Re: [PATCH] platform/x86: Add Steam Deck driver

Hans de Goede
2022-02-17T16:35:41Z

Hi Andrey,

On 2/6/22 03:20, Andrey Smirnov wrote:
> Add a driver exposing various bits and pieces of functionality
> provided by Steam Deck specific VLV0100 device presented by EC
> firmware. This includes but not limited to:
>
> - CPU/device's fan control
> - Read-only access to DDIC registers
> - Battery tempreature measurements
> - Various display related control knobs
> - USB Type-C connector event notification
>
> Cc: Hans de Goede <hdegoede@redhat.com>
> Cc: Mark Gross <markgross@kernel.org>
> Cc: Jean Delvare <jdelvare@suse.com>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: linux-kernel@vger.kernel.org (open list)
> Cc: platform-driver-x86@vger.kernel.org
> Cc: linux-hwmon@vger.kernel.org
> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>

The .c file says: "Copyright (C) 2021-2022 Valve Corporation"
yet you are using a personal email address. This is not really
an issue, but it does look a bit weird.

> ---
>
> This driver is really a kitchen sink of various small bits. Maybe it
> is worth splitting into an MFD + child drivers/devices?

Yes with the extcon thing I think you should definitely go for
a MFD device. In which case the main driver registering the
regmap + the cells would go under drivers/mfd and most of the
other drivers would go in their own subsystems.

And as the drivers/platform/x86/ subsystem maintainer I guess
that means I don't have to do much with this driver :)

I would still be happy to yake any bits which don't fit
anywhere else attaching to say a "misc" MFD cell.

Regards,

Hans

>
> drivers/platform/x86/Kconfig | 15 +
> drivers/platform/x86/Makefile | 2 +
> drivers/platform/x86/steamdeck.c | 523 +++++++++++++++++++++++++++++++
> 3 files changed, 540 insertions(+)
> create mode 100644 drivers/platform/x86/steamdeck.c
>
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index c23612d98126..86f014e78a6e 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -1136,6 +1136,21 @@ config SIEMENS_SIMATIC_IPC
> To compile this driver as a module, choose M here: the module
> will be called simatic-ipc.
>
> +config STEAMDECK
> + tristate "Valve Steam Deck platform driver"
> + depends on X86_64
> + help
> + Driver exposing various bits and pieces of functionality
> + provided by Steam Deck specific VLV0100 device presented by
> + EC firmware. This includes but not limited to:
> + - CPU/device's fan control
> + - Read-only access to DDIC registers
> + - Battery tempreature measurements
> + - Various display related control knobs
> + - USB Type-C connector event notification
> +
> + Say N unless you are running on a Steam Deck.
> +
> endif # X86_PLATFORM_DEVICES
>
> config PMC_ATOM
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index c12a9b044fd8..2eb965e14ced 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -129,3 +129,5 @@ obj-$(CONFIG_PMC_ATOM) += pmc_atom.o
>
> # Siemens Simatic Industrial PCs
> obj-$(CONFIG_SIEMENS_SIMATIC_IPC) += simatic-ipc.o
> +
> +obj-$(CONFIG_STEAMDECK) += steamdeck.o
> diff --git a/drivers/platform/x86/steamdeck.c b/drivers/platform/x86/steamdeck.c
> new file mode 100644
> index 000000000000..77a6677ec19e
> --- /dev/null
> +++ b/drivers/platform/x86/steamdeck.c
> @@ -0,0 +1,523 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +
> +/*
> + * Steam Deck ACPI platform driver
> + *
> + * Copyright (C) 2021-2022 Valve Corporation
> + *
> + */
> +#include <linux/acpi.h>
> +#include <linux/hwmon.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/extcon-provider.h>
> +
> +#define ACPI_STEAMDECK_NOTIFY_STATUS 0x80
> +
> +/* 0 - port connected, 1 -port disconnected */
> +#define ACPI_STEAMDECK_PORT_CONNECT BIT(0)
> +/* 0 - Upstream Facing Port, 1 - Downdstream Facing Port */
> +#define ACPI_STEAMDECK_CUR_DATA_ROLE BIT(3)
> +/*
> + * Debouncing delay to allow negotiation process to settle. 2s value
> + * was arrived at via trial and error.
> + */
> +#define STEAMDECK_ROLE_SWITCH_DELAY (msecs_to_jiffies(2000))
> +
> +struct steamdeck {
> + struct acpi_device *adev;
> + struct device *hwmon;
> + void *regmap;
> + long fan_target;
> + struct delayed_work role_work;
> + struct extcon_dev *edev;
> + struct device *dev;
> +};
> +
> +static ssize_t
> +steamdeck_simple_store(struct device *dev, const char *buf, size_t count,
> + const char *method,
> + unsigned long upper_limit)
> +{
> + struct steamdeck *fan = dev_get_drvdata(dev);
> + unsigned long value;
> +
> + if (kstrtoul(buf, 10, &value) || value >= upper_limit)
> + return -EINVAL;
> +
> + if (ACPI_FAILURE(acpi_execute_simple_method(fan->adev->handle,
> + (char *)method, value)))
> + return -EIO;
> +
> + return count;
> +}
> +
> +#define STEAMDECK_ATTR_WO(_name, _method, _upper_limit) \
> + static ssize_t _name##_store(struct device *dev, \
> + struct device_attribute *attr, \
> + const char *buf, size_t count) \
> + { \
> + return steamdeck_simple_store(dev, buf, count, \
> + _method, \
> + _upper_limit); \
> + } \
> + static DEVICE_ATTR_WO(_name)
> +
> +STEAMDECK_ATTR_WO(target_cpu_temp, "STCT", U8_MAX / 2);
> +STEAMDECK_ATTR_WO(gain, "SGAN", U16_MAX);
> +STEAMDECK_ATTR_WO(ramp_rate, "SFRR", U8_MAX);
> +STEAMDECK_ATTR_WO(hysteresis, "SHTS", U16_MAX);
> +STEAMDECK_ATTR_WO(maximum_battery_charge_rate, "CHGR", U16_MAX);
> +STEAMDECK_ATTR_WO(recalculate, "SCHG", U16_MAX);
> +
> +STEAMDECK_ATTR_WO(led_brightness, "CHBV", U8_MAX);
> +STEAMDECK_ATTR_WO(content_adaptive_brightness, "CABC", U8_MAX);
> +STEAMDECK_ATTR_WO(gamma_set, "GAMA", U8_MAX);
> +STEAMDECK_ATTR_WO(display_brightness, "WDBV", U8_MAX);
> +STEAMDECK_ATTR_WO(ctrl_display, "WCDV", U8_MAX);
> +STEAMDECK_ATTR_WO(cabc_minimum_brightness, "WCMB", U8_MAX);
> +STEAMDECK_ATTR_WO(memory_data_access_control, "MDAC", U8_MAX);
> +
> +#define STEAMDECK_ATTR_WO_NOARG(_name, _method) \
> + static ssize_t _name##_store(struct device *dev, \
> + struct device_attribute *attr, \
> + const char *buf, size_t count) \
> + { \
> + struct steamdeck *fan = dev_get_drvdata(dev); \
> + \
> + if (ACPI_FAILURE(acpi_evaluate_object(fan->adev->handle, \
> + _method, NULL, NULL))) \
> + return -EIO; \
> + \
> + return count; \
> + } \
> + static DEVICE_ATTR_WO(_name)
> +
> +STEAMDECK_ATTR_WO_NOARG(power_cycle_display, "DPCY");
> +STEAMDECK_ATTR_WO_NOARG(display_normal_mode_on, "NORO");
> +STEAMDECK_ATTR_WO_NOARG(display_inversion_off, "INOF");
> +STEAMDECK_ATTR_WO_NOARG(display_inversion_on, "INON");
> +STEAMDECK_ATTR_WO_NOARG(idle_mode_on, "WRNE");
> +
> +#define STEAMDECK_ATTR_RO(_name, _method) \
> + static ssize_t _name##_show(struct device *dev, \
> + struct device_attribute *attr, \
> + char *buf) \
> + { \
> + struct steamdeck *jup = dev_get_drvdata(dev); \
> + unsigned long long val; \
> + \
> + if (ACPI_FAILURE(acpi_evaluate_integer( \
> + jup->adev->handle, \
> + _method, NULL, &val))) \
> + return -EIO; \
> + \
> + return sprintf(buf, "%llu\n", val); \
> + } \
> + static DEVICE_ATTR_RO(_name)
> +
> +STEAMDECK_ATTR_RO(firmware_version, "PDFW");
> +STEAMDECK_ATTR_RO(board_id, "BOID");
> +STEAMDECK_ATTR_RO(pdcs, "PDCS");
> +
> +static umode_t
> +steamdeck_is_visible(struct kobject *kobj, struct attribute *attr, int index)
> +{
> + return attr->mode;
> +}
> +
> +static struct attribute *steamdeck_attributes[] = {
> + &dev_attr_target_cpu_temp.attr,
> + &dev_attr_gain.attr,
> + &dev_attr_ramp_rate.attr,
> + &dev_attr_hysteresis.attr,
> + &dev_attr_maximum_battery_charge_rate.attr,
> + &dev_attr_recalculate.attr,
> + &dev_attr_power_cycle_display.attr,
> +
> + &dev_attr_led_brightness.attr,
> + &dev_attr_content_adaptive_brightness.attr,
> + &dev_attr_gamma_set.attr,
> + &dev_attr_display_brightness.attr,
> + &dev_attr_ctrl_display.attr,
> + &dev_attr_cabc_minimum_brightness.attr,
> + &dev_attr_memory_data_access_control.attr,
> +
> + &dev_attr_display_normal_mode_on.attr,
> + &dev_attr_display_inversion_off.attr,
> + &dev_attr_display_inversion_on.attr,
> + &dev_attr_idle_mode_on.attr,
> +
> + &dev_attr_firmware_version.attr,
> + &dev_attr_board_id.attr,
> + &dev_attr_pdcs.attr,
> +
> + NULL
> +};
> +
> +static const struct attribute_group steamdeck_group = {
> + .attrs = steamdeck_attributes,
> + .is_visible = steamdeck_is_visible,
> +};
> +
> +static const struct attribute_group *steamdeck_groups[] = {
> + &steamdeck_group,
> + NULL
> +};
> +
> +static int steamdeck_read_fan_speed(struct steamdeck *jup, long *speed)
> +{
> + unsigned long long val;
> +
> + if (ACPI_FAILURE(acpi_evaluate_integer(jup->adev->handle,
> + "FANR", NULL, &val)))
> + return -EIO;
> +
> + *speed = val;
> + return 0;
> +}
> +
> +static int
> +steamdeck_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long *out)
> +{
> + struct steamdeck *sd = dev_get_drvdata(dev);
> + unsigned long long val;
> +
> + switch (type) {
> + case hwmon_temp:
> + if (attr != hwmon_temp_input)
> + return -EOPNOTSUPP;
> +
> + if (ACPI_FAILURE(acpi_evaluate_integer(sd->adev->handle,
> + "BATT", NULL, &val)))
> + return -EIO;
> + /*
> + * Assuming BATT returns deg C we need to mutiply it
> + * by 1000 to convert to mC
> + */
> + *out = val * 1000;
> + break;
> + case hwmon_fan:
> + switch (attr) {
> + case hwmon_fan_input:
> + return steamdeck_read_fan_speed(sd, out);
> + case hwmon_fan_target:
> + *out = sd->fan_target;
> + break;
> + case hwmon_fan_fault:
> + if (ACPI_FAILURE(acpi_evaluate_integer(
> + sd->adev->handle,
> + "FANC", NULL, &val)))
> + return -EIO;
> + /*
> + * FANC (Fan check):
> + * 0: Abnormal
> + * 1: Normal
> + */
> + *out = !val;
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> +
> + return 0;
> +}
> +
> +static int
> +steamdeck_hwmon_read_string(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, const char **str)
> +{
> + switch (type) {
> + case hwmon_temp:
> + *str = "Battery Temp";
> + break;
> + case hwmon_fan:
> + *str = "System Fan";
> + break;
> + default:
> + return -EOPNOTSUPP;
> + }
> +
> + return 0;
> +}
> +
> +static int
> +steamdeck_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
> + u32 attr, int channel, long val)
> +{
> + struct steamdeck *sd = dev_get_drvdata(dev);
> +
> + if (type != hwmon_fan ||
> + attr != hwmon_fan_target)
> + return -EOPNOTSUPP;
> +
> + if (val > U16_MAX)
> + return -EINVAL;
> +
> + sd->fan_target = val;
> +
> + if (ACPI_FAILURE(acpi_execute_simple_method(sd->adev->handle,
> + "FANS", val)))
> + return -EIO;
> +
> + return 0;
> +}
> +
> +static umode_t
> +steamdeck_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
> + u32 attr, int channel)
> +{
> + if (type == hwmon_fan &&
> + attr == hwmon_fan_target)
> + return 0644;
> +
> + return 0444;
> +}
> +
> +static const struct hwmon_channel_info *steamdeck_info[] = {
> + HWMON_CHANNEL_INFO(temp,
> + HWMON_T_INPUT | HWMON_T_LABEL),
> + HWMON_CHANNEL_INFO(fan,
> + HWMON_F_INPUT | HWMON_F_LABEL |
> + HWMON_F_TARGET | HWMON_F_FAULT),
> + NULL
> +};
> +
> +static const struct hwmon_ops steamdeck_hwmon_ops = {
> + .is_visible = steamdeck_hwmon_is_visible,
> + .read = steamdeck_hwmon_read,
> + .read_string = steamdeck_hwmon_read_string,
> + .write = steamdeck_hwmon_write,
> +};
> +
> +static const struct hwmon_chip_info steamdeck_chip_info = {
> + .ops = &steamdeck_hwmon_ops,
> + .info = steamdeck_info,
> +};
> +
> +#define STEAMDECK_STA_OK \
> + (ACPI_STA_DEVICE_ENABLED | \
> + ACPI_STA_DEVICE_PRESENT | \
> + ACPI_STA_DEVICE_FUNCTIONING)
> +
> +static int
> +steamdeck_ddic_reg_read(void *context, unsigned int reg, unsigned int *val)
> +{
> + union acpi_object obj = { .type = ACPI_TYPE_INTEGER };
> + struct acpi_object_list arg_list = { .count = 1, .pointer = &obj, };
> + struct steamdeck *sd = context;
> + unsigned long long _val;
> +
> + obj.integer.value = reg;
> +
> + if (ACPI_FAILURE(acpi_evaluate_integer(sd->adev->handle,
> + "RDDI", &arg_list, &_val)))
> + return -EIO;
> +
> + *val = _val;
> + return 0;
> +}
> +
> +static int steamdeck_read_pdcs(struct steamdeck *sd, unsigned long long *pdcs)
> +{
> + acpi_status status;
> +
> + status = acpi_evaluate_integer(sd->adev->handle, "PDCS", NULL, pdcs);
> + if (ACPI_FAILURE(status)) {
> + dev_err(sd->dev, "PDCS evaluation failed: %s\n",
> + acpi_format_exception(status));
> + return -EIO;
> + }
> +
> + return 0;
> +}
> +
> +static void steamdeck_usb_role_work(struct work_struct *work)
> +{
> + struct steamdeck *sd =
> + container_of(work, struct steamdeck, role_work.work);
> + unsigned long long pdcs;
> + bool usb_host;
> +
> + if (steamdeck_read_pdcs(sd, &pdcs))
> + return;
> +
> + /*
> + * We only care about these two
> + */
> + pdcs &= ACPI_STEAMDECK_PORT_CONNECT | ACPI_STEAMDECK_CUR_DATA_ROLE;
> +
> + /*
> + * For "connect" events our role is determined by a bit in
> + * PDCS, for "disconnect" we switch to being a gadget
> + * unconditionally. The thinking for the latter is we don't
> + * want to start acting as a USB host until we get
> + * confirmation from the firmware that we are a USB host
> + */
> + usb_host = (pdcs & ACPI_STEAMDECK_PORT_CONNECT) ?
> + pdcs & ACPI_STEAMDECK_CUR_DATA_ROLE : false;
> +
> + WARN_ON(extcon_set_state_sync(sd->edev, EXTCON_USB_HOST,
> + usb_host));
> + dev_dbg(sd->dev, "USB role is %s\n", usb_host ? "host" : "device");
> +}
> +
> +static void steamdeck_notify(acpi_handle handle, u32 event, void *context)
> +{
> + struct device *dev = context;
> + struct steamdeck *sd = dev_get_drvdata(dev);
> + unsigned long long pdcs;
> + unsigned long delay;
> +
> + switch (event) {
> + case ACPI_STEAMDECK_NOTIFY_STATUS:
> + if (steamdeck_read_pdcs(sd, &pdcs))
> + return;
> + /*
> + * We process "disconnect" events immediately and
> + * "connect" events with a delay to give the HW time
> + * to settle. For example attaching USB hub (at least
> + * for HW used for testing) will generate intermediary
> + * event with "host" bit not set, followed by the one
> + * that does have it set.
> + */
> + delay = (pdcs & ACPI_STEAMDECK_PORT_CONNECT) ?
> + STEAMDECK_ROLE_SWITCH_DELAY : 0;
> +
> + queue_delayed_work(system_long_wq, &sd->role_work, delay);
> + break;
> + default:
> + dev_err(dev, "Unsupported event [0x%x]\n", event);
> + }
> +}
> +
> +static void steamdeck_remove_notify_handler(void *data)
> +{
> + struct steamdeck *sd = data;
> +
> + acpi_remove_notify_handler(sd->adev->handle, ACPI_DEVICE_NOTIFY,
> + steamdeck_notify);
> + cancel_delayed_work_sync(&sd->role_work);
> +}
> +
> +static const unsigned int steamdeck_extcon_cable[] = {
> + EXTCON_USB,
> + EXTCON_USB_HOST,
> + EXTCON_CHG_USB_SDP,
> + EXTCON_CHG_USB_CDP,
> + EXTCON_CHG_USB_DCP,
> + EXTCON_CHG_USB_ACA,
> + EXTCON_NONE,
> +};
> +
> +static int steamdeck_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct steamdeck *sd;
> + acpi_status status;
> + unsigned long long sta;
> + int ret;
> +
> + static const struct regmap_config regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 8,
> + .max_register = 255,
> + .cache_type = REGCACHE_NONE,
> + .reg_read = steamdeck_ddic_reg_read,
> + };
> +
> + sd = devm_kzalloc(dev, sizeof(*sd), GFP_KERNEL);
> + if (!sd)
> + return -ENOMEM;
> + sd->adev = ACPI_COMPANION(&pdev->dev);
> + sd->dev = dev;
> + platform_set_drvdata(pdev, sd);
> + INIT_DELAYED_WORK(&sd->role_work, steamdeck_usb_role_work);
> +
> + status = acpi_evaluate_integer(sd->adev->handle, "_STA",
> + NULL, &sta);
> + if (ACPI_FAILURE(status)) {
> + dev_err(dev, "Status check failed (0x%x)\n", status);
> + return -EINVAL;
> + }
> +
> + if ((sta & STEAMDECK_STA_OK) != STEAMDECK_STA_OK) {
> + dev_err(dev, "Device is not ready\n");
> + return -EINVAL;
> + }
> +
> + /*
> + * Our ACPI interface doesn't expose a method to read current
> + * fan target, so we use current fan speed as an
> + * approximation.
> + */
> + if (steamdeck_read_fan_speed(sd, &sd->fan_target))
> + dev_warn(dev, "Failed to read fan speed");
> +
> + sd->hwmon = devm_hwmon_device_register_with_info(dev,
> + "steamdeck",
> + sd,
> + &steamdeck_chip_info,
> + steamdeck_groups);
> + if (IS_ERR(sd->hwmon)) {
> + dev_err(dev, "Failed to register HWMON device");
> + return PTR_ERR(sd->hwmon);
> + }
> +
> + sd->regmap = devm_regmap_init(dev, NULL, sd, &regmap_config);
> + if (IS_ERR(sd->regmap))
> + dev_err(dev, "Failed to register REGMAP");
> +
> + sd->edev = devm_extcon_dev_allocate(dev, steamdeck_extcon_cable);
> + if (IS_ERR(sd->edev))
> + return -ENOMEM;
> +
> + ret = devm_extcon_dev_register(dev, sd->edev);
> + if (ret < 0) {
> + dev_err(dev, "Failed to register extcon device: %d\n", ret);
> + return ret;
> + }
> +
> + /*
> + * Set initial role value
> + */
> + queue_delayed_work(system_long_wq, &sd->role_work, 0);
> + flush_delayed_work(&sd->role_work);
> +
> + status = acpi_install_notify_handler(sd->adev->handle,
> + ACPI_DEVICE_NOTIFY,
> + steamdeck_notify,
> + dev);
> + if (ACPI_FAILURE(status)) {
> + dev_err(dev, "Error installing ACPI notify handler\n");
> + return -EIO;
> + }
> +
> + ret = devm_add_action_or_reset(dev, steamdeck_remove_notify_handler,
> + sd);
> + return ret;
> +}
> +
> +static const struct acpi_device_id steamdeck_device_ids[] = {
> + { "VLV0100", 0 },
> + { "", 0 },
> +};
> +MODULE_DEVICE_TABLE(acpi, steamdeck_device_ids);
> +
> +static struct platform_driver steamdeck_driver = {
> + .probe = steamdeck_probe,
> + .driver = {
> + .name = "steamdeck",
> + .acpi_match_table = steamdeck_device_ids,
> + },
> +};
> +module_platform_driver(steamdeck_driver);
> +
> +MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>");
> +MODULE_DESCRIPTION("Steam Deck ACPI platform driver");
> +MODULE_LICENSE("GPL");
> --
> 2.25.1
>