[PATCH 2/4] reset: add driver for imx8ulp SIM reset controller

[Amit Singh Tomar <amitsinght@marvell.com>]

Hi,

> ----------------------------------------------------------------------
> From: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>
> 
> Certain components can be reset via the SIM module.
> Add reset controller driver for the SIM module to
> allow drivers for said components to control the
> reset signal(s).
> 
> Signed-off-by: Liu Ying <victor.liu@nxp.com>
> Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>
> ---
>   drivers/reset/Kconfig                         |  7 ++
>   drivers/reset/Makefile                        |  1 +
>   drivers/reset/reset-imx8ulp-sim.c             | 98 +++++++++++++++++++

Just out of curiosity, can't this be accomplished using a generic reset 
driver?

https://elixir.bootlin.com/linux/latest/source/drivers/reset/reset-simple.c

>   include/dt-bindings/reset/imx8ulp-sim-reset.h | 16 +++
>   4 files changed, 122 insertions(+)
>   create mode 100644 drivers/reset/reset-imx8ulp-sim.c
>   create mode 100644 include/dt-bindings/reset/imx8ulp-sim-reset.h
> 
> diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
> index 85b27c42cf65..c1f4d9ebd0fd 100644
> --- a/drivers/reset/Kconfig
> +++ b/drivers/reset/Kconfig
> @@ -91,6 +91,13 @@ config RESET_IMX7
>   	help
>   	  This enables the reset controller driver for i.MX7 SoCs.
>   
> +config RESET_IMX8ULP_SIM
> +	tristate "i.MX8ULP SIM Reset Driver"
> +	depends on ARCH_MXC
> +	help
> +	  This enables the SIM (System Integration Module) reset driver
> +	  for the i.MX8ULP SoC.
> +
>   config RESET_INTEL_GW
>   	bool "Intel Reset Controller Driver"
>   	depends on X86 || COMPILE_TEST
> diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
> index fd8b49fa46fc..f257d6a41f1e 100644
> --- a/drivers/reset/Makefile
> +++ b/drivers/reset/Makefile
> @@ -42,3 +42,4 @@ obj-$(CONFIG_RESET_UNIPHIER) += reset-uniphier.o
>   obj-$(CONFIG_RESET_UNIPHIER_GLUE) += reset-uniphier-glue.o
>   obj-$(CONFIG_RESET_ZYNQ) += reset-zynq.o
>   obj-$(CONFIG_ARCH_ZYNQMP) += reset-zynqmp.o
> +obj-$(CONFIG_RESET_IMX8ULP_SIM) += reset-imx8ulp-sim.o
> diff --git a/drivers/reset/reset-imx8ulp-sim.c b/drivers/reset/reset-imx8ulp-sim.c
> new file mode 100644
> index 000000000000..27923b9cd454
> --- /dev/null
> +++ b/drivers/reset/reset-imx8ulp-sim.c
> @@ -0,0 +1,98 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +
> +/*
> + * Copyright 2024 NXP
> + */
> +
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/reset-controller.h>
> +#include <dt-bindings/reset/imx8ulp-sim-reset.h>
> +
> +#define AVD_SIM_SYSCTRL0        0x8
> +
> +struct imx8ulp_sim_reset {
> +	struct reset_controller_dev     rcdev;
> +	struct regmap                   *regmap;
> +};
> +
> +static const u32 imx8ulp_sim_reset_bits[IMX8ULP_SIM_RESET_NUM] = {
> +	[IMX8ULP_SIM_RESET_MIPI_DSI_RST_DPI_N] = BIT(3),
> +	[IMX8ULP_SIM_RESET_MIPI_DSI_RST_ESC_N] = BIT(4),
> +	[IMX8ULP_SIM_RESET_MIPI_DSI_RST_BYTE_N] = BIT(5),
> +};
> +
> +static inline struct imx8ulp_sim_reset *
> +to_imx8ulp_sim_reset(struct reset_controller_dev *rcdev)
> +{
> +	return container_of(rcdev, struct imx8ulp_sim_reset, rcdev);
> +}
> +
> +static int imx8ulp_sim_reset_assert(struct reset_controller_dev *rcdev,
> +				    unsigned long id)
> +{
> +	struct imx8ulp_sim_reset *simr = to_imx8ulp_sim_reset(rcdev);
> +	const u32 bit = imx8ulp_sim_reset_bits[id];
> +
> +	return regmap_update_bits(simr->regmap, AVD_SIM_SYSCTRL0, bit, 0);
> +}
> +
> +static int imx8ulp_sim_reset_deassert(struct reset_controller_dev *rcdev,
> +				      unsigned long id)
> +{
> +	struct imx8ulp_sim_reset *simr = to_imx8ulp_sim_reset(rcdev);
> +	const u32 bit = imx8ulp_sim_reset_bits[id];
> +
> +	return regmap_update_bits(simr->regmap, AVD_SIM_SYSCTRL0, bit, bit);
> +}
> +
> +static const struct reset_control_ops imx8ulp_sim_reset_ops = {
> +	.assert         = imx8ulp_sim_reset_assert,
> +	.deassert       = imx8ulp_sim_reset_deassert,
> +};
> +
> +static const struct of_device_id imx8ulp_sim_reset_dt_ids[] = {
> +	{ .compatible = "nxp,imx8ulp-avd-sim-reset", },
> +	{ /* sentinel */ },
> +};
> +
> +static int imx8ulp_sim_reset_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct imx8ulp_sim_reset *simr;
> +	int ret;
> +
> +	simr = devm_kzalloc(dev, sizeof(*simr), GFP_KERNEL);
> +	if (!simr)
> +		return -ENOMEM;
> +
> +	simr->regmap = syscon_node_to_regmap(dev->of_node->parent);
> +	if (IS_ERR(simr->regmap)) {
> +		ret = PTR_ERR(simr->regmap);
> +		dev_err(dev, "failed to get regmap: %d\n", ret);
> +		return ret;
> +	}
> +
> +	simr->rcdev.owner = THIS_MODULE;
> +	simr->rcdev.nr_resets = IMX8ULP_SIM_RESET_NUM;
> +	simr->rcdev.ops = &imx8ulp_sim_reset_ops;
> +	simr->rcdev.of_node = dev->of_node;
> +
> +	return devm_reset_controller_register(dev, &simr->rcdev);
> +}
> +
> +static struct platform_driver imx8ulp_sim_reset_driver = {
> +	.probe  = imx8ulp_sim_reset_probe,
> +	.driver = {
> +		.name           = KBUILD_MODNAME,
> +		.of_match_table = imx8ulp_sim_reset_dt_ids,
> +	},
> +};
> +module_platform_driver(imx8ulp_sim_reset_driver);
> +
> +MODULE_AUTHOR("Liu Ying <victor.liu@nxp.com>");
> +MODULE_DESCRIPTION("NXP i.MX8ULP System Integration Module Reset driver");
> +MODULE_LICENSE("GPL");
> diff --git a/include/dt-bindings/reset/imx8ulp-sim-reset.h b/include/dt-bindings/reset/imx8ulp-sim-reset.h
> new file mode 100644
> index 000000000000..a3cee0d60773
> --- /dev/null
> +++ b/include/dt-bindings/reset/imx8ulp-sim-reset.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0-only OR BSD-3-Clause */
> +
> +/*
> + * Copyright 2024 NXP
> + */
> +
> +#ifndef DT_BINDINGS_RESET_IMX8ULP_SIM_RESET_H
> +#define DT_BINDINGS_RESET_IMX8ULP_SIM_RESET_H
> +
> +#define IMX8ULP_SIM_RESET_MIPI_DSI_RST_DPI_N    0
> +#define IMX8ULP_SIM_RESET_MIPI_DSI_RST_ESC_N    1
> +#define IMX8ULP_SIM_RESET_MIPI_DSI_RST_BYTE_N   2
> +
> +#define IMX8ULP_SIM_RESET_NUM                   3
> +
> +#endif /* DT_BINDINGS_RESET_IMX8ULP_SIM_RESET_H */