clk: ti: am33xx: add DPLL clock drivers

The digital phase-locked loop (DPLL) provides all interface clocks and
functional clocks to the processor of the AM33xx device. The AM33xx
device integrates five different DPLLs:
 * Core DPLL
 * Per DPLL
 * LCD DPLL
 * DDR DPLL
 * MPU DPLL

The patch adds support for the compatible strings:
 * "ti,am3-dpll-core-clock"
 * "ti,am3-dpll-no-gate-clock"
 * "ti,am3-dpll-no-gate-j-type-clock"
 * "ti,am3-dpll-x2-clock"

The code is loosely based on the drivers/clk/ti/dpll.c drivers of the
Linux kernel version 5.9-rc7.
For DT binding details see:
- Documentation/devicetree/bindings/clock/ti/dpll.txt

Signed-off-by: Dario Binacchi <dariobin@libero.it>

1 files changed, 79 insertions, 0 deletions

diff --git a/drivers/clk/ti/clk-am3-dpll-x2.c b/drivers/clk/ti/clk-am3-dpll-x2.c
new file mode 100644
index 0000000000..3cf279d6a3
--- /dev/null
+++ b/drivers/clk/ti/clk-am3-dpll-x2.c
@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * TI DPLL x2 clock support
+ *
+ * Copyright (C) 2020 Dario Binacchi <dariobin@libero.it>
+ *
+ * Loosely based on Linux kernel drivers/clk/ti/dpll.c
+ */
+
+#include <common.h>
+#include <clk-uclass.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <linux/clk-provider.h>
+
+struct clk_ti_am3_dpll_x2_priv {
+	struct clk parent;
+};
+
+static ulong clk_ti_am3_dpll_x2_get_rate(struct clk *clk)
+{
+	struct clk_ti_am3_dpll_x2_priv *priv = dev_get_priv(clk->dev);
+	unsigned long rate;
+
+	rate = clk_get_rate(&priv->parent);
+	if (IS_ERR_VALUE(rate))
+		return rate;
+
+	rate *= 2;
+	dev_dbg(clk->dev, "rate=%ld\n", rate);
+	return rate;
+}
+
+const struct clk_ops clk_ti_am3_dpll_x2_ops = {
+	.get_rate = clk_ti_am3_dpll_x2_get_rate,
+};
+
+static int clk_ti_am3_dpll_x2_remove(struct udevice *dev)
+{
+	struct clk_ti_am3_dpll_x2_priv *priv = dev_get_priv(dev);
+	int err;
+
+	err = clk_release_all(&priv->parent, 1);
+	if (err) {
+		dev_err(dev, "failed to release parent clock\n");
+		return err;
+	}
+
+	return 0;
+}
+
+static int clk_ti_am3_dpll_x2_probe(struct udevice *dev)
+{
+	struct clk_ti_am3_dpll_x2_priv *priv = dev_get_priv(dev);
+	int err;
+
+	err = clk_get_by_index(dev, 0, &priv->parent);
+	if (err) {
+		dev_err(dev, "%s: failed to get parent clock\n", __func__);
+		return err;
+	}
+
+	return 0;
+}
+
+static const struct udevice_id clk_ti_am3_dpll_x2_of_match[] = {
+	{.compatible = "ti,am3-dpll-x2-clock"},
+	{}
+};
+
+U_BOOT_DRIVER(clk_ti_am3_dpll_x2) = {
+	.name = "ti_am3_dpll_x2_clock",
+	.id = UCLASS_CLK,
+	.of_match = clk_ti_am3_dpll_x2_of_match,
+	.probe = clk_ti_am3_dpll_x2_probe,
+	.remove = clk_ti_am3_dpll_x2_remove,
+	.priv_auto = sizeof(struct clk_ti_am3_dpll_x2_priv),
+	.ops = &clk_ti_am3_dpll_x2_ops,
+};