2012-07-11 02:31:51 +00:00
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/*
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* Generic driver for the OLPC Embedded Controller.
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*
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* Copyright (C) 2011-2012 One Laptop per Child Foundation.
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*
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* Licensed under the GPL v2 or later.
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*/
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2012-07-12 00:40:25 +00:00
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#include <linux/completion.h>
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2012-07-13 03:45:14 +00:00
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#include <linux/debugfs.h>
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2012-07-12 00:40:25 +00:00
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#include <linux/spinlock.h>
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#include <linux/mutex.h>
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2012-07-13 12:57:17 +00:00
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#include <linux/platform_device.h>
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2012-07-13 22:54:25 +00:00
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#include <linux/slab.h>
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2012-07-12 00:40:25 +00:00
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#include <linux/workqueue.h>
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2012-07-11 02:31:51 +00:00
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#include <linux/module.h>
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2012-07-12 00:40:25 +00:00
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#include <linux/list.h>
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#include <linux/olpc-ec.h>
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2012-07-11 02:31:51 +00:00
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#include <asm/olpc.h>
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2012-07-12 00:40:25 +00:00
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struct ec_cmd_desc {
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u8 cmd;
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u8 *inbuf, *outbuf;
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size_t inlen, outlen;
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int err;
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struct completion finished;
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struct list_head node;
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void *priv;
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};
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2012-07-13 22:54:25 +00:00
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struct olpc_ec_priv {
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struct olpc_ec_driver *drv;
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2012-07-13 03:45:14 +00:00
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struct dentry *dbgfs_dir;
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2012-07-13 22:54:25 +00:00
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/*
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* Running an EC command while suspending means we don't always finish
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* the command before the machine suspends. This means that the EC
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* is expecting the command protocol to finish, but we after a period
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* of time (while the OS is asleep) the EC times out and restarts its
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* idle loop. Meanwhile, the OS wakes up, thinks it's still in the
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* middle of the command protocol, starts throwing random things at
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* the EC... and everyone's uphappy.
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*/
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bool suspended;
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};
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2012-07-12 00:40:25 +00:00
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static void olpc_ec_worker(struct work_struct *w);
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static DECLARE_WORK(ec_worker, olpc_ec_worker);
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static LIST_HEAD(ec_cmd_q);
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static DEFINE_SPINLOCK(ec_cmd_q_lock);
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static struct olpc_ec_driver *ec_driver;
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2012-07-13 22:54:25 +00:00
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static struct olpc_ec_priv *ec_priv;
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2012-07-12 00:40:25 +00:00
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static void *ec_cb_arg;
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static DEFINE_MUTEX(ec_cb_lock);
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void olpc_ec_driver_register(struct olpc_ec_driver *drv, void *arg)
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{
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ec_driver = drv;
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ec_cb_arg = arg;
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}
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EXPORT_SYMBOL_GPL(olpc_ec_driver_register);
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static void olpc_ec_worker(struct work_struct *w)
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{
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struct ec_cmd_desc *desc = NULL;
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unsigned long flags;
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/* Grab the first pending command from the queue */
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spin_lock_irqsave(&ec_cmd_q_lock, flags);
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if (!list_empty(&ec_cmd_q)) {
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desc = list_first_entry(&ec_cmd_q, struct ec_cmd_desc, node);
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list_del(&desc->node);
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}
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spin_unlock_irqrestore(&ec_cmd_q_lock, flags);
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/* Do we actually have anything to do? */
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if (!desc)
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return;
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/* Protect the EC hw with a mutex; only run one cmd at a time */
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mutex_lock(&ec_cb_lock);
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desc->err = ec_driver->ec_cmd(desc->cmd, desc->inbuf, desc->inlen,
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desc->outbuf, desc->outlen, ec_cb_arg);
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mutex_unlock(&ec_cb_lock);
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/* Finished, wake up olpc_ec_cmd() */
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complete(&desc->finished);
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/* Run the worker thread again in case there are more cmds pending */
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schedule_work(&ec_worker);
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}
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/*
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* Throw a cmd descripter onto the list. We now have SMP OLPC machines, so
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* locking is pretty critical.
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*/
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static void queue_ec_descriptor(struct ec_cmd_desc *desc)
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{
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unsigned long flags;
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INIT_LIST_HEAD(&desc->node);
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spin_lock_irqsave(&ec_cmd_q_lock, flags);
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list_add_tail(&desc->node, &ec_cmd_q);
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spin_unlock_irqrestore(&ec_cmd_q_lock, flags);
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schedule_work(&ec_worker);
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}
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2012-07-11 02:31:51 +00:00
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int olpc_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *outbuf, size_t outlen)
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{
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2012-07-13 22:54:25 +00:00
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struct olpc_ec_priv *ec = ec_priv;
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2012-07-12 00:40:25 +00:00
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struct ec_cmd_desc desc;
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/* Ensure a driver and ec hook have been registered */
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if (WARN_ON(!ec_driver || !ec_driver->ec_cmd))
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return -ENODEV;
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2012-07-13 22:54:25 +00:00
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if (!ec)
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return -ENOMEM;
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/* Suspending in the middle of a command hoses things really badly */
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if (WARN_ON(ec->suspended))
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return -EBUSY;
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2012-07-12 00:40:25 +00:00
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might_sleep();
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desc.cmd = cmd;
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desc.inbuf = inbuf;
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desc.outbuf = outbuf;
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desc.inlen = inlen;
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desc.outlen = outlen;
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desc.err = 0;
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init_completion(&desc.finished);
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queue_ec_descriptor(&desc);
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/* Timeouts must be handled in the platform-specific EC hook */
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wait_for_completion(&desc.finished);
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/* The worker thread dequeues the cmd; no need to do anything here */
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return desc.err;
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2012-07-11 02:31:51 +00:00
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}
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EXPORT_SYMBOL_GPL(olpc_ec_cmd);
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2012-07-13 12:57:17 +00:00
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2012-07-13 03:45:14 +00:00
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#ifdef CONFIG_DEBUG_FS
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/*
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* debugfs support for "generic commands", to allow sending
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* arbitrary EC commands from userspace.
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*/
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#define EC_MAX_CMD_ARGS (5 + 1) /* cmd byte + 5 args */
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#define EC_MAX_CMD_REPLY (8)
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static DEFINE_MUTEX(ec_dbgfs_lock);
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static unsigned char ec_dbgfs_resp[EC_MAX_CMD_REPLY];
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static unsigned int ec_dbgfs_resp_bytes;
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static ssize_t ec_dbgfs_cmd_write(struct file *file, const char __user *buf,
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size_t size, loff_t *ppos)
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{
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int i, m;
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unsigned char ec_cmd[EC_MAX_CMD_ARGS];
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unsigned int ec_cmd_int[EC_MAX_CMD_ARGS];
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char cmdbuf[64];
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int ec_cmd_bytes;
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mutex_lock(&ec_dbgfs_lock);
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size = simple_write_to_buffer(cmdbuf, sizeof(cmdbuf), ppos, buf, size);
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m = sscanf(cmdbuf, "%x:%u %x %x %x %x %x", &ec_cmd_int[0],
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&ec_dbgfs_resp_bytes, &ec_cmd_int[1], &ec_cmd_int[2],
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&ec_cmd_int[3], &ec_cmd_int[4], &ec_cmd_int[5]);
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if (m < 2 || ec_dbgfs_resp_bytes > EC_MAX_CMD_REPLY) {
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/* reset to prevent overflow on read */
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ec_dbgfs_resp_bytes = 0;
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pr_debug("olpc-ec: bad ec cmd: cmd:response-count [arg1 [arg2 ...]]\n");
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size = -EINVAL;
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goto out;
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}
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/* convert scanf'd ints to char */
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ec_cmd_bytes = m - 2;
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for (i = 0; i <= ec_cmd_bytes; i++)
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ec_cmd[i] = ec_cmd_int[i];
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pr_debug("olpc-ec: debugfs cmd 0x%02x with %d args %02x %02x %02x %02x %02x, want %d returns\n",
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ec_cmd[0], ec_cmd_bytes, ec_cmd[1], ec_cmd[2],
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ec_cmd[3], ec_cmd[4], ec_cmd[5], ec_dbgfs_resp_bytes);
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olpc_ec_cmd(ec_cmd[0], (ec_cmd_bytes == 0) ? NULL : &ec_cmd[1],
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ec_cmd_bytes, ec_dbgfs_resp, ec_dbgfs_resp_bytes);
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pr_debug("olpc-ec: response %02x %02x %02x %02x %02x %02x %02x %02x (%d bytes expected)\n",
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ec_dbgfs_resp[0], ec_dbgfs_resp[1], ec_dbgfs_resp[2],
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ec_dbgfs_resp[3], ec_dbgfs_resp[4], ec_dbgfs_resp[5],
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ec_dbgfs_resp[6], ec_dbgfs_resp[7],
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ec_dbgfs_resp_bytes);
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out:
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mutex_unlock(&ec_dbgfs_lock);
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return size;
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}
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static ssize_t ec_dbgfs_cmd_read(struct file *file, char __user *buf,
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size_t size, loff_t *ppos)
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{
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unsigned int i, r;
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char *rp;
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char respbuf[64];
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mutex_lock(&ec_dbgfs_lock);
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rp = respbuf;
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rp += sprintf(rp, "%02x", ec_dbgfs_resp[0]);
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for (i = 1; i < ec_dbgfs_resp_bytes; i++)
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rp += sprintf(rp, ", %02x", ec_dbgfs_resp[i]);
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mutex_unlock(&ec_dbgfs_lock);
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rp += sprintf(rp, "\n");
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r = rp - respbuf;
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return simple_read_from_buffer(buf, size, ppos, respbuf, r);
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}
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static const struct file_operations ec_dbgfs_ops = {
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.write = ec_dbgfs_cmd_write,
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.read = ec_dbgfs_cmd_read,
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};
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static struct dentry *olpc_ec_setup_debugfs(void)
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{
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struct dentry *dbgfs_dir;
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dbgfs_dir = debugfs_create_dir("olpc-ec", NULL);
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if (IS_ERR_OR_NULL(dbgfs_dir))
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return NULL;
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debugfs_create_file("cmd", 0600, dbgfs_dir, NULL, &ec_dbgfs_ops);
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return dbgfs_dir;
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}
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#else
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static struct dentry *olpc_ec_setup_debugfs(void)
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{
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return NULL;
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}
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#endif /* CONFIG_DEBUG_FS */
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2012-07-13 12:57:17 +00:00
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static int olpc_ec_probe(struct platform_device *pdev)
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{
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2012-07-13 22:54:25 +00:00
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struct olpc_ec_priv *ec;
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2012-07-13 12:57:17 +00:00
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int err;
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if (!ec_driver)
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return -ENODEV;
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2012-07-13 22:54:25 +00:00
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ec = kzalloc(sizeof(*ec), GFP_KERNEL);
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if (!ec)
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return -ENOMEM;
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ec->drv = ec_driver;
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ec_priv = ec;
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platform_set_drvdata(pdev, ec);
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2012-07-13 12:57:17 +00:00
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err = ec_driver->probe ? ec_driver->probe(pdev) : 0;
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2012-07-13 03:45:14 +00:00
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if (err) {
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ec_priv = NULL;
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kfree(ec);
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} else {
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ec->dbgfs_dir = olpc_ec_setup_debugfs();
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}
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2012-07-13 12:57:17 +00:00
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return err;
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}
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static int olpc_ec_suspend(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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2012-07-13 22:54:25 +00:00
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struct olpc_ec_priv *ec = platform_get_drvdata(pdev);
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int err = 0;
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if (ec_driver->suspend)
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err = ec_driver->suspend(pdev);
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if (!err)
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ec->suspended = true;
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return err;
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2012-07-13 12:57:17 +00:00
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}
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static int olpc_ec_resume(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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2012-07-13 22:54:25 +00:00
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struct olpc_ec_priv *ec = platform_get_drvdata(pdev);
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ec->suspended = false;
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2012-07-13 12:57:17 +00:00
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return ec_driver->resume ? ec_driver->resume(pdev) : 0;
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}
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static const struct dev_pm_ops olpc_ec_pm_ops = {
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.suspend_late = olpc_ec_suspend,
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.resume_early = olpc_ec_resume,
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};
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static struct platform_driver olpc_ec_plat_driver = {
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.probe = olpc_ec_probe,
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.driver = {
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.name = "olpc-ec",
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.pm = &olpc_ec_pm_ops,
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},
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};
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static int __init olpc_ec_init_module(void)
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{
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return platform_driver_register(&olpc_ec_plat_driver);
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}
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module_init(olpc_ec_init_module);
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MODULE_AUTHOR("Andres Salomon <dilinger@queued.net>");
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MODULE_LICENSE("GPL");
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