From: Jonathan Cameron <jic23@kernel.org>
To: "Nuno Sá" <nuno.sa@analog.com>
Cc: <linux-arm-kernel@lists.infradead.org>,
<linux-rockchip@lists.infradead.org>,
<linux-amlogic@lists.infradead.org>, <linux-imx@nxp.com>,
<linux-iio@vger.kernel.org>, Chunyan Zhang <zhang.lyra@gmail.com>,
Michael Hennerich <Michael.Hennerich@analog.com>,
Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
Sascha Hauer <s.hauer@pengutronix.de>,
Cixi Geng <cixi.geng1@unisoc.com>,
Kevin Hilman <khilman@baylibre.com>,
Vladimir Zapolskiy <vz@mleia.com>,
Pengutronix Kernel Team <kernel@pengutronix.de>,
Alexandru Ardelean <aardelean@deviqon.com>,
Fabio Estevam <festevam@gmail.com>,
Andriy Tryshnivskyy <andriy.tryshnivskyy@opensynergy.com>,
Haibo Chen <haibo.chen@nxp.com>, Shawn Guo <shawnguo@kernel.org>,
Hans de Goede <hdegoede@redhat.com>,
Miquel Raynal <miquel.raynal@bootlin.com>,
Jerome Brunet <jbrunet@baylibre.com>,
Heiko Stuebner <heiko@sntech.de>,
Florian Boor <florian.boor@kernelconcepts.de>,
Ciprian Regus <ciprian.regus@analog.com>,
Lars-Peter Clausen <lars@metafoo.de>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
Neil Armstrong <narmstrong@baylibre.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
Jyoti Bhayana <jbhayana@google.com>, Chen-Yu Tsai <wens@csie.org>,
Orson Zhai <orsonzhai@gmail.com>
Subject: Re: [PATCH 14/15] iio: health: max30102: do not use internal iio_dev lock
Date: Sat, 24 Sep 2022 16:54:17 +0100 [thread overview]
Message-ID: <20220924165417.46a1fc44@jic23-huawei> (raw)
In-Reply-To: <20220920112821.975359-15-nuno.sa@analog.com>
On Tue, 20 Sep 2022 13:28:20 +0200
Nuno Sá <nuno.sa@analog.com> wrote:
> The pattern used in this device does not quite fit in the
> iio_device_claim_direct_mode() typical usage. In this case,
> iio_buffer_enabled() was being used not to prevent the raw access
> but to decide whether or not the device needs to be powered on before.
> If buffering, then the device is already on. To guarantee the same
> behavior, a combination of locks is being used:
>
> 1. Use iio_device_claim_direct_mode() to check if direct mode can be
> claimed and if we can, then we keep it until the reading is done (which
> also means the device will be powered on and off);
> 2. If already buffering, we need to make sure that buffering is not
> disabled (and hence, powering off the device) while doing a raw read. For
> that, we can make use of the local lock that already exists.
>
> Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Obviously same dance in here as the related previous patch. So same solution
needs adopting. I just thought I'd reply to make sure we didn't forget to
cover them both :)
Jonathan
> ---
> drivers/iio/health/max30102.c | 25 +++++++++++++++++++------
> 1 file changed, 19 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/iio/health/max30102.c b/drivers/iio/health/max30102.c
> index abbcef563807..e984c78b99f6 100644
> --- a/drivers/iio/health/max30102.c
> +++ b/drivers/iio/health/max30102.c
> @@ -227,9 +227,20 @@ static int max30102_buffer_postenable(struct iio_dev *indio_dev)
> static int max30102_buffer_predisable(struct iio_dev *indio_dev)
> {
> struct max30102_data *data = iio_priv(indio_dev);
> + int ret;
> +
> + /*
> + * As stated in the comment in the read_raw() function, temperature
> + * can only be acquired if the engine is running. As such the mutex
> + * is used to make sure we do not power down while doing a temperature
> + * reading.
> + */
> + mutex_lock(&data->lock);
> + ret = max30102_set_powermode(data, MAX30102_REG_MODE_CONFIG_MODE_NONE,
> + false);
> + mutex_unlock(&data->lock);
>
> - return max30102_set_powermode(data, MAX30102_REG_MODE_CONFIG_MODE_NONE,
> - false);
> + return ret;
> }
>
> static const struct iio_buffer_setup_ops max30102_buffer_setup_ops = {
> @@ -477,12 +488,14 @@ static int max30102_read_raw(struct iio_dev *indio_dev,
> * Temperature reading can only be acquired when not in
> * shutdown; leave shutdown briefly when buffer not running
> */
> - mutex_lock(&indio_dev->mlock);
> - if (!iio_buffer_enabled(indio_dev))
> + if (!iio_device_claim_direct_mode(indio_dev)) {
> ret = max30102_get_temp(data, val, true);
> - else
> + iio_device_release_direct_mode(indio_dev);
> + } else {
> + mutex_lock(&data->lock);
> ret = max30102_get_temp(data, val, false);
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&data->lock);
> + }
> if (ret)
> return ret;
>
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next prev parent reply other threads:[~2022-09-24 15:54 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-20 11:28 [PATCH 00/15] Make 'mlock' really private Nuno Sá
2022-09-20 11:28 ` [PATCH 01/15] iio: adc: ad_sigma_delta: do not use internal iio_dev lock Nuno Sá
2022-09-20 11:54 ` Miquel Raynal
2022-09-24 14:22 ` Jonathan Cameron
2022-09-20 11:28 ` [PATCH 02/15] iio: adc: ad799x: " Nuno Sá
2022-09-24 14:45 ` Jonathan Cameron
2022-09-26 11:22 ` Nuno Sá
2022-09-20 11:28 ` [PATCH 03/15] iio: adc: axp288_adc: " Nuno Sá
2022-09-20 13:13 ` Andy Shevchenko
2022-09-20 13:18 ` Sa, Nuno
2022-09-20 13:37 ` Andy Shevchenko
2022-09-20 13:39 ` Andy Shevchenko
2022-09-20 13:46 ` Sa, Nuno
2022-09-20 15:12 ` Andy Shevchenko
2022-09-21 9:07 ` Nuno Sá
2022-09-24 15:23 ` Jonathan Cameron
2022-09-24 15:24 ` Jonathan Cameron
2022-09-20 11:28 ` [PATCH 04/15] iio: adc: imx7d_adc: " Nuno Sá
2022-09-24 15:26 ` Jonathan Cameron
2022-09-20 11:28 ` [PATCH 05/15] iio: adc: lpc32xx_adc: " Nuno Sá
2022-09-24 15:27 ` Jonathan Cameron
2022-09-20 11:28 ` [PATCH 06/15] iio: adc: ltc2947-core: " Nuno Sá
2022-09-20 11:28 ` [PATCH 07/15] iio: adc: meson_saradc: " Nuno Sá
2022-09-25 20:38 ` Martin Blumenstingl
2022-09-20 11:28 ` [PATCH 08/15] iio: adc: rockchip_saradc: " Nuno Sá
2022-09-20 11:28 ` [PATCH 09/15] iio: adc: sc27xx_adc: " Nuno Sá
2022-09-20 11:28 ` [PATCH 10/15] iio: adc: vf610_adc: " Nuno Sá
2022-09-24 15:37 ` Jonathan Cameron
2022-09-20 11:28 ` [PATCH 11/15] iio: common: scmi_iio: " Nuno Sá
2022-09-24 15:42 ` Jonathan Cameron
2022-09-20 11:28 ` [PATCH 12/15] iio: fyro: itg3200_core: " Nuno Sá
2022-09-24 15:43 ` Jonathan Cameron
2022-09-24 15:46 ` Jonathan Cameron
2022-09-20 11:28 ` [PATCH 13/15] iio: health: max30100: " Nuno Sá
2022-09-20 12:23 ` Miquel Raynal
2022-09-20 12:44 ` Sa, Nuno
2022-09-20 12:55 ` Miquel Raynal
2022-09-20 13:15 ` Sa, Nuno
2022-09-20 13:53 ` Miquel Raynal
2022-09-20 14:56 ` Nuno Sá
2022-09-20 15:10 ` Miquel Raynal
2022-09-24 15:53 ` Jonathan Cameron
2022-09-26 10:06 ` Nuno Sá
2022-10-02 11:03 ` Jonathan Cameron
2022-10-04 7:57 ` Nuno Sá
2022-09-20 11:28 ` [PATCH 14/15] iio: health: max30102: " Nuno Sá
2022-09-24 15:54 ` Jonathan Cameron [this message]
2022-09-30 10:04 ` Nuno Sá
2022-10-02 11:08 ` Jonathan Cameron
2022-10-04 7:53 ` Nuno Sá
2022-09-20 11:28 ` [PATCH 15/15] iio: core: move 'mlock' to 'struct iio_dev_opaque' Nuno Sá
2022-09-24 15:56 ` Jonathan Cameron
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