[PATCH 2/2] clk: qoriq: Separate root input clock for core PLLs on ls1012a

[yuantian.tang at nxp.com]

From: Tang Yuantian <Yuantian.Tang at nxp.com>

ls1012a has separate input root clocks for core PLLs versus the
platform PLL, with the latter described as sysclk in the hw docs.
If a second input clock, named "coreclk", is present, this clock will be
used for the core PLLs.

Signed-off-by: Scott Wood <oss at buserror.net>
Signed-off-by: Tang Yuantian <yuantian.tang at nxp.com>
---
 drivers/clk/clk-qoriq.c | 91 +++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 77 insertions(+), 14 deletions(-)

diff --git a/drivers/clk/clk-qoriq.c b/drivers/clk/clk-qoriq.c
index d0bf8b1..f3931e3 100644
--- a/drivers/clk/clk-qoriq.c
+++ b/drivers/clk/clk-qoriq.c
@@ -87,7 +87,7 @@ struct clockgen {
 	struct device_node *node;
 	void __iomem *regs;
 	struct clockgen_chipinfo info; /* mutable copy */
-	struct clk *sysclk;
+	struct clk *sysclk, *coreclk;
 	struct clockgen_pll pll[6];
 	struct clk *cmux[NUM_CMUX];
 	struct clk *hwaccel[NUM_HWACCEL];
@@ -904,7 +904,12 @@ static void __init create_muxes(struct clockgen *cg)
 
 static void __init clockgen_init(struct device_node *np);
 
-/* Legacy nodes may get probed before the parent clockgen node */
+/*
+ * Legacy nodes may get probed before the parent clockgen node.
+ * It is assumed that device trees with legacy nodes will not
+ * contain a "clocks" property -- otherwise the input clocks may
+ * not be initialized at this point.
+ */
 static void __init legacy_init_clockgen(struct device_node *np)
 {
 	if (!clockgen.node)
@@ -945,18 +950,13 @@ static struct clk __init
 	return clk_register_fixed_rate(NULL, name, NULL, 0, rate);
 }
 
-static struct clk *sysclk_from_parent(const char *name)
+static struct clk __init *input_clock(const char *name, struct clk *clk)
 {
-	struct clk *clk;
-	const char *parent_name;
-
-	clk = of_clk_get(clockgen.node, 0);
-	if (IS_ERR(clk))
-		return clk;
+	const char *input_name;
 
 	/* Register the input clock under the desired name. */
-	parent_name = __clk_get_name(clk);
-	clk = clk_register_fixed_factor(NULL, name, parent_name,
+	input_name = __clk_get_name(clk);
+	clk = clk_register_fixed_factor(NULL, name, input_name,
 					0, 1, 1);
 	if (IS_ERR(clk))
 		pr_err("%s: Couldn't register %s: %ld\n", __func__, name,
@@ -965,6 +965,29 @@ static struct clk *sysclk_from_parent(const char *name)
 	return clk;
 }
 
+static struct clk __init *input_clock_by_name(const char *name,
+					      const char *dtname)
+{
+	struct clk *clk;
+
+	clk = of_clk_get_by_name(clockgen.node, dtname);
+	if (IS_ERR(clk))
+		return clk;
+
+	return input_clock(name, clk);
+}
+
+static struct clk __init *input_clock_by_index(const char *name, int idx)
+{
+	struct clk *clk;
+
+	clk = of_clk_get(clockgen.node, 0);
+	if (IS_ERR(clk))
+		return clk;
+
+	return input_clock(name, clk);
+}
+
 static struct clk * __init create_sysclk(const char *name)
 {
 	struct device_node *sysclk;
@@ -974,7 +997,11 @@ static struct clk * __init create_sysclk(const char *name)
 	if (!IS_ERR(clk))
 		return clk;
 
-	clk = sysclk_from_parent(name);
+	clk = input_clock_by_name(name, "sysclk");
+	if (!IS_ERR(clk))
+		return clk;
+
+	clk = input_clock_by_index(name, 0);
 	if (!IS_ERR(clk))
 		return clk;
 
@@ -985,7 +1012,27 @@ static struct clk * __init create_sysclk(const char *name)
 			return clk;
 	}
 
-	pr_err("%s: No input clock\n", __func__);
+	pr_err("%s: No input sysclk\n", __func__);
+	return NULL;
+}
+
+static struct clk * __init create_coreclk(const char *name)
+{
+	struct clk *clk;
+
+	clk = input_clock_by_name(name, "coreclk");
+	if (!IS_ERR(clk))
+		return clk;
+
+	/*
+	 * This indicates a mix of legacy nodes with the new coreclk
+	 * mechanism, which should never happen.  If this error occurs,
+	 * don't use the wrong input clock just because coreclk isn't
+	 * ready yet.
+	 */
+	if (WARN_ON(PTR_ERR(clk) == -EPROBE_DEFER))
+		return clk;
+
 	return NULL;
 }
 
@@ -1008,11 +1055,19 @@ static void __init create_one_pll(struct clockgen *cg, int idx)
 	u32 __iomem *reg;
 	u32 mult;
 	struct clockgen_pll *pll = &cg->pll[idx];
+	const char *input = "cg-sysclk";
 	int i;
 
 	if (!(cg->info.pll_mask & (1 << idx)))
 		return;
 
+	if (cg->coreclk && idx != PLATFORM_PLL) {
+		if (IS_ERR(cg->coreclk))
+			return;
+
+		input = "cg-coreclk";
+	}
+
 	if (cg->info.flags & CG_VER3) {
 		switch (idx) {
 		case PLATFORM_PLL:
@@ -1063,7 +1118,7 @@ static void __init create_one_pll(struct clockgen *cg, int idx)
 			 "cg-pll%d-div%d", idx, i + 1);
 
 		clk = clk_register_fixed_factor(NULL,
-				pll->div[i].name, "cg-sysclk", 0, mult, i + 1);
+				pll->div[i].name, input, 0, mult, i + 1);
 		if (IS_ERR(clk)) {
 			pr_err("%s: %s: register failed %ld\n",
 			       __func__, pll->div[i].name, PTR_ERR(clk));
@@ -1200,6 +1255,13 @@ static struct clk *clockgen_clk_get(struct of_phandle_args *clkspec, void *data)
 			goto bad_args;
 		clk = pll->div[idx].clk;
 		break;
+	case 5:
+		if (idx != 0)
+			goto bad_args;
+		clk = cg->coreclk;
+		if (IS_ERR(clk))
+			clk = NULL;
+		break;
 	default:
 		goto bad_args;
 	}
@@ -1311,6 +1373,7 @@ static void __init clockgen_init(struct device_node *np)
 		clockgen.info.flags |= CG_CMUX_GE_PLAT;
 
 	clockgen.sysclk = create_sysclk("cg-sysclk");
+	clockgen.coreclk = create_coreclk("cg-coreclk");
 	create_plls(&clockgen);
 	create_muxes(&clockgen);
 
-- 
2.1.0.27.g96db324