281 строка
7.1 KiB
C
281 строка
7.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* debugfs attributes for Wilco EC
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*
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* Copyright 2019 Google LLC
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*
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* See Documentation/ABI/testing/debugfs-wilco-ec for usage.
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*/
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#include <linux/ctype.h>
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#include <linux/debugfs.h>
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#include <linux/fs.h>
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#include <linux/module.h>
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#include <linux/platform_data/wilco-ec.h>
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#include <linux/platform_device.h>
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#define DRV_NAME "wilco-ec-debugfs"
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/* The raw bytes will take up more space when represented as a hex string */
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#define FORMATTED_BUFFER_SIZE (EC_MAILBOX_DATA_SIZE * 4)
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struct wilco_ec_debugfs {
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struct wilco_ec_device *ec;
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struct dentry *dir;
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size_t response_size;
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u8 raw_data[EC_MAILBOX_DATA_SIZE];
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u8 formatted_data[FORMATTED_BUFFER_SIZE];
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};
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static struct wilco_ec_debugfs *debug_info;
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/**
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* parse_hex_sentence() - Convert a ascii hex representation into byte array.
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* @in: Input buffer of ascii.
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* @isize: Length of input buffer.
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* @out: Output buffer.
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* @osize: Length of output buffer, e.g. max number of bytes to parse.
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*
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* An valid input is a series of ascii hexadecimal numbers, separated by spaces.
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* An example valid input is
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* " 00 f2 0 000076 6 0 ff"
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*
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* If an individual "word" within the hex sentence is longer than MAX_WORD_SIZE,
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* then the sentence is illegal, and parsing will fail.
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*
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* Return: Number of bytes parsed, or negative error code on failure.
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*/
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static int parse_hex_sentence(const char *in, int isize, u8 *out, int osize)
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{
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int n_parsed = 0;
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int word_start = 0;
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int word_end;
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int word_len;
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/* Temp buffer for holding a "word" of chars that represents one byte */
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#define MAX_WORD_SIZE 16
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char tmp[MAX_WORD_SIZE + 1];
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u8 byte;
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while (word_start < isize && n_parsed < osize) {
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/* Find the start of the next word */
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while (word_start < isize && isspace(in[word_start]))
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word_start++;
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/* reached the end of the input before next word? */
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if (word_start >= isize)
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break;
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/* Find the end of this word */
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word_end = word_start;
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while (word_end < isize && !isspace(in[word_end]))
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word_end++;
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/* Copy to a tmp NULL terminated string */
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word_len = word_end - word_start;
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if (word_len > MAX_WORD_SIZE)
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return -EINVAL;
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memcpy(tmp, in + word_start, word_len);
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tmp[word_len] = '\0';
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/*
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* Convert from hex string, place in output. If fails to parse,
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* just return -EINVAL because specific error code is only
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* relevant for this one word, returning it would be confusing.
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*/
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if (kstrtou8(tmp, 16, &byte))
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return -EINVAL;
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out[n_parsed++] = byte;
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word_start = word_end;
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}
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return n_parsed;
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}
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/* The message type takes up two bytes*/
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#define TYPE_AND_DATA_SIZE ((EC_MAILBOX_DATA_SIZE) + 2)
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static ssize_t raw_write(struct file *file, const char __user *user_buf,
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size_t count, loff_t *ppos)
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{
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char *buf = debug_info->formatted_data;
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struct wilco_ec_message msg;
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u8 request_data[TYPE_AND_DATA_SIZE];
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ssize_t kcount;
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int ret;
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if (count > FORMATTED_BUFFER_SIZE)
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return -EINVAL;
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kcount = simple_write_to_buffer(buf, FORMATTED_BUFFER_SIZE, ppos,
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user_buf, count);
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if (kcount < 0)
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return kcount;
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ret = parse_hex_sentence(buf, kcount, request_data, TYPE_AND_DATA_SIZE);
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if (ret < 0)
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return ret;
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/* Need at least two bytes for message type and one byte of data */
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if (ret < 3)
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return -EINVAL;
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msg.type = request_data[0] << 8 | request_data[1];
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msg.flags = 0;
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msg.request_data = request_data + 2;
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msg.request_size = ret - 2;
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memset(debug_info->raw_data, 0, sizeof(debug_info->raw_data));
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msg.response_data = debug_info->raw_data;
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msg.response_size = EC_MAILBOX_DATA_SIZE;
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ret = wilco_ec_mailbox(debug_info->ec, &msg);
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if (ret < 0)
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return ret;
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debug_info->response_size = ret;
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return count;
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}
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static ssize_t raw_read(struct file *file, char __user *user_buf, size_t count,
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loff_t *ppos)
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{
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int fmt_len = 0;
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if (debug_info->response_size) {
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fmt_len = hex_dump_to_buffer(debug_info->raw_data,
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debug_info->response_size,
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16, 1, debug_info->formatted_data,
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sizeof(debug_info->formatted_data),
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true);
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/* Only return response the first time it is read */
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debug_info->response_size = 0;
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}
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return simple_read_from_buffer(user_buf, count, ppos,
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debug_info->formatted_data, fmt_len);
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}
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static const struct file_operations fops_raw = {
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.owner = THIS_MODULE,
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.read = raw_read,
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.write = raw_write,
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.llseek = no_llseek,
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};
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#define CMD_KB_CHROME 0x88
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#define SUB_CMD_H1_GPIO 0x0A
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#define SUB_CMD_TEST_EVENT 0x0B
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struct ec_request {
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u8 cmd; /* Always CMD_KB_CHROME */
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u8 reserved;
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u8 sub_cmd;
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} __packed;
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struct ec_response {
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u8 status; /* 0 if allowed */
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u8 val;
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} __packed;
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static int send_ec_cmd(struct wilco_ec_device *ec, u8 sub_cmd, u8 *out_val)
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{
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struct ec_request rq;
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struct ec_response rs;
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struct wilco_ec_message msg;
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int ret;
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memset(&rq, 0, sizeof(rq));
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rq.cmd = CMD_KB_CHROME;
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rq.sub_cmd = sub_cmd;
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memset(&msg, 0, sizeof(msg));
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msg.type = WILCO_EC_MSG_LEGACY;
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msg.request_data = &rq;
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msg.request_size = sizeof(rq);
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msg.response_data = &rs;
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msg.response_size = sizeof(rs);
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ret = wilco_ec_mailbox(ec, &msg);
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if (ret < 0)
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return ret;
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if (rs.status)
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return -EIO;
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*out_val = rs.val;
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return 0;
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}
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/**
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* h1_gpio_get() - Gets h1 gpio status.
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* @arg: The wilco EC device.
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* @val: BIT(0)=ENTRY_TO_FACT_MODE, BIT(1)=SPI_CHROME_SEL
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*/
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static int h1_gpio_get(void *arg, u64 *val)
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{
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return send_ec_cmd(arg, SUB_CMD_H1_GPIO, (u8 *)val);
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}
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DEFINE_DEBUGFS_ATTRIBUTE(fops_h1_gpio, h1_gpio_get, NULL, "0x%02llx\n");
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/**
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* test_event_set() - Sends command to EC to cause an EC test event.
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* @arg: The wilco EC device.
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* @val: unused.
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*/
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static int test_event_set(void *arg, u64 val)
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{
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u8 ret;
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return send_ec_cmd(arg, SUB_CMD_TEST_EVENT, &ret);
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}
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/* Format is unused since it is only required for get method which is NULL */
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DEFINE_DEBUGFS_ATTRIBUTE(fops_test_event, NULL, test_event_set, "%llu\n");
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/**
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* wilco_ec_debugfs_probe() - Create the debugfs node
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* @pdev: The platform device, probably created in core.c
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*
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* Try to create a debugfs node. If it fails, then we don't want to change
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* behavior at all, this is for debugging after all. Just fail silently.
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*
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* Return: 0 always.
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*/
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static int wilco_ec_debugfs_probe(struct platform_device *pdev)
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{
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struct wilco_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
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debug_info = devm_kzalloc(&pdev->dev, sizeof(*debug_info), GFP_KERNEL);
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if (!debug_info)
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return 0;
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debug_info->ec = ec;
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debug_info->dir = debugfs_create_dir("wilco_ec", NULL);
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if (!debug_info->dir)
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return 0;
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debugfs_create_file("raw", 0644, debug_info->dir, NULL, &fops_raw);
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debugfs_create_file("h1_gpio", 0444, debug_info->dir, ec,
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&fops_h1_gpio);
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debugfs_create_file("test_event", 0200, debug_info->dir, ec,
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&fops_test_event);
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return 0;
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}
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static int wilco_ec_debugfs_remove(struct platform_device *pdev)
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{
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debugfs_remove_recursive(debug_info->dir);
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return 0;
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}
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static struct platform_driver wilco_ec_debugfs_driver = {
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.driver = {
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.name = DRV_NAME,
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},
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.probe = wilco_ec_debugfs_probe,
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.remove = wilco_ec_debugfs_remove,
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};
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module_platform_driver(wilco_ec_debugfs_driver);
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MODULE_ALIAS("platform:" DRV_NAME);
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MODULE_AUTHOR("Nick Crews <ncrews@chromium.org>");
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MODULE_LICENSE("GPL v2");
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MODULE_DESCRIPTION("Wilco EC debugfs driver");
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