[PATCH net-next v3 4/5] net: stmmac: sun55i: Support TX delay extension bits

[Jerome Brunet]

On the A733 GMAC210, the TX clock delay is 5 bits wide: the 3 low bits are
in the ETXDC field and the 2 high bits in a separate field.

Add an optional mask for the high bits to the match data and set it when
necessary.

Signed-off-by: Jerome Brunet <jbrunet at baylibre.com>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-sun55i.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun55i.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun55i.c
index e759311f40fc..49abbb248b61 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-sun55i.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-sun55i.c
@@ -42,6 +42,7 @@ struct sun55i_gmac_data {
 	int (*init_resources)(struct platform_device *pdev,
 			      struct sun55i_gmac *gmac);
 	unsigned int flags;
+	u32 etxdc_ext_mask;
 	u32 txdly_step_ps;
 	u32 rxdly_step_ps;
 	u32 offset;
@@ -86,17 +87,21 @@ static int sun55i_gmac200_setup(struct device *dev,
 				const struct sun55i_gmac *gmac)
 {
 	struct device_node *node = dev->of_node;
-	u32 val, step, max, reg = 0;
+	u32 val, step, max, low_bits, reg = 0;
 	int ret;
 
 	if (!of_property_read_u32(node, "tx-internal-delay-ps", &val)) {
+		low_bits = hweight32(SYSCON_ETXDC_MASK);
 		step = gmac->data->txdly_step_ps;
-		max = FIELD_MAX(SYSCON_ETXDC_MASK);
+		max = (1U << (low_bits + hweight32(gmac->data->etxdc_ext_mask))) - 1;
 		ret = sun55i_gmac200_validate_delay(dev, "tx", &val, step, max);
 		if (ret)
 			return ret;
 
 		reg |= FIELD_PREP(SYSCON_ETXDC_MASK, val);
+		if (gmac->data->etxdc_ext_mask)
+			reg |= field_prep(gmac->data->etxdc_ext_mask,
+					  val >> low_bits);
 	}
 
 	if (!of_property_read_u32(node, "rx-internal-delay-ps", &val)) {

-- 
2.53.0