On Thu, Jun 13, 2013 at 3:36 AM, Simon Glass <s...@chromium.org> wrote: > Hi Jagan, > > On Wed, Jun 12, 2013 at 12:51 PM, Jagan Teki <jagannadh.t...@gmail.com> > wrote: >> >> Hi, >> >> >> On 30-05-2013 10:49, Rajeshwari Shinde wrote: >>> >>> For devices that need some time to react after a spi transaction >>> finishes, add the ability to set a delay. >>> >>> Implement this as a delay on the first/next transaction to avoid >>> any delay in the fairly common case where a SPI transaction is >>> followed by other processing. >>> >>> Based on: >>> "[U-Boot] [PATCH 0/2 V5] spi: Enable SPI_PREAMBLE Mode" >> >> >> Please use the below format for referring previous commits >> ex: >> "<PREVIOUS_COMMIT_HEAD>" >> (sha1: PREVIOUS_COMMIT_ID) >> >> in this case >> "spi: exynos: Support SPI_PREAMBLE mode" >> (sha1: e4eaef8910df805d511b1cb9b2caafa7d2827fdc) > > > I hope you don't mind me answering part of this... > >> >> >> >>> >>> Signed-off-by: Simon Glass <s...@chromium.org> >>> Signed-off-by: Rajeshwari Shinde <rajeshwar...@samsung.com> >>> --- >>> Changes in V2: >>> - None. >>> Changes in V3: >>> - Rebased on "[PATCH 0/2 V5] spi: Enable SPI_PREAMBLE Mode" >>> drivers/spi/exynos_spi.c | 19 +++++++++++++++++++ >>> 1 files changed, 19 insertions(+), 0 deletions(-) >>> >>> diff --git a/drivers/spi/exynos_spi.c b/drivers/spi/exynos_spi.c >>> index 01378d0..03cf503 100644 >>> --- a/drivers/spi/exynos_spi.c >>> +++ b/drivers/spi/exynos_spi.c >>> @@ -38,6 +38,7 @@ struct spi_bus { >>> struct exynos_spi *regs; >>> int inited; /* 1 if this bus is ready for use */ >>> int node; >>> + uint deactivate_delay_us; /* Delay to wait after deactivate >>> */ >>> }; >>> >>> /* A list of spi buses that we know about */ >>> @@ -52,6 +53,8 @@ struct exynos_spi_slave { >>> enum periph_id periph_id; /* Peripheral ID for this device >>> */ >>> unsigned int fifo_size; >>> int skip_preamble; >>> + struct spi_bus *bus; /* Pointer to our SPI bus info */ >>> + ulong last_transaction_us; /* Time of last transaction end >>> */ >>> }; >>> >>> static struct spi_bus *spi_get_bus(unsigned dev_index) >>> @@ -97,6 +100,7 @@ struct spi_slave *spi_setup_slave(unsigned int busnum, >>> unsigned int cs, >>> } >>> >>> bus = &spi_bus[busnum]; >>> + spi_slave->bus = bus; >>> spi_slave->regs = bus->regs; >>> spi_slave->mode = mode; >>> spi_slave->periph_id = bus->periph_id; >>> @@ -107,6 +111,7 @@ struct spi_slave *spi_setup_slave(unsigned int >>> busnum, unsigned int cs, >>> spi_slave->fifo_size = 256; >>> >>> spi_slave->skip_preamble = 0; >>> + spi_slave->last_transaction_us = timer_get_us(); >>> >>> spi_slave->freq = bus->frequency; >>> if (max_hz) >>> @@ -371,9 +376,21 @@ void spi_cs_activate(struct spi_slave *slave) >>> { >>> struct exynos_spi_slave *spi_slave = to_exynos_spi(slave); >>> >>> + /* If it's too soon to do another transaction, wait */ >>> + if (spi_slave->bus->deactivate_delay_us && >>> + spi_slave->last_transaction_us) { >>> + ulong delay_us; /* The delay completed so far */ >>> + delay_us = timer_get_us() - >>> spi_slave->last_transaction_us; >>> + if (delay_us < spi_slave->bus->deactivate_delay_us) >>> + udelay(spi_slave->bus->deactivate_delay_us - >>> delay_us); >>> + } >> >> Add one space >> >> >>> clrbits_le32(&spi_slave->regs->cs_reg, SPI_SLAVE_SIG_INACT); >>> debug("Activate CS, bus %d\n", spi_slave->slave.bus); >>> spi_slave->skip_preamble = spi_slave->mode & SPI_PREAMBLE; >>> + >>> + /* Remember time of this transaction so we can honour the bus >>> delay */ >>> + if (spi_slave->bus->deactivate_delay_us) >>> + spi_slave->last_transaction_us = timer_get_us(); >>> } >>> >>> /** >>> @@ -423,6 +440,8 @@ static int spi_get_config(const void *blob, int node, >>> struct spi_bus *bus) >>> /* Use 500KHz as a suitable default */ >>> bus->frequency = fdtdec_get_int(blob, node, "spi-max-frequency", >>> 500000); >>> + bus->deactivate_delay_us = fdtdec_get_int(blob, node, >>> + "spi-deactivate-delay", 0); >>> >>> return 0; >>> } >>> >> >> Was this tested, usually what is the max deactivate delay? > > > This was tested with 50us. > >> >> In this case your are passing through dts is it? > > > Yes that's right. > > Regards, > Simon > >> >> >> Thanks, >> Jagan. >> >> >
Can you please send the next version patches. -- Thanks, Jagan. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot