soc: apple: Add driver for Apple PMGR misc controls

Apple SoCs have PMGR blocks that control a bunch of power-related
features. Besides the existing device power state controls (which are
very uniform and handled by apple-pmgr-pwrstate), we also need to manage
more random registers such as SoC-wide fabric and memory controller
power states, which have a different interface.

Add a driver for these kitchen sink controls. Right now it implements
fabric and memory controller power state switching on system
standby/s2idle, which saves about 1W of power or so on t60xx platforms.

Signed-off-by: Hector Martin <marcan@marcan.st>
Reviewed-by: Sven Peter <sven@kernel.org>
Co-developed-by: Sasha Finkelstein <k@chaosmail.tech>
Signed-off-by: Sasha Finkelstein <k@chaosmail.tech>
Reviewed-by: Joshua Peisach <jpeisach@ubuntu.com>
Link: https://patch.msgid.link/20260705-pmgr-misc-v3-2-51b75fed6f73@chaosmail.tech
Signed-off-by: Sven Peter <sven@kernel.org>

drivers/soc/apple/Kconfig

@@ -16,6 +16,16 @@ config APPLE_MAILBOX
 
 	  Say Y here if you have an Apple SoC.
 
+config APPLE_PMGR_MISC
+	tristate "Apple SoC PMGR miscellaneous support"
+	depends on PM
+	help
+	  The PMGR block in Apple SoCs provides high-level power state
+	  controls for SoC devices. This driver manages miscellaneous
+	  power controls.
+
+	  Say 'y' here if you have a Pro/Max/Ultra Apple SoC.
+
 config APPLE_RTKIT
 	tristate "Apple RTKit co-processor IPC protocol"
 	depends on APPLE_MAILBOX

drivers/soc/apple/Makefile

@@ -3,6 +3,8 @@
 obj-$(CONFIG_APPLE_MAILBOX) += apple-mailbox.o
 apple-mailbox-y = mailbox.o
 
+obj-$(CONFIG_APPLE_PMGR_MISC)	+= apple-pmgr-misc.o
+
 obj-$(CONFIG_APPLE_RTKIT) += apple-rtkit.o
 apple-rtkit-y = rtkit.o rtkit-crashlog.o
 

drivers/soc/apple/apple-pmgr-misc.c

@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Apple SoC PMGR device power state driver
+ *
+ * Copyright The Asahi Linux Contributors
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+
+#define APPLE_CLKGEN_PSTATE 0
+#define APPLE_CLKGEN_PSTATE_DESIRED GENMASK(3, 0)
+
+#define DCS_DEV_PSTATE_MIN_T600X 7
+#define SYS_DEV_PSTATE_SUSPEND 1
+
+enum sys_device {
+	DEV_FABRIC,
+	DEV_DCS,
+	DEV_MAX,
+};
+
+struct apple_pmgr_sys_device {
+	void __iomem *base;
+	u32 active_state;
+	u32 suspend_state;
+};
+
+struct apple_pmgr_misc_hw {
+	u32 dev_min_ps[DEV_MAX];
+};
+
+struct apple_pmgr_misc {
+	struct device *dev;
+	struct apple_pmgr_sys_device devices[DEV_MAX];
+};
+
+static void apple_pmgr_sys_dev_set_pstate(struct apple_pmgr_misc *misc,
+					  enum sys_device dev, bool active)
+{
+	u32 pstate;
+	u32 val;
+
+	if (!misc->devices[dev].base)
+		return;
+
+	if (active)
+		pstate = misc->devices[dev].active_state;
+	else
+		pstate = misc->devices[dev].suspend_state;
+
+	dev_dbg(misc->dev, "set %d ps to pstate %d\n", dev, pstate);
+
+	val = readl_relaxed(misc->devices[dev].base + APPLE_CLKGEN_PSTATE);
+	FIELD_MODIFY(APPLE_CLKGEN_PSTATE_DESIRED, &val, pstate);
+	writel_relaxed(val, misc->devices[dev].base + APPLE_CLKGEN_PSTATE);
+}
+
+static int __maybe_unused apple_pmgr_misc_suspend_noirq(struct device *dev)
+{
+	struct apple_pmgr_misc *misc = dev_get_drvdata(dev);
+	int i;
+
+	for (i = 0; i < DEV_MAX; i++)
+		apple_pmgr_sys_dev_set_pstate(misc, i, false);
+
+	return 0;
+}
+
+static int __maybe_unused apple_pmgr_misc_resume_noirq(struct device *dev)
+{
+	struct apple_pmgr_misc *misc = dev_get_drvdata(dev);
+	int i;
+
+	for (i = 0; i < DEV_MAX; i++)
+		apple_pmgr_sys_dev_set_pstate(misc, i, true);
+
+	return 0;
+}
+
+static int apple_pmgr_init_device(struct apple_pmgr_misc *misc,
+				  const struct apple_pmgr_misc_hw *hw,
+				  enum sys_device dev,
+				  const char *device_name)
+{
+	void __iomem *base;
+	char name[32];
+	u32 val;
+
+	snprintf(name, sizeof(name), "%s-ps", device_name);
+
+	base = devm_platform_ioremap_resource_byname(
+		to_platform_device(misc->dev), name);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	val = readl_relaxed(base + APPLE_CLKGEN_PSTATE);
+
+	misc->devices[dev].base = base;
+	misc->devices[dev].active_state =
+		FIELD_GET(APPLE_CLKGEN_PSTATE_DESIRED, val);
+	misc->devices[dev].suspend_state = hw->dev_min_ps[dev];
+
+	return 0;
+}
+
+static int apple_pmgr_misc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct apple_pmgr_misc_hw *hw;
+	struct apple_pmgr_misc *misc;
+	int ret;
+
+	misc = devm_kzalloc(dev, sizeof(*misc), GFP_KERNEL);
+	if (!misc)
+		return -ENOMEM;
+
+	misc->dev = dev;
+	hw = of_device_get_match_data(dev);
+	if (!hw)
+		return -EINVAL;
+
+	ret = apple_pmgr_init_device(misc, hw, DEV_FABRIC, "fabric");
+	if (ret)
+		return ret;
+
+	ret = apple_pmgr_init_device(misc, hw, DEV_DCS, "dcs");
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, misc);
+
+	return 0;
+}
+
+static const struct apple_pmgr_misc_hw apple_pmgr_misc_hw_t600x = {
+	.dev_min_ps = {
+		[DEV_FABRIC] = SYS_DEV_PSTATE_SUSPEND,
+		[DEV_DCS] = DCS_DEV_PSTATE_MIN_T600X,
+	},
+};
+
+static const struct apple_pmgr_misc_hw apple_pmgr_misc_hw_t602x = {
+	.dev_min_ps = {
+		[DEV_FABRIC] = SYS_DEV_PSTATE_SUSPEND,
+		[DEV_DCS] = SYS_DEV_PSTATE_SUSPEND,
+	},
+};
+
+static const struct of_device_id apple_pmgr_misc_of_match[] = {
+	{ .compatible = "apple,t6000-pmgr-misc", .data = &apple_pmgr_misc_hw_t600x },
+	{ .compatible = "apple,t6020-pmgr-misc", .data = &apple_pmgr_misc_hw_t602x },
+	{}
+};
+
+MODULE_DEVICE_TABLE(of, apple_pmgr_misc_of_match);
+
+static const struct dev_pm_ops apple_pmgr_misc_pm_ops = {
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(apple_pmgr_misc_suspend_noirq,
+				      apple_pmgr_misc_resume_noirq)
+};
+
+static struct platform_driver apple_pmgr_misc_driver = {
+	.probe = apple_pmgr_misc_probe,
+	.driver = {
+		.name = "apple-pmgr-misc",
+		.of_match_table = apple_pmgr_misc_of_match,
+		.pm = pm_ptr(&apple_pmgr_misc_pm_ops),
+	},
+};
+
+MODULE_AUTHOR("Hector Martin <marcan@marcan.st>");
+MODULE_DESCRIPTION("PMGR misc driver for Apple SoCs");
+MODULE_LICENSE("GPL");
+
+module_platform_driver(apple_pmgr_misc_driver);