@@ -4936,6 +4936,12 @@ S: Maintained
F: drivers/platform/chrome/cros_usbpd_notify.c
F: include/linux/platform_data/cros_usbpd_notify.h
+CHROMEOS HPS DRIVER
+M: Dan Callaghan <dcallagh@chromium.org>
+R: Sami Kyöstilä <skyostil@chromium.org>
+S: Maintained
+F: drivers/platform/chrome/cros_hps_i2c.c
+
CHRONTEL CH7322 CEC DRIVER
M: Joe Tessler <jrt@google.com>
L: linux-media@vger.kernel.org
@@ -228,6 +228,16 @@ config CROS_EC_TYPEC
To compile this driver as a module, choose M here: the module will be
called cros_ec_typec.
+config CROS_HPS_I2C
+ tristate "ChromeOS HPS device"
+ depends on HID && I2C && PM
+ help
+ Say Y here if you want to enable support for the ChromeOS
+ human presence sensor (HPS), attached via I2C. The driver supports a
+ sensor connected to the I2C bus and exposes it as a character device.
+ To save power, the sensor is automatically powered down when no
+ clients are accessing it.
+
config CROS_USBPD_LOGGER
tristate "Logging driver for USB PD charger"
depends on CHARGER_CROS_USBPD
@@ -27,6 +27,7 @@ obj-$(CONFIG_CROS_EC_DEBUGFS) += cros_ec_debugfs.o
cros-ec-sensorhub-objs := cros_ec_sensorhub.o cros_ec_sensorhub_ring.o
obj-$(CONFIG_CROS_EC_SENSORHUB) += cros-ec-sensorhub.o
obj-$(CONFIG_CROS_EC_SYSFS) += cros_ec_sysfs.o
+obj-$(CONFIG_CROS_HPS_I2C) += cros_hps_i2c.o
obj-$(CONFIG_CROS_USBPD_LOGGER) += cros_usbpd_logger.o
obj-$(CONFIG_CROS_USBPD_NOTIFY) += cros_usbpd_notify.o
new file mode 100644
@@ -0,0 +1,162 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for the ChromeOS human presence sensor (HPS), attached via I2C.
+ *
+ * The driver exposes HPS as a character device, although currently no read or
+ * write operations are supported. Instead, the driver only controls the power
+ * state of the sensor, keeping it on only while userspace holds an open file
+ * descriptor to the HPS device.
+ *
+ * Copyright 2022 Google LLC.
+ */
+
+#include <linux/acpi.h>
+#include <linux/fs.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+
+#define HPS_ACPI_ID "GOOG0020"
+
+struct hps_drvdata {
+ struct i2c_client *client;
+ struct miscdevice misc_device;
+ struct gpio_desc *enable_gpio;
+};
+
+static void hps_set_power(struct hps_drvdata *hps, bool state)
+{
+ gpiod_set_value_cansleep(hps->enable_gpio, state);
+}
+
+static int hps_open(struct inode *inode, struct file *file)
+{
+ struct hps_drvdata *hps = container_of(file->private_data,
+ struct hps_drvdata, misc_device);
+ struct device *dev = &hps->client->dev;
+
+ return pm_runtime_resume_and_get(dev);
+}
+
+static int hps_release(struct inode *inode, struct file *file)
+{
+ struct hps_drvdata *hps = container_of(file->private_data,
+ struct hps_drvdata, misc_device);
+ struct device *dev = &hps->client->dev;
+
+ return pm_runtime_put(dev);
+}
+
+static const struct file_operations hps_fops = {
+ .owner = THIS_MODULE,
+ .open = hps_open,
+ .release = hps_release,
+};
+
+static int hps_i2c_probe(struct i2c_client *client)
+{
+ struct hps_drvdata *hps;
+ int ret;
+
+ hps = devm_kzalloc(&client->dev, sizeof(*hps), GFP_KERNEL);
+ if (!hps)
+ return -ENOMEM;
+
+ hps->misc_device.parent = &client->dev;
+ hps->misc_device.minor = MISC_DYNAMIC_MINOR;
+ hps->misc_device.name = "cros-hps";
+ hps->misc_device.fops = &hps_fops;
+
+ i2c_set_clientdata(client, hps);
+ hps->client = client;
+
+ /*
+ * HPS is powered on from firmware before entering the kernel, so we
+ * acquire the line with GPIOD_OUT_HIGH here to preserve the existing
+ * state. The peripheral is powered off after successful probe below.
+ */
+ hps->enable_gpio = devm_gpiod_get(&client->dev, "enable", GPIOD_OUT_HIGH);
+ if (IS_ERR(hps->enable_gpio)) {
+ ret = PTR_ERR(hps->enable_gpio);
+ dev_err(&client->dev, "failed to get enable gpio: %d\n", ret);
+ return ret;
+ }
+
+ ret = misc_register(&hps->misc_device);
+ if (ret) {
+ dev_err(&client->dev, "failed to initialize misc device: %d\n", ret);
+ return ret;
+ }
+
+ hps_set_power(hps, false);
+ pm_runtime_enable(&client->dev);
+ return 0;
+}
+
+static int hps_i2c_remove(struct i2c_client *client)
+{
+ struct hps_drvdata *hps = i2c_get_clientdata(client);
+
+ pm_runtime_disable(&client->dev);
+ misc_deregister(&hps->misc_device);
+
+ /*
+ * Re-enable HPS, in order to return it to its default state
+ * (i.e. powered on).
+ */
+ hps_set_power(hps, true);
+
+ return 0;
+}
+
+static int hps_suspend(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct hps_drvdata *hps = i2c_get_clientdata(client);
+
+ hps_set_power(hps, false);
+ return 0;
+}
+
+static int hps_resume(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct hps_drvdata *hps = i2c_get_clientdata(client);
+
+ hps_set_power(hps, true);
+ return 0;
+}
+static UNIVERSAL_DEV_PM_OPS(hps_pm_ops, hps_suspend, hps_resume, NULL);
+
+static const struct i2c_device_id hps_i2c_id[] = {
+ { "cros-hps", 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, hps_i2c_id);
+
+#ifdef CONFIG_ACPI
+static const struct acpi_device_id hps_acpi_id[] = {
+ { HPS_ACPI_ID, 0 },
+ { }
+};
+MODULE_DEVICE_TABLE(acpi, hps_acpi_id);
+#endif /* CONFIG_ACPI */
+
+static struct i2c_driver hps_i2c_driver = {
+ .probe_new = hps_i2c_probe,
+ .remove = hps_i2c_remove,
+ .id_table = hps_i2c_id,
+ .driver = {
+ .name = "cros-hps",
+ .pm = &hps_pm_ops,
+ .acpi_match_table = ACPI_PTR(hps_acpi_id),
+ },
+};
+module_i2c_driver(hps_i2c_driver);
+
+MODULE_ALIAS("acpi:" HPS_ACPI_ID);
+MODULE_AUTHOR("Sami Kyöstilä <skyostil@chromium.org>");
+MODULE_DESCRIPTION("Driver for ChromeOS HPS");
+MODULE_LICENSE("GPL");