[v1] Generic SPMI NVMEM cell driver

[PATCH 2/3] nvmem: Add spmi-nvmem driver

Posted by Sasha Finkelstein via B4 Relay 8 months, 1 week ago

From: Hector Martin <marcan@marcan.st>

This driver exposes a SPMI device as an NVMEM device.
It is intended to be used with e.g. PMUs/PMICs that are used to
hold power management configuration, such as used on Apple Silicon
Macs.

Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
---
 MAINTAINERS                |  1 +
 drivers/nvmem/Kconfig      | 14 +++++++++++
 drivers/nvmem/Makefile     |  2 ++
 drivers/nvmem/spmi-nvmem.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 79 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index e7b2d0df81b387ba5398957131971588dc7b89dc..63c12f901aed1f3e6de8227d6db34af1bd046fe6 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/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 8671b7c974b933e147154bb40b5d41b5730518d2..9ec907d8aa6ef7df0ea45cc35e92d8239d2705ee 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -310,6 +310,20 @@ config NVMEM_SNVS_LPGPR
 	  This driver can also be built as a module. If so, the module
 	  will be called nvmem-snvs-lpgpr.
 
+config NVMEM_SPMI
+	tristate "Generic SPMI NVMEM"
+	default ARCH_APPLE
+	depends on SPMI
+	select REGMAP_SPMI
+	help
+	  Say y here to build a generic driver to expose a SPMI device
+	  as a NVMEM provider. This can be used for PMIC/PMU devices which
+	  are used to store power and RTC-related settings on certain
+	  platforms, such as Apple Silicon Macs.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called nvmem-spmi.
+
 config NVMEM_SPMI_SDAM
 	tristate "SPMI SDAM Support"
 	depends on SPMI
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 5b77bbb6488bf89bfb305750a1cbf4a6731a0a58..b639f4284184db026bb27b11e04d54b8f7ff166f 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -64,6 +64,8 @@ obj-$(CONFIG_NVMEM_SC27XX_EFUSE)	+= nvmem-sc27xx-efuse.o
 nvmem-sc27xx-efuse-y			:= sc27xx-efuse.o
 obj-$(CONFIG_NVMEM_SNVS_LPGPR)		+= nvmem_snvs_lpgpr.o
 nvmem_snvs_lpgpr-y			:= snvs_lpgpr.o
+obj-$(CONFIG_NVMEM_SPMI)		+= nvmem_spmi.o
+nvmem_spmi-y				:= spmi-nvmem.o
 obj-$(CONFIG_NVMEM_SPMI_SDAM)		+= nvmem_qcom-spmi-sdam.o
 nvmem_qcom-spmi-sdam-y			+= qcom-spmi-sdam.o
 obj-$(CONFIG_NVMEM_SPRD_EFUSE)		+= nvmem_sprd_efuse.o
diff --git a/drivers/nvmem/spmi-nvmem.c b/drivers/nvmem/spmi-nvmem.c
new file mode 100644
index 0000000000000000000000000000000000000000..fff6162cb22dd7ab45883f004f5b63ebae014698
--- /dev/null
+++ b/drivers/nvmem/spmi-nvmem.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Generic 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 spmi_regmap_config = {
+	.reg_bits	= 16,
+	.val_bits	= 8,
+	.max_register	= 0xffff,
+};
+
+static int 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, &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 spmi_nvmem_id_table[] = {
+	{ .compatible = "spmi-nvmem" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, spmi_nvmem_id_table);
+
+static struct spmi_driver spmi_nvmem_driver = {
+	.probe = spmi_nvmem_probe,
+	.driver = {
+		.name = "spmi-nvmem",
+		.of_match_table	= spmi_nvmem_id_table,
+	},
+};
+
+module_spmi_driver(spmi_nvmem_driver);
+
+MODULE_LICENSE("Dual MIT/GPL");
+MODULE_AUTHOR("Hector Martin <marcan@marcan.st>");
+MODULE_DESCRIPTION("SPMI NVMEM driver");

-- 
2.49.0

Re: [PATCH 2/3] nvmem: Add spmi-nvmem driver

Posted by Srinivas Kandagatla 8 months ago


On 15/04/2025 22:52, Sasha Finkelstein via B4 Relay wrote:
> From: Hector Martin <marcan@marcan.st>
> 
> This driver exposes a SPMI device as an NVMEM device.
> It is intended to be used with e.g. PMUs/PMICs that are used to
> hold power management configuration, such as used on Apple Silicon
> Macs.
> 
> Signed-off-by: Hector Martin <marcan@marcan.st>
> Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
> ---
>   MAINTAINERS                |  1 +
>   drivers/nvmem/Kconfig      | 14 +++++++++++
>   drivers/nvmem/Makefile     |  2 ++
>   drivers/nvmem/spmi-nvmem.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++
>   4 files changed, 79 insertions(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e7b2d0df81b387ba5398957131971588dc7b89dc..63c12f901aed1f3e6de8227d6db34af1bd046fe6 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/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 8671b7c974b933e147154bb40b5d41b5730518d2..9ec907d8aa6ef7df0ea45cc35e92d8239d2705ee 100644
> --- a/drivers/nvmem/Kconfig
> +++ b/drivers/nvmem/Kconfig
> @@ -310,6 +310,20 @@ config NVMEM_SNVS_LPGPR
>   	  This driver can also be built as a module. If so, the module
>   	  will be called nvmem-snvs-lpgpr.
>   
> +config NVMEM_SPMI
> +	tristate "Generic SPMI NVMEM"
> +	default ARCH_APPLE
Why default is set to ARCH_APPLE?

This will endup with y in arm64 defconfig, means increasing the size of 
kernel.

should it be:

depends on ARCH_APPLE || COMPILE_TEST


--srini
> +	depends on SPMI
> +	select REGMAP_SPMI
> +	help
> +	  Say y here to build a generic driver to expose a SPMI device
> +	  as a NVMEM provider. This can be used for PMIC/PMU devices which
> +	  are used to store power and RTC-related settings on certain
> +	  platforms, such as Apple Silicon Macs.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called nvmem-spmi.
> +
>   config NVMEM_SPMI_SDAM
>   	tristate "SPMI SDAM Support"
>   	depends on SPMI
> diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
> index 5b77bbb6488bf89bfb305750a1cbf4a6731a0a58..b639f4284184db026bb27b11e04d54b8f7ff166f 100644
> --- a/drivers/nvmem/Makefile
> +++ b/drivers/nvmem/Makefile
> @@ -64,6 +64,8 @@ obj-$(CONFIG_NVMEM_SC27XX_EFUSE)	+= nvmem-sc27xx-efuse.o
>   nvmem-sc27xx-efuse-y			:= sc27xx-efuse.o
>   obj-$(CONFIG_NVMEM_SNVS_LPGPR)		+= nvmem_snvs_lpgpr.o
>   nvmem_snvs_lpgpr-y			:= snvs_lpgpr.o
> +obj-$(CONFIG_NVMEM_SPMI)		+= nvmem_spmi.o
> +nvmem_spmi-y				:= spmi-nvmem.o
>   obj-$(CONFIG_NVMEM_SPMI_SDAM)		+= nvmem_qcom-spmi-sdam.o
>   nvmem_qcom-spmi-sdam-y			+= qcom-spmi-sdam.o
>   obj-$(CONFIG_NVMEM_SPRD_EFUSE)		+= nvmem_sprd_efuse.o
> diff --git a/drivers/nvmem/spmi-nvmem.c b/drivers/nvmem/spmi-nvmem.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..fff6162cb22dd7ab45883f004f5b63ebae014698
> --- /dev/null
> +++ b/drivers/nvmem/spmi-nvmem.c
> @@ -0,0 +1,62 @@
> +// SPDX-License-Identifier: GPL-2.0-only OR MIT
> +/*
> + * Generic 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 spmi_regmap_config = {
> +	.reg_bits	= 16,
> +	.val_bits	= 8,
> +	.max_register	= 0xffff,
> +};
> +
> +static int 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, &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 spmi_nvmem_id_table[] = {
> +	{ .compatible = "spmi-nvmem" },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, spmi_nvmem_id_table);
> +
> +static struct spmi_driver spmi_nvmem_driver = {
> +	.probe = spmi_nvmem_probe,
> +	.driver = {
> +		.name = "spmi-nvmem",
> +		.of_match_table	= spmi_nvmem_id_table,
> +	},
> +};
> +
> +module_spmi_driver(spmi_nvmem_driver);
> +
> +MODULE_LICENSE("Dual MIT/GPL");
> +MODULE_AUTHOR("Hector Martin <marcan@marcan.st>");
> +MODULE_DESCRIPTION("SPMI NVMEM driver");
>

Re: [PATCH 2/3] nvmem: Add spmi-nvmem driver

Posted by Janne Grunau 8 months ago

On Thu, Apr 17, 2025 at 02:34:37PM +0100, Srinivas Kandagatla wrote:
> 
> 
> On 15/04/2025 22:52, Sasha Finkelstein via B4 Relay wrote:
> > From: Hector Martin <marcan@marcan.st>
> > 
> > This driver exposes a SPMI device as an NVMEM device.
> > It is intended to be used with e.g. PMUs/PMICs that are used to
> > hold power management configuration, such as used on Apple Silicon
> > Macs.
> > 
> > Signed-off-by: Hector Martin <marcan@marcan.st>
> > Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
> > ---
> >   MAINTAINERS                |  1 +
> >   drivers/nvmem/Kconfig      | 14 +++++++++++
> >   drivers/nvmem/Makefile     |  2 ++
> >   drivers/nvmem/spmi-nvmem.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++
> >   4 files changed, 79 insertions(+)
> > 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index e7b2d0df81b387ba5398957131971588dc7b89dc..63c12f901aed1f3e6de8227d6db34af1bd046fe6 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/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 8671b7c974b933e147154bb40b5d41b5730518d2..9ec907d8aa6ef7df0ea45cc35e92d8239d2705ee 100644
> > --- a/drivers/nvmem/Kconfig
> > +++ b/drivers/nvmem/Kconfig
> > @@ -310,6 +310,20 @@ config NVMEM_SNVS_LPGPR
> >   	  This driver can also be built as a module. If so, the module
> >   	  will be called nvmem-snvs-lpgpr.
> >   
> > +config NVMEM_SPMI
> > +	tristate "Generic SPMI NVMEM"
> > +	default ARCH_APPLE
> Why default is set to ARCH_APPLE?
> 
> This will endup with y in arm64 defconfig, means increasing the size of 
> kernel.
> 
> should it be:
> 
> depends on ARCH_APPLE || COMPILE_TEST

I don't think it should depend on ARCH_APPLE. There is nothing
ARCH_APPLE specific in the driver or dt-bindings even apple platforms
are currently only user.

`default m if ARCH_APPLE` might an alternative but in this specific case
the driver which will uses the nvmem cells should just select it. So I
would remove the default.

Janne

Re: [PATCH 2/3] nvmem: Add spmi-nvmem driver

Posted by Srinivas Kandagatla 8 months ago

On Thu, Apr 17, 2025 at 04:30:53PM +0200, Janne Grunau wrote:
> On Thu, Apr 17, 2025 at 02:34:37PM +0100, Srinivas Kandagatla wrote:
> > 
> > 
> > On 15/04/2025 22:52, Sasha Finkelstein via B4 Relay wrote:
> > > From: Hector Martin <marcan@marcan.st>
> > > 
> > > This driver exposes a SPMI device as an NVMEM device.
> > > It is intended to be used with e.g. PMUs/PMICs that are used to
> > > hold power management configuration, such as used on Apple Silicon
> > > Macs.
> > > 
> > > Signed-off-by: Hector Martin <marcan@marcan.st>
> > > Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
> > > ---
> > >   MAINTAINERS                |  1 +
> > >   drivers/nvmem/Kconfig      | 14 +++++++++++
> > >   drivers/nvmem/Makefile     |  2 ++
> > >   drivers/nvmem/spmi-nvmem.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++
> > >   4 files changed, 79 insertions(+)
> > > 
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index e7b2d0df81b387ba5398957131971588dc7b89dc..63c12f901aed1f3e6de8227d6db34af1bd046fe6 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/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 8671b7c974b933e147154bb40b5d41b5730518d2..9ec907d8aa6ef7df0ea45cc35e92d8239d2705ee 100644
> > > --- a/drivers/nvmem/Kconfig
> > > +++ b/drivers/nvmem/Kconfig
> > > @@ -310,6 +310,20 @@ config NVMEM_SNVS_LPGPR
> > >   	  This driver can also be built as a module. If so, the module
> > >   	  will be called nvmem-snvs-lpgpr.
> > >   
> > > +config NVMEM_SPMI
> > > +	tristate "Generic SPMI NVMEM"
> > > +	default ARCH_APPLE
> > Why default is set to ARCH_APPLE?
> > 
> > This will endup with y in arm64 defconfig, means increasing the size of 
> > kernel.
> > 
> > should it be:
> > 
> > depends on ARCH_APPLE || COMPILE_TEST
> 
> I don't think it should depend on ARCH_APPLE. There is nothing
> ARCH_APPLE specific in the driver or dt-bindings even apple platforms
> are currently only user.

irrespective of this is generic or not none of the drivers should have
default set to y.


> 
> `default m if ARCH_APPLE` might an alternative but in this specific case
> the driver which will uses the nvmem cells should just select it. So I
> would remove the default.

remove the default, and let it be selected in defconfig as m as
required, like any other drivers.

--srini
> 
> Janne

Re: [PATCH 2/3] nvmem: Add spmi-nvmem driver

Posted by Sasha Finkelstein 8 months ago

On Thu, 17 Apr 2025 at 15:34, Srinivas Kandagatla <srini@kernel.org> wrote:
> should it be:
>
> depends on ARCH_APPLE || COMPILE_TEST

No, this is not a driver for an apple-specific hw, but a generic thing
for re-exporting
a set of spmi registers as nvmem cells.

Re: [PATCH 2/3] nvmem: Add spmi-nvmem driver

Posted by Alyssa Rosenzweig 8 months ago

> > +config NVMEM_SPMI
> > +	tristate "Generic SPMI NVMEM"
> > +	default ARCH_APPLE
> Why default is set to ARCH_APPLE?
> 
> This will endup with y in arm64 defconfig, means increasing the size of
> kernel.

I mean, eventually I think we /do/ want M1 properly supported in the
arm64 defconfig, no? I'm not sure what the criteria is for any other
driver to be defconfig or not, though.

Re: [PATCH 2/3] nvmem: Add spmi-nvmem driver

Posted by Srinivas Kandagatla 8 months ago

On Thu, Apr 17, 2025 at 09:49:28AM -0400, Alyssa Rosenzweig wrote:
> > > +config NVMEM_SPMI
> > > +	tristate "Generic SPMI NVMEM"
> > > +	default ARCH_APPLE
> > Why default is set to ARCH_APPLE?
> > 
> > This will endup with y in arm64 defconfig, means increasing the size of
> > kernel.
> 
> I mean, eventually I think we /do/ want M1 properly supported in the
> arm64 defconfig, no? I'm not sure what the criteria is for any other
> driver to be defconfig or not, though.
cat arch/arm64/configs/defconfig  | grep APPLE
CONFIG_ARCH_APPLE=y

Criteria for other drivers default should be not selected, 
and should be module if they are part of defconfig, rather than
inbuilt. Not sure how most of the ARCH_APPLE drivers ended up using
default ARCH_APPLE.

--srini

Re: [PATCH 2/3] nvmem: Add spmi-nvmem driver

Posted by Alyssa Rosenzweig 8 months ago

> > > > +config NVMEM_SPMI
> > > > +	tristate "Generic SPMI NVMEM"
> > > > +	default ARCH_APPLE
> > > Why default is set to ARCH_APPLE?
> > > 
> > > This will endup with y in arm64 defconfig, means increasing the size of
> > > kernel.
> > 
> > I mean, eventually I think we /do/ want M1 properly supported in the
> > arm64 defconfig, no? I'm not sure what the criteria is for any other
> > driver to be defconfig or not, though.
> cat arch/arm64/configs/defconfig  | grep APPLE
> CONFIG_ARCH_APPLE=y
> 
> Criteria for other drivers default should be not selected, 
> and should be module if they are part of defconfig, rather than
> inbuilt. Not sure how most of the ARCH_APPLE drivers ended up using
> default ARCH_APPLE.

Oh, I see what you mean, module vs in-built. Understood now, thanks for
explaining :)

Re: [PATCH 2/3] nvmem: Add spmi-nvmem driver

Posted by Alyssa Rosenzweig 8 months, 1 week ago

This should have a Co-developed-by tag in addition to the two sign-offs,
given you've made significant changes.

> This driver exposes a SPMI device as an NVMEM device.
> It is intended to be used with e.g. PMUs/PMICs that are used to
> hold power management configuration, such as used on Apple Silicon
> Macs.
> 
> Signed-off-by: Hector Martin <marcan@marcan.st>
> Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
> ---
>  MAINTAINERS                |  1 +
>  drivers/nvmem/Kconfig      | 14 +++++++++++
>  drivers/nvmem/Makefile     |  2 ++
>  drivers/nvmem/spmi-nvmem.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 79 insertions(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e7b2d0df81b387ba5398957131971588dc7b89dc..63c12f901aed1f3e6de8227d6db34af1bd046fe6 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/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 8671b7c974b933e147154bb40b5d41b5730518d2..9ec907d8aa6ef7df0ea45cc35e92d8239d2705ee 100644
> --- a/drivers/nvmem/Kconfig
> +++ b/drivers/nvmem/Kconfig
> @@ -310,6 +310,20 @@ config NVMEM_SNVS_LPGPR
>  	  This driver can also be built as a module. If so, the module
>  	  will be called nvmem-snvs-lpgpr.
>  
> +config NVMEM_SPMI
> +	tristate "Generic SPMI NVMEM"
> +	default ARCH_APPLE
> +	depends on SPMI
> +	select REGMAP_SPMI
> +	help
> +	  Say y here to build a generic driver to expose a SPMI device
> +	  as a NVMEM provider. This can be used for PMIC/PMU devices which
> +	  are used to store power and RTC-related settings on certain
> +	  platforms, such as Apple Silicon Macs.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called nvmem-spmi.
> +
>  config NVMEM_SPMI_SDAM
>  	tristate "SPMI SDAM Support"
>  	depends on SPMI
> diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
> index 5b77bbb6488bf89bfb305750a1cbf4a6731a0a58..b639f4284184db026bb27b11e04d54b8f7ff166f 100644
> --- a/drivers/nvmem/Makefile
> +++ b/drivers/nvmem/Makefile
> @@ -64,6 +64,8 @@ obj-$(CONFIG_NVMEM_SC27XX_EFUSE)	+= nvmem-sc27xx-efuse.o
>  nvmem-sc27xx-efuse-y			:= sc27xx-efuse.o
>  obj-$(CONFIG_NVMEM_SNVS_LPGPR)		+= nvmem_snvs_lpgpr.o
>  nvmem_snvs_lpgpr-y			:= snvs_lpgpr.o
> +obj-$(CONFIG_NVMEM_SPMI)		+= nvmem_spmi.o
> +nvmem_spmi-y				:= spmi-nvmem.o
>  obj-$(CONFIG_NVMEM_SPMI_SDAM)		+= nvmem_qcom-spmi-sdam.o
>  nvmem_qcom-spmi-sdam-y			+= qcom-spmi-sdam.o
>  obj-$(CONFIG_NVMEM_SPRD_EFUSE)		+= nvmem_sprd_efuse.o
> diff --git a/drivers/nvmem/spmi-nvmem.c b/drivers/nvmem/spmi-nvmem.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..fff6162cb22dd7ab45883f004f5b63ebae014698
> --- /dev/null
> +++ b/drivers/nvmem/spmi-nvmem.c
> @@ -0,0 +1,62 @@
> +// SPDX-License-Identifier: GPL-2.0-only OR MIT
> +/*
> + * Generic 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 spmi_regmap_config = {
> +	.reg_bits	= 16,
> +	.val_bits	= 8,
> +	.max_register	= 0xffff,
> +};
> +
> +static int 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, &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 spmi_nvmem_id_table[] = {
> +	{ .compatible = "spmi-nvmem" },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, spmi_nvmem_id_table);
> +
> +static struct spmi_driver spmi_nvmem_driver = {
> +	.probe = spmi_nvmem_probe,
> +	.driver = {
> +		.name = "spmi-nvmem",
> +		.of_match_table	= spmi_nvmem_id_table,
> +	},
> +};
> +
> +module_spmi_driver(spmi_nvmem_driver);
> +
> +MODULE_LICENSE("Dual MIT/GPL");
> +MODULE_AUTHOR("Hector Martin <marcan@marcan.st>");
> +MODULE_DESCRIPTION("SPMI NVMEM driver");
> 
> -- 
> 2.49.0
> 
>

Re: [PATCH 2/3] nvmem: Add spmi-nvmem driver

Posted by Neal Gompa 8 months, 1 week ago

On Tue, Apr 15, 2025 at 5:52 PM Sasha Finkelstein via B4 Relay
<devnull+fnkl.kernel.gmail.com@kernel.org> wrote:
>
> From: Hector Martin <marcan@marcan.st>
>
> This driver exposes a SPMI device as an NVMEM device.
> It is intended to be used with e.g. PMUs/PMICs that are used to
> hold power management configuration, such as used on Apple Silicon
> Macs.
>
> Signed-off-by: Hector Martin <marcan@marcan.st>
> Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
> ---
>  MAINTAINERS                |  1 +
>  drivers/nvmem/Kconfig      | 14 +++++++++++
>  drivers/nvmem/Makefile     |  2 ++
>  drivers/nvmem/spmi-nvmem.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 79 insertions(+)
>

This driver code looks reasonable to me.

Reviewed-by: Neal Gompa <neal@gompa.dev>


-- 
真実はいつも一つ！/ Always, there's only one truth!