Re: [PATCH v3 4/5] clk: microchip: add PolarFire SoC fabric clock support

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On 24.08.2022 12:33, Conor Dooley wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> Add a driver to support the PLLs in PolarFire SoC's Clock Conditioning
> Circuitry, an instance of which is located in each ordinal corner of
> the FPGA. Only get_rate() is supported as these clocks are intended to
> be statically configured by the FPGA design. Currently, the DLLs are
> not supported by this driver. For more information on the hardware, see
> "PolarFire SoC FPGA Clocking Resources" in the link below.
> 
> Link: https://onlinedocs.microchip.com/pr/GUID-8F0CC4C0-0317-4262-89CA-CE7773ED1931-en-US-1/index.html
> Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
> ---
>  drivers/clk/microchip/Makefile       |   1 +
>  drivers/clk/microchip/clk-mpfs-ccc.c | 293 +++++++++++++++++++++++++++
>  2 files changed, 294 insertions(+)
>  create mode 100644 drivers/clk/microchip/clk-mpfs-ccc.c
> 
> diff --git a/drivers/clk/microchip/Makefile b/drivers/clk/microchip/Makefile
> index 5fa6dcf30a9a..13250e04e46c 100644
> --- a/drivers/clk/microchip/Makefile
> +++ b/drivers/clk/microchip/Makefile
> @@ -2,3 +2,4 @@
>  obj-$(CONFIG_COMMON_CLK_PIC32) += clk-core.o
>  obj-$(CONFIG_PIC32MZDA) += clk-pic32mzda.o
>  obj-$(CONFIG_MCHP_CLK_MPFS) += clk-mpfs.o
> +obj-$(CONFIG_MCHP_CLK_MPFS) += clk-mpfs-ccc.o
> diff --git a/drivers/clk/microchip/clk-mpfs-ccc.c b/drivers/clk/microchip/clk-mpfs-ccc.c
> new file mode 100644
> index 000000000000..2a34034c2c6e
> --- /dev/null
> +++ b/drivers/clk/microchip/clk-mpfs-ccc.c
> @@ -0,0 +1,293 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Author: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
> + *
> + * Copyright (C) 2022 Microchip Technology Inc. and its subsidiaries
> + */
> +#include "asm-generic/errno-base.h"
> +#include <linux/clk-provider.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <dt-bindings/clock/microchip,mpfs-clock.h>
> +
> +/* address offset of control registers */
> +#define MPFS_CCC_PLL_CR                        0x04u
> +#define MPFS_CCC_REF_CR                        0x08u
> +#define MPFS_CCC_SSCG_2_CR             0x2Cu
> +#define MPFS_CCC_POSTDIV01_CR          0x10u
> +#define MPFS_CCC_POSTDIV23_CR          0x14u
> +
> +#define MPFS_CCC_FBDIV_SHIFT           0x00u
> +#define MPFS_CCC_FBDIV_WIDTH           0x0Cu
> +#define MPFS_CCC_POSTDIV0_SHIFT                0x08u
> +#define MPFS_CCC_POSTDIV1_SHIFT                0x18u
> +#define MPFS_CCC_POSTDIV2_SHIFT                MPFS_CCC_POSTDIV0_SHIFT
> +#define MPFS_CCC_POSTDIV3_SHIFT                MPFS_CCC_POSTDIV1_SHIFT
> +#define MPFS_CCC_POSTDIV_WIDTH         0x06u
> +#define MPFS_CCC_REFCLK_SEL            BIT(6)
> +#define MPFS_CCC_REFDIV_SHIFT          0x08u
> +#define MPFS_CCC_REFDIV_WIDTH          0x06u
> +
> +#define MPFS_CCC_FIXED_DIV             4
> +#define MPFS_CCC_OUTPUTS_PER_PLL       4
> +#define MPFS_CCC_REFS_PER_PLL          2
> +
> +struct mpfs_ccc_data {
> +       void __iomem **pll_base;
> +       struct device *dev;
> +       struct clk_hw_onecell_data hw_data;
> +};
> +
> +struct mpfs_ccc_pll_hw_clock {
> +       void __iomem *base;
> +       const char *name;
> +       const struct clk_parent_data *parents;
> +       unsigned int id;
> +       u32 reg_offset;
> +       u32 shift;
> +       u32 width;
> +       u32 flags;
> +       struct clk_hw hw;
> +       struct clk_init_data init;
> +};
> +
> +#define to_mpfs_ccc_clk(_hw) container_of(_hw, struct mpfs_ccc_pll_hw_clock, hw)
> +
> +/*
> + * mpfs_ccc_lock prevents anything else from writing to a fabric ccc
> + * while a software locked register is being written.
> + */
> +static DEFINE_SPINLOCK(mpfs_ccc_lock);
> +
> +static const struct clk_parent_data mpfs_ccc_pll0_refs[] = {
> +       { .fw_name = "pll0_ref0" },
> +       { .fw_name = "pll0_ref1" },
> +};
> +
> +static const struct clk_parent_data mpfs_ccc_pll1_refs[] = {
> +       { .fw_name = "pll1_ref0" },
> +       { .fw_name = "pll1_ref1" },
> +};
> +
> +static unsigned long mpfs_ccc_pll_recalc_rate(struct clk_hw *hw, unsigned long prate)
> +{
> +       struct mpfs_ccc_pll_hw_clock *ccc_hw = to_mpfs_ccc_clk(hw);
> +       void __iomem *mult_addr = ccc_hw->base + ccc_hw->reg_offset;
> +       void __iomem *ref_div_addr = ccc_hw->base + MPFS_CCC_REF_CR;
> +       u32 mult, ref_div;
> +
> +       mult = readl_relaxed(mult_addr) >> MPFS_CCC_FBDIV_SHIFT;
> +       mult &= clk_div_mask(MPFS_CCC_FBDIV_WIDTH);
> +       ref_div = readl_relaxed(ref_div_addr) >> MPFS_CCC_REFDIV_SHIFT;
> +       ref_div &= clk_div_mask(MPFS_CCC_REFDIV_WIDTH);
> +
> +       return prate * mult / (ref_div * MPFS_CCC_FIXED_DIV);
> +}
> +
> +static u8 mpfs_ccc_pll_get_parent(struct clk_hw *hw)
> +{
> +       struct mpfs_ccc_pll_hw_clock *ccc_hw = to_mpfs_ccc_clk(hw);
> +       void __iomem *pll_cr_addr = ccc_hw->base + MPFS_CCC_PLL_CR;
> +
> +       return !!(readl_relaxed(pll_cr_addr) & MPFS_CCC_REFCLK_SEL);
> +}
> +
> +static const struct clk_ops mpfs_ccc_pll_ops = {
> +       .recalc_rate = mpfs_ccc_pll_recalc_rate,
> +       .get_parent = mpfs_ccc_pll_get_parent,
> +};
> +
> +#define CLK_CCC_PLL(_id, _parents, _shift, _width, _flags, _offset) {          \
> +       .id = _id,                                                                      \
> +       .shift = _shift,                                                                \
> +       .width = _width,                                                                \
> +       .reg_offset = _offset,                                                          \
> +       .flags = _flags,                                                                \
> +       .parents = _parents,\
> +}
> +
> +static struct mpfs_ccc_pll_hw_clock mpfs_ccc_pll_clks[] = {
> +       CLK_CCC_PLL(CLK_CCC_PLL0, mpfs_ccc_pll0_refs, MPFS_CCC_FBDIV_SHIFT,
> +                   MPFS_CCC_FBDIV_WIDTH, 0, MPFS_CCC_SSCG_2_CR),
> +       CLK_CCC_PLL(CLK_CCC_PLL1, mpfs_ccc_pll1_refs, MPFS_CCC_FBDIV_SHIFT,
> +                   MPFS_CCC_FBDIV_WIDTH, 0, MPFS_CCC_SSCG_2_CR),
> +};
> +
> +struct mpfs_ccc_out_hw_clock {
> +       struct clk_divider divider;
> +       struct clk_init_data init;
> +       unsigned int id;
> +       u32 reg_offset;
> +};
> +
> +#define CLK_CCC_OUT(_id, _shift, _width, _flags, _offset) {    \
> +       .id = _id,                                              \
> +       .divider.shift = _shift,                                \
> +       .divider.width = _width,                                \
> +       .reg_offset = _offset,                                  \
> +       .divider.flags = _flags,                                \
> +       .divider.lock = &mpfs_ccc_lock,                         \
> +}
> +
> +static struct mpfs_ccc_out_hw_clock mpfs_ccc_pll0out_clks[] = {
> +       CLK_CCC_OUT(CLK_CCC_PLL0_OUT0, MPFS_CCC_POSTDIV0_SHIFT, MPFS_CCC_POSTDIV_WIDTH,
> +                   CLK_DIVIDER_ONE_BASED, MPFS_CCC_POSTDIV01_CR),
> +       CLK_CCC_OUT(CLK_CCC_PLL0_OUT1, MPFS_CCC_POSTDIV1_SHIFT, MPFS_CCC_POSTDIV_WIDTH,
> +                   CLK_DIVIDER_ONE_BASED, MPFS_CCC_POSTDIV01_CR),
> +       CLK_CCC_OUT(CLK_CCC_PLL0_OUT2, MPFS_CCC_POSTDIV2_SHIFT, MPFS_CCC_POSTDIV_WIDTH,
> +                   CLK_DIVIDER_ONE_BASED, MPFS_CCC_POSTDIV23_CR),
> +       CLK_CCC_OUT(CLK_CCC_PLL0_OUT3, MPFS_CCC_POSTDIV3_SHIFT, MPFS_CCC_POSTDIV_WIDTH,
> +                   CLK_DIVIDER_ONE_BASED, MPFS_CCC_POSTDIV23_CR),
> +};
> +
> +static struct mpfs_ccc_out_hw_clock mpfs_ccc_pll1out_clks[] = {
> +       CLK_CCC_OUT(CLK_CCC_PLL1_OUT0, MPFS_CCC_POSTDIV0_SHIFT, MPFS_CCC_POSTDIV_WIDTH, 0,
> +                   MPFS_CCC_POSTDIV01_CR),
> +       CLK_CCC_OUT(CLK_CCC_PLL1_OUT1, MPFS_CCC_POSTDIV1_SHIFT, MPFS_CCC_POSTDIV_WIDTH, 0,
> +                   MPFS_CCC_POSTDIV01_CR),
> +       CLK_CCC_OUT(CLK_CCC_PLL1_OUT2, MPFS_CCC_POSTDIV2_SHIFT, MPFS_CCC_POSTDIV_WIDTH, 0,
> +                   MPFS_CCC_POSTDIV23_CR),
> +       CLK_CCC_OUT(CLK_CCC_PLL1_OUT3, MPFS_CCC_POSTDIV3_SHIFT, MPFS_CCC_POSTDIV_WIDTH, 0,
> +                   MPFS_CCC_POSTDIV23_CR),
> +};
> +
> +static struct mpfs_ccc_out_hw_clock *mpfs_ccc_pllout_clks[] = {
> +       mpfs_ccc_pll0out_clks, mpfs_ccc_pll1out_clks
> +};
> +
> +static int mpfs_ccc_register_outputs(struct device *dev, struct mpfs_ccc_out_hw_clock *out_hws,
> +                                    unsigned int num_clks, struct mpfs_ccc_data *data,
> +                                    struct mpfs_ccc_pll_hw_clock *parent)
> +{
> +       int ret;
> +
> +       for (unsigned int i = 0; i < num_clks; i++) {
> +               struct mpfs_ccc_out_hw_clock *out_hw = &out_hws[i];
> +               char *name = devm_kzalloc(dev, 23, GFP_KERNEL);
> +
> +               snprintf(name, 23, "%s_out%u", parent->name, i);
> +               out_hw->divider.hw.init = CLK_HW_INIT_HW(name, &parent->hw, &clk_divider_ops, 0);
> +               out_hw->divider.reg = data->pll_base[i / MPFS_CCC_OUTPUTS_PER_PLL] +
> +                       out_hw->reg_offset;
> +
> +               ret = devm_clk_hw_register(dev, &out_hw->divider.hw);
> +               if (ret)
> +                       return dev_err_probe(dev, ret, "failed to register clock id: %d\n",
> +                                            out_hw->id);
> +
> +               data->hw_data.hws[out_hw->id] = &out_hw->divider.hw;
> +       }
> +
> +       return 0;
> +}
> +
> +#define CLK_HW_INIT_PARENTS_DATA_FIXED_SIZE(_name, _parents, _ops, _flags)     \
> +       (&(struct clk_init_data) {                                              \
> +               .flags          = _flags,                                       \
> +               .name           = _name,                                        \
> +               .parent_data    = _parents,                                     \
> +               .num_parents    = MPFS_CCC_REFS_PER_PLL,                        \
> +               .ops            = _ops,                                         \
> +       })
> +
> +static int mpfs_ccc_register_plls(struct device *dev, struct mpfs_ccc_pll_hw_clock *pll_hws,
> +                                 unsigned int num_clks, struct mpfs_ccc_data *data)
> +{
> +       int ret;
> +
> +       for (unsigned int i = 0; i < num_clks; i++) {
> +               struct mpfs_ccc_pll_hw_clock *pll_hw = &pll_hws[i];
> +               char *name = devm_kzalloc(dev, 18, GFP_KERNEL);
> +
> +               pll_hw->base = data->pll_base[i];
> +               snprintf(name, 18, "ccc%s_pll%u", strchrnul(dev->of_node->full_name, '@'), i);
> +               pll_hw->name = (const char *)name;
> +               pll_hw->hw.init = CLK_HW_INIT_PARENTS_DATA_FIXED_SIZE(pll_hw->name,
> +                                                                     pll_hw->parents,
> +                                                                     &mpfs_ccc_pll_ops, 0);
> +
> +               ret = devm_clk_hw_register(dev, &pll_hw->hw);
> +               if (ret)
> +                       return dev_err_probe(dev, ret, "failed to register ccc id: %d\n",
> +                                            pll_hw->id);
> +
> +               data->hw_data.hws[pll_hw->id] = &pll_hw->hw;
> +
> +               ret = mpfs_ccc_register_outputs(dev, mpfs_ccc_pllout_clks[i],
> +                                               MPFS_CCC_OUTPUTS_PER_PLL, data, pll_hw);
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static int mpfs_ccc_probe(struct platform_device *pdev)
> +{
> +       struct mpfs_ccc_data *clk_data;
> +       void __iomem *pll_base[ARRAY_SIZE(mpfs_ccc_pll_clks)];
> +       unsigned int num_clks;
> +       int ret;
> +
> +       num_clks = ARRAY_SIZE(mpfs_ccc_pll_clks) + ARRAY_SIZE(mpfs_ccc_pll0out_clks)
> +               + ARRAY_SIZE(mpfs_ccc_pll1out_clks);
> +
> +       clk_data = devm_kzalloc(&pdev->dev, struct_size(clk_data, hw_data.hws, num_clks),
> +                               GFP_KERNEL);
> +       if (!clk_data)
> +               return -ENOMEM;
> +
> +       pll_base[0] = devm_platform_ioremap_resource(pdev, 0);
> +       if (IS_ERR(pll_base[0]))
> +               return PTR_ERR(pll_base[0]);
> +
> +       pll_base[1] = devm_platform_ioremap_resource(pdev, 1);
> +       if (IS_ERR(pll_base[1]))
> +               return PTR_ERR(pll_base[1]);
> +
> +       clk_data->pll_base = pll_base;
> +       clk_data->dev = &pdev->dev;
> +
> +       ret = mpfs_ccc_register_plls(clk_data->dev, mpfs_ccc_pll_clks,
> +                                    ARRAY_SIZE(mpfs_ccc_pll_clks), clk_data);
> +       if (ret)
> +               return ret;
> +
> +       ret = devm_of_clk_add_hw_provider(clk_data->dev, of_clk_hw_onecell_get,
> +                                         &clk_data->hw_data);
> +       if (ret)
> +               return ret;

You can skip this or even directly:
	return devm_of_clk_add_hw_provider(...);

> +
> +       return ret;
> +}
> +
> +static const struct of_device_id mpfs_ccc_of_match_table[] = {
> +       { .compatible = "microchip,mpfs-ccc", },
> +       {}
> +};
> +MODULE_DEVICE_TABLE(of, mpfs_ccc_of_match_table);
> +
> +static struct platform_driver mpfs_ccc_driver = {
> +       .probe = mpfs_ccc_probe,
> +       .driver = {
> +               .name = "microchip-mpfs-ccc",
> +               .of_match_table = mpfs_ccc_of_match_table,
> +       },
> +};
> +
> +static int __init clk_ccc_init(void)
> +{
> +       return platform_driver_register(&mpfs_ccc_driver);
> +}
> +core_initcall(clk_ccc_init);
> +
> +static void __exit clk_ccc_exit(void)
> +{
> +       platform_driver_unregister(&mpfs_ccc_driver);
> +}
> +module_exit(clk_ccc_exit);
> +
> +MODULE_DESCRIPTION("Microchip PolarFire SoC Clock Conditioning Circuitry Driver");
> +MODULE_AUTHOR("Conor Dooley <conor.dooley@xxxxxxxxxxxxx>");
> +MODULE_LICENSE("GPL");
> --
> 2.36.1
> 





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