Re: [PATCH v5 10/23] clk: starfive: Add JHB100 System-2 clock generator driver

[Brian Masney <bmasney@redhat.com>]

Hi Changhuang,

On Wed, Sep 30, 2026 at 05:43:04AM -0700, Changhuang Liang wrote:
> Add support for JHB100 System-2 clock generator (SYS2CRG).
> 
> Signed-off-by: Changhuang Liang <changhuang.liang@starfivetech.com>
> ---
>  drivers/clk/starfive/Kconfig                  |  10 ++
>  drivers/clk/starfive/Makefile                 |   1 +
>  .../clk/starfive/clk-starfive-jhb100-sys2.c   | 129 ++++++++++++++++++
>  3 files changed, 140 insertions(+)
>  create mode 100644 drivers/clk/starfive/clk-starfive-jhb100-sys2.c
> 
> diff --git a/drivers/clk/starfive/Kconfig b/drivers/clk/starfive/Kconfig
> index 11da8bcc4046..cfaac934a8e0 100644
> --- a/drivers/clk/starfive/Kconfig
> +++ b/drivers/clk/starfive/Kconfig
> @@ -92,3 +92,13 @@ config CLK_STARFIVE_JHB100_SYS1
>  	help
>  	  Say yes here to support the system-1 clock controller on the
>  	  StarFive JHB100 SoC.
> +
> +config CLK_STARFIVE_JHB100_SYS2
> +	bool "StarFive JHB100 system-2 clock support"
> +	depends on ARCH_STARFIVE || COMPILE_TEST
> +	select CLK_STARFIVE_JH71X0
> +	select RESET_STARFIVE_JHB100 if RESET_CONTROLLER
> +	default ARCH_STARFIVE
> +	help
> +	  Say yes here to support the system-2 clock controller on the
> +	  StarFive JHB100 SoC.
> diff --git a/drivers/clk/starfive/Makefile b/drivers/clk/starfive/Makefile
> index 0061550e0f7e..29cdef20575e 100644
> --- a/drivers/clk/starfive/Makefile
> +++ b/drivers/clk/starfive/Makefile
> @@ -13,3 +13,4 @@ obj-$(CONFIG_CLK_STARFIVE_JH7110_VOUT)	+= clk-starfive-jh7110-vout.o
>  
>  obj-$(CONFIG_CLK_STARFIVE_JHB100_SYS0)		+= clk-starfive-jhb100-sys0.o
>  obj-$(CONFIG_CLK_STARFIVE_JHB100_SYS1)		+= clk-starfive-jhb100-sys1.o
> +obj-$(CONFIG_CLK_STARFIVE_JHB100_SYS2)		+= clk-starfive-jhb100-sys2.o
> diff --git a/drivers/clk/starfive/clk-starfive-jhb100-sys2.c b/drivers/clk/starfive/clk-starfive-jhb100-sys2.c
> new file mode 100644
> index 000000000000..a2c7e8eba9b6
> --- /dev/null
> +++ b/drivers/clk/starfive/clk-starfive-jhb100-sys2.c
> @@ -0,0 +1,129 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * StarFive JHB100 System-2 Clock Driver
> + *
> + * Copyright (C) 2024 StarFive Technology Co., Ltd.
> + *
> + * Author: Changhuang Liang <changhuang.liang@starfivetech.com>
> + *
> + */
> +
> +#include <dt-bindings/clock/starfive,jhb100-crg.h>
> +#include <linux/init.h>
> +#include <linux/platform_device.h>
> +
> +#include "clk-starfive-jh71x0.h"
> +
> +#define JHB100_SYS2CLK_NUM_CLKS			(JHB100_SYS2CLK_MAIN_ICG_EN_JTAG1 + 1)
> +
> +/* external clocks */
> +#define JHB100_SYS2CLK_OSC			(JHB100_SYS2CLK_NUM_CLKS + 0)
> +#define JHB100_SYS2CLK_PLL1			(JHB100_SYS2CLK_NUM_CLKS + 1)
> +#define JHB100_SYS2CLK_GPU0_NCNOC_INIT		(JHB100_SYS2CLK_NUM_CLKS + 2)
> +#define JHB100_SYS2CLK_GPU1_NCNOC_INIT		(JHB100_SYS2CLK_NUM_CLKS + 3)
> +
> +static const char * const jhb100_sys2_ext_clk[] = {
> +	"osc",
> +	"pll1",
> +	"gpu0_ncnoc_init",
> +	"gpu1_ncnoc_init",
> +};
> +
> +static const struct jh71x0_clk_data jhb100_sys2crg_clk_data[] = {
> +	/* jtag mst*/
> +	JH71X0__DIV(JHB100_SYS2CLK_JTAGM0_HCLK, "jtagm0_hclk", 6,
> +		    JHB100_SYS2CLK_PLL1),
> +	JH71X0__DIV(JHB100_SYS2CLK_JTAGM1_HCLK, "jtagm1_hclk", 6,
> +		    JHB100_SYS2CLK_PLL1),
> +	JH71X0__DIV(JHB100_SYS2CLK_JTAGM0_ATPG, "jtagm0_ATPG", 12,
> +		    JHB100_SYS2CLK_PLL1),
> +	JH71X0__DIV(JHB100_SYS2CLK_JTAGM1_ATPG, "jtagm1_ATPG", 12,
> +		    JHB100_SYS2CLK_PLL1),
> +	JH71X0__DIV(JHB100_SYS2CLK_JTAGM0_ATPG_TCLOCK, "jtagm0_atpg_tclock", 2,
> +		    JHB100_SYS2CLK_JTAGM0_ATPG),
> +	JH71X0__DIV(JHB100_SYS2CLK_JTAGM1_ATPG_TCLOCK, "jtagm1_atpg_tclock", 2,
> +		    JHB100_SYS2CLK_JTAGM1_ATPG),
> +	JH71X0_GATE(JHB100_SYS2CLK_JTAG0_MST_WRAP_HCLK, "jtag0_mst_wrap_hclk",
> +		    CLK_IGNORE_UNUSED, JHB100_SYS2CLK_JTAGM0_HCLK),

Can you leave a comment somewhere about why CLK_IGNORE_UNUSED is on some
of these clocks? We may be able to deprecate this flag once some
variation of the clk sync_state support lands:

https://lore.kernel.org/linux-clk/20260626-clk-sync-state-v1-0-4156d8196dc8@redhat.com/


> +	JH71X0_GATE(JHB100_SYS2CLK_JTAG0_MST_WRAP_CLK_JTAG, "jtag0_mst_wrap_clk_jtag",
> +		    CLK_IGNORE_UNUSED, JHB100_SYS2CLK_JTAGM0_HCLK),
> +	JH71X0_GATE(JHB100_SYS2CLK_JTAG0_MST_WRAP_APB_PCLK, "jtag0_mst_wrap_apb_pclk",
> +		    CLK_IGNORE_UNUSED, JHB100_SYS2CLK_JTAGM0_ATPG),
> +	JH71X0_GATE(JHB100_SYS2CLK_JTAG0_MST_WRAP_ATPG_TCLOCK, "jtag0_mst_wrap_atpg_tclock",
> +		    CLK_IGNORE_UNUSED, JHB100_SYS2CLK_JTAGM0_ATPG),
> +	JH71X0_GATE(JHB100_SYS2CLK_JTAG1_MST_WRAP_HCLK, "jtag1_mst_wrap_hclk",
> +		    CLK_IGNORE_UNUSED, JHB100_SYS2CLK_JTAGM1_HCLK),
> +	JH71X0_GATE(JHB100_SYS2CLK_JTAG1_MST_WRAP_CLK_JTAG, "jtag1_mst_wrap_clk_jtag",
> +		    CLK_IGNORE_UNUSED, JHB100_SYS2CLK_JTAGM1_HCLK),
> +	JH71X0_GATE(JHB100_SYS2CLK_JTAG1_MST_WRAP_APB_PCLK, "jtag1_mst_wrap_apb_pclk",
> +		    CLK_IGNORE_UNUSED, JHB100_SYS2CLK_JTAGM1_ATPG),
> +	JH71X0_GATE(JHB100_SYS2CLK_JTAG1_MST_WRAP_ATPG_TCLOCK, "jtag1_mst_wrap_atpg_tclock",
> +		    CLK_IGNORE_UNUSED, JHB100_SYS2CLK_JTAGM1_ATPG),
> +	/* hostusbcmn */
> +	JH71X0__DIV(JHB100_SYS2CLK_HOSTUSB_NCNOC_TARG, "hostusb_ncnoc_targ", 12,
> +		    JHB100_SYS2CLK_PLL1),
> +	JH71X0__DIV(JHB100_SYS2CLK_HOSTUSBCMN_CFG_500, "hostusbcmn_cfg_500", 4,
> +		    JHB100_SYS2CLK_PLL1),
> +	/* bmcperiph1 */
> +	JH71X0__DIV(JHB100_SYS2CLK_BMCPER1_NCNOC_TARG, "bmcper1_ncnoc_targ", 6,
> +		    JHB100_SYS2CLK_PLL1),
> +	JH71X0__DIV(JHB100_SYS2CLK_BMCPER1_CFG_250, "bmcper1_cfg_250", 5,
> +		    JHB100_SYS2CLK_PLL1),
> +	JH71X0__DIV(JHB100_SYS2CLK_BMCPER1_CFG_143_DFT, "bmcper1_cfg_143_dft", 8,
> +		    JHB100_SYS2CLK_PLL1),
> +	JH71X0_GATE(JHB100_SYS2CLK_BMCPER1_CFG_143, "bmcper1_cfg_143", CLK_IS_CRITICAL,

Also please leave a comment why CLK_IS_CRITICAL is needed as well for
these particular clocks.

Brian