lkml.org 
[lkml]   [2019]   [Jun]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 3/3] iio: light: apple-ib-als: Add driver for ALS on iBridge chip.
Date
On 2016/2017 MacBook Pro's with a Touch Bar the ALS is attached to,
and exposed via the iBridge device. This provides the driver for that
sensor.

Signed-off-by: Ronald Tschalär <ronald@innovation.ch>
---
drivers/iio/light/Kconfig | 12 +
drivers/iio/light/Makefile | 1 +
drivers/iio/light/apple-ib-als.c | 607 +++++++++++++++++++++++++++++++
3 files changed, 620 insertions(+)
create mode 100644 drivers/iio/light/apple-ib-als.c

diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
index 5190eacfeb0a..b477aa5d2024 100644
--- a/drivers/iio/light/Kconfig
+++ b/drivers/iio/light/Kconfig
@@ -64,6 +64,18 @@ config APDS9960
To compile this driver as a module, choose M here: the
module will be called apds9960

+config APPLE_IBRIDGE_ALS
+ tristate "Apple iBridge ambient light sensor"
+ select IIO_BUFFER
+ select IIO_TRIGGERED_BUFFER
+ depends on HID_APPLE_IBRIDGE
+ help
+ Say Y here to build the driver for the Apple iBridge ALS
+ sensor.
+
+ To compile this driver as a module, choose M here: the
+ module will be called apple-ib-als.
+
config BH1750
tristate "ROHM BH1750 ambient light sensor"
depends on I2C
diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
index e40794fbb435..cd6cd5ba6da5 100644
--- a/drivers/iio/light/Makefile
+++ b/drivers/iio/light/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_ADJD_S311) += adjd_s311.o
obj-$(CONFIG_AL3320A) += al3320a.o
obj-$(CONFIG_APDS9300) += apds9300.o
obj-$(CONFIG_APDS9960) += apds9960.o
+obj-$(CONFIG_APPLE_IBRIDGE_ALS) += apple-ib-als.o
obj-$(CONFIG_BH1750) += bh1750.o
obj-$(CONFIG_BH1780) += bh1780.o
obj-$(CONFIG_CM32181) += cm32181.o
diff --git a/drivers/iio/light/apple-ib-als.c b/drivers/iio/light/apple-ib-als.c
new file mode 100644
index 000000000000..b84be0076e0f
--- /dev/null
+++ b/drivers/iio/light/apple-ib-als.c
@@ -0,0 +1,607 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Apple Ambient Light Sensor Driver
+ *
+ * Copyright (c) 2017-2018 Ronald Tschalär
+ */
+
+/*
+ * MacBookPro models with an iBridge chip (13,[23] and 14,[23]) have an
+ * ambient light sensor that is exposed via one of the USB interfaces on
+ * the iBridge as a standard HID light sensor. However, we cannot use the
+ * existing hid-sensor-als driver, for two reasons:
+ *
+ * 1. The hid-sensor-als driver is part of the hid-sensor-hub which in turn
+ * is a hid driver, but you can't have more than one hid driver per hid
+ * device, which is a problem because the touch bar also needs to
+ * register as a driver for this hid device.
+ *
+ * 2. While the hid-sensors-als driver stores sensor readings received via
+ * interrupt in an iio buffer, reads on the sysfs
+ * .../iio:deviceX/in_illuminance_YYY attribute result in a get of the
+ * feature report; however, in the case of this sensor here the
+ * illuminance field of that report is always 0. Instead, the input
+ * report needs to be requested.
+ */
+
+#define dev_fmt(fmt) "als: " fmt
+
+#include <linux/apple-ibridge.h>
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/hid-sensor-ids.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#define APPLEALS_DYN_SENS 0 /* our dynamic sensitivity */
+#define APPLEALS_DEF_CHANGE_SENS APPLEALS_DYN_SENS
+
+struct appleals_device {
+ struct hid_device *hid_dev;
+ struct hid_report *cfg_report;
+ struct hid_field *illum_field;
+ struct iio_dev *iio_dev;
+ int cur_sensitivity;
+ int cur_hysteresis;
+ bool events_enabled;
+};
+
+static struct hid_driver appleals_hid_driver;
+
+/*
+ * This is a primitive way to get a relative sensitivity, one where we get
+ * notified when the value changes by a certain percentage rather than some
+ * absolute value. MacOS somehow manages to configure the sensor to work this
+ * way (with a 15% relative sensitivity), but I haven't been able to figure
+ * out how so far. So until we do, this provides a less-than-perfect
+ * simulation.
+ *
+ * When the brightness value is within one of the ranges, the sensitivity is
+ * set to that range's sensitivity. But in order to reduce flapping when the
+ * brightness is right on the border between two ranges, the ranges overlap
+ * somewhat (by at least one sensitivity), and sensitivity is only changed if
+ * the value leaves the current sensitivity's range.
+ *
+ * The values chosen for the map are somewhat arbitrary: a compromise of not
+ * too many ranges (and hence changing the sensitivity) but not too small or
+ * large of a percentage of the min and max values in the range (currently
+ * from 7.5% to 30%, i.e. within a factor of 2 of 15%), as well as just plain
+ * "this feels reasonable to me".
+ */
+struct appleals_sensitivity_map {
+ int sensitivity;
+ int illum_low;
+ int illum_high;
+};
+
+static const struct appleals_sensitivity_map appleals_sensitivity_map[] = {
+ { 1, 0, 14 },
+ { 3, 10, 40 },
+ { 9, 30, 120 },
+ { 27, 90, 360 },
+ { 81, 270, 1080 },
+ { 243, 810, 3240 },
+ { 729, 2430, 9720 },
+};
+
+static int appleals_compute_sensitivity(int cur_illum, int cur_sens)
+{
+ const struct appleals_sensitivity_map *entry;
+ int i;
+
+ /* see if we're still in current range */
+ for (i = 0; i < ARRAY_SIZE(appleals_sensitivity_map); i++) {
+ entry = &appleals_sensitivity_map[i];
+
+ if (entry->sensitivity == cur_sens &&
+ entry->illum_low <= cur_illum &&
+ entry->illum_high >= cur_illum)
+ return cur_sens;
+ else if (entry->sensitivity > cur_sens)
+ break;
+ }
+
+ /* not in current range, so find new sensitivity */
+ for (i = 0; i < ARRAY_SIZE(appleals_sensitivity_map); i++) {
+ entry = &appleals_sensitivity_map[i];
+
+ if (entry->illum_low <= cur_illum &&
+ entry->illum_high >= cur_illum)
+ return entry->sensitivity;
+ }
+
+ /* hmm, not in table, so assume we are above highest range */
+ i = ARRAY_SIZE(appleals_sensitivity_map) - 1;
+ return appleals_sensitivity_map[i].sensitivity;
+}
+
+static int appleals_get_field_value_for_usage(struct hid_field *field,
+ unsigned int usage)
+{
+ int u;
+
+ if (!field)
+ return -1;
+
+ for (u = 0; u < field->maxusage; u++) {
+ if (field->usage[u].hid == usage)
+ return u + field->logical_minimum;
+ }
+
+ return -1;
+}
+
+static __s32 appleals_get_field_value(struct appleals_device *als_dev,
+ struct hid_field *field)
+{
+ bool powered_on = !hid_hw_power(als_dev->hid_dev, PM_HINT_FULLON);
+
+ hid_hw_request(als_dev->hid_dev, field->report, HID_REQ_GET_REPORT);
+ hid_hw_wait(als_dev->hid_dev);
+
+ if (powered_on)
+ hid_hw_power(als_dev->hid_dev, PM_HINT_NORMAL);
+
+ return field->value[0];
+}
+
+static void appleals_set_field_value(struct appleals_device *als_dev,
+ struct hid_field *field, __s32 value)
+{
+ hid_set_field(field, 0, value);
+ hid_hw_request(als_dev->hid_dev, field->report, HID_REQ_SET_REPORT);
+}
+
+static int appleals_get_config(struct appleals_device *als_dev,
+ unsigned int field_usage, __s32 *value)
+{
+ struct hid_field *field;
+
+ field = appleib_find_report_field(als_dev->cfg_report, field_usage);
+ if (!field)
+ return -EINVAL;
+
+ *value = appleals_get_field_value(als_dev, field);
+
+ return 0;
+}
+
+static int appleals_set_config(struct appleals_device *als_dev,
+ unsigned int field_usage, __s32 value)
+{
+ struct hid_field *field;
+
+ field = appleib_find_report_field(als_dev->cfg_report, field_usage);
+ if (!field)
+ return -EINVAL;
+
+ appleals_set_field_value(als_dev, field, value);
+
+ return 0;
+}
+
+static int appleals_set_enum_config(struct appleals_device *als_dev,
+ unsigned int field_usage,
+ unsigned int value_usage)
+{
+ struct hid_field *field;
+ int value;
+
+ field = appleib_find_report_field(als_dev->cfg_report, field_usage);
+ if (!field)
+ return -EINVAL;
+
+ value = appleals_get_field_value_for_usage(field, value_usage);
+ if (value >= 0)
+ appleals_set_field_value(als_dev, field, value);
+
+ return 0;
+}
+
+static void appleals_update_dyn_sensitivity(struct appleals_device *als_dev,
+ __s32 value)
+{
+ int new_sens;
+ int rc;
+
+ new_sens = appleals_compute_sensitivity(value,
+ als_dev->cur_sensitivity);
+ if (new_sens != als_dev->cur_sensitivity) {
+ rc = appleals_set_config(als_dev,
+ HID_USAGE_SENSOR_LIGHT_ILLUM |
+ HID_USAGE_SENSOR_DATA_MOD_CHANGE_SENSITIVITY_ABS,
+ new_sens);
+ if (!rc)
+ als_dev->cur_sensitivity = new_sens;
+ }
+}
+
+static void appleals_push_new_value(struct appleals_device *als_dev,
+ __s32 value)
+{
+ __s32 buf[2] = { value, value };
+
+ iio_push_to_buffers(als_dev->iio_dev, buf);
+
+ if (als_dev->cur_hysteresis == APPLEALS_DYN_SENS)
+ appleals_update_dyn_sensitivity(als_dev, value);
+}
+
+static int appleals_hid_event(struct hid_device *hdev, struct hid_field *field,
+ struct hid_usage *usage, __s32 value)
+{
+ struct appleals_device *als_dev = hid_get_drvdata(hdev);
+ int rc = 0;
+
+ if ((usage->hid & HID_USAGE_PAGE) != HID_UP_SENSOR)
+ return 0;
+
+ if (usage->hid == HID_USAGE_SENSOR_LIGHT_ILLUM) {
+ appleals_push_new_value(als_dev, value);
+ rc = 1;
+ }
+
+ return rc;
+}
+
+static int appleals_enable_events(struct iio_trigger *trig, bool enable)
+{
+ struct appleals_device *als_dev = iio_trigger_get_drvdata(trig);
+ int value;
+
+ appleals_set_enum_config(als_dev, HID_USAGE_SENSOR_PROP_REPORT_STATE,
+ enable ? HID_USAGE_SENSOR_PROP_REPORTING_STATE_ALL_EVENTS_ENUM :
+ HID_USAGE_SENSOR_PROP_REPORTING_STATE_NO_EVENTS_ENUM);
+ als_dev->events_enabled = enable;
+
+ /* if the sensor was enabled, push an initial value */
+ if (enable) {
+ value = appleals_get_field_value(als_dev, als_dev->illum_field);
+ appleals_push_new_value(als_dev, value);
+ }
+
+ return 0;
+}
+
+static int appleals_read_raw(struct iio_dev *iio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct appleals_device **priv = iio_priv(iio_dev);
+ struct appleals_device *als_dev = *priv;
+ __s32 value;
+ int rc;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_PROCESSED:
+ *val = appleals_get_field_value(als_dev, als_dev->illum_field);
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ rc = appleals_get_config(als_dev,
+ HID_USAGE_SENSOR_PROP_REPORT_INTERVAL,
+ &value);
+ if (rc)
+ return rc;
+
+ /* interval is in ms; val is in HZ, val2 in µHZ */
+ value = 1000000000 / value;
+ *val = value / 1000000;
+ *val2 = value - (*val * 1000000);
+
+ return IIO_VAL_INT_PLUS_MICRO;
+
+ case IIO_CHAN_INFO_HYSTERESIS:
+ if (als_dev->cur_hysteresis == APPLEALS_DYN_SENS) {
+ *val = als_dev->cur_hysteresis;
+ return IIO_VAL_INT;
+ }
+
+ rc = appleals_get_config(als_dev,
+ HID_USAGE_SENSOR_LIGHT_ILLUM |
+ HID_USAGE_SENSOR_DATA_MOD_CHANGE_SENSITIVITY_ABS,
+ val);
+ if (!rc) {
+ als_dev->cur_sensitivity = *val;
+ als_dev->cur_hysteresis = *val;
+ }
+ return rc ? rc : IIO_VAL_INT;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static int appleals_write_raw(struct iio_dev *iio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct appleals_device **priv = iio_priv(iio_dev);
+ struct appleals_device *als_dev = *priv;
+ __s32 illum;
+ int rc;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ rc = appleals_set_config(als_dev,
+ HID_USAGE_SENSOR_PROP_REPORT_INTERVAL,
+ 1000000000 / (val * 1000000 + val2));
+ return rc;
+
+ case IIO_CHAN_INFO_HYSTERESIS:
+ if (val == APPLEALS_DYN_SENS) {
+ if (als_dev->cur_hysteresis != APPLEALS_DYN_SENS) {
+ als_dev->cur_hysteresis = val;
+ illum = appleals_get_field_value(als_dev,
+ als_dev->illum_field);
+ appleals_update_dyn_sensitivity(als_dev, illum);
+ }
+
+ return 0;
+ }
+
+ rc = appleals_set_config(als_dev,
+ HID_USAGE_SENSOR_LIGHT_ILLUM |
+ HID_USAGE_SENSOR_DATA_MOD_CHANGE_SENSITIVITY_ABS,
+ val);
+ if (!rc) {
+ als_dev->cur_sensitivity = val;
+ als_dev->cur_hysteresis = val;
+ }
+
+ return rc;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_chan_spec appleals_channels[] = {
+ {
+ .type = IIO_INTENSITY,
+ .modified = 1,
+ .channel2 = IIO_MOD_LIGHT_BOTH,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) |
+ BIT(IIO_CHAN_INFO_HYSTERESIS),
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 32,
+ .storagebits = 32,
+ },
+ .scan_index = 0,
+ },
+ {
+ .type = IIO_LIGHT,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) |
+ BIT(IIO_CHAN_INFO_HYSTERESIS),
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 32,
+ .storagebits = 32,
+ },
+ .scan_index = 1,
+ }
+};
+
+static const struct iio_trigger_ops appleals_trigger_ops = {
+ .set_trigger_state = &appleals_enable_events,
+};
+
+static const struct iio_info appleals_info = {
+ .read_raw = &appleals_read_raw,
+ .write_raw = &appleals_write_raw,
+};
+
+static void appleals_config_sensor(struct appleals_device *als_dev,
+ bool events_enabled, int sensitivity)
+{
+ struct hid_field *field;
+ bool powered_on;
+ __s32 val;
+
+ powered_on = !hid_hw_power(als_dev->hid_dev, PM_HINT_FULLON);
+
+ hid_hw_request(als_dev->hid_dev, als_dev->cfg_report,
+ HID_REQ_GET_REPORT);
+ hid_hw_wait(als_dev->hid_dev);
+
+ field = appleib_find_report_field(als_dev->cfg_report,
+ HID_USAGE_SENSOR_PROY_POWER_STATE);
+ val = appleals_get_field_value_for_usage(field,
+ HID_USAGE_SENSOR_PROP_POWER_STATE_D0_FULL_POWER_ENUM);
+ if (val >= 0)
+ hid_set_field(field, 0, val);
+
+ field = appleib_find_report_field(als_dev->cfg_report,
+ HID_USAGE_SENSOR_PROP_REPORT_STATE);
+ val = appleals_get_field_value_for_usage(field,
+ events_enabled ?
+ HID_USAGE_SENSOR_PROP_REPORTING_STATE_ALL_EVENTS_ENUM :
+ HID_USAGE_SENSOR_PROP_REPORTING_STATE_NO_EVENTS_ENUM);
+ if (val >= 0)
+ hid_set_field(field, 0, val);
+
+ field = appleib_find_report_field(als_dev->cfg_report,
+ HID_USAGE_SENSOR_PROP_REPORT_INTERVAL);
+ hid_set_field(field, 0, field->logical_minimum);
+
+ /*
+ * Set initial change sensitivity; if dynamic, enabling trigger will set
+ * it instead.
+ */
+ if (sensitivity != APPLEALS_DYN_SENS) {
+ field = appleib_find_report_field(als_dev->cfg_report,
+ HID_USAGE_SENSOR_LIGHT_ILLUM |
+ HID_USAGE_SENSOR_DATA_MOD_CHANGE_SENSITIVITY_ABS);
+
+ hid_set_field(field, 0, sensitivity);
+ }
+
+ hid_hw_request(als_dev->hid_dev, als_dev->cfg_report,
+ HID_REQ_SET_REPORT);
+
+ if (powered_on)
+ hid_hw_power(als_dev->hid_dev, PM_HINT_NORMAL);
+}
+
+static int appleals_config_iio(struct appleals_device *als_dev)
+{
+ struct iio_dev *iio_dev;
+ struct iio_trigger *iio_trig;
+ struct appleals_device **priv;
+ struct device *parent = &als_dev->hid_dev->dev;
+ int rc;
+
+ iio_dev = devm_iio_device_alloc(parent, sizeof(als_dev));
+ if (!iio_dev)
+ return -ENOMEM;
+
+ priv = iio_priv(iio_dev);
+ *priv = als_dev;
+
+ iio_dev->channels = appleals_channels;
+ iio_dev->num_channels = ARRAY_SIZE(appleals_channels);
+ iio_dev->dev.parent = parent;
+ iio_dev->info = &appleals_info;
+ iio_dev->name = "als";
+ iio_dev->modes = INDIO_DIRECT_MODE;
+
+ rc = devm_iio_triggered_buffer_setup(parent, iio_dev,
+ &iio_pollfunc_store_time, NULL,
+ NULL);
+ if (rc) {
+ hid_err(als_dev->hid_dev,
+ "Failed to set up iio triggered buffer: %d\n", rc);
+ return rc;
+ }
+
+ iio_trig = devm_iio_trigger_alloc(parent, "%s-dev%d", iio_dev->name,
+ iio_dev->id);
+ if (!iio_trig)
+ return -ENOMEM;
+
+ iio_trig->dev.parent = parent;
+ iio_trig->ops = &appleals_trigger_ops;
+ iio_trigger_set_drvdata(iio_trig, als_dev);
+
+ rc = devm_iio_trigger_register(parent, iio_trig);
+ if (rc) {
+ hid_err(als_dev->hid_dev,
+ "Failed to register iio trigger: %d\n",
+ rc);
+ return rc;
+ }
+
+ rc = devm_iio_device_register(parent, iio_dev);
+ if (rc) {
+ hid_err(als_dev->hid_dev, "Failed to register iio device: %d\n",
+ rc);
+ return rc;
+ }
+
+ als_dev->iio_dev = iio_dev;
+
+ return 0;
+}
+
+static int appleals_probe(struct hid_device *hdev,
+ const struct hid_device_id *id)
+{
+ struct appleals_device *als_dev;
+ struct hid_field *state_field;
+ struct hid_field *illum_field;
+ int rc;
+
+ /* find als fields and reports */
+ rc = hid_parse(hdev);
+ if (rc) {
+ hid_err(hdev, "als: hid parse failed (%d)\n", rc);
+ return rc;
+ }
+
+ state_field = appleib_find_hid_field(hdev, HID_USAGE_SENSOR_ALS,
+ HID_USAGE_SENSOR_PROP_REPORT_STATE);
+ illum_field = appleib_find_hid_field(hdev, HID_USAGE_SENSOR_ALS,
+ HID_USAGE_SENSOR_LIGHT_ILLUM);
+ if (!state_field || !illum_field)
+ return -ENODEV;
+
+ hid_dbg(hdev, "Found ambient light sensor\n");
+
+ /* initialize device */
+ als_dev = devm_kzalloc(&hdev->dev, sizeof(*als_dev), GFP_KERNEL);
+ if (!als_dev)
+ return -ENOMEM;
+
+ als_dev->hid_dev = hdev;
+ als_dev->cfg_report = state_field->report;
+ als_dev->illum_field = illum_field;
+
+ als_dev->cur_hysteresis = APPLEALS_DEF_CHANGE_SENS;
+ als_dev->cur_sensitivity = APPLEALS_DEF_CHANGE_SENS;
+
+ hid_set_drvdata(hdev, als_dev);
+
+ rc = hid_hw_start(hdev, HID_CONNECT_DRIVER);
+ if (rc) {
+ hid_err(hdev, "als: hw start failed (%d)\n", rc);
+ return rc;
+ }
+
+ hid_device_io_start(hdev);
+ appleals_config_sensor(als_dev, false, als_dev->cur_sensitivity);
+ hid_device_io_stop(hdev);
+
+ rc = appleals_config_iio(als_dev);
+ if (rc)
+ return rc;
+
+ return hid_hw_open(hdev);
+}
+
+#ifdef CONFIG_PM
+static int appleals_reset_resume(struct hid_device *hdev)
+{
+ struct appleals_device *als_dev = hid_get_drvdata(hdev);
+ __s32 illum;
+
+ appleals_config_sensor(als_dev, als_dev->events_enabled,
+ als_dev->cur_sensitivity);
+
+ illum = appleals_get_field_value(als_dev, als_dev->illum_field);
+ appleals_push_new_value(als_dev, illum);
+
+ return 0;
+}
+#endif
+
+static const struct hid_device_id appleals_hid_ids[] = {
+ { HID_USB_DEVICE(USB_VENDOR_ID_LINUX_FOUNDATION,
+ USB_DEVICE_ID_IBRIDGE_ALS) },
+ { },
+};
+
+MODULE_DEVICE_TABLE(hid, appleals_hid_ids);
+
+static struct hid_driver appleals_hid_driver = {
+ .name = "apple-ib-als",
+ .id_table = appleals_hid_ids,
+ .probe = appleals_probe,
+ .event = appleals_hid_event,
+#ifdef CONFIG_PM
+ .reset_resume = appleals_reset_resume,
+#endif
+};
+
+module_hid_driver(appleals_hid_driver);
+
+MODULE_AUTHOR("Ronald Tschalär");
+MODULE_DESCRIPTION("Apple iBridge ALS driver");
+MODULE_LICENSE("GPL v2");
--
2.21.0
\
 
 \ /
  Last update: 2019-06-12 10:34    [W:0.073 / U:1.564 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site