@@ -61,6 +61,17 @@ config CHROMEOS_TBMC
To compile this driver as a module, choose M here: the
module will be called chromeos_tbmc.
+config CHROMEOS_OF_HW_PROBER
+ tristate "ChromeOS Device Tree Hardware Prober"
+ depends on OF
+ depends on I2C
+ select OF_DYNAMIC
+ default OF
+ help
+ This option enables the device tree hardware prober for ChromeOS
+ devices. The driver will probe the correct component variant in
+ devices that have multiple drop-in options for one component.
+
config CROS_EC
tristate "ChromeOS Embedded Controller"
select CROS_EC_PROTO
@@ -6,6 +6,7 @@ CFLAGS_cros_ec_sensorhub_ring.o:= -I$(src)
obj-$(CONFIG_CHROMEOS_ACPI) += chromeos_acpi.o
obj-$(CONFIG_CHROMEOS_LAPTOP) += chromeos_laptop.o
+obj-$(CONFIG_CHROMEOS_OF_HW_PROBER) += chromeos_of_hw_prober.o
obj-$(CONFIG_CHROMEOS_PRIVACY_SCREEN) += chromeos_privacy_screen.o
obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o
obj-$(CONFIG_CHROMEOS_TBMC) += chromeos_tbmc.o
new file mode 100644
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ChromeOS Device Tree Hardware Prober
+ *
+ * Copyright (c) 2024 Google LLC
+ */
+
+#include <linux/array_size.h>
+#include <linux/errno.h>
+#include <linux/i2c-of-prober.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/stddef.h>
+
+#define DRV_NAME "chromeos_of_hw_prober"
+
+/**
+ * struct hw_prober_entry - Holds an entry for the hardware prober
+ *
+ * @compatible: compatible string to match against the machine
+ * @prober: prober function to call when machine matches
+ * @data: extra data for the prober function
+ */
+struct hw_prober_entry {
+ const char *compatible;
+ int (*prober)(struct device *dev, const void *data);
+ const void *data;
+};
+
+struct chromeos_i2c_probe_data {
+ const struct i2c_of_probe_cfg *cfg;
+ const struct i2c_of_probe_simple_opts *opts;
+};
+
+static int chromeos_i2c_component_prober(struct device *dev, const void *_data)
+{
+ const struct chromeos_i2c_probe_data *data = _data;
+ struct i2c_of_probe_simple_ctx ctx = {
+ .opts = data->opts,
+ };
+
+ return i2c_of_probe_component(dev, data->cfg, &ctx);
+}
+
+#define DEFINE_CHROMEOS_I2C_PROBE_CFG_SIMPLE_BY_TYPE(_type) \
+ static const struct i2c_of_probe_cfg chromeos_i2c_probe_simple_ ## _type ## _cfg = { \
+ .type = #_type, \
+ .ops = &i2c_of_probe_simple_ops, \
+ }
+
+#define DEFINE_CHROMEOS_I2C_PROBE_DATA_DUMB_BY_TYPE(_type) \
+ static const struct chromeos_i2c_probe_data chromeos_i2c_probe_dumb_ ## _type = { \
+ .cfg = &(const struct i2c_of_probe_cfg) { \
+ .type = #_type, \
+ }, \
+ }
+
+DEFINE_CHROMEOS_I2C_PROBE_DATA_DUMB_BY_TYPE(touchscreen);
+
+DEFINE_CHROMEOS_I2C_PROBE_CFG_SIMPLE_BY_TYPE(trackpad);
+
+static const struct chromeos_i2c_probe_data chromeos_i2c_probe_hana_trackpad = {
+ .cfg = &chromeos_i2c_probe_simple_trackpad_cfg,
+ .opts = &(const struct i2c_of_probe_simple_opts) {
+ .res_node_compatible = "elan,ekth3000",
+ .supply_name = "vcc",
+ /*
+ * ELAN trackpad needs 2 ms for H/W init and 100 ms for F/W init.
+ * Synaptics trackpad needs 100 ms.
+ * However, the regulator is set to "always-on", presumably to
+ * avoid this delay. The ELAN driver is also missing delays.
+ */
+ .post_power_on_delay_ms = 0,
+ },
+};
+
+static const struct hw_prober_entry hw_prober_platforms[] = {
+ {
+ .compatible = "google,hana",
+ .prober = chromeos_i2c_component_prober,
+ .data = &chromeos_i2c_probe_dumb_touchscreen,
+ }, {
+ .compatible = "google,hana",
+ .prober = chromeos_i2c_component_prober,
+ .data = &chromeos_i2c_probe_hana_trackpad,
+ },
+};
+
+static int chromeos_of_hw_prober_probe(struct platform_device *pdev)
+{
+ for (size_t i = 0; i < ARRAY_SIZE(hw_prober_platforms); i++) {
+ int ret;
+
+ if (!of_machine_is_compatible(hw_prober_platforms[i].compatible))
+ continue;
+
+ ret = hw_prober_platforms[i].prober(&pdev->dev, hw_prober_platforms[i].data);
+ /* Ignore unrecoverable errors and keep going through other probers */
+ if (ret == -EPROBE_DEFER)
+ return ret;
+ }
+
+ return 0;
+}
+
+static struct platform_driver chromeos_of_hw_prober_driver = {
+ .probe = chromeos_of_hw_prober_probe,
+ .driver = {
+ .name = DRV_NAME,
+ },
+};
+
+static struct platform_device *chromeos_of_hw_prober_pdev;
+
+static int chromeos_of_hw_prober_driver_init(void)
+{
+ size_t i;
+ int ret;
+
+ for (i = 0; i < ARRAY_SIZE(hw_prober_platforms); i++)
+ if (of_machine_is_compatible(hw_prober_platforms[i].compatible))
+ break;
+ if (i == ARRAY_SIZE(hw_prober_platforms))
+ return -ENODEV;
+
+ ret = platform_driver_register(&chromeos_of_hw_prober_driver);
+ if (ret)
+ return ret;
+
+ chromeos_of_hw_prober_pdev =
+ platform_device_register_simple(DRV_NAME, PLATFORM_DEVID_NONE, NULL, 0);
+ if (IS_ERR(chromeos_of_hw_prober_pdev))
+ goto err;
+
+ return 0;
+
+err:
+ platform_driver_unregister(&chromeos_of_hw_prober_driver);
+
+ return PTR_ERR(chromeos_of_hw_prober_pdev);
+}
+module_init(chromeos_of_hw_prober_driver_init);
+
+static void chromeos_of_hw_prober_driver_exit(void)
+{
+ platform_device_unregister(chromeos_of_hw_prober_pdev);
+ platform_driver_unregister(&chromeos_of_hw_prober_driver);
+}
+module_exit(chromeos_of_hw_prober_driver_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("ChromeOS device tree hardware prober");
+MODULE_IMPORT_NS(I2C_OF_PROBER);