clk: add clock driver for MediaTek MT7620 SoC

This patch adds a clock driver for MediaTek MT7620 SoC.
This driver provides clock gate control as well as getting clock frequency
for CPU/SYS/XTAL and some peripherals.

Reviewed-by: Stefan Roese <sr@denx.de>
Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>

2 files changed, 160 insertions, 0 deletions

diff --git a/drivers/clk/mtmips/Makefile b/drivers/clk/mtmips/Makefile
index e1938418da..732e7f2545 100644
--- a/drivers/clk/mtmips/Makefile
+++ b/drivers/clk/mtmips/Makefile
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
 
+obj-$(CONFIG_SOC_MT7620) += clk-mt7620.o
 obj-$(CONFIG_SOC_MT7628) += clk-mt7628.o
diff --git a/drivers/clk/mtmips/clk-mt7620.c b/drivers/clk/mtmips/clk-mt7620.c
new file mode 100644
index 0000000000..57d2e2f04c
--- /dev/null
+++ b/drivers/clk/mtmips/clk-mt7620.c
@@ -0,0 +1,159 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 MediaTek Inc. All Rights Reserved.
+ *
+ * Author: Weijie Gao <weijie.gao@mediatek.com>
+ */
+
+#include <clk-uclass.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <dt-bindings/clock/mt7620-clk.h>
+#include <misc.h>
+#include <mach/mt7620-sysc.h>
+
+/* CLKCFG1 */
+#define CLKCFG1_REG			0x30
+
+#define CLK_SRC_CPU			-1
+#define CLK_SRC_CPU_D2			-2
+#define CLK_SRC_SYS			-3
+#define CLK_SRC_XTAL			-4
+#define CLK_SRC_PERI			-5
+
+struct mt7620_clk_priv {
+	struct udevice *dev;
+	struct udevice *sysc;
+	struct mt7620_sysc_clks clks;
+};
+
+static const int mt7620_clks[] = {
+	[CLK_SYS] = CLK_SRC_SYS,
+	[CLK_CPU] = CLK_SRC_CPU,
+	[CLK_XTAL] = CLK_SRC_XTAL,
+	[CLK_MIPS_CNT] = CLK_SRC_CPU_D2,
+	[CLK_UARTF] = CLK_SRC_PERI,
+	[CLK_UARTL] = CLK_SRC_PERI,
+	[CLK_SPI] = CLK_SRC_SYS,
+	[CLK_I2C] = CLK_SRC_PERI,
+	[CLK_I2S] = CLK_SRC_PERI,
+};
+
+static ulong mt7620_clk_get_rate(struct clk *clk)
+{
+	struct mt7620_clk_priv *priv = dev_get_priv(clk->dev);
+
+	if (clk->id >= ARRAY_SIZE(mt7620_clks))
+		return 0;
+
+	switch (mt7620_clks[clk->id]) {
+	case CLK_SRC_CPU:
+		return priv->clks.cpu_clk;
+	case CLK_SRC_CPU_D2:
+		return priv->clks.cpu_clk / 2;
+	case CLK_SRC_SYS:
+		return priv->clks.sys_clk;
+	case CLK_SRC_XTAL:
+		return priv->clks.xtal_clk;
+	case CLK_SRC_PERI:
+		return priv->clks.peri_clk;
+	default:
+		return mt7620_clks[clk->id];
+	}
+}
+
+static int mt7620_clkcfg1_rmw(struct mt7620_clk_priv *priv, u32 clr, u32 set)
+{
+	u32 val;
+	int ret;
+
+	ret = misc_read(priv->sysc, CLKCFG1_REG, &val, sizeof(val));
+	if (ret) {
+		dev_err(priv->dev, "mt7620_clk: failed to read CLKCFG1\n");
+		return ret;
+	}
+
+	val &= ~clr;
+	val |= set;
+
+	ret = misc_write(priv->sysc, CLKCFG1_REG, &val, sizeof(val));
+	if (ret) {
+		dev_err(priv->dev, "mt7620_clk: failed to write CLKCFG1\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int mt7620_clk_enable(struct clk *clk)
+{
+	struct mt7620_clk_priv *priv = dev_get_priv(clk->dev);
+
+	if (clk->id > 30)
+		return -1;
+
+	return mt7620_clkcfg1_rmw(priv, 0, BIT(clk->id));
+}
+
+static int mt7620_clk_disable(struct clk *clk)
+{
+	struct mt7620_clk_priv *priv = dev_get_priv(clk->dev);
+
+	if (clk->id > 30)
+		return -1;
+
+	return mt7620_clkcfg1_rmw(priv, BIT(clk->id), 0);
+}
+
+const struct clk_ops mt7620_clk_ops = {
+	.enable = mt7620_clk_enable,
+	.disable = mt7620_clk_disable,
+	.get_rate = mt7620_clk_get_rate,
+};
+
+static int mt7620_clk_probe(struct udevice *dev)
+{
+	struct mt7620_clk_priv *priv = dev_get_priv(dev);
+	struct ofnode_phandle_args sysc_args;
+	int ret;
+
+	ret = ofnode_parse_phandle_with_args(dev_ofnode(dev), "mediatek,sysc", NULL,
+					     0, 0, &sysc_args);
+	if (ret) {
+		dev_err(dev, "mt7620_clk: sysc property not found\n");
+		return ret;
+	}
+
+	ret = uclass_get_device_by_ofnode(UCLASS_MISC, sysc_args.node,
+					  &priv->sysc);
+	if (ret) {
+		dev_err(dev, "mt7620_clk: failed to sysc device\n");
+		return ret;
+	}
+
+	ret = misc_ioctl(priv->sysc, MT7620_SYSC_IOCTL_GET_CLK,
+			 &priv->clks);
+	if (ret) {
+		dev_err(dev, "mt7620_clk: failed to get base clocks\n");
+		return ret;
+	}
+
+	priv->dev = dev;
+
+	return 0;
+}
+
+static const struct udevice_id mt7620_clk_ids[] = {
+	{ .compatible = "mediatek,mt7620-clk" },
+	{ }
+};
+
+U_BOOT_DRIVER(mt7620_clk) = {
+	.name = "mt7620-clk",
+	.id = UCLASS_CLK,
+	.of_match = mt7620_clk_ids,
+	.probe = mt7620_clk_probe,
+	.priv_auto = sizeof(struct mt7620_clk_priv),
+	.ops = &mt7620_clk_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};