From: Andy Shevchenko <andriy.shevchenko@intel.com>
To: Abdelnasser Hussein <abdelnasserhussein11@gmail.com>
Cc: jic23@kernel.org, gregkh@linuxfoundation.org, nuno.sa@analog.com,
Michael.Hennerich@analog.com, dlechner@baylibre.com,
andy@kernel.org, linux@analog.com, linux-iio@vger.kernel.org,
linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org,
joshua.crofts1@gmail.com
Subject: Re: [PATCH v6 2/3] staging: iio: adc: ad7816: Serialize SPI read operations
Date: Sun, 13 Sep 2026 11:20:44 +0300 [thread overview]
Message-ID: <aqZc3LR0s0I2S27b@ashevche-desk.local> (raw)
In-Reply-To: <20260912132517.55686-3-abdelnasserhussein11@gmail.com>
On Sat, Sep 12, 2026 at 04:25:16PM +0300, Abdelnasser Hussein wrote:
> The ad7816_spi_read() function performs a sequence of GPIO state
> changes followed by an SPI transfer. If multiple read operations
> occur simultaneously, the GPIO state could be changed by one thread
> while another is in the middle of a read. This leads to a race
> condition where the sensor state is disrupted.
>
> Introduce a mutex to serialize the read sequence, ensuring that the
> GPIO toggling and the SPI transfer are treated as a single atomic
> operation.
...
> struct ad7816_chip_info {
> u8 oti_data[AD7816_CS_MAX + 1];
> u8 channel_id; /* 0 always be temperature */
> u8 mode;
> + struct mutex lock; /* protect device state during SPI transfers */
> };
Is `pahole` happy with the chosen layout?
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2026-09-13 8:20 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-12 13:25 [PATCH v6 0/3] staging: iio: adc: ad7816: Fix SPI read race condition and DMA safety Abdelnasser Hussein
2026-09-12 13:25 ` [PATCH v6 1/3] staging: iio: adc: ad7816: Sort headers alphabetically Abdelnasser Hussein
2026-09-12 13:25 ` [PATCH v6 2/3] staging: iio: adc: ad7816: Serialize SPI read operations Abdelnasser Hussein
2026-09-13 8:20 ` Andy Shevchenko [this message]
2026-09-13 13:21 ` nasser
2026-09-12 13:25 ` [PATCH v6 3/3] staging: iio: adc: ad7816: Use DMA-safe buffer for SPI read Abdelnasser Hussein
2026-09-13 2:59 ` Jonathan Cameron
2026-09-13 6:35 ` nasser
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