If you are not sure, say Y here. The driver enables polling only if
it is strictly necessary to do so.
+config INTEL_ATOMISP2_LED
+ tristate "Intel AtomISP2 camera LED driver"
+ depends on GPIOLIB && LEDS_GPIO
+ help
+ Many Bay Trail and Cherry Trail devices come with a camera attached
+ to Intel's Image Signal Processor. Linux currently does not have a
+ driver for these, so they do not work as a camera. Some of these
+ camera's have a LED which is controlled through a GPIO.
+
+ Some of these devices have a firmware issue where the LED gets turned
+ on at boot. This driver will turn the LED off at boot and also allows
+ controlling the LED (repurposing it) through the sysfs LED interface.
+
+ Which GPIO is attached to the LED is usually not described in the
+ ACPI tables, so this driver contains per-system info about the GPIO
+ inside the driver, this means that this driver only works on systems
+ the driver knows about.
+
+ To compile this driver as a module, choose M here: the module
+ will be called intel_atomisp2_led.
+
config INTEL_ATOMISP2_PM
tristate "Intel AtomISP2 dummy / power-management driver"
depends on PCI && IOSF_MBI && PM
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Driver for controlling LEDs for cameras connected to the Intel atomisp2
+ * The main purpose of this driver is to turn off LEDs which are on at boot.
+ *
+ * Copyright (C) 2020 Hans de Goede <hdegoede@redhat.com>
+ */
+
+#include <linux/dmi.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/machine.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/workqueue.h>
+
+/* This must be leds-gpio as the leds-gpio driver binds to the name */
+#define DEV_NAME "leds-gpio"
+
+static const struct gpio_led atomisp2_leds[] = {
+ {
+ .name = "atomisp2::camera",
+ .default_state = LEDS_GPIO_DEFSTATE_OFF,
+ },
+};
+
+static const struct gpio_led_platform_data atomisp2_leds_pdata = {
+ .num_leds = ARRAY_SIZE(atomisp2_leds),
+ .leds = atomisp2_leds,
+};
+
+static struct gpiod_lookup_table asus_t100ta_lookup = {
+ .dev_id = DEV_NAME,
+ .table = {
+ GPIO_LOOKUP_IDX("INT33FC:02", 8, NULL, 0, GPIO_ACTIVE_HIGH),
+ { }
+ }
+};
+
+static struct gpiod_lookup_table asus_t100chi_lookup = {
+ .dev_id = DEV_NAME,
+ .table = {
+ GPIO_LOOKUP_IDX("INT33FC:01", 24, NULL, 0, GPIO_ACTIVE_HIGH),
+ { }
+ }
+};
+
+static const struct dmi_system_id atomisp2_led_systems[] __initconst = {
+ {
+ .matches = {
+ DMI_EXACT_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+ DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "T100TA"),
+ },
+ .driver_data = &asus_t100ta_lookup,
+ },
+ {
+ .matches = {
+ DMI_EXACT_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+ DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "T200TA"),
+ },
+ .driver_data = &asus_t100ta_lookup,
+ },
+ {
+ .matches = {
+ DMI_EXACT_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
+ DMI_EXACT_MATCH(DMI_PRODUCT_NAME, "T100CHI"),
+ },
+ .driver_data = &asus_t100chi_lookup,
+ },
+ {} /* Terminating entry */
+};
+MODULE_DEVICE_TABLE(dmi, atomisp2_led_systems);
+
+static struct gpiod_lookup_table *gpio_lookup;
+static struct platform_device *pdev;
+
+static int __init atomisp2_led_init(void)
+{
+ const struct dmi_system_id *system;
+
+ system = dmi_first_match(atomisp2_led_systems);
+ if (!system)
+ return -ENODEV;
+
+ gpio_lookup = system->driver_data;
+ gpiod_add_lookup_table(gpio_lookup);
+
+ pdev = platform_device_register_resndata(NULL,
+ DEV_NAME, PLATFORM_DEVID_NONE,
+ NULL, 0, &atomisp2_leds_pdata,
+ sizeof(atomisp2_leds_pdata));
+ if (IS_ERR(pdev))
+ gpiod_remove_lookup_table(gpio_lookup);
+
+ return PTR_ERR_OR_ZERO(pdev);
+}
+
+static void __exit atomisp2_led_cleanup(void)
+{
+ platform_device_unregister(pdev);
+ gpiod_remove_lookup_table(gpio_lookup);
+}
+
+module_init(atomisp2_led_init);
+module_exit(atomisp2_led_cleanup);
+
+/*
+ * The ACPI INIT method from Asus WMI's code on the T100TA and T200TA turns the
+ * LED on (without the WMI interface allowing further control over the LED).
+ * Ensure we are loaded after asus-nb-wmi so that we turn the LED off again.
+ */
+MODULE_SOFTDEP("pre: asus_nb_wmi");
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com");
+MODULE_DESCRIPTION("Intel atomisp2 camera LED driver");
+MODULE_LICENSE("GPL");
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