -596,6 +678,8 @@ 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, > }; > @@ -711,8 +795,9 @@ static int ad2s1210_probe(struct spi_device *spi) > > mutex_init(&st->lock); > st->sdev = spi; > - st->hysteresis = true; > st->resolution = 12; > + st->hysteresis_available[0] = 0; > + st->hysteresis_available[1] = 1 << (16 - st->resolution); > > ret = ad2s1210_setup_clocks(st); > if (ret < 0) >