linux-kernel - [PATCH 3/3] nvmem: Add apple-spmi-nvmem driver

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Message-ID: <20250509122452.11827-4-srini@kernel.org>
Date: Fri,  9 May 2025 13:24:52 +0100
From: srini@...nel.org
To: gregkh@...uxfoundation.org
Cc: linux-kernel@...r.kernel.org,
	Hector Martin <marcan@...can.st>,
	Neal Gompa <neal@...pa.dev>,
	Alyssa Rosenzweig <alyssa@...enzweig.io>,
	Sasha Finkelstein <fnkl.kernel@...il.com>,
	Srinivas Kandagatla <srini@...nel.org>
Subject: [PATCH 3/3] nvmem: Add apple-spmi-nvmem driver

From: Hector Martin <marcan@...can.st>

Add a driver for a series of SPMI-attached PMICs present on Apple devices

Reviewed-by: Neal Gompa <neal@...pa.dev>
Reviewed-by: Alyssa Rosenzweig <alyssa@...enzweig.io>
Signed-off-by: Hector Martin <marcan@...can.st>
Co-developed-by: Sasha Finkelstein <fnkl.kernel@...il.com>
Signed-off-by: Sasha Finkelstein <fnkl.kernel@...il.com>
Signed-off-by: Srinivas Kandagatla <srini@...nel.org>
---
 MAINTAINERS                      |  1 +
 drivers/nvmem/Kconfig            | 13 +++++++
 drivers/nvmem/Makefile           |  2 ++
 drivers/nvmem/apple-spmi-nvmem.c | 62 ++++++++++++++++++++++++++++++++
 4 files changed, 78 insertions(+)
 create mode 100644 drivers/nvmem/apple-spmi-nvmem.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 9936fa9fe87c..65abe712170d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2298,6 +2298,7 @@ F:	drivers/iommu/io-pgtable-dart.c
 F:	drivers/irqchip/irq-apple-aic.c
 F:	drivers/nvme/host/apple.c
 F:	drivers/nvmem/apple-efuses.c
+F:	drivers/nvmem/apple-spmi-nvmem.c
 F:	drivers/pinctrl/pinctrl-apple-gpio.c
 F:	drivers/pwm/pwm-apple.c
 F:	drivers/soc/apple/*
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 8671b7c974b9..ae4afbd8293c 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -40,6 +40,19 @@ config NVMEM_APPLE_EFUSES
 	  This driver can also be built as a module. If so, the module will
 	  be called nvmem-apple-efuses.
 
+config NVMEM_APPLE_SPMI
+	tristate "Apple SPMI NVMEM"
+	depends on ARCH_APPLE || COMPILE_TEST
+	depends on SPMI
+	select REGMAP_SPMI
+	help
+	  Say y here to build a driver to expose NVMEM cells for a set of power
+	  and RTC-related settings on a SPMI-attached PMIC present on Apple
+	  devices, such as Apple Silicon Macs.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called apple-nvmem-spmi.
+
 config NVMEM_BCM_OCOTP
 	tristate "Broadcom On-Chip OTP Controller support"
 	depends on ARCH_BCM_IPROC || COMPILE_TEST
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 5b77bbb6488b..89a3c252c2c8 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -12,6 +12,8 @@ obj-y				+= layouts/
 # Devices
 obj-$(CONFIG_NVMEM_APPLE_EFUSES)	+= nvmem-apple-efuses.o
 nvmem-apple-efuses-y 			:= apple-efuses.o
+obj-$(CONFIG_NVMEM_APPLE_SPMI)		+= apple_nvmem_spmi.o
+apple_nvmem_spmi-y			:= apple-spmi-nvmem.o
 obj-$(CONFIG_NVMEM_BCM_OCOTP)		+= nvmem-bcm-ocotp.o
 nvmem-bcm-ocotp-y			:= bcm-ocotp.o
 obj-$(CONFIG_NVMEM_BRCM_NVRAM)		+= nvmem_brcm_nvram.o
diff --git a/drivers/nvmem/apple-spmi-nvmem.c b/drivers/nvmem/apple-spmi-nvmem.c
new file mode 100644
index 000000000000..88614005d5ce
--- /dev/null
+++ b/drivers/nvmem/apple-spmi-nvmem.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Apple SPMI NVMEM driver
+ *
+ * Copyright The Asahi Linux Contributors
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/of.h>
+#include <linux/spmi.h>
+#include <linux/regmap.h>
+
+static const struct regmap_config apple_spmi_regmap_config = {
+	.reg_bits	= 16,
+	.val_bits	= 8,
+	.max_register	= 0xffff,
+};
+
+static int apple_spmi_nvmem_probe(struct spmi_device *sdev)
+{
+	struct regmap *regmap;
+	struct nvmem_config nvmem_cfg = {
+		.dev = &sdev->dev,
+		.name = "spmi_nvmem",
+		.id = NVMEM_DEVID_AUTO,
+		.word_size = 1,
+		.stride = 1,
+		.size = 0xffff,
+		.reg_read = (void *)regmap_bulk_read,
+		.reg_write = (void *)regmap_bulk_write,
+	};
+
+	regmap = devm_regmap_init_spmi_ext(sdev, &apple_spmi_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	nvmem_cfg.priv = regmap;
+
+	return PTR_ERR_OR_ZERO(devm_nvmem_register(&sdev->dev, &nvmem_cfg));
+}
+
+static const struct of_device_id apple_spmi_nvmem_id_table[] = {
+	{ .compatible = "apple,spmi-nvmem" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, apple_spmi_nvmem_id_table);
+
+static struct spmi_driver apple_spmi_nvmem_driver = {
+	.probe = apple_spmi_nvmem_probe,
+	.driver = {
+		.name = "apple-spmi-nvmem",
+		.of_match_table	= apple_spmi_nvmem_id_table,
+	},
+};
+
+module_spmi_driver(apple_spmi_nvmem_driver);
+
+MODULE_LICENSE("Dual MIT/GPL");
+MODULE_AUTHOR("Hector Martin <marcan@...can.st>");
+MODULE_DESCRIPTION("Apple SPMI NVMEM driver");
-- 
2.43.0