Re: [PATCH v10 2/6] clk: en7523: Add clock driver for Airoha EN7523 SoC

[Matthias Brugger <matthias.bgg@gmail.com>]

On 14/03/2022 09:44, Felix Fietkau wrote:
> This driver only registers fixed rate clocks, since the clocks are fully
> initialized by the boot loader and should not be changed later, according
> to Airoha.
> 
> Signed-off-by: Felix Fietkau <nbd@nbd.name>

Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>

> ---
>   drivers/clk/Kconfig      |   9 +
>   drivers/clk/Makefile     |   1 +
>   drivers/clk/clk-en7523.c | 351 +++++++++++++++++++++++++++++++++++++++
>   3 files changed, 361 insertions(+)
>   create mode 100644 drivers/clk/clk-en7523.c
> 
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> index ad4256d54361..4765e4c6f2a1 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -200,6 +200,15 @@ 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
> +	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
> index 16e588630472..da8dd3ab304f 100644
> --- a/drivers/clk/Makefile
> +++ b/drivers/clk/Makefile
> @@ -27,6 +27,7 @@ obj-$(CONFIG_COMMON_CLK_CDCE925)	+= clk-cdce925.o
>   obj-$(CONFIG_ARCH_CLPS711X)		+= clk-clps711x.o
>   obj-$(CONFIG_COMMON_CLK_CS2000_CP)	+= clk-cs2000-cp.o
>   obj-$(CONFIG_ARCH_SPARX5)		+= clk-sparx5.o
> +obj-$(CONFIG_COMMON_CLK_EN7523)		+= clk-en7523.o
>   obj-$(CONFIG_COMMON_CLK_FIXED_MMIO)	+= clk-fixed-mmio.o
>   obj-$(CONFIG_COMMON_CLK_FSL_FLEXSPI)	+= clk-fsl-flexspi.o
>   obj-$(CONFIG_COMMON_CLK_FSL_SAI)	+= clk-fsl-sai.o
> diff --git a/drivers/clk/clk-en7523.c b/drivers/clk/clk-en7523.c
> new file mode 100644
> index 000000000000..076a70c2e173
> --- /dev/null
> +++ b/drivers/clk/clk-en7523.c
> @@ -0,0 +1,351 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +#include <linux/delay.h>
> +#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;
> +	u8 base_bits;
> +	u8 base_shift;
> +	union {
> +		const unsigned int *base_values;
> +		unsigned int base_value;
> +	};
> +	size_t n_base_values;
> +
> +	u16 div_reg;
> +	u8 div_bits;
> +	u8 div_shift;
> +	u16 div_val0;
> +	u8 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[] = {
> +	{ .compatible = "airoha,en7523-scu", },
> +	{ /* sentinel */ }
> +};
> +
> +static unsigned int en7523_get_base_rate(void __iomem *base, unsigned 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_prepare(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);
> +
> +	/* 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_unprepare(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;
> +
> +	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,
> +		.prepare = en7523_pci_prepare,
> +		.unprepare = en7523_pci_unprepare,
> +	};
> +	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_unprepare(&cg->hw);
> +
> +	if (clk_hw_register(dev, &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(dev, desc->name, NULL, 0, rate);
> +		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,
> +		.suppress_bind_attrs = true,
> +	},
> +};
> +
> +static int __init clk_en7523_init(void)
> +{
> +	return platform_driver_register(&clk_en7523_drv);
> +}
> +
> +arch_initcall(clk_en7523_init);