On Thursday, September 03, 2015 at 03:41:59 PM, Chin Liang See wrote:
> Ensuring spi_calibration is run when there is a change of sclk
> frequency. This will ensure the qspi flash access works for high
> sclk frequency
>
> Signed-off-by: Chin Liang See <cl...@altera.com>
> Cc: Dinh Nguyen <dingu...@opensource.altera.com>
> Cc: Dinh Nguyen <dinh.li...@gmail.com>
> Cc: Marek Vasut <ma...@denx.de>
> Cc: Stefan Roese <s...@denx.de>
> Cc: Vikas Manocha <vikas.mano...@st.com>
> Cc: Jagannadh Teki <jt...@openedev.com>
> Cc: Pavel Machek <pa...@denx.de>
> ---
> drivers/spi/cadence_qspi.c | 8 ++++----
> 1 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/spi/cadence_qspi.c b/drivers/spi/cadence_qspi.c
> index 34a0f46..300934e 100644
> --- a/drivers/spi/cadence_qspi.c
> +++ b/drivers/spi/cadence_qspi.c
> @@ -37,7 +37,7 @@ static int cadence_spi_write_speed(struct udevice *bus,
> uint hz) }
>
> /* Calibration sequence to determine the read data capture delay register
> */ -static int spi_calibration(struct udevice *bus)
> +static int spi_calibration(struct udevice *bus, uint hz)
> {
> struct cadence_spi_platdata *plat = bus->platdata;
> struct cadence_spi_priv *priv = dev_get_priv(bus);
> @@ -64,7 +64,7 @@ static int spi_calibration(struct udevice *bus)
> }
>
> /* use back the intended clock and find low range */
> - cadence_spi_write_speed(bus, plat->max_hz);
> + cadence_spi_write_speed(bus, hz);
> for (i = 0; i < CQSPI_READ_CAPTURE_MAX_DELAY; i++) {
> /* Disable QSPI */
> cadence_qspi_apb_controller_disable(base);
> @@ -111,7 +111,7 @@ static int spi_calibration(struct udevice *bus)
> (range_hi + range_lo) / 2, range_lo, range_hi);
>
> /* just to ensure we do once only when speed or chip select change */
> - priv->qspi_calibrated_hz = plat->max_hz;
> + priv->qspi_calibrated_hz = hz;
> priv->qspi_calibrated_cs = spi_chip_select(bus);
>
> return 0;
> @@ -131,7 +131,7 @@ static int cadence_spi_set_speed(struct udevice *bus,
Hi,
My impression is that the logic here should be like this:
if (hz > plat->max_hz) {
printf("error, freq. too high");
return -EINVAL;
}
if (priv->previous_hz != hz) /* Bus frequency changed, re-calibrate */
spi_calibrate(bus, hz)
cadence_spi_write_speed(bus, priv->qspi_calibrated_hz);
priv->previous_hz = hz;
Note that you need a new private variable, previous_hz, to hold the previous
value of "hz". This is needed since the calibrated frequency might not be
equal to requested frequency.
> uint hz) /* Calibration required for different SCLK speed or chip select
> */ if (priv->qspi_calibrated_hz != plat->max_hz ||
> priv->qspi_calibrated_cs != spi_chip_select(bus)) {
> - err = spi_calibration(bus);
> + err = spi_calibration(bus, hz);
This is called after the frequency is configured in this function, this looks
really backwards.
> if (err)
> return err;
> }
Best regards,
Marek Vasut
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