Messages in this thread | | | Date | Thu, 15 Feb 2024 19:03:27 +0200 | From | Andy Shevchenko <> | Subject | Re: [PATCH] drivers: iio: pressure: Add SPI support for BMP38x and BMP390 |
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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.
> + memcpy(&buf, reg, reg_size);
I prefer to see a switch case with cases based on allowed sizes and proper endianess accessors.
> + buf |= 0x80;
This is done by regmap, no?
> + /* > + * According to the BMP380, BMP388, BMP390 datasheets, for a basic > + * read operation, after the write is done, 2 bytes are received and > + * the first one has to be dropped. The 2nd one is the requested > + * value. > + */ > + status = spi_write_then_read(spi, &buf, 1, ret, val_size + 1);
sizeof() ?
> + if (status) > + return status;
> + memcpy(val, ret + 1, val_size);
As per above.
> + return 0; > +}
-- With Best Regards, Andy Shevchenko
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