On Wed, Apr 16, 2014 at 3:43 AM, Russell King
<rmk+kernel@xxxxxxxxxxxxxxxx> wrote:
> Spread-spectrum doesn't work with Cubox-i hardware, so we have to
> disable this feature. Add a DT property so that platforms can
> indicate that this feature should not be enabled.
This is for spread-spectrum tx or rx? Transmit SS is optional to
support, but the receiver must support SS. Otherwise random drives
won't work which makes for a good user experience. Is this really a
board quirk rather than a Si issue?
Rob
>
> Having it as a negative property keeps existing DT files working.
>
> Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
> ---
> arch/arm/boot/dts/imx6q-cubox-i.dts | 1 +
> drivers/ata/ahci_imx.c | 14 +++++++++++++-
> 2 files changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/boot/dts/imx6q-cubox-i.dts b/arch/arm/boot/dts/imx6q-cubox-i.dts
> index 941365d7ee65..9efd8b0c8011 100644
> --- a/arch/arm/boot/dts/imx6q-cubox-i.dts
> +++ b/arch/arm/boot/dts/imx6q-cubox-i.dts
> @@ -16,4 +16,5 @@
> fsl,transmit-level-mV = <1104>;
> fsl,transmit-boost-mdB = <0>;
> fsl,transmit-atten-16ths = <9>;
> + fsl,no-spread-spectrum;
> };
> diff --git a/drivers/ata/ahci_imx.c b/drivers/ata/ahci_imx.c
> index 1251d719cc73..f3221b8bfafa 100644
> --- a/drivers/ata/ahci_imx.c
> +++ b/drivers/ata/ahci_imx.c
> @@ -208,6 +208,7 @@ struct reg_property {
> const struct reg_value *values;
> size_t num_values;
> u32 def_value;
> + u32 set_value;
> };
>
> static const struct reg_value gpr13_tx_level[] = {
> @@ -305,6 +306,10 @@ static const struct reg_property gpr13_props[] = {
> .values = gpr13_rx_eq,
> .num_values = ARRAY_SIZE(gpr13_rx_eq),
> .def_value = IMX6Q_GPR13_SATA_RX_EQ_VAL_3_0_DB,
> + }, {
> + .name = "fsl,no-spread-spectrum",
> + .def_value = IMX6Q_GPR13_SATA_MPLL_SS_EN,
> + .set_value = 0,
> },
> };
>
> @@ -318,6 +323,14 @@ static u32 imx_ahci_parse_props(struct device *dev,
> for (i = 0; i < num; i++, prop++) {
> u32 of_val;
>
> + if (prop->num_values == 0) {
> + if (of_property_read_bool(np, prop->name))
> + reg_value |= prop->set_value;
> + else
> + reg_value |= prop->def_value;
> + continue;
> + }
> +
> if (of_property_read_u32(np, prop->name, &of_val)) {
> dev_info(dev, "%s not specified, using %08x\n",
> prop->name, prop->def_value);
> @@ -392,7 +405,6 @@ static int imx_ahci_probe(struct platform_device *pdev)
> IMX6Q_GPR13_SATA_RX_LOS_LVL_SATA2M |
> IMX6Q_GPR13_SATA_RX_DPLL_MODE_2P_4F |
> IMX6Q_GPR13_SATA_SPD_MODE_3P0G |
> - IMX6Q_GPR13_SATA_MPLL_SS_EN |
> reg_value;
> }
>
> --
> 1.8.3.1
>
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