[PATCH v4 2/3] reset: add driver for imx8ulp SIM reset controller

[Laurentiu Mihalcea]

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@xxxxxxx>
Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@xxxxxxx>
---
 drivers/reset/Kconfig             |   7 ++
 drivers/reset/Makefile            |   1 +
 drivers/reset/reset-imx8ulp-sim.c | 106 ++++++++++++++++++++++++++++++
 3 files changed, 114 insertions(+)
 create mode 100644 drivers/reset/reset-imx8ulp-sim.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index 5484a65f66b9..492081354d03 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -113,6 +113,13 @@ config RESET_IMX8MP_AUDIOMIX
 	help
 	  This enables the reset controller driver for i.MX8MP AudioMix
 
+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 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 4411a2a124d7..38354e701811 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_RESET_GPIO) += reset-gpio.o
 obj-$(CONFIG_RESET_HSDK) += reset-hsdk.o
 obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
 obj-$(CONFIG_RESET_IMX8MP_AUDIOMIX) += reset-imx8mp-audiomix.o
+obj-$(CONFIG_RESET_IMX8ULP_SIM) += reset-imx8ulp-sim.o
 obj-$(CONFIG_RESET_INTEL_GW) += reset-intel-gw.o
 obj-$(CONFIG_RESET_K210) += reset-k210.o
 obj-$(CONFIG_RESET_LANTIQ) += reset-lantiq.o
diff --git a/drivers/reset/reset-imx8ulp-sim.c b/drivers/reset/reset-imx8ulp-sim.c
new file mode 100644
index 000000000000..04ff11d41e10
--- /dev/null
+++ b/drivers/reset/reset-imx8ulp-sim.c
@@ -0,0 +1,106 @@
+// 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 <linux/of_platform.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
+
+#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);
+	if (IS_ERR(simr->regmap))
+		return dev_err_probe(&pdev->dev, PTR_ERR(simr->regmap),
+				     "failed to get regmap\n");
+
+	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;
+
+	ret = devm_of_platform_populate(dev);
+	if (ret)
+		return ret;
+
+	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@xxxxxxx>");
+MODULE_DESCRIPTION("NXP i.MX8ULP System Integration Module Reset driver");
+MODULE_LICENSE("GPL");
-- 
2.34.1