net: phy: dp83867: Add binding for the CLK_OUT pin muxing option

The DP83867 has a muxing option for the CLK_OUT pin. It is possible
to set CLK_OUT for different channels.
Create a binding to select a specific clock for CLK_OUT pin.

Signed-off-by: Wadim Egorov <[e-mail]>
Signed-off-by: Daniel Schultz <[e-mail]>
Reviewed-by: Andrew Lunn <[e-mail]>
Reviewed-by: Florian Fainelli <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/phy/dp83867.c

···
 
 #define DP83867_IO_MUX_CFG_IO_IMPEDANCE_MAX	0x0
 #define DP83867_IO_MUX_CFG_IO_IMPEDANCE_MIN	0x1f
+#define DP83867_IO_MUX_CFG_CLK_O_SEL_MASK	(0x1f << 8)
+#define DP83867_IO_MUX_CFG_CLK_O_SEL_SHIFT	8
 
 /* CFG4 bits */
 #define DP83867_CFG4_PORT_MIRROR_EN              BIT(0)
···
 	int io_impedance;
 	int port_mirroring;
 	bool rxctrl_strap_quirk;
+	int clk_output_sel;
 };
 
 static int dp83867_ack_interrupt(struct phy_device *phydev)
···
 	dp83867->io_impedance = -EINVAL;
 
 	/* Optional configuration */
+	ret = of_property_read_u32(of_node, "ti,clk-output-sel",
+				   &dp83867->clk_output_sel);
+	if (ret || dp83867->clk_output_sel > DP83867_CLK_O_SEL_REF_CLK)
+		/* Keep the default value if ti,clk-output-sel is not set
+		 * or too high
+		 */
+		dp83867->clk_output_sel = DP83867_CLK_O_SEL_REF_CLK;
+
 	if (of_property_read_bool(of_node, "ti,max-output-impedance"))
 		dp83867->io_impedance = DP83867_IO_MUX_CFG_IO_IMPEDANCE_MAX;
 	else if (of_property_read_bool(of_node, "ti,min-output-impedance"))
···
 
 	if (dp83867->port_mirroring != DP83867_PORT_MIRROING_KEEP)
 		dp83867_config_port_mirroring(phydev);
+
+	/* Clock output selection if muxing property is set */
+	if (dp83867->clk_output_sel != DP83867_CLK_O_SEL_REF_CLK) {
+		val = phy_read_mmd(phydev, DP83867_DEVADDR, DP83867_IO_MUX_CFG);
+		val &= ~DP83867_IO_MUX_CFG_CLK_O_SEL_MASK;
+		val |= (dp83867->clk_output_sel << DP83867_IO_MUX_CFG_CLK_O_SEL_SHIFT);
+		phy_write_mmd(phydev, DP83867_DEVADDR, DP83867_IO_MUX_CFG, val);
+	}
 
 	return 0;
 }

include/dt-bindings/net/ti-dp83867.h

···
 #define	DP83867_RGMIIDCTL_3_75_NS	0xe
 #define	DP83867_RGMIIDCTL_4_00_NS	0xf
 
+/* IO_MUX_CFG - Clock output selection */
+#define DP83867_CLK_O_SEL_CHN_A_RCLK		0x0
+#define DP83867_CLK_O_SEL_CHN_B_RCLK		0x1
+#define DP83867_CLK_O_SEL_CHN_C_RCLK		0x2
+#define DP83867_CLK_O_SEL_CHN_D_RCLK		0x3
+#define DP83867_CLK_O_SEL_CHN_A_RCLK_DIV5	0x4
+#define DP83867_CLK_O_SEL_CHN_B_RCLK_DIV5	0x5
+#define DP83867_CLK_O_SEL_CHN_C_RCLK_DIV5	0x6
+#define DP83867_CLK_O_SEL_CHN_D_RCLK_DIV5	0x7
+#define DP83867_CLK_O_SEL_CHN_A_TCLK		0x8
+#define DP83867_CLK_O_SEL_CHN_B_TCLK		0x9
+#define DP83867_CLK_O_SEL_CHN_C_TCLK		0xA
+#define DP83867_CLK_O_SEL_CHN_D_TCLK		0xB
+#define DP83867_CLK_O_SEL_REF_CLK		0xC
 #endif