On Mon, Dec 21, 2020 at 4:15 PM Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> wrote: > > From: Dragos Bogdan <dragos.bogdan@xxxxxxxxxx> > > 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. > > Signed-off-by: Dragos Bogdan <dragos.bogdan@xxxxxxxxxx> Missed Co-developed-by: Alexandru ... ? Anyway, looks good to me, Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> > --- > > Changelog v4 -> v5: > * https://lore.kernel.org/linux-spi/20201203140531.74470-2-alexandru.ardelean@xxxxxxxxxx/ > * using static_assert() vs BUILD_BUG_ON() > * added comments for SPI_MODE_KERNEL_MASK & SPI_MODE_USER_MASK > * using shorter form defining SPI_MODE_KERNEL_MASK & SPI_MODE_USER_MASK > > drivers/spi/spi.c | 26 +++++++++++++++++++++----- > include/linux/spi/spi.h | 17 +++++++++++++++++ > include/uapi/linux/spi/spi.h | 10 ++++++++++ > 3 files changed, 48 insertions(+), 5 deletions(-) > > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c > index 51d7c004fbab..0b69934698c3 100644 > --- a/drivers/spi/spi.c > +++ b/drivers/spi/spi.c > @@ -1941,6 +1941,9 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi, > /* Device DUAL/QUAD mode */ > if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) { > switch (value) { > + case 0: > + spi->mode |= SPI_NO_TX; > + break; > case 1: > break; > case 2: > @@ -1962,6 +1965,9 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi, > > if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) { > switch (value) { > + case 0: > + spi->mode |= SPI_NO_RX; > + break; > case 1: > break; > case 2: > @@ -3329,12 +3335,17 @@ int spi_setup(struct spi_device *spi) > unsigned bad_bits, ugly_bits; > int status; > > - /* check mode to prevent that DUAL and QUAD set at the same time > + /* > + * check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO > + * are set at the same time > */ > - if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) || > - ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) { > + 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"); > return -EINVAL; > } > /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden > @@ -3348,7 +3359,8 @@ int spi_setup(struct spi_device *spi) > * SPI_CS_WORD has a fallback software implementation, > * so it is ignored here. > */ > - bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD); > + bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD | > + SPI_NO_TX | SPI_NO_RX); > /* nothing prevents from working with active-high CS in case if it > * is driven by GPIO. > */ > @@ -3610,6 +3622,8 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message) > * 2. check tx/rx_nbits match the mode in spi_device > */ > if (xfer->tx_buf) { > + if (spi->mode & SPI_NO_TX) > + return -EINVAL; > if (xfer->tx_nbits != SPI_NBITS_SINGLE && > xfer->tx_nbits != SPI_NBITS_DUAL && > xfer->tx_nbits != SPI_NBITS_QUAD) > @@ -3623,6 +3637,8 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message) > } > /* check transfer rx_nbits */ > if (xfer->rx_buf) { > + if (spi->mode & SPI_NO_RX) > + return -EINVAL; > if (xfer->rx_nbits != SPI_NBITS_SINGLE && > xfer->rx_nbits != SPI_NBITS_DUAL && > xfer->rx_nbits != SPI_NBITS_QUAD) > diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h > index a08c3f37e202..9bfdfaf286eb 100644 > --- a/include/linux/spi/spi.h > +++ b/include/linux/spi/spi.h > @@ -6,6 +6,7 @@ > #ifndef __LINUX_SPI_H > #define __LINUX_SPI_H > > +#include <linux/bits.h> > #include <linux/device.h> > #include <linux/mod_devicetable.h> > #include <linux/slab.h> > @@ -166,6 +167,18 @@ struct spi_device { > u8 chip_select; > u8 bits_per_word; > bool rt; > +#define SPI_NO_TX BIT(31) /* no transmit wire */ > +#define SPI_NO_RX BIT(30) /* no receive wire */ > + /* > + * All bits defined above should be covered by SPI_MODE_KERNEL_MASK. > + * The SPI_MODE_KERNEL_MASK has the SPI_MODE_USER_MASK counterpart, > + * which is defined in 'include/uapi/linux/spi/spi.h'. > + * The bits defined here are from bit 31 downwards, while in > + * SPI_MODE_USER_MASK are from 0 upwards. > + * These bits must not overlap. A static assert check should make sure of that. > + * If adding extra bits, make sure to decrease the bit index below as well. > + */ > +#define SPI_MODE_KERNEL_MASK (~(BIT(30) - 1)) > u32 mode; > int irq; > void *controller_state; > @@ -189,6 +202,10 @@ struct spi_device { > */ > }; > > +/* Make sure that SPI_MODE_KERNEL_MASK & SPI_MODE_USER_MASK don't overlap */ > +static_assert((SPI_MODE_KERNEL_MASK & SPI_MODE_USER_MASK) == 0, > + "SPI_MODE_USER_MASK & SPI_MODE_KERNEL_MASK must not overlap"); > + > static inline struct spi_device *to_spi_device(struct device *dev) > { > return dev ? container_of(dev, struct spi_device, dev) : NULL; > diff --git a/include/uapi/linux/spi/spi.h b/include/uapi/linux/spi/spi.h > index 703b586f35df..236a85f08ded 100644 > --- a/include/uapi/linux/spi/spi.h > +++ b/include/uapi/linux/spi/spi.h > @@ -28,4 +28,14 @@ > #define SPI_RX_OCTAL _BITUL(14) /* receive with 8 wires */ > #define SPI_3WIRE_HIZ _BITUL(15) /* high impedance turnaround */ > > +/* > + * All the bits defined above should be covered by SPI_MODE_USER_MASK. > + * The SPI_MODE_USER_MASK has the SPI_MODE_KERNEL_MASK counterpart in > + * 'include/linux/spi/spi.h'. The bits defined here are from bit 0 upwards > + * while in SPI_MODE_KERNEL_MASK they are from the other end downwards. > + * These bits must not overlap. A static assert check should make sure of that. > + * If adding extra bits, make sure to increase the bit index below as well. > + */ > +#define SPI_MODE_USER_MASK (_BITUL(16) - 1) > + > #endif /* _UAPI_SPI_H */ > -- > 2.17.1 > -- With Best Regards, Andy Shevchenko
