[PATCH v3] clk: starfive: jh7100: Use clk_hw for external input clocks

[Geert Uytterhoeven]

The Starfive JH7100 clock driver does not use the DT "clocks" property
to find the external main input clock, but instead relies on the name of
the actual clock provider ("osc_sys").  This is fragile, and caused
breakage when sanitizing clock node names in DTS.

Fix this by obtaining the external main input clock using
devm_clk_get(), and passing the returned clk_hw object to
devm_clk_hw_register_fixed_factor_parent_hw().

While name-based look-up of the other external input clocks works as-is,
convert them to a similar clk_hw-based scheme to increase uniformity,
and to decrease the number of (multiple identical) name-based look-ups.

Fixes: f03606470886 ("riscv: dts: starfive: replace underscores in node names")
Fixes: 4210be668a09ee20 ("clk: starfive: Add JH7100 clock generator driver")
Signed-off-by: Geert Uytterhoeven <geert at linux-m68k.org>
Reviewed-by: Samuel Holland <samuel.holland at sifive.com>
---
After this is applied, the workaround in commit 7921e231f85a349d
("riscv: dts: starfive: jh7100: fix root clock names") can be reverted.

v3:
  - Add Reviewed-by,
  - Make jh7100_ext_clk[] const/__initconst,
  - Add "(multiple identical)".

v2:
  - Use devm_clk_hw_register_fixed_factor_parent_hw(),
  - Drop no longer needed local osc_sys name.
---
 drivers/clk/starfive/clk-starfive-jh7100.c | 48 ++++++++++++++--------
 drivers/clk/starfive/clk-starfive-jh71x0.h |  1 +
 2 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/drivers/clk/starfive/clk-starfive-jh7100.c b/drivers/clk/starfive/clk-starfive-jh7100.c
index 0342db24c27e10df..bdff207aa1f766e6 100644
--- a/drivers/clk/starfive/clk-starfive-jh7100.c
+++ b/drivers/clk/starfive/clk-starfive-jh7100.c
@@ -7,6 +7,7 @@
  * Copyright (C) 2021 Emil Renner Berthing <kernel at 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,
@@ -284,8 +293,11 @@ 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 * const jh7100_ext_clk[EXT_NUM_CLKS] __initconst =
+		{ "osc_sys", "osc_aud", "gmac_rmii_ref", "gmac_gr_mii_rxclk" };
 	struct jh71x0_clk_priv *priv;
 	unsigned int idx;
+	struct clk *clk;
 	int ret;
 
 	priv = devm_kzalloc(&pdev->dev, struct_size(priv, reg, JH7100_CLK_PLL0_OUT), GFP_KERNEL);
@@ -298,13 +310,21 @@ static int __init clk_starfive_jh7100_probe(struct platform_device *pdev)
 	if (IS_ERR(priv->base))
 		return PTR_ERR(priv->base);
 
-	priv->pll[0] = devm_clk_hw_register_fixed_factor(priv->dev, "pll0_out",
-							 "osc_sys", 0, 40, 1);
+	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);
+	}
+
+	priv->pll[0] = devm_clk_hw_register_fixed_factor_parent_hw(priv->dev,
+			"pll0_out", priv->ext[EXT_CLK_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);
+	priv->pll[1] = devm_clk_hw_register_fixed_factor_parent_hw(priv->dev,
+			"pll1_out", priv->ext[EXT_CLK_OSC_SYS], 0, 64, 1);
 	if (IS_ERR(priv->pll[1]))
 		return PTR_ERR(priv->pll[1]);
 
@@ -331,16 +351,10 @@ 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;
diff --git a/drivers/clk/starfive/clk-starfive-jh71x0.h b/drivers/clk/starfive/clk-starfive-jh71x0.h
index 23e052fc15495c41..4f46939179cd7418 100644
--- a/drivers/clk/starfive/clk-starfive-jh71x0.h
+++ b/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[];
 };
 
-- 
2.34.1