clk: at91: Add clock driver

The patch is referred to at91 clock driver of Linux, to make
the clock node descriptions in DT aligned with the Linux's.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/clk/at91/clk-plla.c b/drivers/clk/at91/clk-plla.c
new file mode 100644
index 0000000..2a71399
--- /dev/null
+++ b/drivers/clk/at91/clk-plla.c
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2016 Atmel Corporation
+ *               Wenyou.Yang <wenyou.yang@atmel.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <clk-uclass.h>
+#include <dm/device.h>
+#include <linux/io.h>
+#include <mach/at91_pmc.h>
+#include "pmc.h"
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static int plla_clk_enable(struct clk *clk)
+{
+	struct pmc_platdata *plat = dev_get_platdata(clk->dev);
+	struct at91_pmc *pmc = plat->reg_base;
+
+	if (readl(&pmc->sr) & AT91_PMC_LOCKA)
+		return 0;
+
+	return -EINVAL;
+}
+
+static ulong plla_clk_get_rate(struct clk *clk)
+{
+	return gd->arch.plla_rate_hz;
+}
+
+static struct clk_ops plla_clk_ops = {
+	.enable = plla_clk_enable,
+	.get_rate = plla_clk_get_rate,
+};
+
+static int plla_clk_probe(struct udevice *dev)
+{
+	return at91_pmc_core_probe(dev);
+}
+
+static const struct udevice_id plla_clk_match[] = {
+	{ .compatible = "atmel,sama5d3-clk-pll" },
+	{}
+};
+
+U_BOOT_DRIVER(at91_plla_clk) = {
+	.name = "at91-plla-clk",
+	.id = UCLASS_CLK,
+	.of_match = plla_clk_match,
+	.probe = plla_clk_probe,
+	.platdata_auto_alloc_size = sizeof(struct pmc_platdata),
+	.ops = &plla_clk_ops,
+};