[PATCH v4 2/3] clk: clk-loongson2: add clock controller driver support

[Yinbo Zhu <zhuyinbo@loongson.cn>]

This driver provides support for clock controller on Loongson2 SoC
, the Loongson2 SoC uses a 100MHz clock as the PLL reference clock
, there are five independent PLLs inside, each of which PLL can
provide up to three sets of frequency dependent clock outputs.

Signed-off-by: Yinbo Zhu <zhuyinbo@loongson.cn>
---
Change in v4:
		1. Fixup clock-names that replace "xxx-clk" with "xxx".

 MAINTAINERS                  |   1 +
 arch/loongarch/Kconfig       |   1 +
 arch/loongarch/kernel/time.c |   3 +
 drivers/clk/Kconfig          |   9 ++
 drivers/clk/Makefile         |   1 +
 drivers/clk/clk-loongson2.c  | 285 +++++++++++++++++++++++++++++++++++
 6 files changed, 300 insertions(+)
 create mode 100644 drivers/clk/clk-loongson2.c

diff --git a/MAINTAINERS b/MAINTAINERS
index b6aae412de9c..f01d60cd5c3b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11911,6 +11911,7 @@ LOONGSON2 SOC SERIES CLOCK DRIVER
 M:	Yinbo Zhu <zhuyinbo@loongson.cn>
 L:	linux-clk@vger.kernel.org
 S:	Maintained
+F:	drivers/clk/clk-loongson2.c
 F:	include/dt-bindings/clock/loongson,ls2k-clk.h
 
 LSILOGIC MPT FUSION DRIVERS (FC/SAS/SPI)
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 26aeb1408e56..8b65f349cd6e 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -122,6 +122,7 @@ config LOONGARCH
 	select USE_PERCPU_NUMA_NODE_ID
 	select USER_STACKTRACE_SUPPORT
 	select ZONE_DMA32
+	select COMMON_CLK
 
 config 32BIT
 	bool
diff --git a/arch/loongarch/kernel/time.c b/arch/loongarch/kernel/time.c
index 786735dcc8d6..09f20bc81798 100644
--- a/arch/loongarch/kernel/time.c
+++ b/arch/loongarch/kernel/time.c
@@ -12,6 +12,7 @@
 #include <linux/kernel.h>
 #include <linux/sched_clock.h>
 #include <linux/spinlock.h>
+#include <linux/of_clk.h>
 
 #include <asm/cpu-features.h>
 #include <asm/loongarch.h>
@@ -214,6 +215,8 @@ int __init constant_clocksource_init(void)
 
 void __init time_init(void)
 {
+	of_clk_init(NULL);
+
 	if (!cpu_has_cpucfg)
 		const_clock_freq = cpu_clock_freq;
 	else
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 48f8f4221e21..88620f86373f 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -428,6 +428,15 @@ config COMMON_CLK_K210
 	help
 	  Support for the Canaan Kendryte K210 RISC-V SoC clocks.
 
+config COMMON_CLK_LOONGSON2
+	bool "Clock driver for Loongson2 SoC"
+	depends on COMMON_CLK && OF
+	help
+	  This driver provides support for Clock Controller that base on
+	  Common Clock Framework Controller (CCF) on Loongson2 SoC.  The
+	  Clock Controller can generates and supplies clock to various
+	  peripherals within the SoC.
+
 source "drivers/clk/actions/Kconfig"
 source "drivers/clk/analogbits/Kconfig"
 source "drivers/clk/baikal-t1/Kconfig"
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index d5db170d38d2..8ccc7436052f 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -75,6 +75,7 @@ obj-$(CONFIG_COMMON_CLK_RS9_PCIE)	+= clk-renesas-pcie.o
 obj-$(CONFIG_COMMON_CLK_VC5)		+= clk-versaclock5.o
 obj-$(CONFIG_COMMON_CLK_WM831X)		+= clk-wm831x.o
 obj-$(CONFIG_COMMON_CLK_XGENE)		+= clk-xgene.o
+obj-$(CONFIG_COMMON_CLK_LOONGSON2)	+= clk-loongson2.o
 
 # please keep this section sorted lexicographically by directory path name
 obj-y					+= actions/
diff --git a/drivers/clk/clk-loongson2.c b/drivers/clk/clk-loongson2.c
new file mode 100644
index 000000000000..359fede40112
--- /dev/null
+++ b/drivers/clk/clk-loongson2.c
@@ -0,0 +1,285 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Author: Yinbo Zhu <zhuyinbo@loongson.cn>
+ * Copyright (C) 2022-2023 Loongson Technology Corporation Limited
+ */
+
+#include <linux/clkdev.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <dt-bindings/clock/loongson,ls2k-clk.h>
+#include <linux/clk-provider.h>
+#include <linux/slab.h>
+#include <linux/clk.h>
+
+#define LOONGSON2_PLL_MULT_SHIFT		32
+#define LOONGSON2_PLL_MULT_WIDTH		10
+#define LOONGSON2_PLL_DIV_SHIFT			26
+#define LOONGSON2_PLL_DIV_WIDTH			6
+#define LOONGSON2_APB_FREQSCALE_SHIFT		20
+#define LOONGSON2_APB_FREQSCALE_WIDTH		3
+#define LOONGSON2_USB_FREQSCALE_SHIFT		16
+#define LOONGSON2_USB_FREQSCALE_WIDTH		3
+#define LOONGSON2_SATA_FREQSCALE_SHIFT		12
+#define LOONGSON2_SATA_FREQSCALE_WIDTH		3
+
+void __iomem *loongson2_pll_base;
+static DEFINE_SPINLOCK(loongson2_clk_lock);
+static struct clk_hw **hws;
+static struct clk_hw_onecell_data *clk_hw_data;
+
+static struct clk_hw *loongson2_clk_register(struct device *dev,
+					  const char *name,
+					  const char *parent_name,
+					  const struct clk_ops *ops,
+					  unsigned long flags)
+{
+	int ret;
+	struct clk_hw *hw;
+	struct clk_init_data init;
+
+	/* allocate the divider */
+	hw = kzalloc(sizeof(*hw), GFP_KERNEL);
+	if (!hw)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = ops;
+	init.flags = flags | CLK_IS_BASIC;
+	init.parent_names = (parent_name ? &parent_name : NULL);
+	init.num_parents = (parent_name ? 1 : 0);
+	hw->init = &init;
+
+	/* register the clock */
+	ret = clk_hw_register(dev, hw);
+	if (ret) {
+		kfree(hw);
+		hw = ERR_PTR(ret);
+	}
+
+	return hw;
+}
+
+static struct clk_hw *loongson2_clk_pll_register(const char *name,
+				const char *parent, void __iomem *reg)
+{
+	u64 val;
+	u32 mult = 1, div = 1;
+
+	val = readq((void *)reg);
+
+	mult = (val >> LOONGSON2_PLL_MULT_SHIFT) &
+			clk_div_mask(LOONGSON2_PLL_MULT_WIDTH);
+	div = (val >> LOONGSON2_PLL_DIV_SHIFT) &
+			clk_div_mask(LOONGSON2_PLL_DIV_WIDTH);
+
+	return clk_hw_register_fixed_factor(NULL, name, parent,
+				CLK_SET_RATE_PARENT, mult, div);
+}
+
+static unsigned long loongson2_apb_recalc_rate(struct clk_hw *hw,
+					  unsigned long parent_rate)
+{
+	u64 val;
+	u32 mult;
+	unsigned long rate;
+
+	val = readq((void *)(loongson2_pll_base + 0x50));
+
+	mult = (val >> LOONGSON2_APB_FREQSCALE_SHIFT) &
+			clk_div_mask(LOONGSON2_APB_FREQSCALE_WIDTH);
+
+	rate = parent_rate * (mult + 1);
+	do_div(rate, 8);
+
+	return rate;
+}
+
+static const struct clk_ops loongson2_apb_clk_ops = {
+	.recalc_rate = loongson2_apb_recalc_rate,
+};
+
+static unsigned long loongson2_usb_recalc_rate(struct clk_hw *hw,
+					  unsigned long parent_rate)
+{
+	u64 val;
+	u32 mult;
+	unsigned long rate;
+
+	val = readq((void *)(loongson2_pll_base + 0x50));
+
+	mult = (val >> LOONGSON2_USB_FREQSCALE_SHIFT) &
+			clk_div_mask(LOONGSON2_USB_FREQSCALE_WIDTH);
+
+	rate = parent_rate * (mult + 1);
+	do_div(rate, 8);
+
+	return rate;
+}
+
+static const struct clk_ops loongson2_usb_clk_ops = {
+	.recalc_rate = loongson2_usb_recalc_rate,
+};
+
+static unsigned long loongson2_sata_recalc_rate(struct clk_hw *hw,
+					  unsigned long parent_rate)
+{
+	u64 val;
+	u32 mult;
+	unsigned long rate;
+
+	val = readq((void *)(loongson2_pll_base + 0x50));
+
+	mult = (val >> LOONGSON2_SATA_FREQSCALE_SHIFT) &
+			clk_div_mask(LOONGSON2_SATA_FREQSCALE_WIDTH);
+
+	rate = parent_rate * (mult + 1);
+	do_div(rate, 8);
+
+	return rate;
+}
+
+static const struct clk_ops loongson2_sata_clk_ops = {
+	.recalc_rate = loongson2_sata_recalc_rate,
+};
+
+static void loongson2_check_clk_hws(struct clk_hw *clks[], unsigned int count)
+{
+	unsigned int i;
+
+	for (i = 0; i < count; i++)
+		if (IS_ERR(clks[i]))
+			pr_err("Loongson2 clk %u: register failed with %ld\n"
+				, i, PTR_ERR(clks[i]));
+}
+
+static struct clk_hw *loongson2_obtain_fixed_clk_hw(
+					struct device_node *np,
+					const char *name)
+{
+	struct clk *clk;
+
+	clk = of_clk_get_by_name(np, name);
+	if (IS_ERR(clk))
+		return ERR_PTR(-ENOENT);
+
+	return __clk_get_hw(clk);
+}
+
+static void __init loongson2_clocks_init(struct device_node *np)
+{
+	loongson2_pll_base = of_iomap(np, 0);
+
+	if (!loongson2_pll_base) {
+		pr_err("clk: unable to map loongson2 clk registers\n");
+		goto err;
+	}
+
+	clk_hw_data = kzalloc(struct_size(clk_hw_data, hws, LOONGSON2_CLK_END),
+					GFP_KERNEL);
+	if (WARN_ON(!clk_hw_data))
+		goto err;
+
+	clk_hw_data->num = LOONGSON2_CLK_END;
+	hws = clk_hw_data->hws;
+
+	hws[LOONGSON2_REF_100M] = loongson2_obtain_fixed_clk_hw(np,
+						"ref_100m");
+
+	hws[LOONGSON2_NODE_PLL] = loongson2_clk_pll_register("node_pll",
+						"ref_100m",
+						loongson2_pll_base);
+
+	hws[LOONGSON2_DDR_PLL] = loongson2_clk_pll_register("ddr_pll",
+						"ref_100m",
+						loongson2_pll_base + 0x10);
+
+	hws[LOONGSON2_DC_PLL] = loongson2_clk_pll_register("dc_pll",
+						"ref_100m",
+						loongson2_pll_base + 0x20);
+
+	hws[LOONGSON2_PIX0_PLL] = loongson2_clk_pll_register("pix0_pll",
+						"ref_100m",
+						loongson2_pll_base + 0x30);
+
+	hws[LOONGSON2_PIX1_PLL] = loongson2_clk_pll_register("pix1_pll",
+						"ref_100m",
+						loongson2_pll_base + 0x40);
+
+	hws[LOONGSON2_NODE_CLK] = clk_hw_register_divider(NULL, "node",
+						"node_pll", 0,
+						loongson2_pll_base + 0x8, 0,
+						6, CLK_DIVIDER_ONE_BASED,
+						&loongson2_clk_lock);
+
+	/*
+	 * The hda clk divisor in the upper 32bits and the clk-prodiver
+	 * layer code doesn't support 64bit io operation thus a conversion
+	 * is required that subtract shift by 32 and add 4byte to the hda
+	 * address
+	 */
+	hws[LOONGSON2_HDA_CLK] = clk_hw_register_divider(NULL, "hda",
+						"ddr_pll", 0,
+						loongson2_pll_base + 0x22, 12,
+						7, CLK_DIVIDER_ONE_BASED,
+						&loongson2_clk_lock);
+
+	hws[LOONGSON2_GPU_CLK] = clk_hw_register_divider(NULL, "gpu",
+						"ddr_pll", 0,
+						loongson2_pll_base + 0x18, 22,
+						6, CLK_DIVIDER_ONE_BASED,
+						&loongson2_clk_lock);
+
+	hws[LOONGSON2_DDR_CLK] = clk_hw_register_divider(NULL, "ddr",
+						"ddr_pll", 0,
+						loongson2_pll_base + 0x18, 0,
+						6, CLK_DIVIDER_ONE_BASED,
+						&loongson2_clk_lock);
+
+	hws[LOONGSON2_GMAC_CLK] = clk_hw_register_divider(NULL, "gmac",
+						"dc_pll", 0,
+						loongson2_pll_base + 0x28, 22,
+						6, CLK_DIVIDER_ONE_BASED,
+						&loongson2_clk_lock);
+
+	hws[LOONGSON2_DC_CLK] = clk_hw_register_divider(NULL, "dc",
+						"dc_pll", 0,
+						loongson2_pll_base + 0x28, 0,
+						6, CLK_DIVIDER_ONE_BASED,
+						&loongson2_clk_lock);
+
+	hws[LOONGSON2_APB_CLK] = loongson2_clk_register(NULL, "apb",
+						"gmac",
+						&loongson2_apb_clk_ops, 0);
+
+	hws[LOONGSON2_USB_CLK] = loongson2_clk_register(NULL, "usb",
+						"gmac",
+						&loongson2_usb_clk_ops, 0);
+
+	hws[LOONGSON2_SATA_CLK] = loongson2_clk_register(NULL, "sata",
+						"gmac",
+						&loongson2_sata_clk_ops, 0);
+
+	hws[LOONGSON2_PIX0_CLK] = clk_hw_register_divider(NULL, "pix0",
+						"pix0_pll", 0,
+						loongson2_pll_base + 0x38, 0, 6,
+						CLK_DIVIDER_ONE_BASED,
+						&loongson2_clk_lock);
+
+	hws[LOONGSON2_PIX1_CLK] = clk_hw_register_divider(NULL, "pix1",
+						"pix1_pll", 0,
+						loongson2_pll_base + 0x48, 0, 6,
+						CLK_DIVIDER_ONE_BASED,
+						&loongson2_clk_lock);
+
+	loongson2_check_clk_hws(hws, LOONGSON2_CLK_END);
+
+	of_clk_add_hw_provider(np, of_clk_hw_onecell_get, clk_hw_data);
+
+err:
+	iounmap(loongson2_pll_base);
+}
+
+CLK_OF_DECLARE(loongson2_clk, "loongson,ls2k-clk", loongson2_clocks_init);
-- 
2.31.1