diff options
Diffstat (limited to 'drivers/platform/chrome/cros_ec_lightbar.c')
-rw-r--r-- | drivers/platform/chrome/cros_ec_lightbar.c | 613 |
1 files changed, 613 insertions, 0 deletions
diff --git a/drivers/platform/chrome/cros_ec_lightbar.c b/drivers/platform/chrome/cros_ec_lightbar.c new file mode 100644 index 0000000000..376425bbd8 --- /dev/null +++ b/drivers/platform/chrome/cros_ec_lightbar.c @@ -0,0 +1,613 @@ +// SPDX-License-Identifier: GPL-2.0+ +// Expose the Chromebook Pixel lightbar to userspace +// +// Copyright (C) 2014 Google, Inc. + +#include <linux/ctype.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/fs.h> +#include <linux/kobject.h> +#include <linux/kstrtox.h> +#include <linux/module.h> +#include <linux/platform_data/cros_ec_commands.h> +#include <linux/platform_data/cros_ec_proto.h> +#include <linux/platform_device.h> +#include <linux/sched.h> +#include <linux/types.h> +#include <linux/uaccess.h> +#include <linux/slab.h> + +#define DRV_NAME "cros-ec-lightbar" + +/* Rate-limit the lightbar interface to prevent DoS. */ +static unsigned long lb_interval_jiffies = 50 * HZ / 1000; + +/* + * Whether or not we have given userspace control of the lightbar. + * If this is true, we won't do anything during suspend/resume. + */ +static bool userspace_control; + +static ssize_t interval_msec_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + unsigned long msec = lb_interval_jiffies * 1000 / HZ; + + return sysfs_emit(buf, "%lu\n", msec); +} + +static ssize_t interval_msec_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + unsigned long msec; + + if (kstrtoul(buf, 0, &msec)) + return -EINVAL; + + lb_interval_jiffies = msec * HZ / 1000; + + return count; +} + +static DEFINE_MUTEX(lb_mutex); +/* Return 0 if able to throttle correctly, error otherwise */ +static int lb_throttle(void) +{ + static unsigned long last_access; + unsigned long now, next_timeslot; + long delay; + int ret = 0; + + mutex_lock(&lb_mutex); + + now = jiffies; + next_timeslot = last_access + lb_interval_jiffies; + + if (time_before(now, next_timeslot)) { + delay = (long)(next_timeslot) - (long)now; + set_current_state(TASK_INTERRUPTIBLE); + if (schedule_timeout(delay) > 0) { + /* interrupted - just abort */ + ret = -EINTR; + goto out; + } + now = jiffies; + } + + last_access = now; +out: + mutex_unlock(&lb_mutex); + + return ret; +} + +static struct cros_ec_command *alloc_lightbar_cmd_msg(struct cros_ec_dev *ec) +{ + struct cros_ec_command *msg; + int len; + + len = max(sizeof(struct ec_params_lightbar), + sizeof(struct ec_response_lightbar)); + + msg = kmalloc(sizeof(*msg) + len, GFP_KERNEL); + if (!msg) + return NULL; + + msg->version = 0; + msg->command = EC_CMD_LIGHTBAR_CMD + ec->cmd_offset; + msg->outsize = sizeof(struct ec_params_lightbar); + msg->insize = sizeof(struct ec_response_lightbar); + + return msg; +} + +static int get_lightbar_version(struct cros_ec_dev *ec, + uint32_t *ver_ptr, uint32_t *flg_ptr) +{ + struct ec_params_lightbar *param; + struct ec_response_lightbar *resp; + struct cros_ec_command *msg; + int ret; + + msg = alloc_lightbar_cmd_msg(ec); + if (!msg) + return 0; + + param = (struct ec_params_lightbar *)msg->data; + param->cmd = LIGHTBAR_CMD_VERSION; + msg->outsize = sizeof(param->cmd); + msg->result = sizeof(resp->version); + ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg); + if (ret < 0 && ret != -EINVAL) { + ret = 0; + goto exit; + } + + switch (msg->result) { + case EC_RES_INVALID_PARAM: + /* Pixel had no version command. */ + if (ver_ptr) + *ver_ptr = 0; + if (flg_ptr) + *flg_ptr = 0; + ret = 1; + goto exit; + + case EC_RES_SUCCESS: + resp = (struct ec_response_lightbar *)msg->data; + + /* Future devices w/lightbars should implement this command */ + if (ver_ptr) + *ver_ptr = resp->version.num; + if (flg_ptr) + *flg_ptr = resp->version.flags; + ret = 1; + goto exit; + } + + /* Anything else (ie, EC_RES_INVALID_COMMAND) - no lightbar */ + ret = 0; +exit: + kfree(msg); + return ret; +} + +static ssize_t version_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + uint32_t version = 0, flags = 0; + struct cros_ec_dev *ec = to_cros_ec_dev(dev); + int ret; + + ret = lb_throttle(); + if (ret) + return ret; + + /* This should always succeed, because we check during init. */ + if (!get_lightbar_version(ec, &version, &flags)) + return -EIO; + + return sysfs_emit(buf, "%d %d\n", version, flags); +} + +static ssize_t brightness_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct ec_params_lightbar *param; + struct cros_ec_command *msg; + int ret; + unsigned int val; + struct cros_ec_dev *ec = to_cros_ec_dev(dev); + + if (kstrtouint(buf, 0, &val)) + return -EINVAL; + + msg = alloc_lightbar_cmd_msg(ec); + if (!msg) + return -ENOMEM; + + param = (struct ec_params_lightbar *)msg->data; + param->cmd = LIGHTBAR_CMD_SET_BRIGHTNESS; + param->set_brightness.num = val; + ret = lb_throttle(); + if (ret) + goto exit; + + ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg); + if (ret < 0) + goto exit; + + ret = count; +exit: + kfree(msg); + return ret; +} + + +/* + * We expect numbers, and we'll keep reading until we find them, skipping over + * any whitespace (sysfs guarantees that the input is null-terminated). Every + * four numbers are sent to the lightbar as <LED,R,G,B>. We fail at the first + * parsing error, if we don't parse any numbers, or if we have numbers left + * over. + */ +static ssize_t led_rgb_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct ec_params_lightbar *param; + struct cros_ec_command *msg; + struct cros_ec_dev *ec = to_cros_ec_dev(dev); + unsigned int val[4]; + int ret, i = 0, j = 0, ok = 0; + + msg = alloc_lightbar_cmd_msg(ec); + if (!msg) + return -ENOMEM; + + do { + /* Skip any whitespace */ + while (*buf && isspace(*buf)) + buf++; + + if (!*buf) + break; + + ret = sscanf(buf, "%i", &val[i++]); + if (ret == 0) + goto exit; + + if (i == 4) { + param = (struct ec_params_lightbar *)msg->data; + param->cmd = LIGHTBAR_CMD_SET_RGB; + param->set_rgb.led = val[0]; + param->set_rgb.red = val[1]; + param->set_rgb.green = val[2]; + param->set_rgb.blue = val[3]; + /* + * Throttle only the first of every four transactions, + * so that the user can update all four LEDs at once. + */ + if ((j++ % 4) == 0) { + ret = lb_throttle(); + if (ret) + goto exit; + } + + ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg); + if (ret < 0) + goto exit; + + i = 0; + ok = 1; + } + + /* Skip over the number we just read */ + while (*buf && !isspace(*buf)) + buf++; + + } while (*buf); + +exit: + kfree(msg); + return (ok && i == 0) ? count : -EINVAL; +} + +static char const *seqname[] = { + "ERROR", "S5", "S3", "S0", "S5S3", "S3S0", + "S0S3", "S3S5", "STOP", "RUN", "KONAMI", + "TAP", "PROGRAM", +}; + +static ssize_t sequence_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct ec_params_lightbar *param; + struct ec_response_lightbar *resp; + struct cros_ec_command *msg; + int ret; + struct cros_ec_dev *ec = to_cros_ec_dev(dev); + + msg = alloc_lightbar_cmd_msg(ec); + if (!msg) + return -ENOMEM; + + param = (struct ec_params_lightbar *)msg->data; + param->cmd = LIGHTBAR_CMD_GET_SEQ; + ret = lb_throttle(); + if (ret) + goto exit; + + ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg); + if (ret < 0) { + ret = sysfs_emit(buf, "XFER / EC ERROR %d / %d\n", ret, msg->result); + goto exit; + } + + resp = (struct ec_response_lightbar *)msg->data; + if (resp->get_seq.num >= ARRAY_SIZE(seqname)) + ret = sysfs_emit(buf, "%d\n", resp->get_seq.num); + else + ret = sysfs_emit(buf, "%s\n", seqname[resp->get_seq.num]); + +exit: + kfree(msg); + return ret; +} + +static int lb_send_empty_cmd(struct cros_ec_dev *ec, uint8_t cmd) +{ + struct ec_params_lightbar *param; + struct cros_ec_command *msg; + int ret; + + msg = alloc_lightbar_cmd_msg(ec); + if (!msg) + return -ENOMEM; + + param = (struct ec_params_lightbar *)msg->data; + param->cmd = cmd; + + ret = lb_throttle(); + if (ret) + goto error; + + ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg); + if (ret < 0) + goto error; + + ret = 0; +error: + kfree(msg); + + return ret; +} + +static int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable) +{ + struct ec_params_lightbar *param; + struct cros_ec_command *msg; + int ret; + + msg = alloc_lightbar_cmd_msg(ec); + if (!msg) + return -ENOMEM; + + param = (struct ec_params_lightbar *)msg->data; + + param->cmd = LIGHTBAR_CMD_MANUAL_SUSPEND_CTRL; + param->manual_suspend_ctrl.enable = enable; + + ret = lb_throttle(); + if (ret) + goto error; + + ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg); + if (ret < 0) + goto error; + + ret = 0; +error: + kfree(msg); + + return ret; +} + +static ssize_t sequence_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct ec_params_lightbar *param; + struct cros_ec_command *msg; + unsigned int num; + int ret, len; + struct cros_ec_dev *ec = to_cros_ec_dev(dev); + + for (len = 0; len < count; len++) + if (!isalnum(buf[len])) + break; + + for (num = 0; num < ARRAY_SIZE(seqname); num++) + if (!strncasecmp(seqname[num], buf, len)) + break; + + if (num >= ARRAY_SIZE(seqname)) { + ret = kstrtouint(buf, 0, &num); + if (ret) + return ret; + } + + msg = alloc_lightbar_cmd_msg(ec); + if (!msg) + return -ENOMEM; + + param = (struct ec_params_lightbar *)msg->data; + param->cmd = LIGHTBAR_CMD_SEQ; + param->seq.num = num; + ret = lb_throttle(); + if (ret) + goto exit; + + ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg); + if (ret < 0) + goto exit; + + ret = count; +exit: + kfree(msg); + return ret; +} + +static ssize_t program_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + int extra_bytes, max_size, ret; + struct ec_params_lightbar *param; + struct cros_ec_command *msg; + struct cros_ec_dev *ec = to_cros_ec_dev(dev); + + /* + * We might need to reject the program for size reasons. The EC + * enforces a maximum program size, but we also don't want to try + * and send a program that is too big for the protocol. In order + * to ensure the latter, we also need to ensure we have extra bytes + * to represent the rest of the packet. + */ + extra_bytes = sizeof(*param) - sizeof(param->set_program.data); + max_size = min(EC_LB_PROG_LEN, ec->ec_dev->max_request - extra_bytes); + if (count > max_size) { + dev_err(dev, "Program is %u bytes, too long to send (max: %u)", + (unsigned int)count, max_size); + + return -EINVAL; + } + + msg = alloc_lightbar_cmd_msg(ec); + if (!msg) + return -ENOMEM; + + ret = lb_throttle(); + if (ret) + goto exit; + + dev_info(dev, "Copying %zu byte program to EC", count); + + param = (struct ec_params_lightbar *)msg->data; + param->cmd = LIGHTBAR_CMD_SET_PROGRAM; + + param->set_program.size = count; + memcpy(param->set_program.data, buf, count); + + /* + * We need to set the message size manually or else it will use + * EC_LB_PROG_LEN. This might be too long, and the program + * is unlikely to use all of the space. + */ + msg->outsize = count + extra_bytes; + + ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg); + if (ret < 0) + goto exit; + + ret = count; +exit: + kfree(msg); + + return ret; +} + +static ssize_t userspace_control_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%d\n", userspace_control); +} + +static ssize_t userspace_control_store(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t count) +{ + bool enable; + int ret; + + ret = kstrtobool(buf, &enable); + if (ret < 0) + return ret; + + userspace_control = enable; + + return count; +} + +/* Module initialization */ + +static DEVICE_ATTR_RW(interval_msec); +static DEVICE_ATTR_RO(version); +static DEVICE_ATTR_WO(brightness); +static DEVICE_ATTR_WO(led_rgb); +static DEVICE_ATTR_RW(sequence); +static DEVICE_ATTR_WO(program); +static DEVICE_ATTR_RW(userspace_control); + +static struct attribute *__lb_cmds_attrs[] = { + &dev_attr_interval_msec.attr, + &dev_attr_version.attr, + &dev_attr_brightness.attr, + &dev_attr_led_rgb.attr, + &dev_attr_sequence.attr, + &dev_attr_program.attr, + &dev_attr_userspace_control.attr, + NULL, +}; + +static const struct attribute_group cros_ec_lightbar_attr_group = { + .name = "lightbar", + .attrs = __lb_cmds_attrs, +}; + +static int cros_ec_lightbar_probe(struct platform_device *pd) +{ + struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent); + struct cros_ec_platform *pdata = dev_get_platdata(ec_dev->dev); + struct device *dev = &pd->dev; + int ret; + + /* + * Only instantiate the lightbar if the EC name is 'cros_ec'. Other EC + * devices like 'cros_pd' doesn't have a lightbar. + */ + if (strcmp(pdata->ec_name, CROS_EC_DEV_NAME) != 0) + return -ENODEV; + + /* + * Ask then for the lightbar version, if it's 0 then the 'cros_ec' + * doesn't have a lightbar. + */ + if (!get_lightbar_version(ec_dev, NULL, NULL)) + return -ENODEV; + + /* Take control of the lightbar from the EC. */ + lb_manual_suspend_ctrl(ec_dev, 1); + + ret = sysfs_create_group(&ec_dev->class_dev.kobj, + &cros_ec_lightbar_attr_group); + if (ret < 0) + dev_err(dev, "failed to create %s attributes. err=%d\n", + cros_ec_lightbar_attr_group.name, ret); + + return ret; +} + +static int cros_ec_lightbar_remove(struct platform_device *pd) +{ + struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent); + + sysfs_remove_group(&ec_dev->class_dev.kobj, + &cros_ec_lightbar_attr_group); + + /* Let the EC take over the lightbar again. */ + lb_manual_suspend_ctrl(ec_dev, 0); + + return 0; +} + +static int __maybe_unused cros_ec_lightbar_resume(struct device *dev) +{ + struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent); + + if (userspace_control) + return 0; + + return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_RESUME); +} + +static int __maybe_unused cros_ec_lightbar_suspend(struct device *dev) +{ + struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent); + + if (userspace_control) + return 0; + + return lb_send_empty_cmd(ec_dev, LIGHTBAR_CMD_SUSPEND); +} + +static SIMPLE_DEV_PM_OPS(cros_ec_lightbar_pm_ops, + cros_ec_lightbar_suspend, cros_ec_lightbar_resume); + +static struct platform_driver cros_ec_lightbar_driver = { + .driver = { + .name = DRV_NAME, + .pm = &cros_ec_lightbar_pm_ops, + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + }, + .probe = cros_ec_lightbar_probe, + .remove = cros_ec_lightbar_remove, +}; + +module_platform_driver(cros_ec_lightbar_driver); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Expose the Chromebook Pixel's lightbar to userspace"); +MODULE_ALIAS("platform:" DRV_NAME); |