Re: [PATCH] platform/x86:dell-laptop: Add knobs to change battery charge settings

Hans de Goede
2024-07-29T10:03:05Z

Hi,

On 7/20/24 7:22 AM, Andres Salomon wrote:
>
> The Dell BIOS allows you to set custom charging modes, which is useful
> in particular for extending battery life. This adds support for tweaking
> those various settings from Linux via sysfs knobs. One might, for
> example, have their laptop plugged into power at their desk the vast
> majority of the time and choose fairly aggressive battery-saving
> settings (only charging once the battery drops to 50% and only charging
> up to 80%). When leaving for a trip, they might want to switch those
> settings to charge to 100% and charge any time power is available;
> rebooting into the BIOS to change those settings is a hassle.
>
> For the Custom charging type mode, we reuse the common
> charge_control_{start,end}_threshold sysfs power_supply entries. The
> BIOS also has a bunch of other charging modes with varying levels of
> usefulness, so this adds a new Dell-specific sysfs entry called
> 'charge_type' that's documented in sysfs-class-power-dell (and looks a
> lot like sysfs-class-power-wilco).
>
> This work is based on a patch by Perry Yuan <perry_yuan@dell.com> and
> Limonciello Mario <Mario_Limonciello@Dell.com> submitted back in 2020:
> https://lore.kernel.org/all/20200729065424.12851-1-Perry_Yuan@Dell.com/
> Both of their email addresses bounce, so I'm assuming they're no longer
> with the company. I've reworked most of the patch to make it smaller and
> cleaner.
>
> Signed-off-by: Andres Salomon <dilinger@queued.net>

Thank you for working on this and it is great to see the discussion
to improve the code between you and Pali going on.

One concern which I have is that work is underway for both upower
and GNOME to add support for
/sys/class/power_supply/*/charge_[start|stop]_threshold

to gnome-control-center.

But if I understand things correctly then these limits will only
be honored when the charging-type is set to custom.

So we need to do something to avoid userspace exposing those
controls when the charging-type is not custom.

I think it would be best to not have the charge_[start|stop]_threshold
attributes visible when the charging mode is not custom.

Regards,

Hans

> ---
> .../ABI/testing/sysfs-class-power-dell | 31 +++
> drivers/platform/x86/dell/Kconfig | 1 +
> drivers/platform/x86/dell/dell-laptop.c | 263 ++++++++++++++++++
> drivers/platform/x86/dell/dell-smbios.h | 17 ++
> 4 files changed, 312 insertions(+)
> create mode 100644 Documentation/ABI/testing/sysfs-class-power-dell
>
> diff --git a/Documentation/ABI/testing/sysfs-class-power-dell b/Documentation/ABI/testing/sysfs-class-power-dell
> new file mode 100644
> index 000000000000..ef72c5f797ce
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-power-dell
> @@ -0,0 +1,31 @@
> +What: /sys/class/power_supply/<supply_name>/charge_type
> +Date: July 2024
> +KernelVersion: 6.11
> +Contact: linux-pm@vger.kernel.org
> +Description:
> + Select the charging algorithm to use for the (primary)
> + battery.
> +
> + Standard:
> + Fully charge the battery at a moderate rate.
> + ExpressCharge™:
> + Quickly charge the battery using fast-charge
> + technology. This is harder on the battery than
> + standard charging and may lower its lifespan.
> + Primarily AC Use:
> + Users who primarily operate the system while
> + plugged into an external power source can extend
> + battery life with this mode.
> + Adaptive:
> + Automatically optimize battery charge rate based
> + on typical usage.
> + Custom:
> + Use the charge_control_* properties to determine
> + when to start and stop charging. Advanced users
> + can use this to drastically extend battery life.
> +
> + Access: Read, Write
> + Valid values:
> + "standard", "express", "primarily_ac",
> + "adaptive", "custom"
> +
> diff --git a/drivers/platform/x86/dell/Kconfig b/drivers/platform/x86/dell/Kconfig
> index 85a78ef91182..02405793163c 100644
> --- a/drivers/platform/x86/dell/Kconfig
> +++ b/drivers/platform/x86/dell/Kconfig
> @@ -49,6 +49,7 @@ config DELL_LAPTOP
> default m
> depends on DMI
> depends on BACKLIGHT_CLASS_DEVICE
> + depends on ACPI_BATTERY
> depends on ACPI_VIDEO || ACPI_VIDEO = n
> depends on RFKILL || RFKILL = n
> depends on DELL_WMI || DELL_WMI = n
> diff --git a/drivers/platform/x86/dell/dell-laptop.c b/drivers/platform/x86/dell/dell-laptop.c
> index 6552dfe491c6..54f47b685a46 100644
> --- a/drivers/platform/x86/dell/dell-laptop.c
> +++ b/drivers/platform/x86/dell/dell-laptop.c
> @@ -22,11 +22,13 @@
> #include <linux/io.h>
> #include <linux/rfkill.h>
> #include <linux/power_supply.h>
> +#include <linux/sysfs.h>
> #include <linux/acpi.h>
> #include <linux/mm.h>
> #include <linux/i8042.h>
> #include <linux/debugfs.h>
> #include <linux/seq_file.h>
> +#include <acpi/battery.h>
> #include <acpi/video.h>
> #include "dell-rbtn.h"
> #include "dell-smbios.h"
> @@ -98,6 +100,14 @@ static struct rfkill *wwan_rfkill;
> static bool force_rfkill;
> static bool micmute_led_registered;
> static bool mute_led_registered;
> +static enum battery_charging_mode bat_chg_current = DELL_BAT_MODE_NONE;
> +static const char * const battery_state[DELL_BAT_MODE_MAX] = {
> + [DELL_BAT_MODE_STANDARD] = "standard",
> + [DELL_BAT_MODE_EXPRESS] = "express",
> + [DELL_BAT_MODE_PRIMARILY_AC] = "primarily_ac",
> + [DELL_BAT_MODE_ADAPTIVE] = "adaptive",
> + [DELL_BAT_MODE_CUSTOM] = "custom",
> +};
>
> module_param(force_rfkill, bool, 0444);
> MODULE_PARM_DESC(force_rfkill, "enable rfkill on non whitelisted models");
> @@ -2183,6 +2193,256 @@ static struct led_classdev mute_led_cdev = {
> .default_trigger = "audio-mute",
> };
>
> +static int dell_battery_read_req(const int type, int *val)
> +{
> + struct calling_interface_buffer buffer;
> + struct calling_interface_token *token;
> + int err;
> +
> + token = dell_smbios_find_token(type);
> + if (!token)
> + return -ENODEV;
> +
> + dell_fill_request(&buffer, token->location, 0, 0, 0);
> + err = dell_send_request(&buffer, CLASS_TOKEN_READ, SELECT_TOKEN_STD);
> + if (!err)
> + *val = buffer.output[1];
> +
> + return err;
> +}
> +
> +static int dell_battery_write_req(const int type, int val)
> +{
> + struct calling_interface_buffer buffer;
> + struct calling_interface_token *token;
> +
> + token = dell_smbios_find_token(type);
> + if (!token)
> + return -ENODEV;
> +
> + dell_fill_request(&buffer, token->location, val, 0, 0);
> + return dell_send_request(&buffer,
> + CLASS_TOKEN_WRITE, SELECT_TOKEN_STD);
> +}
> +
> +/* The rules: the minimum start charging value is 50%. The maximum
> + * start charging value is 95%. The minimum end charging value is
> + * 55%. The maximum end charging value is 100%. And finally, there
> + * has to be at least a 5% difference between start & end values.
> + */
> +#define CHARGE_START_MIN 50
> +#define CHARGE_START_MAX 95
> +#define CHARGE_END_MIN 55
> +#define CHARGE_END_MAX 100
> +#define CHARGE_MIN_DIFF 5
> +
> +static int dell_battery_custom_set(const int type, int val)
> +{
> + if (type == BAT_CUSTOM_CHARGE_START) {
> + int end = CHARGE_END_MAX;
> +
> + if (val < CHARGE_START_MIN)
> + val = CHARGE_START_MIN;
> + else if (val > CHARGE_START_MAX)
> + val = CHARGE_START_MAX;
> +
> + dell_battery_read_req(BAT_CUSTOM_CHARGE_END, &end);
> + if ((end - val) < CHARGE_MIN_DIFF)
> + val = end - CHARGE_MIN_DIFF;
> + } else if (type == BAT_CUSTOM_CHARGE_END) {
> + int start = CHARGE_START_MIN;
> +
> + if (val < CHARGE_END_MIN)
> + val = CHARGE_END_MIN;
> + else if (val > CHARGE_END_MAX)
> + val = CHARGE_END_MAX;
> +
> + dell_battery_read_req(BAT_CUSTOM_CHARGE_START, &start);
> + if ((val - start) < CHARGE_MIN_DIFF)
> + val = start + CHARGE_MIN_DIFF;
> + }
> +
> + return dell_battery_write_req(type, val);
> +}
> +
> +static int battery_charging_mode_set(enum battery_charging_mode mode)
> +{
> + int err;
> +
> + switch (mode) {
> + case DELL_BAT_MODE_STANDARD:
> + err = dell_battery_write_req(BAT_STANDARD_MODE_TOKEN, mode);
> + break;
> + case DELL_BAT_MODE_EXPRESS:
> + err = dell_battery_write_req(BAT_EXPRESS_MODE_TOKEN, mode);
> + break;
> + case DELL_BAT_MODE_PRIMARILY_AC:
> + err = dell_battery_write_req(BAT_PRI_AC_MODE_TOKEN, mode);
> + break;
> + case DELL_BAT_MODE_ADAPTIVE:
> + err = dell_battery_write_req(BAT_ADAPTIVE_MODE_TOKEN, mode);
> + break;
> + case DELL_BAT_MODE_CUSTOM:
> + err = dell_battery_write_req(BAT_CUSTOM_MODE_TOKEN, mode);
> + break;
> + default:
> + err = -EINVAL;
> + }
> +
> + return err;
> +}
> +
> +static ssize_t charge_type_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + enum battery_charging_mode mode;
> + ssize_t count = 0;
> +
> + for (mode = DELL_BAT_MODE_STANDARD; mode < DELL_BAT_MODE_MAX; mode++) {
> + if (battery_state[mode]) {
> + count += sysfs_emit_at(buf, count,
> + mode == bat_chg_current ? "[%s] " : "%s ",
> + battery_state[mode]);
> + }
> + }
> +
> + /* convert the last space to a newline */
> + count--;
> + count += sysfs_emit_at(buf, count, "\n");
> +
> + return count;
> +}
> +
> +static ssize_t charge_type_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t size)
> +{
> + enum battery_charging_mode mode;
> + const char *label;
> + int ret = -EINVAL;
> +
> + for (mode = DELL_BAT_MODE_STANDARD; mode < DELL_BAT_MODE_MAX; mode++) {
> + label = battery_state[mode];
> + if (label && sysfs_streq(label, buf))
> + break;
> + }
> +
> + if (mode > DELL_BAT_MODE_NONE && mode < DELL_BAT_MODE_MAX) {
> + ret = battery_charging_mode_set(mode);
> + if (!ret) {
> + bat_chg_current = mode;
> + ret = size;
> + }
> + }
> +
> + return ret;
> +}
> +
> +static ssize_t charge_control_start_threshold_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + int ret, start;
> +
> + ret = dell_battery_read_req(BAT_CUSTOM_CHARGE_START, &start);
> + if (!ret)
> + ret = sysfs_emit(buf, "%d\n", start);
> +
> + return ret;
> +}
> +
> +static ssize_t charge_control_start_threshold_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t size)
> +{
> + int ret, start;
> +
> + ret = kstrtoint(buf, 10, &start);
> + if (!ret)
> + ret = dell_battery_custom_set(BAT_CUSTOM_CHARGE_START, start);
> + if (!ret)
> + ret = size;
> +
> + return ret;
> +}
> +
> +static ssize_t charge_control_end_threshold_show(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + int ret, end;
> +
> + ret = dell_battery_read_req(BAT_CUSTOM_CHARGE_END, &end);
> + if (!ret)
> + ret = sysfs_emit(buf, "%d\n", end);
> +
> + return ret;
> +}
> +
> +static ssize_t charge_control_end_threshold_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t size)
> +{
> + int ret, end;
> +
> + ret = kstrtouint(buf, 10, &end);
> + if (!ret)
> + ret = dell_battery_custom_set(BAT_CUSTOM_CHARGE_END, end);
> + if (!ret)
> + ret = size;
> +
> + return ret;
> +}
> +
> +static DEVICE_ATTR_RW(charge_control_start_threshold);
> +static DEVICE_ATTR_RW(charge_control_end_threshold);
> +static DEVICE_ATTR_RW(charge_type);
> +
> +static struct attribute *dell_battery_attrs[] = {
> + &dev_attr_charge_control_start_threshold.attr,
> + &dev_attr_charge_control_end_threshold.attr,
> + &dev_attr_charge_type.attr,
> + NULL,
> +};
> +ATTRIBUTE_GROUPS(dell_battery);
> +
> +static int dell_battery_add(struct power_supply *battery,
> + struct acpi_battery_hook *hook)
> +{
> + return device_add_groups(&battery->dev, dell_battery_groups);
> +}
> +
> +static int dell_battery_remove(struct power_supply *battery,
> + struct acpi_battery_hook *hook)
> +{
> + device_remove_groups(&battery->dev, dell_battery_groups);
> + return 0;
> +}
> +
> +static struct acpi_battery_hook dell_battery_hook = {
> + .add_battery = dell_battery_add,
> + .remove_battery = dell_battery_remove,
> + .name = "Dell Primary Battery Extension",
> +};
> +
> +static void __init dell_battery_init(struct device *dev)
> +{
> + enum battery_charging_mode current_mode = DELL_BAT_MODE_NONE;
> +
> + dell_battery_read_req(BAT_CUSTOM_MODE_TOKEN, (int *) &current_mode);
> + if (current_mode != DELL_BAT_MODE_NONE) {
> + bat_chg_current = current_mode;
> + battery_hook_register(&dell_battery_hook);
> + }
> +}
> +
> +static void __exit dell_battery_exit(void)
> +{
> + if (bat_chg_current != DELL_BAT_MODE_NONE)
> + battery_hook_unregister(&dell_battery_hook);
> +}
> +
> static int __init dell_init(void)
> {
> struct calling_interface_token *token;
> @@ -2219,6 +2479,7 @@ static int __init dell_init(void)
> touchpad_led_init(&platform_device->dev);
>
> kbd_led_init(&platform_device->dev);
> + dell_battery_init(&platform_device->dev);
>
> dell_laptop_dir = debugfs_create_dir("dell_laptop", NULL);
> debugfs_create_file("rfkill", 0444, dell_laptop_dir, NULL,
> @@ -2293,6 +2554,7 @@ static int __init dell_init(void)
> if (mute_led_registered)
> led_classdev_unregister(&mute_led_cdev);
> fail_led:
> + dell_battery_exit();
> dell_cleanup_rfkill();
> fail_rfkill:
> platform_device_del(platform_device);
> @@ -2311,6 +2573,7 @@ static void __exit dell_exit(void)
> if (quirks && quirks->touchpad_led)
> touchpad_led_exit();
> kbd_led_exit();
> + dell_battery_exit();
> backlight_device_unregister(dell_backlight_device);
> if (micmute_led_registered)
> led_classdev_unregister(&micmute_led_cdev);
> diff --git a/drivers/platform/x86/dell/dell-smbios.h b/drivers/platform/x86/dell/dell-smbios.h
> index ea0cc38642a2..f7c07b4d72e3 100644
> --- a/drivers/platform/x86/dell/dell-smbios.h
> +++ b/drivers/platform/x86/dell/dell-smbios.h
> @@ -33,11 +33,28 @@
> #define KBD_LED_AUTO_50_TOKEN 0x02EB
> #define KBD_LED_AUTO_75_TOKEN 0x02EC
> #define KBD_LED_AUTO_100_TOKEN 0x02F6
> +#define BAT_PRI_AC_MODE_TOKEN 0x0341
> +#define BAT_ADAPTIVE_MODE_TOKEN 0x0342
> +#define BAT_CUSTOM_MODE_TOKEN 0x0343
> +#define BAT_STANDARD_MODE_TOKEN 0x0346
> +#define BAT_EXPRESS_MODE_TOKEN 0x0347
> +#define BAT_CUSTOM_CHARGE_START 0x0349
> +#define BAT_CUSTOM_CHARGE_END 0x034A
> #define GLOBAL_MIC_MUTE_ENABLE 0x0364
> #define GLOBAL_MIC_MUTE_DISABLE 0x0365
> #define GLOBAL_MUTE_ENABLE 0x058C
> #define GLOBAL_MUTE_DISABLE 0x058D
>
> +enum battery_charging_mode {
> + DELL_BAT_MODE_NONE = 0,
> + DELL_BAT_MODE_STANDARD,
> + DELL_BAT_MODE_EXPRESS,
> + DELL_BAT_MODE_PRIMARILY_AC,
> + DELL_BAT_MODE_ADAPTIVE,
> + DELL_BAT_MODE_CUSTOM,
> + DELL_BAT_MODE_MAX,
> +};
> +
> struct notifier_block;
>
> struct calling_interface_token {