rockchip: rk3288: Add clock support for the gmac ethernet interface

Setup the clocks for the gmac ethernet interface. This assumes the mac
clock is fed by an external clock which is common on RK3288 based
devices.

Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/include/asm/arch-rockchip/cru_rk3288.h

@@ -90,6 +90,23 @@ enum {
 	SDIO0_DIV_MASK		= 0x3f,
 };
 
+/* CRU_CLKSEL21_CON */
+enum {
+	MAC_DIV_CON_SHIFT = 0xf,
+	MAC_DIV_CON_MASK = 0x1f,
+
+	RMII_EXTCLK_SHIFT = 4,
+	RMII_EXTCLK_MASK = 1,
+	RMII_EXTCLK_SELECT_INT_DIV_CLK = 0,
+	RMII_EXTCLK_SELECT_EXT_CLK = 1,
+
+	EMAC_PLL_SHIFT = 0,
+	EMAC_PLL_MASK = 0x3,
+	EMAC_PLL_SELECT_NEW = 0x0,
+	EMAC_PLL_SELECT_CODEC = 0x1,
+	EMAC_PLL_SELECT_GENERAL = 0x2,
+};
+
 /* CRU_CLKSEL25_CON */
 enum {
 	SPI1_PLL_SHIFT		= 0xf,

drivers/clk/clk_rk3288.c

@@ -326,6 +326,17 @@ static int pll_para_config(ulong freq_hz, struct pll_div *div, uint *ext_div)
 	return 0;
 }
 
+static int rockchip_mac_set_clk(struct rk3288_cru *cru,
+				  int periph, uint freq)
+{
+	/* Assuming mac_clk is fed by an external clock */
+	rk_clrsetreg(&cru->cru_clksel_con[21],
+		     RMII_EXTCLK_MASK << RMII_EXTCLK_SHIFT,
+		     RMII_EXTCLK_SELECT_EXT_CLK << RMII_EXTCLK_SHIFT);
+
+	 return 0;
+}
+
 static int rockchip_vop_set_clk(struct rk3288_cru *cru, struct rk3288_grf *grf,
 				int periph, unsigned int rate_hz)
 {
@@ -759,6 +770,9 @@ static ulong rk3288_set_periph_rate(struct udevice *dev, int periph, ulong rate)
 		new_rate = rockchip_spi_set_clk(cru, gclk_rate, periph, rate);
 		break;
 #ifndef CONFIG_SPL_BUILD
+	case SCLK_MAC:
+		new_rate = rockchip_mac_set_clk(priv->cru, periph, rate);
+		break;
 	case DCLK_VOP0:
 	case DCLK_VOP1:
 		new_rate = rockchip_vop_set_clk(cru, priv->grf, periph, rate);