clk: rockchip: clk_rk3288: Implement "assign-clock-parent" and "assign-clock-rate"

The RK3288 CRU-node assigns rates to a number of clocks that are not
implemented in the RK3288 clock-driver (but which have been
sufficiently initialised from rkclk_init()): for these clocks, we
implement the gmac clock set parent, but simply ignore the
others' set_rate() operation and return 0 to signal success.

Signed-off-by: David Wu <david.wu@rock-chips.com>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

drivers/clk/rockchip/clk_rk3288.c

@@ -295,15 +295,42 @@ 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)
+static int rockchip_mac_set_clk(struct rk3288_cru *cru, uint freq)
 {
-	/* Assuming mac_clk is fed by an external clock */
-	rk_clrsetreg(&cru->cru_clksel_con[21],
-		     RMII_EXTCLK_MASK,
-		     RMII_EXTCLK_SELECT_EXT_CLK << RMII_EXTCLK_SHIFT);
+	ulong ret;
 
-	 return 0;
+	/*
+	 * The gmac clock can be derived either from an external clock
+	 * or can be generated from internally by a divider from SCLK_MAC.
+	 */
+	if (readl(&cru->cru_clksel_con[21]) & RMII_EXTCLK_MASK) {
+		/* An external clock will always generate the right rate... */
+		ret = freq;
+	} else {
+		u32 con = readl(&cru->cru_clksel_con[21]);
+		ulong pll_rate;
+		u8 div;
+
+		if (((con >> EMAC_PLL_SHIFT) & EMAC_PLL_MASK) ==
+		    EMAC_PLL_SELECT_GENERAL)
+			pll_rate = GPLL_HZ;
+		else if (((con >> EMAC_PLL_SHIFT) & EMAC_PLL_MASK) ==
+			 EMAC_PLL_SELECT_CODEC)
+			pll_rate = CPLL_HZ;
+		else
+			pll_rate = NPLL_HZ;
+
+		div = DIV_ROUND_UP(pll_rate, freq) - 1;
+		if (div <= 0x1f)
+			rk_clrsetreg(&cru->cru_clksel_con[21], MAC_DIV_CON_MASK,
+				     div << MAC_DIV_CON_SHIFT);
+		else
+			debug("Unsupported div for gmac:%d\n", div);
+
+		return DIV_TO_RATE(pll_rate, div);
+	}
+
+	return ret;
 }
 
 static int rockchip_vop_set_clk(struct rk3288_cru *cru, struct rk3288_grf *grf,
@@ -744,7 +771,7 @@ static ulong rk3288_clk_set_rate(struct clk *clk, ulong rate)
 		break;
 #ifndef CONFIG_SPL_BUILD
 	case SCLK_MAC:
-		new_rate = rockchip_mac_set_clk(priv->cru, clk->id, rate);
+		new_rate = rockchip_mac_set_clk(priv->cru, rate);
 		break;
 	case DCLK_VOP0:
 	case DCLK_VOP1:
@@ -797,6 +824,17 @@ static ulong rk3288_clk_set_rate(struct clk *clk, ulong rate)
 	case SCLK_SARADC:
 		new_rate = rockchip_saradc_set_clk(priv->cru, rate);
 		break;
+	case PLL_GPLL:
+	case PLL_CPLL:
+	case PLL_NPLL:
+	case ACLK_CPU:
+	case HCLK_CPU:
+	case PCLK_CPU:
+	case ACLK_PERI:
+	case HCLK_PERI:
+	case PCLK_PERI:
+	case SCLK_UART0:
+		return 0;
 	default:
 		return -ENOENT;
 	}
@@ -804,9 +842,61 @@ static ulong rk3288_clk_set_rate(struct clk *clk, ulong rate)
 	return new_rate;
 }
 
+static int rk3288_gmac_set_parent(struct clk *clk, struct clk *parent)
+{
+	struct rk3288_clk_priv *priv = dev_get_priv(clk->dev);
+	struct rk3288_cru *cru = priv->cru;
+	const char *clock_output_name;
+	int ret;
+
+	/*
+	 * If the requested parent is in the same clock-controller and
+	 * the id is SCLK_MAC_PLL ("mac_pll_src"), switch to the internal
+	 * clock.
+	 */
+	if ((parent->dev == clk->dev) && (parent->id == SCLK_MAC_PLL)) {
+		debug("%s: switching GAMC to SCLK_MAC_PLL\n", __func__);
+		rk_clrsetreg(&cru->cru_clksel_con[21], RMII_EXTCLK_MASK, 0);
+		return 0;
+	}
+
+	/*
+	 * Otherwise, we need to check the clock-output-names of the
+	 * requested parent to see if the requested id is "ext_gmac".
+	 */
+	ret = dev_read_string_index(parent->dev, "clock-output-names",
+				    parent->id, &clock_output_name);
+	if (ret < 0)
+		return -ENODATA;
+
+	/* If this is "ext_gmac", switch to the external clock input */
+	if (!strcmp(clock_output_name, "ext_gmac")) {
+		debug("%s: switching GMAC to external clock\n", __func__);
+		rk_clrsetreg(&cru->cru_clksel_con[21], RMII_EXTCLK_MASK,
+			     RMII_EXTCLK_SELECT_EXT_CLK << RMII_EXTCLK_SHIFT);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static int rk3288_clk_set_parent(struct clk *clk, struct clk *parent)
+{
+	switch (clk->id) {
+	case SCLK_MAC:
+		return rk3288_gmac_set_parent(clk, parent);
+	case SCLK_USBPHY480M_SRC:
+		return 0;
+	}
+
+	debug("%s: unsupported clk %ld\n", __func__, clk->id);
+	return -ENOENT;
+}
+
 static struct clk_ops rk3288_clk_ops = {
 	.get_rate	= rk3288_clk_get_rate,
 	.set_rate	= rk3288_clk_set_rate,
+	.set_parent	= rk3288_clk_set_parent,
 };
 
 static int rk3288_clk_ofdata_to_platdata(struct udevice *dev)

include/dt-bindings/clock/rk3288-cru.h

@@ -76,6 +76,7 @@
 #define SCLK_PVTM_CORE		123
 #define SCLK_PVTM_GPU		124
 
+#define SCLK_MAC_PLL		150
 #define SCLK_MAC		151
 #define SCLK_MACREF_OUT		152