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path: root/drivers/platform/chrome/chromeos_acpi.c
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Diffstat (limited to 'drivers/platform/chrome/chromeos_acpi.c')
-rw-r--r--drivers/platform/chrome/chromeos_acpi.c286
1 files changed, 286 insertions, 0 deletions
diff --git a/drivers/platform/chrome/chromeos_acpi.c b/drivers/platform/chrome/chromeos_acpi.c
new file mode 100644
index 000000000..1312aaaa8
--- /dev/null
+++ b/drivers/platform/chrome/chromeos_acpi.c
@@ -0,0 +1,286 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ChromeOS specific ACPI extensions
+ *
+ * Copyright 2022 Google LLC
+ *
+ * This driver attaches to the ChromeOS ACPI device and then exports the
+ * values reported by the ACPI in a sysfs directory. All values are
+ * presented in the string form (numbers as decimal values) and can be
+ * accessed as the contents of the appropriate read only files in the
+ * sysfs directory tree.
+ */
+#include <linux/acpi.h>
+#include <linux/platform_device.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+
+#define ACPI_ATTR_NAME_LEN 4
+
+#define DEV_ATTR(_var, _name) \
+ static struct device_attribute dev_attr_##_var = \
+ __ATTR(_name, 0444, chromeos_first_level_attr_show, NULL);
+
+#define GPIO_ATTR_GROUP(_group, _name, _num) \
+ static umode_t attr_is_visible_gpio_##_num(struct kobject *kobj, \
+ struct attribute *attr, int n) \
+ { \
+ if (_num < chromeos_acpi_gpio_groups) \
+ return attr->mode; \
+ return 0; \
+ } \
+ static ssize_t chromeos_attr_show_gpio_##_num(struct device *dev, \
+ struct device_attribute *attr, \
+ char *buf) \
+ { \
+ char name[ACPI_ATTR_NAME_LEN + 1]; \
+ int ret, num; \
+ \
+ ret = parse_attr_name(attr->attr.name, name, &num); \
+ if (ret) \
+ return ret; \
+ return chromeos_acpi_evaluate_method(dev, _num, num, name, buf); \
+ } \
+ static struct device_attribute dev_attr_0_##_group = \
+ __ATTR(GPIO.0, 0444, chromeos_attr_show_gpio_##_num, NULL); \
+ static struct device_attribute dev_attr_1_##_group = \
+ __ATTR(GPIO.1, 0444, chromeos_attr_show_gpio_##_num, NULL); \
+ static struct device_attribute dev_attr_2_##_group = \
+ __ATTR(GPIO.2, 0444, chromeos_attr_show_gpio_##_num, NULL); \
+ static struct device_attribute dev_attr_3_##_group = \
+ __ATTR(GPIO.3, 0444, chromeos_attr_show_gpio_##_num, NULL); \
+ \
+ static struct attribute *attrs_##_group[] = { \
+ &dev_attr_0_##_group.attr, \
+ &dev_attr_1_##_group.attr, \
+ &dev_attr_2_##_group.attr, \
+ &dev_attr_3_##_group.attr, \
+ NULL \
+ }; \
+ static const struct attribute_group attr_group_##_group = { \
+ .name = _name, \
+ .is_visible = attr_is_visible_gpio_##_num, \
+ .attrs = attrs_##_group, \
+ };
+
+static unsigned int chromeos_acpi_gpio_groups;
+
+/* Parse the ACPI package and return the data related to that attribute */
+static int chromeos_acpi_handle_package(struct device *dev, union acpi_object *obj,
+ int pkg_num, int sub_pkg_num, char *name, char *buf)
+{
+ union acpi_object *element = obj->package.elements;
+
+ if (pkg_num >= obj->package.count)
+ return -EINVAL;
+ element += pkg_num;
+
+ if (element->type == ACPI_TYPE_PACKAGE) {
+ if (sub_pkg_num >= element->package.count)
+ return -EINVAL;
+ /* select sub element inside this package */
+ element = element->package.elements;
+ element += sub_pkg_num;
+ }
+
+ switch (element->type) {
+ case ACPI_TYPE_INTEGER:
+ return sysfs_emit(buf, "%d\n", (int)element->integer.value);
+ case ACPI_TYPE_STRING:
+ return sysfs_emit(buf, "%s\n", element->string.pointer);
+ case ACPI_TYPE_BUFFER:
+ {
+ int i, r, at, room_left;
+ const int byte_per_line = 16;
+
+ at = 0;
+ room_left = PAGE_SIZE - 1;
+ for (i = 0; i < element->buffer.length && room_left; i += byte_per_line) {
+ r = hex_dump_to_buffer(element->buffer.pointer + i,
+ element->buffer.length - i,
+ byte_per_line, 1, buf + at, room_left,
+ false);
+ if (r > room_left)
+ goto truncating;
+ at += r;
+ room_left -= r;
+
+ r = sysfs_emit_at(buf, at, "\n");
+ if (!r)
+ goto truncating;
+ at += r;
+ room_left -= r;
+ }
+
+ buf[at] = 0;
+ return at;
+truncating:
+ dev_info_once(dev, "truncating sysfs content for %s\n", name);
+ sysfs_emit_at(buf, PAGE_SIZE - 4, "..\n");
+ return PAGE_SIZE - 1;
+ }
+ default:
+ dev_err(dev, "element type %d not supported\n", element->type);
+ return -EINVAL;
+ }
+}
+
+static int chromeos_acpi_evaluate_method(struct device *dev, int pkg_num, int sub_pkg_num,
+ char *name, char *buf)
+{
+ struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
+ acpi_status status;
+ int ret = -EINVAL;
+
+ status = acpi_evaluate_object(ACPI_HANDLE(dev), name, NULL, &output);
+ if (ACPI_FAILURE(status)) {
+ dev_err(dev, "failed to retrieve %s. %s\n", name, acpi_format_exception(status));
+ return ret;
+ }
+
+ if (((union acpi_object *)output.pointer)->type == ACPI_TYPE_PACKAGE)
+ ret = chromeos_acpi_handle_package(dev, output.pointer, pkg_num, sub_pkg_num,
+ name, buf);
+
+ kfree(output.pointer);
+ return ret;
+}
+
+static int parse_attr_name(const char *name, char *attr_name, int *attr_num)
+{
+ int ret;
+
+ ret = strscpy(attr_name, name, ACPI_ATTR_NAME_LEN + 1);
+ if (ret == -E2BIG)
+ return kstrtoint(&name[ACPI_ATTR_NAME_LEN + 1], 0, attr_num);
+ return 0;
+}
+
+static ssize_t chromeos_first_level_attr_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ char attr_name[ACPI_ATTR_NAME_LEN + 1];
+ int ret, attr_num = 0;
+
+ ret = parse_attr_name(attr->attr.name, attr_name, &attr_num);
+ if (ret)
+ return ret;
+ return chromeos_acpi_evaluate_method(dev, attr_num, 0, attr_name, buf);
+}
+
+static unsigned int get_gpio_pkg_num(struct device *dev)
+{
+ struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
+ union acpi_object *obj;
+ acpi_status status;
+ unsigned int count = 0;
+ char *name = "GPIO";
+
+ status = acpi_evaluate_object(ACPI_HANDLE(dev), name, NULL, &output);
+ if (ACPI_FAILURE(status)) {
+ dev_err(dev, "failed to retrieve %s. %s\n", name, acpi_format_exception(status));
+ return count;
+ }
+
+ obj = output.pointer;
+
+ if (obj->type == ACPI_TYPE_PACKAGE)
+ count = obj->package.count;
+
+ kfree(output.pointer);
+ return count;
+}
+
+DEV_ATTR(binf2, BINF.2)
+DEV_ATTR(binf3, BINF.3)
+DEV_ATTR(chsw, CHSW)
+DEV_ATTR(fmap, FMAP)
+DEV_ATTR(frid, FRID)
+DEV_ATTR(fwid, FWID)
+DEV_ATTR(hwid, HWID)
+DEV_ATTR(meck, MECK)
+DEV_ATTR(vbnv0, VBNV.0)
+DEV_ATTR(vbnv1, VBNV.1)
+DEV_ATTR(vdat, VDAT)
+
+static struct attribute *first_level_attrs[] = {
+ &dev_attr_binf2.attr,
+ &dev_attr_binf3.attr,
+ &dev_attr_chsw.attr,
+ &dev_attr_fmap.attr,
+ &dev_attr_frid.attr,
+ &dev_attr_fwid.attr,
+ &dev_attr_hwid.attr,
+ &dev_attr_meck.attr,
+ &dev_attr_vbnv0.attr,
+ &dev_attr_vbnv1.attr,
+ &dev_attr_vdat.attr,
+ NULL
+};
+
+static const struct attribute_group first_level_attr_group = {
+ .attrs = first_level_attrs,
+};
+
+/*
+ * Every platform can have a different number of GPIO attribute groups.
+ * Define upper limit groups. At run time, the platform decides to show
+ * the present number of groups only, others are hidden.
+ */
+GPIO_ATTR_GROUP(gpio0, "GPIO.0", 0)
+GPIO_ATTR_GROUP(gpio1, "GPIO.1", 1)
+GPIO_ATTR_GROUP(gpio2, "GPIO.2", 2)
+GPIO_ATTR_GROUP(gpio3, "GPIO.3", 3)
+GPIO_ATTR_GROUP(gpio4, "GPIO.4", 4)
+GPIO_ATTR_GROUP(gpio5, "GPIO.5", 5)
+GPIO_ATTR_GROUP(gpio6, "GPIO.6", 6)
+GPIO_ATTR_GROUP(gpio7, "GPIO.7", 7)
+
+static const struct attribute_group *chromeos_acpi_all_groups[] = {
+ &first_level_attr_group,
+ &attr_group_gpio0,
+ &attr_group_gpio1,
+ &attr_group_gpio2,
+ &attr_group_gpio3,
+ &attr_group_gpio4,
+ &attr_group_gpio5,
+ &attr_group_gpio6,
+ &attr_group_gpio7,
+ NULL
+};
+
+static int chromeos_acpi_device_probe(struct platform_device *pdev)
+{
+ chromeos_acpi_gpio_groups = get_gpio_pkg_num(&pdev->dev);
+
+ /*
+ * If the platform has more GPIO attribute groups than the number of
+ * groups this driver supports, give out a warning message.
+ */
+ if (chromeos_acpi_gpio_groups > ARRAY_SIZE(chromeos_acpi_all_groups) - 2)
+ dev_warn(&pdev->dev, "Only %zu GPIO attr groups supported by the driver out of total %u.\n",
+ ARRAY_SIZE(chromeos_acpi_all_groups) - 2, chromeos_acpi_gpio_groups);
+ return 0;
+}
+
+/* GGL is valid PNP ID of Google. PNP ID can be used with the ACPI devices. */
+static const struct acpi_device_id chromeos_device_ids[] = {
+ { "GGL0001", 0 },
+ {}
+};
+MODULE_DEVICE_TABLE(acpi, chromeos_device_ids);
+
+static struct platform_driver chromeos_acpi_device_driver = {
+ .probe = chromeos_acpi_device_probe,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .dev_groups = chromeos_acpi_all_groups,
+ .acpi_match_table = chromeos_device_ids,
+ }
+};
+module_platform_driver(chromeos_acpi_device_driver);
+
+MODULE_AUTHOR("Muhammad Usama Anjum <usama.anjum@collabora.com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("ChromeOS specific ACPI extensions");
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-02 00:38:20 +0000