ata: ahci_imx: add disable for spread-spectrum

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.

Having it as a negative property keeps existing DT files working.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Reviewed-by: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 13 insertions, 1 deletions

diff --git a/drivers/ata/ahci_imx.c b/drivers/ata/ahci_imx.c
index e032e95ddee3..685a4db030b1 100644
--- a/drivers/ata/ahci_imx.c
+++ b/drivers/ata/ahci_imx.c
@@ -368,6 +368,7 @@ 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[] = {
@@ -465,6 +466,10 @@ 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,
         },
 };
 
@@ -478,6 +483,14 @@ 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);
@@ -549,7 +562,6 @@ 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;
         }