* [PATCH] ACPI: platform: Add basic support for ACPI 6.5 fixed clock resources
@ 2026-11-03 8:47 Paul Cercueil
2026-11-10 17:18 ` Rafael J. Wysocki (Intel)
0 siblings, 1 reply; 3+ messages in thread
From: Paul Cercueil @ 2026-11-03 8:47 UTC (permalink / raw)
To: Rafael J. Wysocki, Len Brown
Cc: linux-acpi, linux-kernel, Thomas Petazzoni, Paul Cercueil
ACPI 6.5 introduced a clock input resource descriptor, which allows to
specify in the ACPI tables what clocks are connected to a given device.
This patch adds support for the most basic clock resource, which is the
one that represents a fixed clock. The new code will then create a
clk_hw for each fixed clock resource, which is then made available to
the device drivers, that can obtain it through a regular call to
clk_get(NULL).
Signed-off-by: Paul Cercueil <paul.cercueil@bootlin.com>
---
drivers/acpi/acpi_platform.c | 64 ++++++++++++++++++++++++++++++++++++
1 file changed, 64 insertions(+)
diff --git a/drivers/acpi/acpi_platform.c b/drivers/acpi/acpi_platform.c
index 80ea7121744d..bae6a2eacd71 100644
--- a/drivers/acpi/acpi_platform.c
+++ b/drivers/acpi/acpi_platform.c
@@ -10,17 +10,27 @@
#include <linux/acpi.h>
#include <linux/bits.h>
+#include <linux/clk-provider.h>
+#include <linux/clkdev.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/ioport.h>
+#include <linux/kconfig.h>
#include <linux/kernel.h>
+#include <linux/list.h>
#include <linux/module.h>
#include <linux/dma-mapping.h>
#include <linux/pci.h>
#include <linux/platform_device.h>
+#include <linux/units.h>
#include "internal.h"
+struct acpi_clk_data {
+ struct device *dev;
+ unsigned int idx;
+};
+
/* Exclude devices that have no _CRS resources provided */
#define ACPI_ALLOW_WO_RESOURCES BIT(0)
@@ -130,6 +140,57 @@ static unsigned int acpi_platform_resource_count(struct acpi_resource *ares, voi
return AE_CTRL_TERMINATE;
}
+static int acpi_add_fixed_clock(struct acpi_resource *res, void *d)
+{
+ static const unsigned long clk_scale[] = { 1, HZ_PER_KHZ, HZ_PER_MHZ };
+ struct acpi_resource_clock_input *clkres;
+ struct acpi_clk_data *data = d;
+ struct device *dev = data->dev;
+ struct clk_hw *clk;
+ unsigned long rate;
+ char name[64];
+ int err;
+
+ if (res->type == ACPI_RESOURCE_TYPE_CLOCK_INPUT) {
+ clkres = &res->data.clock_input;
+
+ if (clkres->mode) {
+ dev_warn(dev, "Only fixed rate clocks supported for now.\n");
+ return 1; /* keep going */
+ }
+
+ if (clkres->frequency_divisor == 0)
+ return -EINVAL;
+
+ rate = DIV_ROUND_UP(clkres->frequency_numerator * clk_scale[clkres->scale],
+ clkres->frequency_divisor);
+
+ clk = devm_clk_hw_register_fixed_rate(dev, dev_name(dev), NULL, 0, rate);
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+
+ snprintf(name, sizeof(name), "%s-clk%u", dev_name(dev), data->idx++);
+
+ err = devm_clk_hw_register_clkdev(dev, clk, name, dev_name(dev));
+ if (err)
+ return err;
+ }
+
+ return 1;
+}
+
+static void acpi_platform_init_clocks(struct acpi_device *adev)
+{
+ struct device *dev = &adev->dev;
+ struct acpi_clk_data data = { .dev = dev };
+ LIST_HEAD(list);
+ int ret;
+
+ ret = acpi_dev_get_resources(adev, &list, acpi_add_fixed_clock, &data);
+ if (ret < 0)
+ dev_err(dev, "Failed to add clock resources: %d\n", ret);
+}
+
/**
* acpi_create_platform_device - Create platform device for ACPI device node
* @adev: ACPI device node to create a platform device for.
@@ -217,6 +278,9 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *adev,
else
pdevinfo.dma_mask = 0;
+ if (IS_ENABLED(CONFIG_COMMON_CLK))
+ acpi_platform_init_clocks(adev);
+
pdev = platform_device_register_full(&pdevinfo);
if (IS_ERR(pdev))
dev_err(&adev->dev, "platform device creation failed: %ld\n",
--
2.47.3
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] ACPI: platform: Add basic support for ACPI 6.5 fixed clock resources
2026-11-03 8:47 [PATCH] ACPI: platform: Add basic support for ACPI 6.5 fixed clock resources Paul Cercueil
@ 2026-11-10 17:18 ` Rafael J. Wysocki (Intel)
2026-11-11 8:36 ` Paul Cercueil
0 siblings, 1 reply; 3+ messages in thread
From: Rafael J. Wysocki (Intel) @ 2026-11-10 17:18 UTC (permalink / raw)
To: Paul Cercueil
Cc: Rafael J. Wysocki, Len Brown, linux-acpi, linux-kernel, Thomas Petazzoni
On Tue, Nov 3, 2026 at 9:47 AM Paul Cercueil <paul.cercueil@bootlin.com> wrote:
>
> ACPI 6.5 introduced a clock input resource descriptor, which allows to
> specify in the ACPI tables what clocks are connected to a given device.
>
> This patch adds support for the most basic clock resource, which is the
> one that represents a fixed clock. The new code will then create a
> clk_hw for each fixed clock resource, which is then made available to
> the device drivers, that can obtain it through a regular call to
> clk_get(NULL).
>
> Signed-off-by: Paul Cercueil <paul.cercueil@bootlin.com>
You need to look at Sashiko's feedback on this:
https://sashiko.dev/#/patchset/20261103084718.8222-1-paul.cercueil%40bootlin.com
> ---
> drivers/acpi/acpi_platform.c | 64 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 64 insertions(+)
>
> diff --git a/drivers/acpi/acpi_platform.c b/drivers/acpi/acpi_platform.c
> index 80ea7121744d..bae6a2eacd71 100644
> --- a/drivers/acpi/acpi_platform.c
> +++ b/drivers/acpi/acpi_platform.c
> @@ -10,17 +10,27 @@
>
> #include <linux/acpi.h>
> #include <linux/bits.h>
> +#include <linux/clk-provider.h>
> +#include <linux/clkdev.h>
> #include <linux/device.h>
> #include <linux/err.h>
> #include <linux/ioport.h>
> +#include <linux/kconfig.h>
> #include <linux/kernel.h>
> +#include <linux/list.h>
> #include <linux/module.h>
> #include <linux/dma-mapping.h>
> #include <linux/pci.h>
> #include <linux/platform_device.h>
> +#include <linux/units.h>
>
> #include "internal.h"
>
> +struct acpi_clk_data {
> + struct device *dev;
> + unsigned int idx;
> +};
> +
> /* Exclude devices that have no _CRS resources provided */
> #define ACPI_ALLOW_WO_RESOURCES BIT(0)
>
> @@ -130,6 +140,57 @@ static unsigned int acpi_platform_resource_count(struct acpi_resource *ares, voi
> return AE_CTRL_TERMINATE;
> }
>
> +static int acpi_add_fixed_clock(struct acpi_resource *res, void *d)
> +{
> + static const unsigned long clk_scale[] = { 1, HZ_PER_KHZ, HZ_PER_MHZ };
> + struct acpi_resource_clock_input *clkres;
> + struct acpi_clk_data *data = d;
> + struct device *dev = data->dev;
> + struct clk_hw *clk;
> + unsigned long rate;
> + char name[64];
> + int err;
> +
> + if (res->type == ACPI_RESOURCE_TYPE_CLOCK_INPUT) {
> + clkres = &res->data.clock_input;
> +
> + if (clkres->mode) {
> + dev_warn(dev, "Only fixed rate clocks supported for now.\n");
> + return 1; /* keep going */
> + }
> +
> + if (clkres->frequency_divisor == 0)
> + return -EINVAL;
> +
> + rate = DIV_ROUND_UP(clkres->frequency_numerator * clk_scale[clkres->scale],
> + clkres->frequency_divisor);
> +
> + clk = devm_clk_hw_register_fixed_rate(dev, dev_name(dev), NULL, 0, rate);
> + if (IS_ERR(clk))
> + return PTR_ERR(clk);
> +
> + snprintf(name, sizeof(name), "%s-clk%u", dev_name(dev), data->idx++);
> +
> + err = devm_clk_hw_register_clkdev(dev, clk, name, dev_name(dev));
> + if (err)
> + return err;
> + }
> +
> + return 1;
> +}
> +
> +static void acpi_platform_init_clocks(struct acpi_device *adev)
> +{
> + struct device *dev = &adev->dev;
> + struct acpi_clk_data data = { .dev = dev };
> + LIST_HEAD(list);
> + int ret;
> +
> + ret = acpi_dev_get_resources(adev, &list, acpi_add_fixed_clock, &data);
> + if (ret < 0)
> + dev_err(dev, "Failed to add clock resources: %d\n", ret);
> +}
> +
> /**
> * acpi_create_platform_device - Create platform device for ACPI device node
> * @adev: ACPI device node to create a platform device for.
> @@ -217,6 +278,9 @@ struct platform_device *acpi_create_platform_device(struct acpi_device *adev,
> else
> pdevinfo.dma_mask = 0;
>
> + if (IS_ENABLED(CONFIG_COMMON_CLK))
> + acpi_platform_init_clocks(adev);
> +
> pdev = platform_device_register_full(&pdevinfo);
> if (IS_ERR(pdev))
> dev_err(&adev->dev, "platform device creation failed: %ld\n",
> --
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] ACPI: platform: Add basic support for ACPI 6.5 fixed clock resources
2026-11-10 17:18 ` Rafael J. Wysocki (Intel)
@ 2026-11-11 8:36 ` Paul Cercueil
0 siblings, 0 replies; 3+ messages in thread
From: Paul Cercueil @ 2026-11-11 8:36 UTC (permalink / raw)
To: Rafael J. Wysocki (Intel)
Cc: Len Brown, linux-acpi, linux-kernel, Thomas Petazzoni
Hi Rafael,
Le mardi 10 novembre 2026 à 18:18 +0100, Rafael J. Wysocki (Intel) a écrit :
> On Tue, Nov 3, 2026 at 9:47 AM Paul Cercueil <paul.cercueil@bootlin.com>
> wrote:
> >
> > ACPI 6.5 introduced a clock input resource descriptor, which allows to
> > specify in the ACPI tables what clocks are connected to a given device.
> >
> > This patch adds support for the most basic clock resource, which is the
> > one that represents a fixed clock. The new code will then create a
> > clk_hw for each fixed clock resource, which is then made available to
> > the device drivers, that can obtain it through a regular call to
> > clk_get(NULL).
> >
> > Signed-off-by: Paul Cercueil <paul.cercueil@bootlin.com>
>
> You need to look at Sashiko's feedback on this:
>
> https://sashiko.dev/#/patchset/20261103084718.8222-1-paul.cercueil%40bootlin.com
I was expecting Sashiko to send me an email, but it didn't?
I'll v2 with the feedback addressed.
Cheers,
-Paul
> > ---
> > drivers/acpi/acpi_platform.c | 64 ++++++++++++++++++++++++++++++++++++
> > 1 file changed, 64 insertions(+)
> >
> > diff --git a/drivers/acpi/acpi_platform.c b/drivers/acpi/acpi_platform.c
> > index 80ea7121744d..bae6a2eacd71 100644
> > --- a/drivers/acpi/acpi_platform.c
> > +++ b/drivers/acpi/acpi_platform.c
> > @@ -10,17 +10,27 @@
> >
> > #include <linux/acpi.h>
> > #include <linux/bits.h>
> > +#include <linux/clk-provider.h>
> > +#include <linux/clkdev.h>
> > #include <linux/device.h>
> > #include <linux/err.h>
> > #include <linux/ioport.h>
> > +#include <linux/kconfig.h>
> > #include <linux/kernel.h>
> > +#include <linux/list.h>
> > #include <linux/module.h>
> > #include <linux/dma-mapping.h>
> > #include <linux/pci.h>
> > #include <linux/platform_device.h>
> > +#include <linux/units.h>
> >
> > #include "internal.h"
> >
> > +struct acpi_clk_data {
> > + struct device *dev;
> > + unsigned int idx;
> > +};
> > +
> > /* Exclude devices that have no _CRS resources provided */
> > #define ACPI_ALLOW_WO_RESOURCES BIT(0)
> >
> > @@ -130,6 +140,57 @@ static unsigned int acpi_platform_resource_count(struct
> > acpi_resource *ares, voi
> > return AE_CTRL_TERMINATE;
> > }
> >
> > +static int acpi_add_fixed_clock(struct acpi_resource *res, void *d)
> > +{
> > + static const unsigned long clk_scale[] = { 1, HZ_PER_KHZ, HZ_PER_MHZ
> > };
> > + struct acpi_resource_clock_input *clkres;
> > + struct acpi_clk_data *data = d;
> > + struct device *dev = data->dev;
> > + struct clk_hw *clk;
> > + unsigned long rate;
> > + char name[64];
> > + int err;
> > +
> > + if (res->type == ACPI_RESOURCE_TYPE_CLOCK_INPUT) {
> > + clkres = &res->data.clock_input;
> > +
> > + if (clkres->mode) {
> > + dev_warn(dev, "Only fixed rate clocks supported for
> > now.\n");
> > + return 1; /* keep going */
> > + }
> > +
> > + if (clkres->frequency_divisor == 0)
> > + return -EINVAL;
> > +
> > + rate = DIV_ROUND_UP(clkres->frequency_numerator *
> > clk_scale[clkres->scale],
> > + clkres->frequency_divisor);
> > +
> > + clk = devm_clk_hw_register_fixed_rate(dev, dev_name(dev),
> > NULL, 0, rate);
> > + if (IS_ERR(clk))
> > + return PTR_ERR(clk);
> > +
> > + snprintf(name, sizeof(name), "%s-clk%u", dev_name(dev),
> > data->idx++);
> > +
> > + err = devm_clk_hw_register_clkdev(dev, clk, name,
> > dev_name(dev));
> > + if (err)
> > + return err;
> > + }
> > +
> > + return 1;
> > +}
> > +
> > +static void acpi_platform_init_clocks(struct acpi_device *adev)
> > +{
> > + struct device *dev = &adev->dev;
> > + struct acpi_clk_data data = { .dev = dev };
> > + LIST_HEAD(list);
> > + int ret;
> > +
> > + ret = acpi_dev_get_resources(adev, &list, acpi_add_fixed_clock,
> > &data);
> > + if (ret < 0)
> > + dev_err(dev, "Failed to add clock resources: %d\n", ret);
> > +}
> > +
> > /**
> > * acpi_create_platform_device - Create platform device for ACPI device
> > node
> > * @adev: ACPI device node to create a platform device for.
> > @@ -217,6 +278,9 @@ struct platform_device
> > *acpi_create_platform_device(struct acpi_device *adev,
> > else
> > pdevinfo.dma_mask = 0;
> >
> > + if (IS_ENABLED(CONFIG_COMMON_CLK))
> > + acpi_platform_init_clocks(adev);
> > +
> > pdev = platform_device_register_full(&pdevinfo);
> > if (IS_ERR(pdev))
> > dev_err(&adev->dev, "platform device creation failed:
> > %ld\n",
> > --
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2026-11-11 8:36 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2026-11-03 8:47 [PATCH] ACPI: platform: Add basic support for ACPI 6.5 fixed clock resources Paul Cercueil
2026-11-10 17:18 ` Rafael J. Wysocki (Intel)
2026-11-11 8:36 ` Paul Cercueil
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