[PATCH] platform/x86: Add Steam Deck driver

From: Andrey Smirnov
Date: Sat Feb 05 2022 - 21:21:06 EST

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@xxxxxxxxxx>
Cc: Mark Gross <markgross@xxxxxxxxxx>
Cc: Jean Delvare <jdelvare@xxxxxxxx>
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx (open list)
Cc: platform-driver-x86@xxxxxxxxxxxxxxx
Cc: linux-hwmon@xxxxxxxxxxxxxxx
Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
---

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

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@xxxxxxxxx>");
+MODULE_DESCRIPTION("Steam Deck ACPI platform driver");
+MODULE_LICENSE("GPL");
--
2.25.1