clk: starfive: jh7100: Use provided clocks instead of hardcoded names

The Starfive JH7100 clock driver does not use the DT "clocks" property
to find its external input clocks, but instead relies on the names of
the actual external clock providers.  This is fragile, and caused
breakage when sanitizing clock names in DT.

Fix this by obtaining the external input clocks through the DT "clocks"
property, and using their clk_hw objects or corresponding name.

Fixes: f036064 ("riscv: dts: starfive: replace underscores in node names")
Fixes: 4210be6 ("clk: starfive: Add JH7100 clock generator driver")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>

drivers/clk/starfive/clk-starfive-jh7100.c

@@ -7,6 +7,7 @@
  * Copyright (C) 2021 Emil Renner Berthing <kernel@esmil.dk>
  */
 
+#include <linux/clk.h>
 #include <linux/clk-provider.h>
 #include <linux/device.h>
 #include <linux/init.h>
@@ -18,10 +19,18 @@
 #include "clk-starfive-jh71x0.h"
 
 /* external clocks */
-#define JH7100_CLK_OSC_SYS		(JH7100_CLK_END + 0)
-#define JH7100_CLK_OSC_AUD		(JH7100_CLK_END + 1)
-#define JH7100_CLK_GMAC_RMII_REF	(JH7100_CLK_END + 2)
-#define JH7100_CLK_GMAC_GR_MII_RX	(JH7100_CLK_END + 3)
+enum {
+	EXT_CLK_OSC_SYS,
+	EXT_CLK_OSC_AUD,
+	EXT_CLK_GMAC_RMII_REF,
+	EXT_CLK_GMAC_GR_MII_RX,
+	EXT_NUM_CLKS
+};
+
+#define JH7100_CLK_OSC_SYS		(JH7100_CLK_END + EXT_CLK_OSC_SYS)
+#define JH7100_CLK_OSC_AUD		(JH7100_CLK_END + EXT_CLK_OSC_AUD)
+#define JH7100_CLK_GMAC_RMII_REF	(JH7100_CLK_END + EXT_CLK_GMAC_RMII_REF)
+#define JH7100_CLK_GMAC_GR_MII_RX	(JH7100_CLK_END + EXT_CLK_GMAC_GR_MII_RX)
 
 static const struct jh71x0_clk_data jh7100_clk_data[] __initconst = {
 	JH71X0__MUX(JH7100_CLK_CPUNDBUS_ROOT, "cpundbus_root", 0, 4,
@@ -283,8 +292,12 @@ static struct clk_hw *jh7100_clk_get(struct of_phandle_args *clkspec, void *data
 
 static int __init clk_starfive_jh7100_probe(struct platform_device *pdev)
 {
+	static const char *jh7100_ext_clk[EXT_NUM_CLKS] =
+		{ "osc_sys", "osc_aud", "gmac_rmii_ref", "gmac_gr_mii_rxclk" };
 	struct jh71x0_clk_priv *priv;
+	const char *osc_sys;
 	unsigned int idx;
+	struct clk *clk;
 	int ret;
 
 	priv = devm_kzalloc(&pdev->dev, struct_size(priv, reg, JH7100_CLK_PLL0_OUT), GFP_KERNEL);
@@ -297,13 +310,23 @@ static int __init clk_starfive_jh7100_probe(struct platform_device *pdev)
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);
 
+	for (idx = 0; idx < EXT_NUM_CLKS; idx++) {
+		clk = devm_clk_get(&pdev->dev, jh7100_ext_clk[idx]);
+		if (IS_ERR(clk))
+			return PTR_ERR(clk);
+
+		priv->ext[idx] = __clk_get_hw(clk);
+	}
+
+	osc_sys = clk_hw_get_name(priv->ext[EXT_CLK_OSC_SYS]);
+
 	priv->pll[0] = devm_clk_hw_register_fixed_factor(priv->dev, "pll0_out",
-							 "osc_sys", 0, 40, 1);
+							 osc_sys, 0, 40, 1);
 	if (IS_ERR(priv->pll[0]))
 		return PTR_ERR(priv->pll[0]);
 
 	priv->pll[1] = devm_clk_hw_register_fixed_factor(priv->dev, "pll1_out",
-							 "osc_sys", 0, 64, 1);
+							 osc_sys, 0, 64, 1);
 	if (IS_ERR(priv->pll[1]))
 		return PTR_ERR(priv->pll[1]);
 
@@ -330,16 +353,10 @@ static int __init clk_starfive_jh7100_probe(struct platform_device *pdev)
 
 			if (pidx < JH7100_CLK_PLL0_OUT)
 				parents[i].hw = &priv->reg[pidx].hw;
-			else if (pidx < JH7100_CLK_END)
+			else if (pidx < JH7100_CLK_OSC_SYS)
 				parents[i].hw = priv->pll[pidx - JH7100_CLK_PLL0_OUT];
-			else if (pidx == JH7100_CLK_OSC_SYS)
-				parents[i].fw_name = "osc_sys";
-			else if (pidx == JH7100_CLK_OSC_AUD)
-				parents[i].fw_name = "osc_aud";
-			else if (pidx == JH7100_CLK_GMAC_RMII_REF)
-				parents[i].fw_name = "gmac_rmii_ref";
-			else if (pidx == JH7100_CLK_GMAC_GR_MII_RX)
-				parents[i].fw_name = "gmac_gr_mii_rxclk";
+			else if (pidx <= JH7100_CLK_GMAC_GR_MII_RX)
+				parents[i].hw = priv->ext[pidx - JH7100_CLK_OSC_SYS];
 		}
 
 		clk->hw.init = &init;

drivers/clk/starfive/clk-starfive-jh71x0.h

@@ -115,6 +115,7 @@ struct jh71x0_clk_priv {
 	struct device *dev;
 	void __iomem *base;
 	struct clk_hw *pll[3];
+	struct clk_hw *ext[4];
 	struct jh71x0_clk reg[];
 };