Subject: Re: [PATCH v7 07/14] clk: en7523: Add clock driver for Airoha EN7523 SoC

From: Stephen Boyd <[email-masked]>
Date: Wed, 05 Jan 2022 17:29:54 -0800

Quoting Felix Fietkau (2021-12-17 03:23:37)
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> index c5b3dc97396a..c973ac1a4890 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -192,6 +192,15 @@ config COMMON_CLK_CS2000_CP
>         help
>           If you say yes here you get support for the CS2000 clock multiplier.
>  
> +config COMMON_CLK_EN7523
> +       bool "Clock driver for Airoha EN7523 SoC system clocks"
> +       depends on OF

What depends on OF?

> +       depends on ARCH_AIROHA || COMPILE_TEST
> +       default ARCH_AIROHA
> +       help
> +         This driver provides the fixed clocks and gates present on Airoha
> +         ARM silicon.
> +
>  config COMMON_CLK_FSL_FLEXSPI
>         tristate "Clock driver for FlexSPI on Layerscape SoCs"
>         depends on ARCH_LAYERSCAPE || COMPILE_TEST
> diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
> diff --git a/drivers/clk/clk-en7523.c b/drivers/clk/clk-en7523.c
> new file mode 100644
> index 000000000000..828c35da0968
> --- /dev/null
> +++ b/drivers/clk/clk-en7523.c
> @@ -0,0 +1,350 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +#include <linux/regmap.h>

Is this include used? Please remove unused includes.

> +#include <linux/clk-provider.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <dt-bindings/clock/en7523-clk.h>
> +
> +#define REG_PCI_CONTROL                        0x88
> +#define   REG_PCI_CONTROL_PERSTOUT     BIT(29)
> +#define   REG_PCI_CONTROL_PERSTOUT1    BIT(26)
> +#define   REG_PCI_CONTROL_REFCLK_EN1   BIT(22)
> +#define REG_GSW_CLK_DIV_SEL            0x1b4
> +#define REG_EMI_CLK_DIV_SEL            0x1b8
> +#define REG_BUS_CLK_DIV_SEL            0x1bc
> +#define REG_SPI_CLK_DIV_SEL            0x1c4
> +#define REG_SPI_CLK_FREQ_SEL           0x1c8
> +#define REG_NPU_CLK_DIV_SEL            0x1fc
> +#define REG_CRYPTO_CLKSRC              0x200
> +#define REG_RESET_CONTROL              0x834
> +#define   REG_RESET_CONTROL_PCIEHB     BIT(29)
> +#define   REG_RESET_CONTROL_PCIE1      BIT(27)
> +#define   REG_RESET_CONTROL_PCIE2      BIT(26)
> +
> +struct en_clk_desc {
> +       int id;
> +       const char *name;
> +       u32 base_reg;
> +       u32 base_bits;
> +       u32 base_shift;
> +       union {
> +               const u32 *base_values;
> +               u32 base_value;
> +       };
> +       int n_base_values;
> +
> +       u32 div_reg;
> +       u32 div_bits;
> +       u32 div_shift;
> +       u32 div_val0;
> +       u32 div_step;
> +};
> +
> +struct en_clk_gate {
> +       void __iomem *base;
> +       struct clk_hw hw;
> +};
> +
> +static const u32 gsw_base[] = { 400000000, 500000000 };
> +static const u32 emi_base[] = { 333000000, 400000000 };
> +static const u32 bus_base[] = { 500000000, 540000000 };
> +static const u32 slic_base[] = { 100000000, 3125000 };
> +static const u32 npu_base[] = { 333000000, 400000000, 500000000 };
> +
> +static const struct en_clk_desc en7523_base_clks[] = {
> +       {
> +               .id = EN7523_CLK_GSW,
> +               .name = "gsw",
> +
> +               .base_reg = REG_GSW_CLK_DIV_SEL,
> +               .base_bits = 1,
> +               .base_shift = 8,
> +               .base_values = gsw_base,
> +               .n_base_values = ARRAY_SIZE(gsw_base),
> +
> +               .div_bits = 3,
> +               .div_shift = 0,
> +               .div_step = 1,
> +       }, {
> +               .id = EN7523_CLK_EMI,
> +               .name = "emi",
> +
> +               .base_reg = REG_EMI_CLK_DIV_SEL,
> +               .base_bits = 1,
> +               .base_shift = 8,
> +               .base_values = emi_base,
> +               .n_base_values = ARRAY_SIZE(emi_base),
> +
> +               .div_bits = 3,
> +               .div_shift = 0,
> +               .div_step = 1,
> +       }, {
> +               .id = EN7523_CLK_BUS,
> +               .name = "bus",
> +
> +               .base_reg = REG_BUS_CLK_DIV_SEL,
> +               .base_bits = 1,
> +               .base_shift = 8,
> +               .base_values = bus_base,
> +               .n_base_values = ARRAY_SIZE(bus_base),
> +
> +               .div_bits = 3,
> +               .div_shift = 0,
> +               .div_step = 1,
> +       }, {
> +               .id = EN7523_CLK_SLIC,
> +               .name = "slic",
> +
> +               .base_reg = REG_SPI_CLK_FREQ_SEL,
> +               .base_bits = 1,
> +               .base_shift = 0,
> +               .base_values = slic_base,
> +               .n_base_values = ARRAY_SIZE(slic_base),
> +
> +               .div_reg = REG_SPI_CLK_DIV_SEL,
> +               .div_bits = 5,
> +               .div_shift = 24,
> +               .div_val0 = 20,
> +               .div_step = 2,
> +       }, {
> +               .id = EN7523_CLK_SPI,
> +               .name = "spi",
> +
> +               .base_reg = REG_SPI_CLK_DIV_SEL,
> +
> +               .base_value = 400000000,
> +
> +               .div_bits = 5,
> +               .div_shift = 8,
> +               .div_val0 = 40,
> +               .div_step = 2,
> +       }, {
> +               .id = EN7523_CLK_NPU,
> +               .name = "npu",
> +
> +               .base_reg = REG_NPU_CLK_DIV_SEL,
> +               .base_bits = 2,
> +               .base_shift = 8,
> +               .base_values = npu_base,
> +               .n_base_values = ARRAY_SIZE(npu_base),
> +
> +               .div_bits = 3,
> +               .div_shift = 0,
> +               .div_step = 1,
> +       }, {
> +               .id = EN7523_CLK_CRYPTO,
> +               .name = "crypto",
> +
> +               .base_reg = REG_CRYPTO_CLKSRC,
> +               .base_bits = 1,
> +               .base_shift = 8,
> +               .base_values = emi_base,
> +               .n_base_values = ARRAY_SIZE(emi_base),
> +       }
> +};
> +
> +static const struct of_device_id of_match_clk_en7523[] = {

Please move this down near the driver struct that uses it.

> +       { .compatible = "airoha,en7523-scu", },
> +       { /* sentinel */ }
> +};
> +
> +static u32 en7523_get_base_rate(void __iomem *base, int i)
> +{
> +       const struct en_clk_desc *desc = &en7523_base_clks[i];
> +       u32 val;
> +
> +       if (!desc->base_bits)
> +               return desc->base_value;
> +
> +       val = readl(base + desc->base_reg);
> +       val >>= desc->base_shift;
> +       val &= (1 << desc->base_bits) - 1;
> +
> +       if (val >= desc->n_base_values)
> +               return 0;
> +
> +       return desc->base_values[val];
> +}
> +
> +static u32 en7523_get_div(void __iomem *base, int i)
> +{
> +       const struct en_clk_desc *desc = &en7523_base_clks[i];
> +       u32 reg, val;
> +
> +       if (!desc->div_bits)
> +               return 1;
> +
> +       reg = desc->div_reg ? desc->div_reg : desc->base_reg;
> +       val = readl(base + reg);
> +       val >>= desc->div_shift;
> +       val &= (1 << desc->div_bits) - 1;
> +
> +       if (!val && desc->div_val0)
> +               return desc->div_val0;
> +
> +       return (val + 1) * desc->div_step;
> +}
> +
> +static int en7523_pci_is_enabled(struct clk_hw *hw)
> +{
> +       struct en_clk_gate *cg = container_of(hw, struct en_clk_gate, hw);
> +
> +       return !!(readl(cg->base + REG_PCI_CONTROL) & REG_PCI_CONTROL_REFCLK_EN1);
> +}
> +
> +static int en7523_pci_enable(struct clk_hw *hw)
> +{
> +       struct en_clk_gate *cg = container_of(hw, struct en_clk_gate, hw);
> +       void __iomem *np_base = cg->base;
> +       u32 val, mask;
> +
> +       /* Need to pull device low before reset */
> +       val = readl(np_base + REG_PCI_CONTROL);
> +       val &= ~(REG_PCI_CONTROL_PERSTOUT1 | REG_PCI_CONTROL_PERSTOUT);
> +       writel(val, np_base + REG_PCI_CONTROL);
> +       usleep_range(1000, 2000);

This clk_op is called under a spinlock and thus nothing in here can
sleep. These need to be udelays and mdelays instead, or this needs to be
a prepare clk_op.

> +
> +       /* Enable PCIe port 1 */
> +       val |= REG_PCI_CONTROL_REFCLK_EN1;
> +       writel(val, np_base + REG_PCI_CONTROL);
> +       usleep_range(1000, 2000);
> +
> +       /* Reset to default */
> +       val = readl(np_base + REG_RESET_CONTROL);
> +       mask = REG_RESET_CONTROL_PCIE1 | REG_RESET_CONTROL_PCIE2 |
> +              REG_RESET_CONTROL_PCIEHB;
> +       writel(val & ~mask, np_base + REG_RESET_CONTROL);
> +       usleep_range(1000, 2000);
> +       writel(val | mask, np_base + REG_RESET_CONTROL);
> +       msleep(100);
> +       writel(val & ~mask, np_base + REG_RESET_CONTROL);
> +       usleep_range(5000, 10000);
> +
> +       /* Release device */
> +       mask = REG_PCI_CONTROL_PERSTOUT1 | REG_PCI_CONTROL_PERSTOUT;
> +       val = readl(np_base + REG_PCI_CONTROL);
> +       writel(val & ~mask, np_base + REG_PCI_CONTROL);
> +       usleep_range(1000, 2000);
> +       writel(val | mask, np_base + REG_PCI_CONTROL);
> +       msleep(250);
> +
> +       return 0;
> +}
> +
> +static void en7523_pci_disable(struct clk_hw *hw)
> +{
> +       struct en_clk_gate *cg = container_of(hw, struct en_clk_gate, hw);
> +       void *np_base = cg->base;
> +       u32 val;
> +
> +       val = readl(np_base + REG_PCI_CONTROL);
> +       val &= ~REG_PCI_CONTROL_REFCLK_EN1;
> +       writel(val, np_base + REG_PCI_CONTROL);
> +}
> +
> +static struct clk_hw *en7523_register_pcie_clk(struct device *dev,
> +                                              void __iomem *np_base)
> +{
> +       static const struct clk_ops pcie_gate_ops = {
> +               .is_enabled = en7523_pci_is_enabled,
> +               .enable = en7523_pci_enable,
> +               .disable = en7523_pci_disable,
> +       };
> +       struct clk_init_data init = {
> +               .name = "pcie",
> +               .ops = &pcie_gate_ops,
> +       };
> +       struct en_clk_gate *cg;
> +
> +       cg = devm_kzalloc(dev, sizeof(*cg), GFP_KERNEL);
> +       if (!cg)
> +               return NULL;
> +
> +       cg->base = np_base;
> +       cg->hw.init = &init;
> +       en7523_pci_disable(&cg->hw);
> +
> +       if (clk_hw_register(NULL, &cg->hw))
> +               return NULL;
> +
> +       return &cg->hw;
> +}
> +
> +static void en7523_register_clocks(struct device *dev, struct clk_hw_onecell_data *clk_data,
> +                                  void __iomem *base, void __iomem *np_base)
> +{
> +       struct clk_hw *hw;
> +       u32 rate;
> +       int i;
> +
> +       for (i = 0; i < ARRAY_SIZE(en7523_base_clks); i++) {
> +               const struct en_clk_desc *desc = &en7523_base_clks[i];
> +
> +               rate = en7523_get_base_rate(base, i);
> +               rate /= en7523_get_div(base, i);
> +
> +               hw = clk_hw_register_fixed_rate(NULL, desc->name, NULL, 0, rate);

Please pass 'dev' to this function.

> +               if (IS_ERR(hw)) {
> +                       pr_err("Failed to register clk %s: %ld\n",
> +                              desc->name, PTR_ERR(hw));
> +                       continue;
> +               }
> +
> +               clk_data->hws[desc->id] = hw;
> +       }
> +
> +       hw = en7523_register_pcie_clk(dev, np_base);
> +       clk_data->hws[EN7523_CLK_PCIE] = hw;
> +
> +       clk_data->num = EN7523_NUM_CLOCKS;
> +}
> +
> +static int en7523_clk_probe(struct platform_device *pdev)
> +{
> +       struct device_node *node = pdev->dev.of_node;
> +       struct clk_hw_onecell_data *clk_data;
> +       void __iomem *base, *np_base;
> +       int r;
> +
> +       base = devm_platform_ioremap_resource(pdev, 0);
> +       if (IS_ERR(base))
> +               return PTR_ERR(base);
> +
> +       np_base = devm_platform_ioremap_resource(pdev, 1);
> +       if (IS_ERR(base))
> +               return PTR_ERR(np_base);
> +
> +       clk_data = devm_kzalloc(&pdev->dev,
> +                               struct_size(clk_data, hws, EN7523_NUM_CLOCKS),
> +                               GFP_KERNEL);
> +       if (!clk_data)
> +               return -ENOMEM;
> +
> +       en7523_register_clocks(&pdev->dev, clk_data, base, np_base);
> +
> +       r = of_clk_add_hw_provider(node, of_clk_hw_onecell_get, clk_data);
> +       if (r)
> +               dev_err(&pdev->dev,
> +                       "could not register clock provider: %s: %d\n",
> +                       pdev->name, r);
> +
> +       return r;
> +}
> +
> +static struct platform_driver clk_en7523_drv = {
> +       .probe = en7523_clk_probe,
> +       .driver = {
> +               .name = "clk-en7523",
> +               .of_match_table = of_match_clk_en7523,
> +       },
> +};
> +
> +static int clk_en7523_init(void)

Add __init

> +{
> +       return platform_driver_register(&clk_en7523_drv);
> +}
> +
> +arch_initcall(clk_en7523_init);

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