Message-ID: <f0399e7d-d9be-d72f-2693-fb07984a4be6@loongson.cn>
Date:   Wed, 30 Nov 2022 11:32:46 +0800
From:   XiaochuanMao <maoxiaochuan@...ngson.cn>
To:     Yinbo Zhu <zhuyinbo@...ngson.cn>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Huacai Chen <chenhuacai@...nel.org>,
        WANG Xuerui <kernel@...0n.name>,
        Jiaxun Yang <jiaxun.yang@...goat.com>,
        Jianmin Lv <lvjianmin@...ngson.cn>,
        Yang Li <yang.lee@...ux.alibaba.com>,
        linux-clk@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, loongarch@...ts.linux.dev
Subject: Re: [PATCH v10 2/4] clk: clk-loongson2: add clock controller driver
 support

hi, yinbo

On 2022/11/29 11:41, Yinbo Zhu wrote:
> This driver provides support for clock controller on Loongson-2 SoC,
> the Loongson-2 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@...ngson.cn>
> ---
> Change in v10:
> 		1. Detach of_clk_init to another patch.
> Change in v9:
> 		1. Add all history changelog information.
> Change in v8:
> 		1. Remove the flag "CLK_IS_BASIC".
> Change in v7:
> 		1. Adjust position alphabetically in Kconfig and Makefile.
> 		2. Add static for loongson2_pll_base.
> 		3. Move other file-scope variables in probe.
> Change in v6:
> 		1. NO change, but other patch in this series of patches has
> 		   changes.
> Change in v5:
> 		1. Replace loongson2 with Loongson-2 in commit info.
> 		2. Replace Loongson2 with Loongson-2 in binding and
> 		   Kconfig file.
> 		3. Replace soc with SoC.
> Change in v4:
> 		1. Fixup clock-names that replace "xxx-clk" with "xxx".
> Change in v3:
> 		1. NO change, but other patch in this series of patches has
> 		   changes.
> Change in v2:
> 		1. Update the include filename.
> 		2. Change string from refclk/REFCLK to ref/REF.
>
>   MAINTAINERS                 |   1 +
>   arch/loongarch/Kconfig      |   1 +
>   drivers/clk/Kconfig         |   9 ++
>   drivers/clk/Makefile        |   1 +
>   drivers/clk/clk-loongson2.c | 286 ++++++++++++++++++++++++++++++++++++
>   5 files changed, 298 insertions(+)
>   create mode 100644 drivers/clk/clk-loongson2.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index ab94893fe2f6..73fa56f1fd5d 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -12025,6 +12025,7 @@ LOONGSON-2 SOC SERIES CLOCK DRIVER
>   M:	Yinbo Zhu <zhuyinbo@...ngson.cn>
>   L:	linux-clk@...r.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 903096bd87f8..4f8f1b8f796d 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -127,6 +127,7 @@ config LOONGARCH
>   	select USE_PERCPU_NUMA_NODE_ID
>   	select USER_STACKTRACE_SUPPORT
>   	select ZONE_DMA32
> +	select COMMON_CLK
>   
>   config 32BIT
>   	bool
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> index d79905f3e174..d13626f63739 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -326,6 +326,15 @@ config COMMON_CLK_LOCHNAGAR
>   	  This driver supports the clocking features of the Cirrus Logic
>   	  Lochnagar audio development board.
>   
> +config COMMON_CLK_LOONGSON2
> +	bool "Clock driver for Loongson-2 SoC"
> +	depends on COMMON_CLK && OF
> +	help
> +	  This driver provides support for Clock Controller that base on
> +	  Common Clock Framework Controller (CCF) on Loongson-2 SoC. The
> +	  Clock Controller can generates and supplies clock to various
> +	  peripherals within the SoC.
> +
>   config COMMON_CLK_NXP
>   	def_bool COMMON_CLK && (ARCH_LPC18XX || ARCH_LPC32XX)
>   	select REGMAP_MMIO if ARCH_LPC32XX
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> index e3ca0d058a25..b298c5dabc1a 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -43,6 +43,7 @@ obj-$(CONFIG_COMMON_CLK_K210)		+= clk-k210.o
>   obj-$(CONFIG_LMK04832)			+= clk-lmk04832.o
>   obj-$(CONFIG_COMMON_CLK_LAN966X)	+= clk-lan966x.o
>   obj-$(CONFIG_COMMON_CLK_LOCHNAGAR)	+= clk-lochnagar.o
> +obj-$(CONFIG_COMMON_CLK_LOONGSON2)	+= clk-loongson2.o
>   obj-$(CONFIG_COMMON_CLK_MAX77686)	+= clk-max77686.o
>   obj-$(CONFIG_COMMON_CLK_MAX9485)	+= clk-max9485.o
>   obj-$(CONFIG_ARCH_MILBEAUT_M10V)	+= clk-milbeaut.o
> diff --git a/drivers/clk/clk-loongson2.c b/drivers/clk/clk-loongson2.c
> new file mode 100644
> index 000000000000..7487effceeab
> --- /dev/null
> +++ b/drivers/clk/clk-loongson2.c
> @@ -0,0 +1,286 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Author: Yinbo Zhu <zhuyinbo@...ngson.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
> +
> +static void __iomem *loongson2_pll_base;
> +
> +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;
> +	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));
it may be more common to use macro defintions instead of magic number. 
the clock configuration logic of  2k500 is  same as 2k1000, only the 
base  and offset are different。
> +
> +	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)
> +{
> +	struct clk_hw **hws;
> +	struct clk_hw_onecell_data *clk_hw_data;
> +	spinlock_t loongson2_clk_lock;
> +
> +	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);
> +
above this,   it may be more common to use macro defintions instead of 
magic number. the clock configuration logic of 2k500 is same as 2k1000， 
only the base  and offset are different
> +	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);

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