rockchip: clk: rk3368: support configuring the DRAM PLL (from TPL)

As part of the DRAM initialisation process (running as part of the TPL
stage) on the RK3368, we need to set up the DRAM PLL.

This implements support for configuring the PLL to for 1200, 1332 or
1600 MHz (i.e. for DDR3-1200, DDR3-1333, DDR3-1600 operating modes).

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/clk/rockchip/clk_rk3368.c

@@ -308,18 +308,16 @@ static ulong rk3368_clk_get_rate(struct clk *clk)
 	return rate;
 }
 
+#if IS_ENABLED(CONFIG_TPL_BUILD)
 static ulong rk3368_ddr_set_clk(struct rk3368_cru *cru, ulong set_rate)
 {
 	const struct pll_div *dpll_cfg = NULL;
 	const ulong MHz = 1000000;
 
 	/* Fout = ((Fin /NR) * NF )/ NO */
-	static const struct pll_div dpll_1200 =
-		PLL_DIVISORS(1200 * MHz, 1, 1);
-	static const struct pll_div dpll_1332 =
-		PLL_DIVISORS(1332 * MHz, 2, 1);
-	static const struct pll_div dpll_1600 =
-		PLL_DIVISORS(1600 * MHz, 3, 2);
+	static const struct pll_div dpll_1200 = PLL_DIVISORS(1200 * MHz, 1, 1);
+	static const struct pll_div dpll_1332 =	PLL_DIVISORS(1332 * MHz, 2, 1);
+	static const struct pll_div dpll_1600 =	PLL_DIVISORS(1600 * MHz, 3, 2);
 
 	switch (set_rate) {
 	case 1200*MHz:
@@ -338,6 +336,7 @@ static ulong rk3368_ddr_set_clk(struct rk3368_cru *cru, ulong set_rate)
 
 	return set_rate;
 }
+#endif
 
 static ulong rk3368_clk_set_rate(struct clk *clk, ulong rate)
 {
@@ -346,9 +345,11 @@ static ulong rk3368_clk_set_rate(struct clk *clk, ulong rate)
 
 	debug("%s id:%ld rate:%ld\n", __func__, clk->id, rate);
 	switch (clk->id) {
+#if IS_ENABLED(CONFIG_TPL_BUILD)
 	case CLK_DDR:
 		ret = rk3368_ddr_set_clk(priv->cru, rate);
 		break;
+#endif
 #if !IS_ENABLED(CONFIG_SPL_BUILD) || CONFIG_IS_ENABLED(MMC_SUPPORT)
 	case HCLK_SDMMC:
 	case HCLK_EMMC: