nvmem: Add apple-spmi-nvmem driver

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

Reviewed-by: Neal Gompa <neal@gompa.dev>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Signed-off-by: Hector Martin <marcan@marcan.st>
Co-developed-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
Signed-off-by: Srinivas Kandagatla <srini@kernel.org>
Link: https://lore.kernel.org/r/20250509122452.11827-4-srini@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/MAINTAINERS b/MAINTAINERS
index e1eaaba..b599566 100644 (file)
--- 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 eceb3cd..114140c 100644 (file)
--- 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 5b77bbb..89a3c25 100644 (file)
--- 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 (file)
index 0000000..8861400
--- /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@marcan.st>");
+MODULE_DESCRIPTION("Apple SPMI NVMEM driver");