Re: [PATCH v3 3/8] clk: imx: add driver for imx8ulp's sim lpav

Frank Li
2025-10-29T16:17:41Z

On Wed, Oct 29, 2025 at 06:52:24AM -0700, Laurentiu Mihalcea wrote:
> From: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>
>
> The i.MX8ULP System Integration Module (SIM) LPAV module is a block
> control module found inside the LPAV subsystem, which offers some clock
> gating options and reset line assertion/de-assertion capabilities.
>
> Therefore, the clock gate management is supported by registering the
> module's driver as a clock provider, while the reset capabilities are
> managed via the auxiliary device API to allow the DT node to act as a
> reset and clock provider.
>
> Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>
> ---
> drivers/clk/imx/Makefile | 1 +
> drivers/clk/imx/clk-imx8ulp-sim-lpav.c | 160 +++++++++++++++++++++++++
> 2 files changed, 161 insertions(+)
> create mode 100644 drivers/clk/imx/clk-imx8ulp-sim-lpav.c
>
> diff --git a/drivers/clk/imx/Makefile b/drivers/clk/imx/Makefile
> index 03f2b2a1ab63..208b46873a18 100644
> --- a/drivers/clk/imx/Makefile
> +++ b/drivers/clk/imx/Makefile
> @@ -41,6 +41,7 @@ clk-imx-lpcg-scu-$(CONFIG_CLK_IMX8QXP) += clk-lpcg-scu.o clk-imx8qxp-lpcg.o
> clk-imx-acm-$(CONFIG_CLK_IMX8QXP) = clk-imx8-acm.o
>
> obj-$(CONFIG_CLK_IMX8ULP) += clk-imx8ulp.o
> +obj-$(CONFIG_CLK_IMX8ULP) += clk-imx8ulp-sim-lpav.o
>
> obj-$(CONFIG_CLK_IMX1) += clk-imx1.o
> obj-$(CONFIG_CLK_IMX25) += clk-imx25.o
> diff --git a/drivers/clk/imx/clk-imx8ulp-sim-lpav.c b/drivers/clk/imx/clk-imx8ulp-sim-lpav.c
> new file mode 100644
> index 000000000000..1614d9209734
> --- /dev/null
> +++ b/drivers/clk/imx/clk-imx8ulp-sim-lpav.c
> @@ -0,0 +1,160 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2025 NXP
> + */
> +
> +#include <dt-bindings/clock/imx8ulp-clock.h>
> +
> +#include <linux/auxiliary_bus.h>
> +#include <linux/clk-provider.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +
> +#define SYSCTRL0 0x8
> +
> +#define IMX8ULP_HIFI_CLK_GATE(gname, cname, pname, bidx) \
> + { \
> + .name = gname "_cg", \
> + .id = IMX8ULP_CLK_SIM_LPAV_HIFI_##cname, \
> + .parent = { .fw_name = pname }, \
> + .bit = bidx, \
> + }
> +
> +struct clk_imx8ulp_sim_lpav_data {
> + void __iomem *base;
> + struct regmap *regmap;
> + spinlock_t lock; /* shared by MUX, clock gate and reset */
> + unsigned long flags; /* for spinlock usage */
> + struct clk_hw_onecell_data clk_data; /* keep last */
> +};
> +
> +struct clk_imx8ulp_sim_lpav_gate {
> + const char *name;
> + int id;
> + const struct clk_parent_data parent;
> + u8 bit;
> +};
> +
> +static struct clk_imx8ulp_sim_lpav_gate gates[] = {
> + IMX8ULP_HIFI_CLK_GATE("hifi_core", CORE, "core", 17),
> + IMX8ULP_HIFI_CLK_GATE("hifi_pbclk", PBCLK, "bus", 18),
> + IMX8ULP_HIFI_CLK_GATE("hifi_plat", PLAT, "plat", 19)
> +};
> +
> +static void clk_imx8ulp_sim_lpav_lock(void *arg) __acquires(&data->lock)
> +{
> + struct clk_imx8ulp_sim_lpav_data *data = dev_get_drvdata(arg);
> +
> + spin_lock_irqsave(&data->lock, data->flags);
> +}
> +
> +static void clk_imx8ulp_sim_lpav_unlock(void *arg) __releases(&data->lock)
> +{
> + struct clk_imx8ulp_sim_lpav_data *data = dev_get_drvdata(arg);
> +
> + spin_unlock_irqrestore(&data->lock, data->flags);
> +}
> +
> +static const struct regmap_config clk_imx8ulp_sim_lpav_regmap_cfg = {
> + .reg_bits = 32,
> + .val_bits = 32,
> + .reg_stride = 4,
> + .lock = clk_imx8ulp_sim_lpav_lock,
> + .unlock = clk_imx8ulp_sim_lpav_unlock,
> +};
> +
> +static int clk_imx8ulp_sim_lpav_probe(struct platform_device *pdev)
> +{
> + struct clk_imx8ulp_sim_lpav_data *data;
> + struct regmap_config regmap_config;
> + struct auxiliary_device *adev;
> + struct clk_hw *hw;
> + int i, ret;
> +
> + data = devm_kzalloc(&pdev->dev,
> + struct_size(data, clk_data.hws, ARRAY_SIZE(gates)),
> + GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> + dev_set_drvdata(&pdev->dev, data);
> +
> + memcpy(&regmap_config, &clk_imx8ulp_sim_lpav_regmap_cfg, sizeof(regmap_config));
> + regmap_config.lock_arg = &pdev->dev;

You copy clk_imx8ulp_sim_lpav_regmap_cfg to regmap_config and only once.
look like not neccessary to use clk_imx8ulp_sim_lpav_regmap_cfg at
all.

struct regmap_config regmap_config = {
.reg_bits = 32,
.val_bits = 32,
.reg_stride = 4,
.lock = clk_imx8ulp_sim_lpav_lock,
.unlock = clk_imx8ulp_sim_lpav_unlock,
.lock_arg = &pdev->dev;
};

it will be more straightforward.

Frank

> +
> + /*
> + * this lock is used directly by the clock gate and indirectly
> + * by the reset and mux controller via the regmap API
> + */
> + spin_lock_init(&data->lock);
> +
> + data->base = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(data->base))
> + return dev_err_probe(&pdev->dev, PTR_ERR(data->base),
> + "failed to ioremap base\n");
> + /*
> + * although the clock gate doesn't use the regmap API to modify the
> + * registers, we still need the regmap because of the reset auxiliary
> + * driver and the MUX drivers, which use the parent device's regmap
> + */
> + data->regmap = devm_regmap_init_mmio(&pdev->dev, data->base, &regmap_config);
> + if (IS_ERR(data->regmap))
> + return dev_err_probe(&pdev->dev, PTR_ERR(data->regmap),
> + "failed to initialize regmap\n");
> +
> + data->clk_data.num = ARRAY_SIZE(gates);
> +
> + for (i = 0; i < ARRAY_SIZE(gates); i++) {
> + hw = devm_clk_hw_register_gate_parent_data(&pdev->dev,
> + gates[i].name,
> + &gates[i].parent,
> + CLK_SET_RATE_PARENT,
> + data->base + SYSCTRL0,
> + gates[i].bit,
> + 0x0, &data->lock);
> + if (IS_ERR(hw))
> + return dev_err_probe(&pdev->dev, PTR_ERR(hw),
> + "failed to register %s gate\n",
> + gates[i].name);
> +
> + data->clk_data.hws[i] = hw;
> + }
> +
> + adev = devm_auxiliary_device_create(&pdev->dev, "reset", NULL);
> + if (!adev)
> + return dev_err_probe(&pdev->dev, -ENODEV,
> + "failed to register aux reset\n");
> +
> + ret = devm_of_clk_add_hw_provider(&pdev->dev,
> + of_clk_hw_onecell_get,
> + &data->clk_data);
> + if (ret)
> + return dev_err_probe(&pdev->dev, ret,
> + "failed to register clk hw provider\n");
> +
> + /* used to probe MUX child device */
> + return devm_of_platform_populate(&pdev->dev);
> +}
> +
> +static const struct of_device_id clk_imx8ulp_sim_lpav_of_match[] = {
> + { .compatible = "fsl,imx8ulp-sim-lpav" },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, clk_imx8ulp_sim_lpav_of_match);
> +
> +static struct platform_driver clk_imx8ulp_sim_lpav_driver = {
> + .probe = clk_imx8ulp_sim_lpav_probe,
> + .driver = {
> + .name = "clk-imx8ulp-sim-lpav",
> + .of_match_table = clk_imx8ulp_sim_lpav_of_match,
> + },
> +};
> +module_platform_driver(clk_imx8ulp_sim_lpav_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("i.MX8ULP LPAV System Integration Module (SIM) clock driver");
> +MODULE_AUTHOR("Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>");
> --
> 2.43.0
>