stmmac: socfpga: Provide dt node to config ptp clk source.

Provides an options to use the ptp clock routed from the Altera FPGA
fabric. Instead of the defalt eosc1 clock connected to the ARM HPS core.
This setting affects all emacs in the core as the ptp clock is common.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Phil Reid <preid@electromag.com.au>
Acked-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/socfpga-dwmac.txt

@@ -11,6 +11,8 @@ Required properties:
 		  designware version numbers documented in stmmac.txt
  - altr,sysmgr-syscon : Should be the phandle to the system manager node that
    encompasses the glue register, the register offset, and the register shift.
+ - altr,f2h_ptp_ref_clk use f2h_ptp_ref_clk instead of default eosc1 clock
+   for ptp ref clk. This affects all emacs as the clock is common.
 
 Optional properties:
 altr,emac-splitter: Should be the phandle to the emac splitter soft IP node if

drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c

@@ -32,6 +32,7 @@
 #define SYSMGR_EMACGRP_CTRL_PHYSEL_ENUM_RMII 0x2
 #define SYSMGR_EMACGRP_CTRL_PHYSEL_WIDTH 2
 #define SYSMGR_EMACGRP_CTRL_PHYSEL_MASK 0x00000003
+#define SYSMGR_EMACGRP_CTRL_PTP_REF_CLK_MASK 0x00000010
 
 #define EMAC_SPLITTER_CTRL_REG			0x0
 #define EMAC_SPLITTER_CTRL_SPEED_MASK		0x3
@@ -47,6 +48,7 @@ struct socfpga_dwmac {
 	struct regmap *sys_mgr_base_addr;
 	struct reset_control *stmmac_rst;
 	void __iomem *splitter_base;
+	bool f2h_ptp_ref_clk;
 };
 
 static void socfpga_dwmac_fix_mac_speed(void *priv, unsigned int speed)
@@ -116,6 +118,8 @@ static int socfpga_dwmac_parse_data(struct socfpga_dwmac *dwmac, struct device *
 		return -EINVAL;
 	}
 
+	dwmac->f2h_ptp_ref_clk = of_property_read_bool(np, "altr,f2h_ptp_ref_clk");
+
 	np_splitter = of_parse_phandle(np, "altr,emac-splitter", 0);
 	if (np_splitter) {
 		if (of_address_to_resource(np_splitter, 0, &res_splitter)) {
@@ -171,6 +175,11 @@ static int socfpga_dwmac_setup(struct socfpga_dwmac *dwmac)
 	ctrl &= ~(SYSMGR_EMACGRP_CTRL_PHYSEL_MASK << reg_shift);
 	ctrl |= val << reg_shift;
 
+	if (dwmac->f2h_ptp_ref_clk)
+		ctrl |= SYSMGR_EMACGRP_CTRL_PTP_REF_CLK_MASK << (reg_shift / 2);
+	else
+		ctrl &= ~(SYSMGR_EMACGRP_CTRL_PTP_REF_CLK_MASK << (reg_shift / 2));
+
 	regmap_write(sys_mgr_base_addr, reg_offset, ctrl);
 	return 0;
 }