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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 | // 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; } static const struct acpi_device_id chromeos_device_ids[] = { { "GGL0001", 0 }, { "GOOG0016", 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"); |