[U-Boot] [PATCH v2 02/10] clk: imx: Add i.MX6Q clock driver

[Jagan Teki <jagan@amarulasolutions.com>]

i.MX6 clock control module comprise of parent clocks, gates, multiplexers,
dividers, PODF, PLL, fixed rate and etc.

This patch add i.MX6Q USDHC clocks via gate clock which would eventually
handle enable/disable operations via imx6_clock_gate.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
 arch/arm/include/asm/arch-mx6/clock.h | 44 +++++++++++++++++
 drivers/clk/imx/Kconfig               |  9 +++-
 drivers/clk/imx/Makefile              |  5 ++
 drivers/clk/imx/clk-imx6-common.c     | 69 +++++++++++++++++++++++++++
 drivers/clk/imx/clk-imx6q.c           | 39 +++++++++++++++
 5 files changed, 165 insertions(+), 1 deletion(-)
 create mode 100644 drivers/clk/imx/clk-imx6-common.c
 create mode 100644 drivers/clk/imx/clk-imx6q.c

diff --git a/arch/arm/include/asm/arch-mx6/clock.h b/arch/arm/include/asm/arch-mx6/clock.h
index a9481a5fea..fa921a9f08 100644
--- a/arch/arm/include/asm/arch-mx6/clock.h
+++ b/arch/arm/include/asm/arch-mx6/clock.h
@@ -21,6 +21,50 @@
 #define MXC_CLK32	32768
 #endif
 
+/**
+ * struct imx6_clk_gate - imx6 ccm clock gate
+ *
+ * @off:	ccm gate offset
+ * @bit:	ccm gate bit
+ */
+struct imx6_clk_gate {
+	u16 off;
+	u32 bit;
+};
+
+#define GATE(_off, _bit) {			\
+	.off = _off,				\
+	.bit = _bit,				\
+}
+
+/**
+ * struct imx6_clk_desc - imx6 clock control module descriptor
+ *
+ * @gates:	ccm clock gates
+ */
+struct imx6_clk_desc {
+	const struct imx6_clk_gate *gates;
+};
+
+/**
+ * struct imx6_clk_priv - imx6 clock control module
+ *
+ * @base:	ccm base address
+ * @desc:	ccm descriptor
+ */
+struct imx6_clk_priv {
+	void *base;
+	const struct imx6_clk_desc *desc;
+};
+
+/**
+ * imx6_clk_probe - common imx6 clock probe
+ * @dev:	clock device
+ */
+int imx6_clk_probe(struct udevice *dev);
+
+extern struct clk_ops imx6_clk_ops;
+
 enum mxc_clock {
 	MXC_ARM_CLK = 0,
 	MXC_PER_CLK,
diff --git a/drivers/clk/imx/Kconfig b/drivers/clk/imx/Kconfig
index a125c23a19..f81903dcf4 100644
--- a/drivers/clk/imx/Kconfig
+++ b/drivers/clk/imx/Kconfig
@@ -1,6 +1,6 @@
 config CLK_IMX
 	bool "Clock support for i.MX SoCs"
-	depends on CLK && ARCH_IMX8
+	depends on CLK && (ARCH_MX6 || ARCH_IMX8)
 	default y
 	help
 	  This enables support for common clock driver API on i.MX
@@ -8,6 +8,13 @@ config CLK_IMX
 
 if CLK_IMX
 
+config CLK_IMX6Q
+	bool "Clock driver for i.MX6QDL"
+	default MX6QDL
+	help
+	  This enables common clock driver support for platforms based
+	  on i.MX6 QDL SoC.
+
 config CLK_IMX8
 	bool "Clock support for i.MX8"
 	default ARCH_IMX8
diff --git a/drivers/clk/imx/Makefile b/drivers/clk/imx/Makefile
index 5505ae52e2..a4cb2bbf3b 100644
--- a/drivers/clk/imx/Makefile
+++ b/drivers/clk/imx/Makefile
@@ -2,4 +2,9 @@
 #
 # SPDX-License-Identifier: GPL-2.0
 
+ifdef CONFIG_ARCH_MX6
+obj-$(CONFIG_CLK_IMX) += clk-imx6-common.o
+endif
+
+obj-$(CONFIG_CLK_IMX6Q) += clk-imx6q.o
 obj-$(CONFIG_CLK_IMX8) += clk-imx8.o
diff --git a/drivers/clk/imx/clk-imx6-common.c b/drivers/clk/imx/clk-imx6-common.c
new file mode 100644
index 0000000000..1d38f51f7e
--- /dev/null
+++ b/drivers/clk/imx/clk-imx6-common.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Amarula Solutions.
+ * Author: Jagan Teki <jagan@amarulasolutions.com>
+ */
+
+#include <common.h>
+#include <clk-uclass.h>
+#include <dm.h>
+#include <errno.h>
+#include <asm/io.h>
+#include <asm/arch/clock.h>
+#include <linux/log2.h>
+
+static const struct imx6_clk_gate *priv_to_gate(struct imx6_clk_priv *priv,
+						unsigned long id)
+{
+	return &priv->desc->gates[id];
+}
+
+static int imx6_set_gate(struct clk *clk, bool on)
+{
+	struct imx6_clk_priv *priv = dev_get_priv(clk->dev);
+	const struct imx6_clk_gate *gate = priv_to_gate(priv, clk->id);
+	u32 reg;
+
+	debug("%s: (CLK#%ld) off#0x%x, BIT(%d)\n", __func__,
+	      clk->id, gate->off, ilog2(gate->bit));
+
+	reg = readl(priv->base + gate->off);
+	if (on)
+		reg |= gate->bit;
+	else
+		reg &= ~gate->bit;
+
+	writel(reg, priv->base + gate->off);
+
+	return 0;
+}
+
+static int imx6_clk_enable(struct clk *clk)
+{
+	return imx6_set_gate(clk, true);
+}
+
+static int imx6_clk_disable(struct clk *clk)
+{
+	return imx6_set_gate(clk, false);
+}
+
+struct clk_ops imx6_clk_ops = {
+	.enable = imx6_clk_enable,
+	.disable = imx6_clk_disable,
+};
+
+int imx6_clk_probe(struct udevice *dev)
+{
+	struct imx6_clk_priv *priv = dev_get_priv(dev);
+
+	priv->base = dev_read_addr_ptr(dev);
+	if (!priv->base)
+		return -ENOMEM;
+
+	priv->desc = (const struct imx6_clk_desc *)dev_get_driver_data(dev);
+	if (!priv->desc)
+		return -EINVAL;
+
+	return 0;
+}
diff --git a/drivers/clk/imx/clk-imx6q.c b/drivers/clk/imx/clk-imx6q.c
new file mode 100644
index 0000000000..8ec713298d
--- /dev/null
+++ b/drivers/clk/imx/clk-imx6q.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Amarula Solutions.
+ * Author: Jagan Teki <jagan@amarulasolutions.com>
+ */
+
+#include <common.h>
+#include <clk-uclass.h>
+#include <dm.h>
+#include <asm/arch/clock.h>
+#include <dt-bindings/clock/imx6qdl-clock.h>
+
+static const struct imx6_clk_gate imx6q_gates[] = {
+	[IMX6QDL_CLK_USDHC1]		= GATE(0x080, GENMASK(3, 2)),
+	[IMX6QDL_CLK_USDHC2]		= GATE(0x080, GENMASK(5, 4)),
+	[IMX6QDL_CLK_USDHC3]		= GATE(0x080, GENMASK(7, 6)),
+	[IMX6QDL_CLK_USDHC4]		= GATE(0x080, GENMASK(9, 8)),
+};
+
+static const struct imx6_clk_desc imx6q_clk_desc = {
+	.gates = imx6q_gates,
+};
+
+static const struct udevice_id clk_imx6q_ids[] = {
+	{
+	  .compatible = "fsl,imx6q-ccm",
+	  .data = (ulong)&imx6q_clk_desc
+	},
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(clk_imx6q) = {
+	.name		= "clk_imx6q",
+	.id		= UCLASS_CLK,
+	.of_match	= clk_imx6q_ids,
+	.priv_auto_alloc_size	= sizeof(struct imx6_clk_priv),
+	.ops		= &imx6_clk_ops,
+	.probe		= imx6_clk_probe,
+};
-- 
2.18.0.321.gffc6fa0e3