| Message ID | 1433847889-7220-9-git-send-email-javier.martinez@collabora.co.uk (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Tue, 09 Jun 2015, Javier Martinez Canillas wrote: > From: Alexandru M Stan <amstan@chromium.org> > > Some ECs need a little time for waking up before they can accept > SPI data at a high speed. This is configurable via a DT property > "google,cros-ec-spi-pre-delay". > > This patch makes the cros_ec_spi driver to cause a delay before > the beginning of a SPI transaction, to make sure that the EC has > already woken up, if the property has been defined in the DTS. > > Signed-off-by: Alexandru M Stan <amstan@chromium.org> > Reviewed-by: Doug Anderson <dianders@chromium.org> > Signed-off-by: Chris Zhong <zyw@rock-chips.com> > Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk> > Tested-by: Heiko Stuebner <heiko@sntech.de> > Acked-by: Lee Jones <lee.jones@linaro.org> > Acked-by: Olof Johansson <olof@lixom.net> Applied, thanks. > --- > > Changes since v6: > - Add Olof Johansson Acked-by tag > > Changes since v5: None. > > Changes since v4: None. > > Changes since v3: > - New patch, split DT binding and driver implementation as suggested > by Lee Jones. > - Add tested-by tag from Heiko Stuebner. > - Add acked-by tag from Lee Jones. > --- > drivers/mfd/cros_ec_spi.c | 21 +++++++++++++++++++-- > 1 file changed, 19 insertions(+), 2 deletions(-) > > diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c > index faba03e2f1ef..16f228dc243f 100644 > --- a/drivers/mfd/cros_ec_spi.c > +++ b/drivers/mfd/cros_ec_spi.c > @@ -71,12 +71,15 @@ > * @spi: SPI device we are connected to > * @last_transfer_ns: time that we last finished a transfer, or 0 if there > * if no record > + * @start_of_msg_delay: used to set the delay_usecs on the spi_transfer that > + * is sent when we want to turn on CS at the start of a transaction. > * @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that > * is sent when we want to turn off CS at the end of a transaction. > */ > struct cros_ec_spi { > struct spi_device *spi; > s64 last_transfer_ns; > + unsigned int start_of_msg_delay; > unsigned int end_of_msg_delay; > }; > > @@ -366,7 +369,7 @@ static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev, > struct ec_host_request *request; > struct ec_host_response *response; > struct cros_ec_spi *ec_spi = ec_dev->priv; > - struct spi_transfer trans; > + struct spi_transfer trans, trans_delay; > struct spi_message msg; > int i, len; > u8 *ptr; > @@ -393,13 +396,23 @@ static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev, > goto exit; > } > > + /* > + * Leave a gap between CS assertion and clocking of data to allow the > + * EC time to wakeup. > + */ > + spi_message_init(&msg); > + if (ec_spi->start_of_msg_delay) { > + memset(&trans_delay, 0, sizeof(trans_delay)); > + trans_delay.delay_usecs = ec_spi->start_of_msg_delay; > + spi_message_add_tail(&trans_delay, &msg); > + } > + > /* Transmit phase - send our message */ > memset(&trans, 0, sizeof(trans)); > trans.tx_buf = ec_dev->dout; > trans.rx_buf = rx_buf; > trans.len = len; > trans.cs_change = 1; > - spi_message_init(&msg); > spi_message_add_tail(&trans, &msg); > ret = spi_sync(ec_spi->spi, &msg); > > @@ -602,6 +615,10 @@ static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev) > u32 val; > int ret; > > + ret = of_property_read_u32(np, "google,cros-ec-spi-pre-delay", &val); > + if (!ret) > + ec_spi->start_of_msg_delay = val; > + > ret = of_property_read_u32(np, "google,cros-ec-spi-msg-delay", &val); > if (!ret) > ec_spi->end_of_msg_delay = val;
diff --git a/drivers/mfd/cros_ec_spi.c b/drivers/mfd/cros_ec_spi.c index faba03e2f1ef..16f228dc243f 100644 --- a/drivers/mfd/cros_ec_spi.c +++ b/drivers/mfd/cros_ec_spi.c @@ -71,12 +71,15 @@ * @spi: SPI device we are connected to * @last_transfer_ns: time that we last finished a transfer, or 0 if there * if no record + * @start_of_msg_delay: used to set the delay_usecs on the spi_transfer that + * is sent when we want to turn on CS at the start of a transaction. * @end_of_msg_delay: used to set the delay_usecs on the spi_transfer that * is sent when we want to turn off CS at the end of a transaction. */ struct cros_ec_spi { struct spi_device *spi; s64 last_transfer_ns; + unsigned int start_of_msg_delay; unsigned int end_of_msg_delay; }; @@ -366,7 +369,7 @@ static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev, struct ec_host_request *request; struct ec_host_response *response; struct cros_ec_spi *ec_spi = ec_dev->priv; - struct spi_transfer trans; + struct spi_transfer trans, trans_delay; struct spi_message msg; int i, len; u8 *ptr; @@ -393,13 +396,23 @@ static int cros_ec_pkt_xfer_spi(struct cros_ec_device *ec_dev, goto exit; } + /* + * Leave a gap between CS assertion and clocking of data to allow the + * EC time to wakeup. + */ + spi_message_init(&msg); + if (ec_spi->start_of_msg_delay) { + memset(&trans_delay, 0, sizeof(trans_delay)); + trans_delay.delay_usecs = ec_spi->start_of_msg_delay; + spi_message_add_tail(&trans_delay, &msg); + } + /* Transmit phase - send our message */ memset(&trans, 0, sizeof(trans)); trans.tx_buf = ec_dev->dout; trans.rx_buf = rx_buf; trans.len = len; trans.cs_change = 1; - spi_message_init(&msg); spi_message_add_tail(&trans, &msg); ret = spi_sync(ec_spi->spi, &msg); @@ -602,6 +615,10 @@ static void cros_ec_spi_dt_probe(struct cros_ec_spi *ec_spi, struct device *dev) u32 val; int ret; + ret = of_property_read_u32(np, "google,cros-ec-spi-pre-delay", &val); + if (!ret) + ec_spi->start_of_msg_delay = val; + ret = of_property_read_u32(np, "google,cros-ec-spi-msg-delay", &val); if (!ret) ec_spi->end_of_msg_delay = val;