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Date: Wed, 20 May 2020 11:42:15 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>,
Len Brown <lenb@...nel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>
Subject: Re: [PATCH] ACPI / DPTF: Add additional attributes to power
participant driver
powerOn Wed, May 20, 2020 at 12:24 AM Srinivas Pandruvada
<srinivas.pandruvada@...ux.intel.com> wrote:
>
> Add two additional attributes to the existing power participant driver:
> rest_of_platform_power_mw: (RO) Shows the rest of worst case platform
> power in mW.
It would be good to explain or at least give an example of what the
"rest of worst case platform power" can be.
> prochot_confirm: (WO) Confirm EC about a prochot notification.
>
> Also userspace is notified via sysfs_notify(), whenever power source or
> rest of the platform power is changed. So user space can use poll()
> system call on those attributes.
>
> The ACPI methods used in this patch are as follows:
>
> PROP
> This object evaluates to the rest of worst case platform power in mW.
> Bits:
> 23:0 Worst case rest of platform power in mW.
>
> PBOK
> PBOK is a method designed to provide a mechanism for OSPM to change power
> setting before EC can de-assert a PROCHOT from a device. The EC may
> receive several PROCHOTs, so it has a sequence number attached to PSRC
> (read via existing attribute "platform_power_source"). Once OSPM takes
> action for a PSRC change notification, it can call PBOK method to confirm
> with the sequence number.
> Bits:
> 3:0 Power Delivery State Change Sequence number
> 30 Reserved
> 31 0 – Not OK to de-assert PROCHOT
> 1 – OK to de-assert PROCHOT
>
> PSRC (Platform Power Source): Not new in this patch but for
> documentation for new bits
> This object evaluates to an integer that represents the system power
> source as well as the power delivery state change sequence number.
> Bits:
> 3:0 The current power source as an integer for AC, DC, USB, Wireless.
> 0 = DC, 1 = AC, 2 = USB, 3 = Wireless Charging
> 7:4 Power Delivery State Change Sequence Number. Default value is 0
>
> Notifications:
> 0x81: (Power State Change) Used to notify when the power source has
> changed.
> 0x84: (PROP change) Used to notify when the platform rest of power has
> changed.
>
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
> ---
> Documentation/ABI/testing/sysfs-platform-dptf | 24 +++++--
> drivers/acpi/dptf/dptf_power.c | 69 ++++++++++++++++++-
> 2 files changed, 88 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-platform-dptf b/Documentation/ABI/testing/sysfs-platform-dptf
> index 325dc0667dbb..cf4eb5d676de 100644
> --- a/Documentation/ABI/testing/sysfs-platform-dptf
> +++ b/Documentation/ABI/testing/sysfs-platform-dptf
> @@ -27,10 +27,12 @@ KernelVersion: v4.10
> Contact: linux-acpi@...r.kernel.org
> Description:
> (RO) Display the platform power source
> - 0x00 = DC
> - 0x01 = AC
> - 0x02 = USB
> - 0x03 = Wireless Charger
> + bits[3:0] Current power source
> + 0x00 = DC
> + 0x01 = AC
> + 0x02 = USB
> + 0x03 = Wireless Charger
> + bits[7:4] Power source sequence number
>
> What: /sys/bus/platform/devices/INT3407:00/dptf_power/battery_steady_power
> Date: Jul, 2016
> @@ -38,3 +40,17 @@ KernelVersion: v4.10
> Contact: linux-acpi@...r.kernel.org
> Description:
> (RO) The maximum sustained power for battery in milliwatts.
> +
> +What: /sys/bus/platform/devices/INT3407:00/dptf_power/rest_of_platform_power_mw
> +Date: June, 2020
> +KernelVersion: v5.8
> +Contact: linux-acpi@...r.kernel.org
> +Description:
> + (RO) Shows the rest of worst case platform power in mW.
> +
> +What: /sys/bus/platform/devices/INT3407:00/dptf_power/prochot_confirm
> +Date: June, 2020
> +KernelVersion: v5.8
> +Contact: linux-acpi@...r.kernel.org
> +Description:
> + (WO) Confirm embedded controller about a prochot notification.
> diff --git a/drivers/acpi/dptf/dptf_power.c b/drivers/acpi/dptf/dptf_power.c
> index e4e8b75d39f0..abe99039af74 100644
> --- a/drivers/acpi/dptf/dptf_power.c
> +++ b/drivers/acpi/dptf/dptf_power.c
> @@ -16,6 +16,7 @@
> * ARTG : Adapter rating
> * CTYP : Charger type
> * PBSS : Battery steady power
> + * PROP : Rest of worst case platform Power
> */
> #define DPTF_POWER_SHOW(name, object) \
> static ssize_t name##_show(struct device *dev,\
> @@ -39,12 +40,34 @@ DPTF_POWER_SHOW(platform_power_source, PSRC)
> DPTF_POWER_SHOW(adapter_rating_mw, ARTG)
> DPTF_POWER_SHOW(battery_steady_power_mw, PBSS)
> DPTF_POWER_SHOW(charger_type, CTYP)
> +DPTF_POWER_SHOW(rest_of_platform_power_mw, PROP)
>
> static DEVICE_ATTR_RO(max_platform_power_mw);
> static DEVICE_ATTR_RO(platform_power_source);
> static DEVICE_ATTR_RO(adapter_rating_mw);
> static DEVICE_ATTR_RO(battery_steady_power_mw);
> static DEVICE_ATTR_RO(charger_type);
> +static DEVICE_ATTR_RO(rest_of_platform_power_mw);
> +
> +static ssize_t prochot_confirm_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct acpi_device *acpi_dev = dev_get_drvdata(dev);
> + acpi_status status;
> + int seq_no;
> +
> + if (kstrtouint(buf, 0, &seq_no) < 0)
> + return -EINVAL;
> +
> + status = acpi_execute_simple_method(acpi_dev->handle, "PBOK", seq_no);
> + if (ACPI_SUCCESS(status))
> + return count;
> +
> + return -EINVAL;
> +}
> +
> +static DEVICE_ATTR_WO(prochot_confirm);
>
> static struct attribute *dptf_power_attrs[] = {
> &dev_attr_max_platform_power_mw.attr,
> @@ -52,6 +75,8 @@ static struct attribute *dptf_power_attrs[] = {
> &dev_attr_adapter_rating_mw.attr,
> &dev_attr_battery_steady_power_mw.attr,
> &dev_attr_charger_type.attr,
> + &dev_attr_rest_of_platform_power_mw.attr,
> + &dev_attr_prochot_confirm.attr,
> NULL
> };
>
> @@ -60,6 +85,33 @@ static const struct attribute_group dptf_power_attribute_group = {
> .name = "dptf_power"
> };
>
> +#define POWER_STATE_CHANGED 0x81
> +#define POWER_PROP_CHANGE_EVENT 0x84
> +
> +static void dptf_power_notify(acpi_handle handle, u32 event, void *data)
> +{
> + struct platform_device *pdev = data;
> + char *attr;
> +
> + switch (event) {
> + case POWER_STATE_CHANGED:
> + attr = "platform_power_source";
> + break;
> + case POWER_PROP_CHANGE_EVENT:
> + attr = "rest_of_platform_power_mw";
> + break;
> + default:
> + dev_err(&pdev->dev, "Unsupported event [0x%x]\n", event);
> + return;
> + }
> +
> + /*
> + * Notify that an attribute is changed, so that user space can read
> + * again.
> + */
> + sysfs_notify(&pdev->dev.kobj, "dptf_power", attr);
> +}
> +
> static int dptf_power_add(struct platform_device *pdev)
> {
> struct acpi_device *acpi_dev;
> @@ -78,10 +130,21 @@ static int dptf_power_add(struct platform_device *pdev)
> if (ptype != 0x11)
> return -ENODEV;
>
> + result = acpi_install_notify_handler(acpi_dev->handle,
> + ACPI_DEVICE_NOTIFY,
> + dptf_power_notify,
> + (void *)pdev);
> + if (result)
> + return result;
> +
> result = sysfs_create_group(&pdev->dev.kobj,
> &dptf_power_attribute_group);
> - if (result)
> + if (result) {
> + acpi_remove_notify_handler(acpi_dev->handle,
> + ACPI_DEVICE_NOTIFY,
> + dptf_power_notify);
> return result;
> + }
>
> platform_set_drvdata(pdev, acpi_dev);
>
> @@ -90,7 +153,11 @@ static int dptf_power_add(struct platform_device *pdev)
>
> static int dptf_power_remove(struct platform_device *pdev)
> {
> + struct acpi_device *acpi_dev = platform_get_drvdata(pdev);
>
> + acpi_remove_notify_handler(acpi_dev->handle,
> + ACPI_DEVICE_NOTIFY,
> + dptf_power_notify);
> sysfs_remove_group(&pdev->dev.kobj, &dptf_power_attribute_group);
>
> return 0;
> --
> 2.25.4
>
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