[v23,3/3] clk: npcm8xx: add clock controller

Commit Message

Tomer Maimon Jan. 31, 2024, 6:26 p.m. UTC

Nuvoton Arbel BMC NPCM8XX contains an integrated clock controller which
generates and supplies clocks to all modules within the BMC.

Signed-off-by: Tomer Maimon <[e-mail]>
Acked-by: Joel Stanley <[e-mail]>
---
 drivers/clk/Kconfig       |   8 +
 drivers/clk/Makefile      |   1 +
 drivers/clk/clk-npcm8xx.c | 509 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 518 insertions(+)
 create mode 100644 drivers/clk/clk-npcm8xx.c

Comments

Stephen Boyd Feb. 22, 2024, 5:58 a.m. UTC | #1

Quoting Tomer Maimon (2024-01-31 10:26:53)
> diff --git a/drivers/clk/clk-npcm8xx.c b/drivers/clk/clk-npcm8xx.c
> new file mode 100644
> index 000000000000..eacb579d30af
> --- /dev/null
> +++ b/drivers/clk/clk-npcm8xx.c
> @@ -0,0 +1,509 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Nuvoton NPCM8xx Clock Generator
> + * All the clocks are initialized by the bootloader, so this driver allows only
[...]
> +
> +/* external clock definition */
> +#define NPCM8XX_CLK_S_REFCLK   "refclk"
> +
> +/* pll definition */
> +#define NPCM8XX_CLK_S_PLL0     "pll0"
> +#define NPCM8XX_CLK_S_PLL1     "pll1"
> +#define NPCM8XX_CLK_S_PLL2     "pll2"
> +#define NPCM8XX_CLK_S_PLL_GFX  "pll_gfx"
> +
> +/* early divider definition */
> +#define NPCM8XX_CLK_S_PLL2_DIV2                "pll2_div2"
> +#define NPCM8XX_CLK_S_PLL_GFX_DIV2     "pll_gfx_div2"
> +#define NPCM8XX_CLK_S_PLL1_DIV2                "pll1_div2"
> +
> +/* mux definition */
> +#define NPCM8XX_CLK_S_CPU_MUX     "cpu_mux"
> +
> +/* div definition */
> +#define NPCM8XX_CLK_S_TH          "th"
> +#define NPCM8XX_CLK_S_AXI         "axi"

Please inline all these string #defines to the place they're used.

> +
> +static struct clk_hw hw_pll1_div2, hw_pll2_div2, hw_gfx_div2, hw_pre_clk;
[..]
> +static struct clk_hw *
> +npcm8xx_clk_register(struct device *dev, const char *name,
> +                    struct regmap *clk_regmap, unsigned int offset,
> +                    unsigned long flags, const struct clk_ops *npcm8xx_clk_ops,
> +                    const struct clk_parent_data *parent_data,
> +                    const struct clk_hw *parent_hw, u8 num_parents,
> +                    u8 shift, u32 mask, unsigned long width,
> +                    const u32 *table, unsigned long clk_flags)
> +{
> +       struct npcm8xx_clk *clk;
> +       struct clk_init_data init = {};
> +       int ret;
> +
> +       clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
> +       if (!clk)
> +               return ERR_PTR(-ENOMEM);
> +
> +       init.name = name;
> +       init.ops = npcm8xx_clk_ops;
> +       init.parent_data = parent_data;
> +       init.parent_hws = parent_hw ? &parent_hw : NULL;

Is it necessary to check? Can't it be set unconditionally?

> +       init.num_parents = num_parents;
> +       init.flags = flags;
> +
> +       clk->clk_regmap = clk_regmap;
> +       clk->hw.init = &init;
> +       clk->offset = offset;
> +       clk->shift = shift;
> +       clk->mask = mask;
> +       clk->width = width;
> +       clk->table = table;
> +       clk->flags = clk_flags;
> +
> +       ret = devm_clk_hw_register(dev, &clk->hw);
> +       if (ret)
> +               return ERR_PTR(ret);
> +
> +       return &clk->hw;
[...]
> +
> +static unsigned long npcm8xx_clk_div_get_parent(struct clk_hw *hw,
> +                                               unsigned long parent_rate)
> +{
> +       struct npcm8xx_clk *div = to_npcm8xx_clk(hw);
> +       unsigned int val;
> +
> +       regmap_read(div->clk_regmap, div->offset, &val);
> +       val = val >> div->shift;
> +       val &= clk_div_mask(div->width);
> +
> +       return divider_recalc_rate(hw, parent_rate, val, NULL, div->flags,
> +                                  div->width);
> +}
> +
> +static const struct clk_ops npcm8xx_clk_div_ops = {
> +       .recalc_rate = npcm8xx_clk_div_get_parent,
> +};
> +
> +static int npcm8xx_clk_probe(struct platform_device *pdev)
> +{
> +       struct device_node *parent_np = of_get_parent(pdev->dev.of_node);

The parent of this device is not a syscon.

> +       struct clk_hw_onecell_data *npcm8xx_clk_data;
> +       struct device *dev = &pdev->dev;
> +       struct regmap *clk_regmap;
> +       struct clk_hw *hw;
> +       unsigned int i;
> +
> +       npcm8xx_clk_data = devm_kzalloc(dev, struct_size(npcm8xx_clk_data, hws,
> +                                                        NPCM8XX_NUM_CLOCKS),
> +                                       GFP_KERNEL);
> +       if (!npcm8xx_clk_data)
> +               return -ENOMEM;
> +
> +       clk_regmap = syscon_node_to_regmap(parent_np);
> +       of_node_put(parent_np);

Is there another binding update that is going to move this node to be a
child of the syscon?

		gcr: system-controller@f0800000 {
                        compatible = "nuvoton,npcm845-gcr", "syscon";
                        reg = <0x0 0xf0800000 0x0 0x1000>;
                };

Tomer Maimon Feb. 25, 2024, 6 p.m. UTC | #2

Hi Stephen,

On Thu, 22 Feb 2024 at 07:58, Stephen Boyd <[e-mail]> wrote:
>
> Quoting Tomer Maimon (2024-01-31 10:26:53)
> > diff --git a/drivers/clk/clk-npcm8xx.c b/drivers/clk/clk-npcm8xx.c
> > new file mode 100644
> > index 000000000000..eacb579d30af
> > --- /dev/null
> > +++ b/drivers/clk/clk-npcm8xx.c
> > @@ -0,0 +1,509 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Nuvoton NPCM8xx Clock Generator
> > + * All the clocks are initialized by the bootloader, so this driver allows only
> [...]
> > +
> > +/* external clock definition */
> > +#define NPCM8XX_CLK_S_REFCLK   "refclk"
> > +
> > +/* pll definition */
> > +#define NPCM8XX_CLK_S_PLL0     "pll0"
> > +#define NPCM8XX_CLK_S_PLL1     "pll1"
> > +#define NPCM8XX_CLK_S_PLL2     "pll2"
> > +#define NPCM8XX_CLK_S_PLL_GFX  "pll_gfx"
> > +
> > +/* early divider definition */
> > +#define NPCM8XX_CLK_S_PLL2_DIV2                "pll2_div2"
> > +#define NPCM8XX_CLK_S_PLL_GFX_DIV2     "pll_gfx_div2"
> > +#define NPCM8XX_CLK_S_PLL1_DIV2                "pll1_div2"
> > +
> > +/* mux definition */
> > +#define NPCM8XX_CLK_S_CPU_MUX     "cpu_mux"
> > +
> > +/* div definition */
> > +#define NPCM8XX_CLK_S_TH          "th"
> > +#define NPCM8XX_CLK_S_AXI         "axi"
>
> Please inline all these string #defines to the place they're used.
The version V21 you mention using define only when the definition is
used more than once
https://www.spinics.net/lists/kernel/msg5045826.html
Should I remove all the string definitions and add the string to the array?
>
> > +
> > +static struct clk_hw hw_pll1_div2, hw_pll2_div2, hw_gfx_div2, hw_pre_clk;
> [..]
> > +static struct clk_hw *
> > +npcm8xx_clk_register(struct device *dev, const char *name,
> > +                    struct regmap *clk_regmap, unsigned int offset,
> > +                    unsigned long flags, const struct clk_ops *npcm8xx_clk_ops,
> > +                    const struct clk_parent_data *parent_data,
> > +                    const struct clk_hw *parent_hw, u8 num_parents,
> > +                    u8 shift, u32 mask, unsigned long width,
> > +                    const u32 *table, unsigned long clk_flags)
> > +{
> > +       struct npcm8xx_clk *clk;
> > +       struct clk_init_data init = {};
> > +       int ret;
> > +
> > +       clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
> > +       if (!clk)
> > +               return ERR_PTR(-ENOMEM);
> > +
> > +       init.name = name;
> > +       init.ops = npcm8xx_clk_ops;
> > +       init.parent_data = parent_data;
> > +       init.parent_hws = parent_hw ? &parent_hw : NULL;
>
> Is it necessary to check? Can't it be set unconditionally?
Will remove
>
> > +       init.num_parents = num_parents;
> > +       init.flags = flags;
> > +
> > +       clk->clk_regmap = clk_regmap;
> > +       clk->hw.init = &init;
> > +       clk->offset = offset;
> > +       clk->shift = shift;
> > +       clk->mask = mask;
> > +       clk->width = width;
> > +       clk->table = table;
> > +       clk->flags = clk_flags;
> > +
> > +       ret = devm_clk_hw_register(dev, &clk->hw);
> > +       if (ret)
> > +               return ERR_PTR(ret);
> > +
> > +       return &clk->hw;
> [...]
> > +
> > +static unsigned long npcm8xx_clk_div_get_parent(struct clk_hw *hw,
> > +                                               unsigned long parent_rate)
> > +{
> > +       struct npcm8xx_clk *div = to_npcm8xx_clk(hw);
> > +       unsigned int val;
> > +
> > +       regmap_read(div->clk_regmap, div->offset, &val);
> > +       val = val >> div->shift;
> > +       val &= clk_div_mask(div->width);
> > +
> > +       return divider_recalc_rate(hw, parent_rate, val, NULL, div->flags,
> > +                                  div->width);
> > +}
> > +
> > +static const struct clk_ops npcm8xx_clk_div_ops = {
> > +       .recalc_rate = npcm8xx_clk_div_get_parent,
> > +};
> > +
> > +static int npcm8xx_clk_probe(struct platform_device *pdev)
> > +{
> > +       struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
>
> The parent of this device is not a syscon.
Once I have registered the map that handles both reset and the clock
in general is syscon, this is why we will modify the DTS so the clock
and the reset will be under syscon father node
                sysctrl: system-controller@f0801000 {
                        compatible = "syscon", "simple-mfd";
                        reg = <0x0 0xf0801000 0x0 0x1000>;

                        rstc: reset-controller {
                                compatible = "nuvoton,npcm845-reset";
                                reg = <0x0 0xf0801000 0x0 0xC4>;
                                #reset-cells = <2>;
                                nuvoton,sysgcr = <&gcr>;
                        };

                        clk: clock-controller {
                                compatible = "nuvoton,npcm845-clk";
                                #clock-cells = <1>;
                                clocks = <&refclk>;
                                clock-names = "refclk";
                        };
                };
You can see other drivers that using the same method like
https://elixir.bootlin.com/linux/v6.8-rc5/source/Documentation/devicetree/bindings/clock/socionext,uniphier-clock.yaml
>
> > +       struct clk_hw_onecell_data *npcm8xx_clk_data;
> > +       struct device *dev = &pdev->dev;
> > +       struct regmap *clk_regmap;
> > +       struct clk_hw *hw;
> > +       unsigned int i;
> > +
> > +       npcm8xx_clk_data = devm_kzalloc(dev, struct_size(npcm8xx_clk_data, hws,
> > +                                                        NPCM8XX_NUM_CLOCKS),
> > +                                       GFP_KERNEL);
> > +       if (!npcm8xx_clk_data)
> > +               return -ENOMEM;
> > +
> > +       clk_regmap = syscon_node_to_regmap(parent_np);
> > +       of_node_put(parent_np);
>
> Is there another binding update that is going to move this node to be a
> child of the syscon?
>
>                 gcr: system-controller@f0800000 {
>                         compatible = "nuvoton,npcm845-gcr", "syscon";
>                         reg = <0x0 0xf0800000 0x0 0x1000>;
>                 };
No, sorry but I'm not going to use the GCR node the handle the clock
and reset modules, the GCR has different memory space.
the clock driver will have the following device tree
               sysctrl: system-controller@f0801000 {
                        compatible = "syscon", "simple-mfd";
                        reg = <0x0 0xf0801000 0x0 0x1000>;

                        rstc: reset-controller {
                                compatible = "nuvoton,npcm845-reset";
                                reg = <0x0 0xf0801000 0x0 0xC4>;
                                #reset-cells = <2>;
                                nuvoton,sysgcr = <&gcr>;
                        };

                        clk: clock-controller {
                                compatible = "nuvoton,npcm845-clk";
                                #clock-cells = <1>;
                                clocks = <&refclk>;
                                clock-names = "refclk";
                        };
                };

Stephen appreciate it if you could speed this upstream and apply it in
this kernel version.
hope the clarification is understood and if it is fine I can send V24 this week.

Thanks,

Tomer

Stephen Boyd Feb. 28, 2024, 10:47 p.m. UTC | #3

Quoting Tomer Maimon (2024-02-25 10:00:35)
> Hi Stephen,
> 
> On Thu, 22 Feb 2024 at 07:58, Stephen Boyd <[e-mail]> wrote:
> >
> > Quoting Tomer Maimon (2024-01-31 10:26:53)
> > > diff --git a/drivers/clk/clk-npcm8xx.c b/drivers/clk/clk-npcm8xx.c
> > > new file mode 100644
> > > index 000000000000..eacb579d30af
> > > --- /dev/null
> > > +++ b/drivers/clk/clk-npcm8xx.c
> > > @@ -0,0 +1,509 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * Nuvoton NPCM8xx Clock Generator
> > > + * All the clocks are initialized by the bootloader, so this driver allows only
> > [...]
> > > +
> > > +/* external clock definition */
> > > +#define NPCM8XX_CLK_S_REFCLK   "refclk"
> > > +
> > > +/* pll definition */
> > > +#define NPCM8XX_CLK_S_PLL0     "pll0"
> > > +#define NPCM8XX_CLK_S_PLL1     "pll1"
> > > +#define NPCM8XX_CLK_S_PLL2     "pll2"
> > > +#define NPCM8XX_CLK_S_PLL_GFX  "pll_gfx"
> > > +
> > > +/* early divider definition */
> > > +#define NPCM8XX_CLK_S_PLL2_DIV2                "pll2_div2"
> > > +#define NPCM8XX_CLK_S_PLL_GFX_DIV2     "pll_gfx_div2"
> > > +#define NPCM8XX_CLK_S_PLL1_DIV2                "pll1_div2"
> > > +
> > > +/* mux definition */
> > > +#define NPCM8XX_CLK_S_CPU_MUX     "cpu_mux"
> > > +
> > > +/* div definition */
> > > +#define NPCM8XX_CLK_S_TH          "th"
> > > +#define NPCM8XX_CLK_S_AXI         "axi"
> >
> > Please inline all these string #defines to the place they're used.
> The version V21 you mention using define only when the definition is
> used more than once
> https://www.spinics.net/lists/kernel/msg5045826.html
> Should I remove all the string definitions and add the string to the array?

If it's a clk name for a clk registered in this file it should be
inlined. Is that the case for everything besides refclk? And even refclk
could be inlined so that we don't have to jump to the definition of a
string.

> > > +
> > > +static unsigned long npcm8xx_clk_div_get_parent(struct clk_hw *hw,
> > > +                                               unsigned long parent_rate)
> > > +{
> > > +       struct npcm8xx_clk *div = to_npcm8xx_clk(hw);
> > > +       unsigned int val;
> > > +
> > > +       regmap_read(div->clk_regmap, div->offset, &val);
> > > +       val = val >> div->shift;
> > > +       val &= clk_div_mask(div->width);
> > > +
> > > +       return divider_recalc_rate(hw, parent_rate, val, NULL, div->flags,
> > > +                                  div->width);
> > > +}
> > > +
> > > +static const struct clk_ops npcm8xx_clk_div_ops = {
> > > +       .recalc_rate = npcm8xx_clk_div_get_parent,
> > > +};
> > > +
> > > +static int npcm8xx_clk_probe(struct platform_device *pdev)
> > > +{
> > > +       struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
> >
> > The parent of this device is not a syscon.
> Once I have registered the map that handles both reset and the clock
> in general is syscon, this is why we will modify the DTS so the clock
> and the reset will be under syscon father node
>                 sysctrl: system-controller@f0801000 {
>                         compatible = "syscon", "simple-mfd";
>                         reg = <0x0 0xf0801000 0x0 0x1000>;
> 
>                         rstc: reset-controller {
>                                 compatible = "nuvoton,npcm845-reset";
>                                 reg = <0x0 0xf0801000 0x0 0xC4>;
>                                 #reset-cells = <2>;
>                                 nuvoton,sysgcr = <&gcr>;
>                         };
> 
>                         clk: clock-controller {
>                                 compatible = "nuvoton,npcm845-clk";
>                                 #clock-cells = <1>;
>                                 clocks = <&refclk>;
>                                 clock-names = "refclk";
>                         };
>                 };
> You can see other drivers that using the same method like
> https://elixir.bootlin.com/linux/v6.8-rc5/source/Documentation/devicetree/bindings/clock/socionext,uniphier-clock.yaml

You will need a similar file like
Documentation/devicetree/bindings/soc/socionext/socionext,uniphier-perictrl.yaml
then to describe the child nodes.

Socionext may not be the best example to follow. I generally try to
avoid syscon and simply put #reset-cells and #clock-cells in the node
for the device. You can use the auxiliary bus to register drivers for
clk and reset and put them into the resepective driver directories.
Avoid syscon means random drivers can't reach into the device with a
regmap handle and read/write registers that they're not supposed to.

> >
> > > +       struct clk_hw_onecell_data *npcm8xx_clk_data;
> > > +       struct device *dev = &pdev->dev;
> > > +       struct regmap *clk_regmap;
> > > +       struct clk_hw *hw;
> > > +       unsigned int i;
> > > +
> > > +       npcm8xx_clk_data = devm_kzalloc(dev, struct_size(npcm8xx_clk_data, hws,
> > > +                                                        NPCM8XX_NUM_CLOCKS),
> > > +                                       GFP_KERNEL);
> > > +       if (!npcm8xx_clk_data)
> > > +               return -ENOMEM;
> > > +
> > > +       clk_regmap = syscon_node_to_regmap(parent_np);
> > > +       of_node_put(parent_np);
> >
> > Is there another binding update that is going to move this node to be a
> > child of the syscon?
> >
> >                 gcr: system-controller@f0800000 {
> >                         compatible = "nuvoton,npcm845-gcr", "syscon";
> >                         reg = <0x0 0xf0800000 0x0 0x1000>;
> >                 };
> No, sorry but I'm not going to use the GCR node the handle the clock
> and reset modules, the GCR has different memory space.
> the clock driver will have the following device tree

What does the reset driver use the CGR node for? The driver looks like
it's using it to control USB phy resets.

>                sysctrl: system-controller@f0801000 {
>                         compatible = "syscon", "simple-mfd";
>                         reg = <0x0 0xf0801000 0x0 0x1000>;
> 
>                         rstc: reset-controller {
>                                 compatible = "nuvoton,npcm845-reset";
>                                 reg = <0x0 0xf0801000 0x0 0xC4>;

This isn't a valid reg property for a child node like this.

>                                 #reset-cells = <2>;
>                                 nuvoton,sysgcr = <&gcr>;
>                         };
> 
>                         clk: clock-controller {
>                                 compatible = "nuvoton,npcm845-clk";
>                                 #clock-cells = <1>;
>                                 clocks = <&refclk>;
>                                 clock-names = "refclk";
>                         };
>                 };

Tomer Maimon Feb. 29, 2024, 9:29 p.m. UTC | #4

Hi Stephen,

Thanks for your reply.

On Thu, 29 Feb 2024 at 00:48, Stephen Boyd <[e-mail]> wrote:
>
> Quoting Tomer Maimon (2024-02-25 10:00:35)
> > Hi Stephen,
> >
> > On Thu, 22 Feb 2024 at 07:58, Stephen Boyd <[e-mail]> wrote:
> > >
> > > Quoting Tomer Maimon (2024-01-31 10:26:53)
> > > > diff --git a/drivers/clk/clk-npcm8xx.c b/drivers/clk/clk-npcm8xx.c
> > > > new file mode 100644
> > > > index 000000000000..eacb579d30af
> > > > --- /dev/null
> > > > +++ b/drivers/clk/clk-npcm8xx.c
> > > > @@ -0,0 +1,509 @@
> > > > +// SPDX-License-Identifier: GPL-2.0
> > > > +/*
> > > > + * Nuvoton NPCM8xx Clock Generator
> > > > + * All the clocks are initialized by the bootloader, so this driver allows only
> > > [...]
> > > > +
> > > > +/* external clock definition */
> > > > +#define NPCM8XX_CLK_S_REFCLK   "refclk"
> > > > +
> > > > +/* pll definition */
> > > > +#define NPCM8XX_CLK_S_PLL0     "pll0"
> > > > +#define NPCM8XX_CLK_S_PLL1     "pll1"
> > > > +#define NPCM8XX_CLK_S_PLL2     "pll2"
> > > > +#define NPCM8XX_CLK_S_PLL_GFX  "pll_gfx"
> > > > +
> > > > +/* early divider definition */
> > > > +#define NPCM8XX_CLK_S_PLL2_DIV2                "pll2_div2"
> > > > +#define NPCM8XX_CLK_S_PLL_GFX_DIV2     "pll_gfx_div2"
> > > > +#define NPCM8XX_CLK_S_PLL1_DIV2                "pll1_div2"
> > > > +
> > > > +/* mux definition */
> > > > +#define NPCM8XX_CLK_S_CPU_MUX     "cpu_mux"
> > > > +
> > > > +/* div definition */
> > > > +#define NPCM8XX_CLK_S_TH          "th"
> > > > +#define NPCM8XX_CLK_S_AXI         "axi"
> > >
> > > Please inline all these string #defines to the place they're used.
> > The version V21 you mention using define only when the definition is
> > used more than once
> > https://www.spinics.net/lists/kernel/msg5045826.html
> > Should I remove all the string definitions and add the string to the array?
>
> If it's a clk name for a clk registered in this file it should be
> inlined. Is that the case for everything besides refclk? And even refclk
> could be inlined so that we don't have to jump to the definition of a
> string.
I will add the string in the clock arrays and remove all the string definitions.
>
> > > > +
> > > > +static unsigned long npcm8xx_clk_div_get_parent(struct clk_hw *hw,
> > > > +                                               unsigned long parent_rate)
> > > > +{
> > > > +       struct npcm8xx_clk *div = to_npcm8xx_clk(hw);
> > > > +       unsigned int val;
> > > > +
> > > > +       regmap_read(div->clk_regmap, div->offset, &val);
> > > > +       val = val >> div->shift;
> > > > +       val &= clk_div_mask(div->width);
> > > > +
> > > > +       return divider_recalc_rate(hw, parent_rate, val, NULL, div->flags,
> > > > +                                  div->width);
> > > > +}
> > > > +
> > > > +static const struct clk_ops npcm8xx_clk_div_ops = {
> > > > +       .recalc_rate = npcm8xx_clk_div_get_parent,
> > > > +};
> > > > +
> > > > +static int npcm8xx_clk_probe(struct platform_device *pdev)
> > > > +{
> > > > +       struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
> > >
> > > The parent of this device is not a syscon.
> > Once I have registered the map that handles both reset and the clock
> > in general is syscon, this is why we will modify the DTS so the clock
> > and the reset will be under syscon father node
> >                 sysctrl: system-controller@f0801000 {
> >                         compatible = "syscon", "simple-mfd";
> >                         reg = <0x0 0xf0801000 0x0 0x1000>;
> >
> >                         rstc: reset-controller {
> >                                 compatible = "nuvoton,npcm845-reset";
> >                                 reg = <0x0 0xf0801000 0x0 0xC4>;
> >                                 #reset-cells = <2>;
> >                                 nuvoton,sysgcr = <&gcr>;
> >                         };
> >
> >                         clk: clock-controller {
> >                                 compatible = "nuvoton,npcm845-clk";
> >                                 #clock-cells = <1>;
> >                                 clocks = <&refclk>;
> >                                 clock-names = "refclk";
> >                         };
> >                 };
> > You can see other drivers that using the same method like
> > https://elixir.bootlin.com/linux/v6.8-rc5/source/Documentation/devicetree/bindings/clock/socionext,uniphier-clock.yaml
>
> You will need a similar file like
> Documentation/devicetree/bindings/soc/socionext/socionext,uniphier-perictrl.yaml
> then to describe the child nodes.
I can do it.
>
> Socionext may not be the best example to follow. I generally try to
> avoid syscon and simply put #reset-cells and #clock-cells in the node
If I remove syscon I can't use syscon_node_to_regmap function, What
should I use If I remove syscon? auxiliary bus? something else?
> for the device. You can use the auxiliary bus to register drivers for
> clk and reset and put them into the resepective driver directories.
I little bit confused, what is an auxiliary bus to register drivers,
can you provide me an example?
> Avoid syscon means random drivers can't reach into the device with a
> regmap handle and read/write registers that they're not supposed to.
Indeed, but the drivers could use the reset and clock memory map only
if the module is also a child node.

Please let me know what is your preferred way to handle it:
1. stick with syscon and upstream-defined documentation for the rst clk syscon.
2. avoid syscon and use an auxiliary bus, appreciate if you could give
me an example of how it should be done.
3. Avoid sycon and handle it differently.
>
> > >
> > > > +       struct clk_hw_onecell_data *npcm8xx_clk_data;
> > > > +       struct device *dev = &pdev->dev;
> > > > +       struct regmap *clk_regmap;
> > > > +       struct clk_hw *hw;
> > > > +       unsigned int i;
> > > > +
> > > > +       npcm8xx_clk_data = devm_kzalloc(dev, struct_size(npcm8xx_clk_data, hws,
> > > > +                                                        NPCM8XX_NUM_CLOCKS),
> > > > +                                       GFP_KERNEL);
> > > > +       if (!npcm8xx_clk_data)
> > > > +               return -ENOMEM;
> > > > +
> > > > +       clk_regmap = syscon_node_to_regmap(parent_np);
> > > > +       of_node_put(parent_np);
> > >
> > > Is there another binding update that is going to move this node to be a
> > > child of the syscon?
> > >
> > >                 gcr: system-controller@f0800000 {
> > >                         compatible = "nuvoton,npcm845-gcr", "syscon";
> > >                         reg = <0x0 0xf0800000 0x0 0x1000>;
> > >                 };
> > No, sorry but I'm not going to use the GCR node the handle the clock
> > and reset modules, the GCR has different memory space.
> > the clock driver will have the following device tree
>
> What does the reset driver use the CGR node for? The driver looks like
> it's using it to control USB phy resets.
Yes, the USB PHY reset is handled through the GCR registers.
>
> >                sysctrl: system-controller@f0801000 {
> >                         compatible = "syscon", "simple-mfd";
> >                         reg = <0x0 0xf0801000 0x0 0x1000>;
> >
> >                         rstc: reset-controller {
> >                                 compatible = "nuvoton,npcm845-reset";
> >                                 reg = <0x0 0xf0801000 0x0 0xC4>;
>
> This isn't a valid reg property for a child node like this.
O.K.
>
> >                                 #reset-cells = <2>;
> >                                 nuvoton,sysgcr = <&gcr>;
> >                         };
> >
> >                         clk: clock-controller {
> >                                 compatible = "nuvoton,npcm845-clk";
> >                                 #clock-cells = <1>;
> >                                 clocks = <&refclk>;
> >                                 clock-names = "refclk";
> >                         };
> >                 };

Appreciate your guidance!

Thanks,

Tomer

Tomer Maimon March 5, 2024, 3:59 p.m. UTC | #5

Hi Stephen,

Appreciate it if you could reply to my email afew days ago, It is
really important to us to move this driver to upstream.

Thanks,

Tomer

On Thu, 29 Feb 2024 at 23:29, Tomer Maimon <[e-mail]> wrote:
>
> Hi Stephen,
>
> Thanks for your reply.
>
> On Thu, 29 Feb 2024 at 00:48, Stephen Boyd <[e-mail]> wrote:
> >
> > Quoting Tomer Maimon (2024-02-25 10:00:35)
> > > Hi Stephen,
> > >
> > > On Thu, 22 Feb 2024 at 07:58, Stephen Boyd <[e-mail]> wrote:
> > > >
> > > > Quoting Tomer Maimon (2024-01-31 10:26:53)
> > > > > diff --git a/drivers/clk/clk-npcm8xx.c b/drivers/clk/clk-npcm8xx.c
> > > > > new file mode 100644
> > > > > index 000000000000..eacb579d30af
> > > > > --- /dev/null
> > > > > +++ b/drivers/clk/clk-npcm8xx.c
> > > > > @@ -0,0 +1,509 @@
> > > > > +// SPDX-License-Identifier: GPL-2.0
> > > > > +/*
> > > > > + * Nuvoton NPCM8xx Clock Generator
> > > > > + * All the clocks are initialized by the bootloader, so this driver allows only
> > > > [...]
> > > > > +
> > > > > +/* external clock definition */
> > > > > +#define NPCM8XX_CLK_S_REFCLK   "refclk"
> > > > > +
> > > > > +/* pll definition */
> > > > > +#define NPCM8XX_CLK_S_PLL0     "pll0"
> > > > > +#define NPCM8XX_CLK_S_PLL1     "pll1"
> > > > > +#define NPCM8XX_CLK_S_PLL2     "pll2"
> > > > > +#define NPCM8XX_CLK_S_PLL_GFX  "pll_gfx"
> > > > > +
> > > > > +/* early divider definition */
> > > > > +#define NPCM8XX_CLK_S_PLL2_DIV2                "pll2_div2"
> > > > > +#define NPCM8XX_CLK_S_PLL_GFX_DIV2     "pll_gfx_div2"
> > > > > +#define NPCM8XX_CLK_S_PLL1_DIV2                "pll1_div2"
> > > > > +
> > > > > +/* mux definition */
> > > > > +#define NPCM8XX_CLK_S_CPU_MUX     "cpu_mux"
> > > > > +
> > > > > +/* div definition */
> > > > > +#define NPCM8XX_CLK_S_TH          "th"
> > > > > +#define NPCM8XX_CLK_S_AXI         "axi"
> > > >
> > > > Please inline all these string #defines to the place they're used.
> > > The version V21 you mention using define only when the definition is
> > > used more than once
> > > https://www.spinics.net/lists/kernel/msg5045826.html
> > > Should I remove all the string definitions and add the string to the array?
> >
> > If it's a clk name for a clk registered in this file it should be
> > inlined. Is that the case for everything besides refclk? And even refclk
> > could be inlined so that we don't have to jump to the definition of a
> > string.
> I will add the string in the clock arrays and remove all the string definitions.
> >
> > > > > +
> > > > > +static unsigned long npcm8xx_clk_div_get_parent(struct clk_hw *hw,
> > > > > +                                               unsigned long parent_rate)
> > > > > +{
> > > > > +       struct npcm8xx_clk *div = to_npcm8xx_clk(hw);
> > > > > +       unsigned int val;
> > > > > +
> > > > > +       regmap_read(div->clk_regmap, div->offset, &val);
> > > > > +       val = val >> div->shift;
> > > > > +       val &= clk_div_mask(div->width);
> > > > > +
> > > > > +       return divider_recalc_rate(hw, parent_rate, val, NULL, div->flags,
> > > > > +                                  div->width);
> > > > > +}
> > > > > +
> > > > > +static const struct clk_ops npcm8xx_clk_div_ops = {
> > > > > +       .recalc_rate = npcm8xx_clk_div_get_parent,
> > > > > +};
> > > > > +
> > > > > +static int npcm8xx_clk_probe(struct platform_device *pdev)
> > > > > +{
> > > > > +       struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
> > > >
> > > > The parent of this device is not a syscon.
> > > Once I have registered the map that handles both reset and the clock
> > > in general is syscon, this is why we will modify the DTS so the clock
> > > and the reset will be under syscon father node
> > >                 sysctrl: system-controller@f0801000 {
> > >                         compatible = "syscon", "simple-mfd";
> > >                         reg = <0x0 0xf0801000 0x0 0x1000>;
> > >
> > >                         rstc: reset-controller {
> > >                                 compatible = "nuvoton,npcm845-reset";
> > >                                 reg = <0x0 0xf0801000 0x0 0xC4>;
> > >                                 #reset-cells = <2>;
> > >                                 nuvoton,sysgcr = <&gcr>;
> > >                         };
> > >
> > >                         clk: clock-controller {
> > >                                 compatible = "nuvoton,npcm845-clk";
> > >                                 #clock-cells = <1>;
> > >                                 clocks = <&refclk>;
> > >                                 clock-names = "refclk";
> > >                         };
> > >                 };
> > > You can see other drivers that using the same method like
> > > https://elixir.bootlin.com/linux/v6.8-rc5/source/Documentation/devicetree/bindings/clock/socionext,uniphier-clock.yaml
> >
> > You will need a similar file like
> > Documentation/devicetree/bindings/soc/socionext/socionext,uniphier-perictrl.yaml
> > then to describe the child nodes.
> I can do it.
> >
> > Socionext may not be the best example to follow. I generally try to
> > avoid syscon and simply put #reset-cells and #clock-cells in the node
> If I remove syscon I can't use syscon_node_to_regmap function, What
> should I use If I remove syscon? auxiliary bus? something else?
> > for the device. You can use the auxiliary bus to register drivers for
> > clk and reset and put them into the resepective driver directories.
> I little bit confused, what is an auxiliary bus to register drivers,
> can you provide me an example?
> > Avoid syscon means random drivers can't reach into the device with a
> > regmap handle and read/write registers that they're not supposed to.
> Indeed, but the drivers could use the reset and clock memory map only
> if the module is also a child node.
>
> Please let me know what is your preferred way to handle it:
> 1. stick with syscon and upstream-defined documentation for the rst clk syscon.
> 2. avoid syscon and use an auxiliary bus, appreciate if you could give
> me an example of how it should be done.
> 3. Avoid sycon and handle it differently.
> >
> > > >
> > > > > +       struct clk_hw_onecell_data *npcm8xx_clk_data;
> > > > > +       struct device *dev = &pdev->dev;
> > > > > +       struct regmap *clk_regmap;
> > > > > +       struct clk_hw *hw;
> > > > > +       unsigned int i;
> > > > > +
> > > > > +       npcm8xx_clk_data = devm_kzalloc(dev, struct_size(npcm8xx_clk_data, hws,
> > > > > +                                                        NPCM8XX_NUM_CLOCKS),
> > > > > +                                       GFP_KERNEL);
> > > > > +       if (!npcm8xx_clk_data)
> > > > > +               return -ENOMEM;
> > > > > +
> > > > > +       clk_regmap = syscon_node_to_regmap(parent_np);
> > > > > +       of_node_put(parent_np);
> > > >
> > > > Is there another binding update that is going to move this node to be a
> > > > child of the syscon?
> > > >
> > > >                 gcr: system-controller@f0800000 {
> > > >                         compatible = "nuvoton,npcm845-gcr", "syscon";
> > > >                         reg = <0x0 0xf0800000 0x0 0x1000>;
> > > >                 };
> > > No, sorry but I'm not going to use the GCR node the handle the clock
> > > and reset modules, the GCR has different memory space.
> > > the clock driver will have the following device tree
> >
> > What does the reset driver use the CGR node for? The driver looks like
> > it's using it to control USB phy resets.
> Yes, the USB PHY reset is handled through the GCR registers.
> >
> > >                sysctrl: system-controller@f0801000 {
> > >                         compatible = "syscon", "simple-mfd";
> > >                         reg = <0x0 0xf0801000 0x0 0x1000>;
> > >
> > >                         rstc: reset-controller {
> > >                                 compatible = "nuvoton,npcm845-reset";
> > >                                 reg = <0x0 0xf0801000 0x0 0xC4>;
> >
> > This isn't a valid reg property for a child node like this.
> O.K.
> >
> > >                                 #reset-cells = <2>;
> > >                                 nuvoton,sysgcr = <&gcr>;
> > >                         };
> > >
> > >                         clk: clock-controller {
> > >                                 compatible = "nuvoton,npcm845-clk";
> > >                                 #clock-cells = <1>;
> > >                                 clocks = <&refclk>;
> > >                                 clock-names = "refclk";
> > >                         };
> > >                 };
>
> Appreciate your guidance!
>
> Thanks,
>
> Tomer

Tomer Maimon April 2, 2024, 7:42 p.m. UTC | #6

Hi Stephen,

Kind remainder, appreciate if you can reply about the comment that
been sent few weeks ago.

Thanks,

Tomer

On Tue, 5 Mar 2024 at 17:59, Tomer Maimon <[e-mail]> wrote:
>
> Hi Stephen,
>
> Appreciate it if you could reply to my email afew days ago, It is
> really important to us to move this driver to upstream.
>
> Thanks,
>
> Tomer
>
> On Thu, 29 Feb 2024 at 23:29, Tomer Maimon <[e-mail]> wrote:
> >
> > Hi Stephen,
> >
> > Thanks for your reply.
> >
> > On Thu, 29 Feb 2024 at 00:48, Stephen Boyd <[e-mail]> wrote:
> > >
> > > Quoting Tomer Maimon (2024-02-25 10:00:35)
> > > > Hi Stephen,
> > > >
> > > > On Thu, 22 Feb 2024 at 07:58, Stephen Boyd <[e-mail]> wrote:
> > > > >
> > > > > Quoting Tomer Maimon (2024-01-31 10:26:53)
> > > > > > diff --git a/drivers/clk/clk-npcm8xx.c b/drivers/clk/clk-npcm8xx.c
> > > > > > new file mode 100644
> > > > > > index 000000000000..eacb579d30af
> > > > > > --- /dev/null
> > > > > > +++ b/drivers/clk/clk-npcm8xx.c
> > > > > > @@ -0,0 +1,509 @@
> > > > > > +// SPDX-License-Identifier: GPL-2.0
> > > > > > +/*
> > > > > > + * Nuvoton NPCM8xx Clock Generator
> > > > > > + * All the clocks are initialized by the bootloader, so this driver allows only
> > > > > [...]
> > > > > > +
> > > > > > +/* external clock definition */
> > > > > > +#define NPCM8XX_CLK_S_REFCLK   "refclk"
> > > > > > +
> > > > > > +/* pll definition */
> > > > > > +#define NPCM8XX_CLK_S_PLL0     "pll0"
> > > > > > +#define NPCM8XX_CLK_S_PLL1     "pll1"
> > > > > > +#define NPCM8XX_CLK_S_PLL2     "pll2"
> > > > > > +#define NPCM8XX_CLK_S_PLL_GFX  "pll_gfx"
> > > > > > +
> > > > > > +/* early divider definition */
> > > > > > +#define NPCM8XX_CLK_S_PLL2_DIV2                "pll2_div2"
> > > > > > +#define NPCM8XX_CLK_S_PLL_GFX_DIV2     "pll_gfx_div2"
> > > > > > +#define NPCM8XX_CLK_S_PLL1_DIV2                "pll1_div2"
> > > > > > +
> > > > > > +/* mux definition */
> > > > > > +#define NPCM8XX_CLK_S_CPU_MUX     "cpu_mux"
> > > > > > +
> > > > > > +/* div definition */
> > > > > > +#define NPCM8XX_CLK_S_TH          "th"
> > > > > > +#define NPCM8XX_CLK_S_AXI         "axi"
> > > > >
> > > > > Please inline all these string #defines to the place they're used.
> > > > The version V21 you mention using define only when the definition is
> > > > used more than once
> > > > https://www.spinics.net/lists/kernel/msg5045826.html
> > > > Should I remove all the string definitions and add the string to the array?
> > >
> > > If it's a clk name for a clk registered in this file it should be
> > > inlined. Is that the case for everything besides refclk? And even refclk
> > > could be inlined so that we don't have to jump to the definition of a
> > > string.
> > I will add the string in the clock arrays and remove all the string definitions.
> > >
> > > > > > +
> > > > > > +static unsigned long npcm8xx_clk_div_get_parent(struct clk_hw *hw,
> > > > > > +                                               unsigned long parent_rate)
> > > > > > +{
> > > > > > +       struct npcm8xx_clk *div = to_npcm8xx_clk(hw);
> > > > > > +       unsigned int val;
> > > > > > +
> > > > > > +       regmap_read(div->clk_regmap, div->offset, &val);
> > > > > > +       val = val >> div->shift;
> > > > > > +       val &= clk_div_mask(div->width);
> > > > > > +
> > > > > > +       return divider_recalc_rate(hw, parent_rate, val, NULL, div->flags,
> > > > > > +                                  div->width);
> > > > > > +}
> > > > > > +
> > > > > > +static const struct clk_ops npcm8xx_clk_div_ops = {
> > > > > > +       .recalc_rate = npcm8xx_clk_div_get_parent,
> > > > > > +};
> > > > > > +
> > > > > > +static int npcm8xx_clk_probe(struct platform_device *pdev)
> > > > > > +{
> > > > > > +       struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
> > > > >
> > > > > The parent of this device is not a syscon.
> > > > Once I have registered the map that handles both reset and the clock
> > > > in general is syscon, this is why we will modify the DTS so the clock
> > > > and the reset will be under syscon father node
> > > >                 sysctrl: system-controller@f0801000 {
> > > >                         compatible = "syscon", "simple-mfd";
> > > >                         reg = <0x0 0xf0801000 0x0 0x1000>;
> > > >
> > > >                         rstc: reset-controller {
> > > >                                 compatible = "nuvoton,npcm845-reset";
> > > >                                 reg = <0x0 0xf0801000 0x0 0xC4>;
> > > >                                 #reset-cells = <2>;
> > > >                                 nuvoton,sysgcr = <&gcr>;
> > > >                         };
> > > >
> > > >                         clk: clock-controller {
> > > >                                 compatible = "nuvoton,npcm845-clk";
> > > >                                 #clock-cells = <1>;
> > > >                                 clocks = <&refclk>;
> > > >                                 clock-names = "refclk";
> > > >                         };
> > > >                 };
> > > > You can see other drivers that using the same method like
> > > > https://elixir.bootlin.com/linux/v6.8-rc5/source/Documentation/devicetree/bindings/clock/socionext,uniphier-clock.yaml
> > >
> > > You will need a similar file like
> > > Documentation/devicetree/bindings/soc/socionext/socionext,uniphier-perictrl.yaml
> > > then to describe the child nodes.
> > I can do it.
> > >
> > > Socionext may not be the best example to follow. I generally try to
> > > avoid syscon and simply put #reset-cells and #clock-cells in the node
> > If I remove syscon I can't use syscon_node_to_regmap function, What
> > should I use If I remove syscon? auxiliary bus? something else?
> > > for the device. You can use the auxiliary bus to register drivers for
> > > clk and reset and put them into the resepective driver directories.
> > I little bit confused, what is an auxiliary bus to register drivers,
> > can you provide me an example?
> > > Avoid syscon means random drivers can't reach into the device with a
> > > regmap handle and read/write registers that they're not supposed to.
> > Indeed, but the drivers could use the reset and clock memory map only
> > if the module is also a child node.
> >
> > Please let me know what is your preferred way to handle it:
> > 1. stick with syscon and upstream-defined documentation for the rst clk syscon.
> > 2. avoid syscon and use an auxiliary bus, appreciate if you could give
> > me an example of how it should be done.
> > 3. Avoid sycon and handle it differently.
> > >
> > > > >
> > > > > > +       struct clk_hw_onecell_data *npcm8xx_clk_data;
> > > > > > +       struct device *dev = &pdev->dev;
> > > > > > +       struct regmap *clk_regmap;
> > > > > > +       struct clk_hw *hw;
> > > > > > +       unsigned int i;
> > > > > > +
> > > > > > +       npcm8xx_clk_data = devm_kzalloc(dev, struct_size(npcm8xx_clk_data, hws,
> > > > > > +                                                        NPCM8XX_NUM_CLOCKS),
> > > > > > +                                       GFP_KERNEL);
> > > > > > +       if (!npcm8xx_clk_data)
> > > > > > +               return -ENOMEM;
> > > > > > +
> > > > > > +       clk_regmap = syscon_node_to_regmap(parent_np);
> > > > > > +       of_node_put(parent_np);
> > > > >
> > > > > Is there another binding update that is going to move this node to be a
> > > > > child of the syscon?
> > > > >
> > > > >                 gcr: system-controller@f0800000 {
> > > > >                         compatible = "nuvoton,npcm845-gcr", "syscon";
> > > > >                         reg = <0x0 0xf0800000 0x0 0x1000>;
> > > > >                 };
> > > > No, sorry but I'm not going to use the GCR node the handle the clock
> > > > and reset modules, the GCR has different memory space.
> > > > the clock driver will have the following device tree
> > >
> > > What does the reset driver use the CGR node for? The driver looks like
> > > it's using it to control USB phy resets.
> > Yes, the USB PHY reset is handled through the GCR registers.
> > >
> > > >                sysctrl: system-controller@f0801000 {
> > > >                         compatible = "syscon", "simple-mfd";
> > > >                         reg = <0x0 0xf0801000 0x0 0x1000>;
> > > >
> > > >                         rstc: reset-controller {
> > > >                                 compatible = "nuvoton,npcm845-reset";
> > > >                                 reg = <0x0 0xf0801000 0x0 0xC4>;
> > >
> > > This isn't a valid reg property for a child node like this.
> > O.K.
> > >
> > > >                                 #reset-cells = <2>;
> > > >                                 nuvoton,sysgcr = <&gcr>;
> > > >                         };
> > > >
> > > >                         clk: clock-controller {
> > > >                                 compatible = "nuvoton,npcm845-clk";
> > > >                                 #clock-cells = <1>;
> > > >                                 clocks = <&refclk>;
> > > >                                 clock-names = "refclk";
> > > >                         };
> > > >                 };
> >
> > Appreciate your guidance!
> >
> > Thanks,
> >
> > Tomer

Stephen Boyd April 11, 2024, 4:51 a.m. UTC | #7

Quoting Tomer Maimon (2024-02-29 13:29:46)
> Hi Stephen,
> 
> Thanks for your reply.
> 
> On Thu, 29 Feb 2024 at 00:48, Stephen Boyd <[e-mail]> wrote:
> >
> > Quoting Tomer Maimon (2024-02-25 10:00:35)
> > > Hi Stephen,
> > >
> > > On Thu, 22 Feb 2024 at 07:58, Stephen Boyd <[e-mail]> wrote:
> > > >
> > > > Quoting Tomer Maimon (2024-01-31 10:26:53)
> > > > > +
> > > > > +static unsigned long npcm8xx_clk_div_get_parent(struct clk_hw *hw,
> > > > > +                                               unsigned long parent_rate)
> > > > > +{
> > > > > +       struct npcm8xx_clk *div = to_npcm8xx_clk(hw);
> > > > > +       unsigned int val;
> > > > > +
> > > > > +       regmap_read(div->clk_regmap, div->offset, &val);
> > > > > +       val = val >> div->shift;
> > > > > +       val &= clk_div_mask(div->width);
> > > > > +
> > > > > +       return divider_recalc_rate(hw, parent_rate, val, NULL, div->flags,
> > > > > +                                  div->width);
> > > > > +}
> > > > > +
> > > > > +static const struct clk_ops npcm8xx_clk_div_ops = {
> > > > > +       .recalc_rate = npcm8xx_clk_div_get_parent,
> > > > > +};
> > > > > +
> > > > > +static int npcm8xx_clk_probe(struct platform_device *pdev)
> > > > > +{
> > > > > +       struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
> > > >
> > > > The parent of this device is not a syscon.
> > > Once I have registered the map that handles both reset and the clock
> > > in general is syscon, this is why we will modify the DTS so the clock
> > > and the reset will be under syscon father node
> > >                 sysctrl: system-controller@f0801000 {
> > >                         compatible = "syscon", "simple-mfd";
> > >                         reg = <0x0 0xf0801000 0x0 0x1000>;
> > >
> > >                         rstc: reset-controller {
> > >                                 compatible = "nuvoton,npcm845-reset";
> > >                                 reg = <0x0 0xf0801000 0x0 0xC4>;
> > >                                 #reset-cells = <2>;
> > >                                 nuvoton,sysgcr = <&gcr>;
> > >                         };
> > >
> > >                         clk: clock-controller {
> > >                                 compatible = "nuvoton,npcm845-clk";
> > >                                 #clock-cells = <1>;
> > >                                 clocks = <&refclk>;
> > >                                 clock-names = "refclk";
> > >                         };
> > >                 };
> > > You can see other drivers that using the same method like
> > > https://elixir.bootlin.com/linux/v6.8-rc5/source/Documentation/devicetree/bindings/clock/socionext,uniphier-clock.yaml
> >
> > You will need a similar file like
> > Documentation/devicetree/bindings/soc/socionext/socionext,uniphier-perictrl.yaml
> > then to describe the child nodes.
> I can do it.
> >
> > Socionext may not be the best example to follow. I generally try to
> > avoid syscon and simply put #reset-cells and #clock-cells in the node
> If I remove syscon I can't use syscon_node_to_regmap function, What
> should I use If I remove syscon? auxiliary bus? something else?

You should use auxiliary bus. You can make a regmap in the parent
driver and pass that to the child auxiliary devices still.

> > for the device. You can use the auxiliary bus to register drivers for
> > clk and reset and put them into the resepective driver directories.
> I little bit confused, what is an auxiliary bus to register drivers,
> can you provide me an example?

$ git grep -l auxiliary_ -- drivers/clk/
drivers/clk/microchip/clk-mpfs.c
drivers/clk/starfive/clk-starfive-jh7110-sys.c

You can decide to make either the clk or the reset driver the "main"
driver that registers the other auxiliary devices. Either way the DT
binding has a single node instead of one per logical driver in the
kernel.

> > Avoid syscon means random drivers can't reach into the device with a
> > regmap handle and read/write registers that they're not supposed to.
> Indeed, but the drivers could use the reset and clock memory map only
> if the module is also a child node.
> 
> Please let me know what is your preferred way to handle it:
> 1. stick with syscon and upstream-defined documentation for the rst clk syscon.
> 2. avoid syscon and use an auxiliary bus, appreciate if you could give
> me an example of how it should be done.
> 3. Avoid sycon and handle it differently.

I prefer 2

Patch

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 50af5fc7f570..a324678f3e12 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -334,6 +334,14 @@  config COMMON_CLK_LOCHNAGAR
 	  This driver supports the clocking features of the Cirrus Logic
 	  Lochnagar audio development board.
 
+config COMMON_CLK_NPCM8XX
+	tristate "Clock driver for the NPCM8XX SoC Family"
+	depends on ARCH_NPCM || COMPILE_TEST
+	help
+	  This driver supports the clocks on the Nuvoton BMC NPCM8XX SoC Family,
+	  all the clocks are initialized by the bootloader, so this driver
+	  allows only reading of current settings directly from the hardware.
+
 config COMMON_CLK_LOONGSON2
 	bool "Clock driver for Loongson-2 SoC"
 	depends on LOONGARCH || COMPILE_TEST
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 14fa8d4ecc1f..584fc82061f8 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -52,6 +52,7 @@  obj-$(CONFIG_ARCH_MILBEAUT_M10V)	+= clk-milbeaut.o
 obj-$(CONFIG_ARCH_MOXART)		+= clk-moxart.o
 obj-$(CONFIG_ARCH_NOMADIK)		+= clk-nomadik.o
 obj-$(CONFIG_ARCH_NPCM7XX)	    	+= clk-npcm7xx.o
+obj-$(CONFIG_COMMON_CLK_NPCM8XX)	+= clk-npcm8xx.o
 obj-$(CONFIG_ARCH_NSPIRE)		+= clk-nspire.o
 obj-$(CONFIG_COMMON_CLK_PALMAS)		+= clk-palmas.o
 obj-$(CONFIG_CLK_LS1028A_PLLDIG)	+= clk-plldig.o
diff --git a/drivers/clk/clk-npcm8xx.c b/drivers/clk/clk-npcm8xx.c
new file mode 100644
index 000000000000..eacb579d30af
--- /dev/null
+++ b/drivers/clk/clk-npcm8xx.c
@@ -0,0 +1,509 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Nuvoton NPCM8xx Clock Generator
+ * All the clocks are initialized by the bootloader, so this driver allows only
+ * reading of current settings directly from the hardware.
+ *
+ * Copyright (C) 2020 Nuvoton Technologies
+ * Author: Tomer Maimon <[e-mail]>
+ */
+
+#define pr_fmt(fmt) "npcm8xx_clk: " fmt
+
+#include <linux/bitfield.h>
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
+
+#include <dt-bindings/clock/nuvoton,npcm845-clk.h>
+
+/* npcm8xx clock registers*/
+#define NPCM8XX_CLKSEL		0x04
+#define NPCM8XX_CLKDIV1		0x08
+#define NPCM8XX_CLKDIV2		0x2C
+#define NPCM8XX_CLKDIV3		0x58
+#define NPCM8XX_CLKDIV4		0x7C
+#define NPCM8XX_PLLCON0		0x0C
+#define NPCM8XX_PLLCON1		0x10
+#define NPCM8XX_PLLCON2		0x54
+#define NPCM8XX_PLLCONG		0x60
+#define NPCM8XX_THRTL_CNT	0xC0
+
+#define PLLCON_LOKI	BIT(31)
+#define PLLCON_LOKS	BIT(30)
+#define PLLCON_FBDV	GENMASK(27, 16)
+#define PLLCON_OTDV2	GENMASK(15, 13)
+#define PLLCON_PWDEN	BIT(12)
+#define PLLCON_OTDV1	GENMASK(10, 8)
+#define PLLCON_INDV	GENMASK(5, 0)
+
+struct npcm8xx_clk {
+	struct regmap	*clk_regmap;
+	unsigned int	offset;
+	const char	*name;
+	const u32	*table;
+	u32		mask;
+	u8		shift;
+	unsigned long	width;
+	unsigned long	flags;
+	struct clk_hw	hw;
+};
+
+#define to_npcm8xx_clk(_hw) container_of(_hw, struct npcm8xx_clk, hw)
+
+struct npcm8xx_clk_pll_data {
+	const char *name;
+	struct clk_parent_data parent;
+	unsigned int reg;
+	unsigned long flags;
+	struct clk_hw hw;
+};
+
+struct npcm8xx_clk_div_data {
+	u32 reg;
+	u8 shift;
+	u8 width;
+	const char *name;
+	const struct clk_hw *parent_hw;
+	unsigned long clk_divider_flags;
+	unsigned long flags;
+	int onecell_idx;
+	struct clk_hw hw;
+};
+
+struct npcm8xx_clk_mux_data {
+	u8 shift;
+	u32 mask;
+	const u32 *table;
+	const char *name;
+	const struct clk_parent_data *parent_data;
+	u8 num_parents;
+	unsigned long flags;
+	struct clk_hw hw;
+};
+
+/* external clock definition */
+#define NPCM8XX_CLK_S_REFCLK	"refclk"
+
+/* pll definition */
+#define NPCM8XX_CLK_S_PLL0	"pll0"
+#define NPCM8XX_CLK_S_PLL1	"pll1"
+#define NPCM8XX_CLK_S_PLL2	"pll2"
+#define NPCM8XX_CLK_S_PLL_GFX	"pll_gfx"
+
+/* early divider definition */
+#define NPCM8XX_CLK_S_PLL2_DIV2		"pll2_div2"
+#define NPCM8XX_CLK_S_PLL_GFX_DIV2	"pll_gfx_div2"
+#define NPCM8XX_CLK_S_PLL1_DIV2		"pll1_div2"
+
+/* mux definition */
+#define NPCM8XX_CLK_S_CPU_MUX     "cpu_mux"
+
+/* div definition */
+#define NPCM8XX_CLK_S_TH          "th"
+#define NPCM8XX_CLK_S_AXI         "axi"
+
+static struct clk_hw hw_pll1_div2, hw_pll2_div2, hw_gfx_div2, hw_pre_clk;
+static struct npcm8xx_clk_pll_data npcm8xx_pll_clks[] = {
+	{ NPCM8XX_CLK_S_PLL0, { .index = 0 }, NPCM8XX_PLLCON0, 0 },
+	{ NPCM8XX_CLK_S_PLL1, { .index = 0 }, NPCM8XX_PLLCON1, 0 },
+	{ NPCM8XX_CLK_S_PLL2, { .index = 0 }, NPCM8XX_PLLCON2, 0 },
+	{ NPCM8XX_CLK_S_PLL_GFX, { .index = 0 }, NPCM8XX_PLLCONG, 0 },
+};
+
+static const u32 cpuck_mux_table[] = { 0, 1, 2, 7 };
+static const struct clk_parent_data cpuck_mux_parents[] = {
+	{ .hw = &npcm8xx_pll_clks[0].hw },
+	{ .hw = &npcm8xx_pll_clks[1].hw },
+	{ .index = 0 },
+	{ .hw = &npcm8xx_pll_clks[2].hw }
+};
+
+static const u32 pixcksel_mux_table[] = { 0, 2 };
+static const struct clk_parent_data pixcksel_mux_parents[] = {
+	{ .hw = &npcm8xx_pll_clks[3].hw },
+	{ .index = 0 }
+};
+
+static const u32 default_mux_table[] = { 0, 1, 2, 3 };
+static const struct clk_parent_data default_mux_parents[] = {
+	{ .hw = &npcm8xx_pll_clks[0].hw },
+	{ .hw = &npcm8xx_pll_clks[1].hw },
+	{ .index = 0 },
+	{ .hw = &hw_pll2_div2 }
+};
+
+static const u32 sucksel_mux_table[] = { 2, 3 };
+static const struct clk_parent_data sucksel_mux_parents[] = {
+	{ .index = 0 },
+	{ .hw = &hw_pll2_div2 }
+};
+
+static const u32 mccksel_mux_table[] = { 0, 2 };
+static const struct clk_parent_data mccksel_mux_parents[] = {
+	{ .hw = &hw_pll1_div2 },
+	{ .index = 0 }
+};
+
+static const u32 clkoutsel_mux_table[] = { 0, 1, 2, 3, 4 };
+static const struct clk_parent_data clkoutsel_mux_parents[] = {
+	{ .hw = &npcm8xx_pll_clks[0].hw },
+	{ .hw = &npcm8xx_pll_clks[1].hw },
+	{ .index = 0 },
+	{ .hw = &hw_gfx_div2 },
+	{ .hw = &hw_pll2_div2 }
+};
+
+static const u32 gfxmsel_mux_table[] = { 2, 3 };
+static const struct clk_parent_data gfxmsel_mux_parents[] = {
+	{ .index = 0 },
+	{ .hw = &npcm8xx_pll_clks[2].hw }
+};
+
+static const u32 dvcssel_mux_table[] = { 2, 3 };
+static const struct clk_parent_data dvcssel_mux_parents[] = {
+	{ .index = 0 },
+	{ .hw = &npcm8xx_pll_clks[2].hw }
+};
+
+static const u32 default3_mux_table[] = { 0, 1, 2 };
+static const struct clk_parent_data default3_mux_parents[] = {
+	{ .hw = &npcm8xx_pll_clks[0].hw },
+	{ .hw = &npcm8xx_pll_clks[1].hw },
+	{ .index = 0 }
+};
+
+static struct npcm8xx_clk_mux_data npcm8xx_muxes[] = {
+	{ 0, 7, cpuck_mux_table, NPCM8XX_CLK_S_CPU_MUX, cpuck_mux_parents,
+		ARRAY_SIZE(cpuck_mux_parents), CLK_IS_CRITICAL },
+	{ 4, 3, pixcksel_mux_table, "gfx_pixel_mux", pixcksel_mux_parents,
+		ARRAY_SIZE(pixcksel_mux_parents), 0 },
+	{ 6, 3, default_mux_table, "sd_mux", default_mux_parents,
+		ARRAY_SIZE(default_mux_parents), 0 },
+	{ 8, 3, default_mux_table, "uart_mux", default_mux_parents,
+		ARRAY_SIZE(default_mux_parents), 0 },
+	{ 10, 3, sucksel_mux_table, "serial_usb_mux", sucksel_mux_parents,
+		ARRAY_SIZE(sucksel_mux_parents), 0 },
+	{ 12, 3, mccksel_mux_table, "mc_mux", mccksel_mux_parents,
+		ARRAY_SIZE(mccksel_mux_parents), 0 },
+	{ 14, 3, default_mux_table, "adc_mux", default_mux_parents,
+		ARRAY_SIZE(default_mux_parents), 0 },
+	{ 16, 3, default_mux_table, "gfx_mux", default_mux_parents,
+		ARRAY_SIZE(default_mux_parents), 0 },
+	{ 18, 7, clkoutsel_mux_table, "clkout_mux", clkoutsel_mux_parents,
+		ARRAY_SIZE(clkoutsel_mux_parents), 0 },
+	{ 21, 3, gfxmsel_mux_table, "gfxm_mux", gfxmsel_mux_parents,
+		ARRAY_SIZE(gfxmsel_mux_parents), 0 },
+	{ 23, 3, dvcssel_mux_table, "dvc_mux", dvcssel_mux_parents,
+		ARRAY_SIZE(dvcssel_mux_parents), 0 },
+	{ 25, 3, default3_mux_table, "rg_mux", default3_mux_parents,
+		ARRAY_SIZE(default3_mux_parents), 0 },
+	{ 27, 3, default3_mux_table, "rcp_mux", default3_mux_parents,
+		ARRAY_SIZE(default3_mux_parents), 0 },
+};
+
+static struct npcm8xx_clk_div_data npcm8xx_pre_divs[] = {
+	{ NPCM8XX_CLKDIV1, 21, 5, "pre_adc", &npcm8xx_muxes[6].hw, CLK_DIVIDER_READ_ONLY, 0, -1 },
+	{ NPCM8XX_CLKDIV1, 26, 2, "ahb", &hw_pre_clk, CLK_DIVIDER_READ_ONLY, CLK_IS_CRITICAL, NPCM8XX_CLK_AHB },
+};
+
+/* configurable dividers: */
+static struct npcm8xx_clk_div_data npcm8xx_divs[] = {
+	{ NPCM8XX_CLKDIV1, 28, 3, "adc", &npcm8xx_pre_divs[0].hw, CLK_DIVIDER_READ_ONLY | CLK_DIVIDER_POWER_OF_TWO, 0, NPCM8XX_CLK_ADC },
+	{ NPCM8XX_CLKDIV1, 16, 5, "uart", &npcm8xx_muxes[3].hw, 0, 0, NPCM8XX_CLK_UART },
+	{ NPCM8XX_CLKDIV1, 11, 5, "mmc", &npcm8xx_muxes[2].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_MMC },
+	{ NPCM8XX_CLKDIV1, 6, 5, "spi3", &npcm8xx_pre_divs[1].hw, 0, 0, NPCM8XX_CLK_SPI3 },
+	{ NPCM8XX_CLKDIV1, 2, 4, "pci", &npcm8xx_muxes[7].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_PCI },
+
+	{ NPCM8XX_CLKDIV2, 30, 2, "apb4", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY | CLK_DIVIDER_POWER_OF_TWO, 0, NPCM8XX_CLK_APB4 },
+	{ NPCM8XX_CLKDIV2, 28, 2, "apb3", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY | CLK_DIVIDER_POWER_OF_TWO, 0, NPCM8XX_CLK_APB3 },
+	{ NPCM8XX_CLKDIV2, 26, 2, "apb2", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY | CLK_DIVIDER_POWER_OF_TWO, 0, NPCM8XX_CLK_APB2 },
+	{ NPCM8XX_CLKDIV2, 24, 2, "apb1", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY | CLK_DIVIDER_POWER_OF_TWO, 0, NPCM8XX_CLK_APB1 },
+	{ NPCM8XX_CLKDIV2, 22, 2, "apb5", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY | CLK_DIVIDER_POWER_OF_TWO, 0, NPCM8XX_CLK_APB5 },
+	{ NPCM8XX_CLKDIV2, 16, 5, "clkout", &npcm8xx_muxes[8].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_CLKOUT },
+	{ NPCM8XX_CLKDIV2, 13, 3, "gfx", &npcm8xx_muxes[7].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_GFX },
+	{ NPCM8XX_CLKDIV2, 8, 5, "usb_bridge", &npcm8xx_muxes[4].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_SU },
+	{ NPCM8XX_CLKDIV2, 4, 4, "usb_host", &npcm8xx_muxes[4].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_SU48 },
+	{ NPCM8XX_CLKDIV2, 0, 4, "sdhc", &npcm8xx_muxes[2].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_SDHC },
+
+	{ NPCM8XX_CLKDIV3, 16, 8, "spi1", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_SPI1 },
+	{ NPCM8XX_CLKDIV3, 11, 5, "uart2", &npcm8xx_muxes[3].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_UART2 },
+	{ NPCM8XX_CLKDIV3, 6, 5, "spi0", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_SPI0 },
+	{ NPCM8XX_CLKDIV3, 1, 5, "spix", &npcm8xx_pre_divs[1].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_SPIX },
+
+	{ NPCM8XX_CLKDIV4, 28, 4, "rg", &npcm8xx_muxes[11].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_RG },
+	{ NPCM8XX_CLKDIV4, 12, 4, "rcp", &npcm8xx_muxes[12].hw, CLK_DIVIDER_READ_ONLY, 0, NPCM8XX_CLK_RCP },
+
+	{ NPCM8XX_THRTL_CNT, 0, 2, NPCM8XX_CLK_S_TH, &npcm8xx_muxes[0].hw, CLK_DIVIDER_READ_ONLY | CLK_DIVIDER_POWER_OF_TWO, 0, NPCM8XX_CLK_TH },
+};
+
+static struct clk_hw *
+npcm8xx_clk_register(struct device *dev, const char *name,
+		     struct regmap *clk_regmap, unsigned int offset,
+		     unsigned long flags, const struct clk_ops *npcm8xx_clk_ops,
+		     const struct clk_parent_data *parent_data,
+		     const struct clk_hw *parent_hw, u8 num_parents,
+		     u8 shift, u32 mask, unsigned long width,
+		     const u32 *table, unsigned long clk_flags)
+{
+	struct npcm8xx_clk *clk;
+	struct clk_init_data init = {};
+	int ret;
+
+	clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
+	if (!clk)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+	init.ops = npcm8xx_clk_ops;
+	init.parent_data = parent_data;
+	init.parent_hws = parent_hw ? &parent_hw : NULL;
+	init.num_parents = num_parents;
+	init.flags = flags;
+
+	clk->clk_regmap = clk_regmap;
+	clk->hw.init = &init;
+	clk->offset = offset;
+	clk->shift = shift;
+	clk->mask = mask;
+	clk->width = width;
+	clk->table = table;
+	clk->flags = clk_flags;
+
+	ret = devm_clk_hw_register(dev, &clk->hw);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return &clk->hw;
+}
+
+static unsigned long npcm8xx_clk_pll_recalc_rate(struct clk_hw *hw,
+						 unsigned long parent_rate)
+{
+	struct npcm8xx_clk *pll = to_npcm8xx_clk(hw);
+	unsigned long fbdv, indv, otdv1, otdv2;
+	unsigned int val;
+	u64 ret;
+
+	if (parent_rate == 0) {
+		pr_debug("%s: parent rate is zero\n", __func__);
+		return 0;
+	}
+
+	regmap_read(pll->clk_regmap, pll->offset, &val);
+
+	indv = FIELD_GET(PLLCON_INDV, val);
+	fbdv = FIELD_GET(PLLCON_FBDV, val);
+	otdv1 = FIELD_GET(PLLCON_OTDV1, val);
+	otdv2 = FIELD_GET(PLLCON_OTDV2, val);
+
+	ret = (u64)parent_rate * fbdv;
+	do_div(ret, indv * otdv1 * otdv2);
+
+	return ret;
+}
+
+static const struct clk_ops npcm8xx_clk_pll_ops = {
+	.recalc_rate = npcm8xx_clk_pll_recalc_rate,
+};
+
+static u8 npcm8xx_clk_mux_get_parent(struct clk_hw *hw)
+{
+	struct npcm8xx_clk *mux = to_npcm8xx_clk(hw);
+	u32 val;
+
+	regmap_read(mux->clk_regmap, mux->offset, &val);
+	val = val >> mux->shift;
+	val &= mux->mask;
+
+	return clk_mux_val_to_index(hw, mux->table, mux->flags, val);
+}
+
+static const struct clk_ops npcm8xx_clk_mux_ops = {
+	.get_parent = npcm8xx_clk_mux_get_parent,
+};
+
+static unsigned long npcm8xx_clk_div_get_parent(struct clk_hw *hw,
+						unsigned long parent_rate)
+{
+	struct npcm8xx_clk *div = to_npcm8xx_clk(hw);
+	unsigned int val;
+
+	regmap_read(div->clk_regmap, div->offset, &val);
+	val = val >> div->shift;
+	val &= clk_div_mask(div->width);
+
+	return divider_recalc_rate(hw, parent_rate, val, NULL, div->flags,
+				   div->width);
+}
+
+static const struct clk_ops npcm8xx_clk_div_ops = {
+	.recalc_rate = npcm8xx_clk_div_get_parent,
+};
+
+static int npcm8xx_clk_probe(struct platform_device *pdev)
+{
+	struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
+	struct clk_hw_onecell_data *npcm8xx_clk_data;
+	struct device *dev = &pdev->dev;
+	struct regmap *clk_regmap;
+	struct clk_hw *hw;
+	unsigned int i;
+
+	npcm8xx_clk_data = devm_kzalloc(dev, struct_size(npcm8xx_clk_data, hws,
+							 NPCM8XX_NUM_CLOCKS),
+					GFP_KERNEL);
+	if (!npcm8xx_clk_data)
+		return -ENOMEM;
+
+	clk_regmap = syscon_node_to_regmap(parent_np);
+	of_node_put(parent_np);
+	if (IS_ERR(clk_regmap))
+		return dev_err_probe(dev, PTR_ERR(clk_regmap), "Can't register clock map\n");
+
+	npcm8xx_clk_data->num = NPCM8XX_NUM_CLOCKS;
+
+	for (i = 0; i < NPCM8XX_NUM_CLOCKS; i++)
+		npcm8xx_clk_data->hws[i] = ERR_PTR(-EPROBE_DEFER);
+
+	/* Register plls */
+	for (i = 0; i < ARRAY_SIZE(npcm8xx_pll_clks); i++) {
+		struct npcm8xx_clk_pll_data *pll_clk = &npcm8xx_pll_clks[i];
+
+		hw = npcm8xx_clk_register(dev, pll_clk->name, clk_regmap,
+					  pll_clk->reg, pll_clk->flags,
+					  &npcm8xx_clk_pll_ops, &pll_clk->parent,
+					  NULL, 1, 0, 0, 0, NULL, 0);
+		if (IS_ERR(hw))
+			return dev_err_probe(dev, PTR_ERR(hw), "Can't register pll\n");
+		pll_clk->hw = *hw;
+	}
+
+	/* Register fixed dividers */
+	hw = devm_clk_hw_register_fixed_factor(dev, NPCM8XX_CLK_S_PLL1_DIV2,
+					       NPCM8XX_CLK_S_PLL1, 0, 1, 2);
+	if (IS_ERR(hw))
+		return dev_err_probe(dev, PTR_ERR(hw), "Can't register fixed div\n");
+	hw_pll1_div2 = *hw;
+
+	hw = devm_clk_hw_register_fixed_factor(dev, NPCM8XX_CLK_S_PLL2_DIV2,
+					       NPCM8XX_CLK_S_PLL2, 0, 1, 2);
+	if (IS_ERR(hw))
+		return dev_err_probe(dev, PTR_ERR(hw), "Can't register pll2 div2\n");
+	hw_pll2_div2 = *hw;
+
+	hw = devm_clk_hw_register_fixed_factor(dev, NPCM8XX_CLK_S_PLL_GFX_DIV2,
+					       NPCM8XX_CLK_S_PLL_GFX, 0, 1, 2);
+	if (IS_ERR(hw))
+		return dev_err_probe(dev, PTR_ERR(hw), "Can't register gfx div2\n");
+	hw_gfx_div2 = *hw;
+
+	/* Register muxes */
+	for (i = 0; i < ARRAY_SIZE(npcm8xx_muxes); i++) {
+		struct npcm8xx_clk_mux_data *mux_data = &npcm8xx_muxes[i];
+
+		hw = npcm8xx_clk_register(dev, mux_data->name, clk_regmap,
+					  NPCM8XX_CLKSEL, mux_data->flags,
+					  &npcm8xx_clk_mux_ops,
+					  mux_data->parent_data, NULL,
+					  mux_data->num_parents,
+					  mux_data->shift, mux_data->mask, 0,
+					  mux_data->table, 0);
+		if (IS_ERR(hw))
+			return dev_err_probe(dev, PTR_ERR(hw), "Can't register mux\n");
+		mux_data->hw = *hw;
+	}
+
+	hw = devm_clk_hw_register_fixed_factor(dev, "pre_clk",
+					       NPCM8XX_CLK_S_CPU_MUX, 0, 1, 2);
+	if (IS_ERR(hw))
+		return dev_err_probe(dev, PTR_ERR(hw), "Can't register pre clk div2\n");
+	hw_pre_clk = *hw;
+
+	hw = devm_clk_hw_register_fixed_factor(dev, NPCM8XX_CLK_S_AXI,
+					       NPCM8XX_CLK_S_TH, 0, 1, 2);
+	if (IS_ERR(hw))
+		return dev_err_probe(dev, PTR_ERR(hw), "Can't register axi div2\n");
+	npcm8xx_clk_data->hws[NPCM8XX_CLK_AXI] = hw;
+
+	hw = devm_clk_hw_register_fixed_factor(dev, "atb", NPCM8XX_CLK_S_AXI, 0,
+					       1, 2);
+	if (IS_ERR(hw))
+		return dev_err_probe(dev, PTR_ERR(hw), "Can't register atb div2\n");
+	npcm8xx_clk_data->hws[NPCM8XX_CLK_ATB] = hw;
+
+	/* Register clock pre dividers specified in npcm8xx_divs */
+	for (i = 0; i < ARRAY_SIZE(npcm8xx_pre_divs); i++) {
+		struct npcm8xx_clk_div_data *div_data = &npcm8xx_pre_divs[i];
+
+		hw = npcm8xx_clk_register(dev, div_data->name, clk_regmap,
+					  div_data->reg, div_data->flags,
+					  &npcm8xx_clk_div_ops, NULL,
+					  div_data->parent_hw, 1,
+					  div_data->shift, 0, div_data->width,
+					  NULL, div_data->clk_divider_flags);
+		if (IS_ERR(hw))
+			return dev_err_probe(dev, PTR_ERR(hw), "Can't register pre div table\n");
+		div_data->hw = *hw;
+
+		if (div_data->onecell_idx >= 0)
+			npcm8xx_clk_data->hws[div_data->onecell_idx] = hw;
+	}
+
+	/* Register clock dividers specified in npcm8xx_divs */
+	for (i = 0; i < ARRAY_SIZE(npcm8xx_divs); i++) {
+		struct npcm8xx_clk_div_data *div_data = &npcm8xx_divs[i];
+
+		hw = npcm8xx_clk_register(dev, div_data->name, clk_regmap,
+					  div_data->reg, div_data->flags,
+					  &npcm8xx_clk_div_ops, NULL,
+					  div_data->parent_hw, 1,
+					  div_data->shift, 0, div_data->width,
+					  NULL, div_data->clk_divider_flags);
+		if (IS_ERR(hw))
+			return dev_err_probe(dev, PTR_ERR(hw), "Can't register div table\n");
+
+		if (div_data->onecell_idx >= 0)
+			npcm8xx_clk_data->hws[div_data->onecell_idx] = hw;
+	}
+
+	return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
+					   npcm8xx_clk_data);
+}
+
+static const struct of_device_id npcm8xx_clk_dt_ids[] = {
+	{ .compatible = "nuvoton,npcm845-clk", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, npcm8xx_clk_dt_ids);
+
+static struct platform_driver npcm8xx_clk_driver = {
+	.probe  = npcm8xx_clk_probe,
+	.driver = {
+		.name = "npcm8xx_clk",
+		.of_match_table = npcm8xx_clk_dt_ids,
+	},
+};
+
+static int __init npcm8xx_clk_driver_init(void)
+{
+	return platform_driver_register(&npcm8xx_clk_driver);
+}
+arch_initcall(npcm8xx_clk_driver_init);
+
+static void __exit npcm8xx_clk_exit(void)
+{
+	platform_driver_unregister(&npcm8xx_clk_driver);
+}
+module_exit(npcm8xx_clk_exit);
+
+MODULE_DESCRIPTION("Clock driver for Nuvoton NPCM8XX BMC SoC");
+MODULE_AUTHOR("Tomer Maimon <[e-mail]>");
+MODULE_LICENSE("GPL v2");
+