Re: [PATCH v3 1/2] spi: support inter-word delay requirement for devices

2019-01-29 Thread Mark Brown
On Tue, Jan 29, 2019 at 11:07:50AM +0100, Geert Uytterhoeven wrote: > On Tue, Jan 29, 2019 at 10:50 AM Jonas Bonn wrote: > > OK. So the user (perhaps in userspace using spidev) has to know the > > rate of the IO clock that the SPI controller sits behind and then has to > > match this to the

Re: [PATCH v3 1/2] spi: support inter-word delay requirement for devices

2019-01-29 Thread Geert Uytterhoeven
Hi Jonas, Baolin, On Tue, Jan 29, 2019 at 10:50 AM Jonas Bonn wrote: > On 29/01/2019 10:35, Baolin Wang wrote: > > On Tue, 29 Jan 2019 at 17:14, Jonas Bonn wrote: > >> On 29/01/2019 10:04, Baolin Wang wrote: > >>> On Tue, 29 Jan 2019 at 05:28, Jonas Bonn wrote: > On 28/01/2019 19:10, Mark

Re: [PATCH v3 1/2] spi: support inter-word delay requirement for devices

2019-01-29 Thread Jonas Bonn
On 29/01/2019 10:35, Baolin Wang wrote: On Tue, 29 Jan 2019 at 17:14, Jonas Bonn wrote: On 29/01/2019 10:04, Baolin Wang wrote: Hi Jonas, On Tue, 29 Jan 2019 at 05:28, Jonas Bonn wrote: Hi, On 28/01/2019 19:10, Mark Brown wrote: On Sat, Jan 26, 2019 at 05:32:19PM +0100, Jonas Bonn

Re: [PATCH v3 1/2] spi: support inter-word delay requirement for devices

2019-01-29 Thread Baolin Wang
On Tue, 29 Jan 2019 at 17:14, Jonas Bonn wrote: > > > > On 29/01/2019 10:04, Baolin Wang wrote: > > Hi Jonas, > > On Tue, 29 Jan 2019 at 05:28, Jonas Bonn wrote: > >> > >> Hi, > >> > >> On 28/01/2019 19:10, Mark Brown wrote: > >>> On Sat, Jan 26, 2019 at 05:32:19PM +0100, Jonas Bonn wrote: > >>>

Re: [PATCH v3 1/2] spi: support inter-word delay requirement for devices

2019-01-29 Thread Jonas Bonn
On 29/01/2019 10:04, Baolin Wang wrote: Hi Jonas, On Tue, 29 Jan 2019 at 05:28, Jonas Bonn wrote: Hi, On 28/01/2019 19:10, Mark Brown wrote: On Sat, Jan 26, 2019 at 05:32:19PM +0100, Jonas Bonn wrote: @@ -164,6 +166,7 @@ struct spi_device { char

Re: [PATCH v3 1/2] spi: support inter-word delay requirement for devices

2019-01-29 Thread Baolin Wang
Hi Jonas, On Tue, 29 Jan 2019 at 05:28, Jonas Bonn wrote: > > Hi, > > On 28/01/2019 19:10, Mark Brown wrote: > > On Sat, Jan 26, 2019 at 05:32:19PM +0100, Jonas Bonn wrote: > > > >> @@ -164,6 +166,7 @@ struct spi_device { > >> charmodalias[SPI_NAME_SIZE]; > >> const

Re: [PATCH v3 1/2] spi: support inter-word delay requirement for devices

2019-01-28 Thread Jonas Bonn
Hi, On 28/01/2019 19:10, Mark Brown wrote: On Sat, Jan 26, 2019 at 05:32:19PM +0100, Jonas Bonn wrote: @@ -164,6 +166,7 @@ struct spi_device { charmodalias[SPI_NAME_SIZE]; const char *driver_override; int cs_gpio;

Re: [PATCH v3 1/2] spi: support inter-word delay requirement for devices

2019-01-28 Thread Mark Brown
On Sat, Jan 26, 2019 at 05:32:19PM +0100, Jonas Bonn wrote: > @@ -164,6 +166,7 @@ struct spi_device { > charmodalias[SPI_NAME_SIZE]; > const char *driver_override; > int cs_gpio;/* chip select gpio */ > + uint16_t

[PATCH v3 1/2] spi: support inter-word delay requirement for devices

2019-01-26 Thread Jonas Bonn
Some devices are slow and cannot keep up with the SPI bus and therefore require a short delay between words of the SPI transfer. The example of this that I'm looking at is a SAMA5D2 with a minimum SPI clock of 400kHz talking to an AVR-based SPI slave. The AVR cannot put bytes on the bus fast