From: Jonathan Cameron <jic23@kernel.org>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Vasileios Amoiridis <vassilisamir@gmail.com>,
lars@metafoo.de, ang.iglesiasg@gmail.com, 579lpy@gmail.com,
linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] drivers: iio: pressure: Add SPI support for BMP38x and BMP390
Date: Fri, 16 Feb 2024 11:05:43 +0000 [thread overview]
Message-ID: <20240216110543.5d6289f6@jic23-huawei> (raw)
In-Reply-To: <Zc5D35_4FdERZXe4@smile.fi.intel.com>
On Thu, 15 Feb 2024 19:03:27 +0200
Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> On Thu, Feb 15, 2024 at 05:43:32PM +0100, Vasileios Amoiridis wrote:
> > According to the datasheet of BMP38x and BMP390 devices, in SPI
> > operation, the first byte that returns after a read operation is
> > garbage and it needs to be dropped and return the rest of the
> > bytes.
>
> Thank you for the patch, my comments below.
>
> ...
>
> > +static int bmp380_regmap_spi_read(void *context, const void *reg,
> > + size_t reg_size, void *val, size_t val_size)
> > +{
> > + struct spi_device *spi = to_spi_device(context);
> > + u8 ret[BMP380_SPI_MAX_REG_COUNT_READ + 1];
> > + ssize_t status;
> > + u8 buf;
>
> AFAIU this buffer is not DMA-capable.
Doesn't matter in this case as spi_write_then_read() bounces anyway so you don't need
to provide it with a dma safe buffer. It's in the docs, so we can rely
on this not changing.
https://elixir.bootlin.com/linux/latest/source/drivers/spi/spi.c#L4391
next prev parent reply other threads:[~2024-02-16 11:05 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-15 16:43 [PATCH] drivers: iio: pressure: Add SPI support for BMP38x and BMP390 Vasileios Amoiridis
2024-02-15 17:03 ` Andy Shevchenko
2024-02-16 11:05 ` Jonathan Cameron [this message]
2024-02-16 13:29 ` Vasileios Amoiridis
2024-02-15 17:20 ` Angel Iglesias
2024-02-16 11:18 ` Jonathan Cameron
2024-02-16 13:26 ` Vasileios Amoiridis
2024-02-16 15:47 ` Jonathan Cameron
2024-02-16 16:40 ` Vasileios Amoiridis
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