Date:   Wed, 30 Nov 2022 21:14:19 +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));
> +
> +	mult = (val >> LOONGSON2_SATA_FREQSCALE_SHIFT) &
> +			clk_div_mask(LOONGSON2_SATA_FREQSCALE_WIDTH);
> +
> +	rate = parent_rate * (mult + 1);
> +	do_div(rate, 8);
> +
> +	return rate;
> +}
> +

loongson2_sata_recalc_rate, loongson2_usb_recalc_rate,loongson2_apb_recalc_rate are have the same calcuate logic code, only the shift and width are different,
I thought it would be possible to abstract out a common function to reduce duplicate code

> +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);
> +
> +	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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