Messages in this thread |  | | From | Andy Shevchenko <> | Date | Fri, 27 Nov 2020 16:22:51 +0200 | Subject | Re: [PATCH v3 2/3] spi: Add SPI_NO_TX/RX support |
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On Fri, Nov 27, 2020 at 3:08 PM Alexandru Ardelean <alexandru.ardelean@analog.com> wrote: > Transmit/receive only is a valid SPI mode. For example, the MOSI/TX line > might be missing from an ADC while for a DAC the MISO/RX line may be > optional. This patch adds these two new modes: SPI_NO_TX and > SPI_NO_RX. This way, the drivers will be able to identify if any of > these two lines is missing and to adjust the transfers accordingly.
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> + /* > + * check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO > + * are set at the same time > */
Since you are here, check -> Check time -> time.
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> + if ((hweight_long(spi->mode & > + (SPI_TX_DUAL | SPI_TX_QUAD | SPI_NO_TX)) > 1) || > + (hweight_long(spi->mode & > + (SPI_RX_DUAL | SPI_RX_QUAD | SPI_NO_RX)) > 1)) { > dev_err(&spi->dev, > - "setup: can not select dual and quad at the same time\n"); > + "setup: can not select any two of dual, quad and no-rx/tx " > + "at the same time\n");
Don't split literals, and probably rephrase (If I can't set 2, can I set 3?) "setup: can't select more than one out of dual, quad, and no-Rx / no-Tx at the same time\n");
> --- a/include/uapi/linux/spi/spi.h > +++ b/include/uapi/linux/spi/spi.h > @@ -43,5 +43,7 @@ > #define SPI_TX_OCTAL 0x2000 /* transmit with 8 wires */ > #define SPI_RX_OCTAL 0x4000 /* receive with 8 wires */ > #define SPI_3WIRE_HIZ 0x8000 /* high impedance turnaround */ > +#define SPI_NO_TX 0x10000 /* no transmit wire */ > +#define SPI_NO_RX 0x20000 /* no receive wire */
Is it really material for uAPI? Perhaps we may have something like SPI_MODE_USER_MASK in uAPI and in internal headers
SPI_MODE_KERNEL_MASK with static_assert(_USER_MASK & _KERNEL_MASK); // check conditional
?
-- With Best Regards, Andy Shevchenko
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