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

From: Amit Singh Tomar
Date: Mon May 20 2024 - 10:42:16 EST



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On Fri, May 17, 2024 at 11:51:30AM +0530, Amit Singh Tomar wrote:
Hi,

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From: Laurentiu Mihalcea <laurentiu.mihalcea@xxxxxxx>

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 | 98 +++++++++++++++++++

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

https://urldefense.proofpoint.com/v2/url?u=https-3A__elixir.bootlin.com_linux_latest_source_drivers_reset_reset-2Dsimple.c&d=DwIBAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=V_GK7jRuCHDErm6txmgDK1-MbUihtnSQ3gPgB-A-JKU&m=MnEcoegPnKc-F7TNf8PB3icMf8uCGrxsh6mEDWgNq3YA-OugL6Y53LxytlBGcsKp&s=6mBPHYYYXoyyxPPbUeOiIpwR3CXdnui1W3nkUJQ76Vo&e=

reset-simple have not use regmap. I think it can use ti's
https://urldefense.proofpoint.com/v2/url?u=https-3A__elixir.bootlin.com_linux_latest_source_drivers_reset_reset-2Dti-2Dsyscon.c&d=DwIBAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=V_GK7jRuCHDErm6txmgDK1-MbUihtnSQ3gPgB-A-JKU&m=MnEcoegPnKc-F7TNf8PB3icMf8uCGrxsh6mEDWgNq3YA-OugL6Y53LxytlBGcsKp&s=D6tqLNYrUbsdG_gYg4G-ORlC9YKz4XRAlVeo1hyoYS4&e=

Or should change ti to reset-simple-syscon? or add regmap support for
reset-simple.c


Quickly looked into U-Boot (not sure if it's the right reference), and it has a separate reset-syscon.c file:

https://elixir.bootlin.com/u-boot/latest/source/drivers/reset/reset-syscon.c

So, converting reset-ti-syscon.c to reset-syscon.c might be the way to go.

Frank Li



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@xxxxxxx>");
+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 */