Microsoft published the protocol specification of HID over i2c:
http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx
This patch introduces an implementation of this protocol.
This implementation does not includes the ACPI part of the specification.
This will come when ACPI 5.0 devices enumeration will be available.
Once the ACPI part is done, OEM will not have to declare HID over I2C
devices in their platform specific driver.
Signed-off-by: Benjamin Tissoires <[email protected]>
---
Hi Guys,
here is the v3 of the HID over I2C driver.
Changes in v3:
* fix i2c_hid_alloc_buffers when allocation failed
* fix error messages to be more "human"
* fix i2c_hid_set_report as it didn't followed the protocol
* remove i2c_hid_write_out_report (hid-core doesn't present the callback that
could use this feature of the protocol)
* reject HID_OUTPUT_REPORT in i2c_hid_get_raw_report
* fix output report id in i2c_hid_output_raw_report and reject HID_INPUT_REPORT
Changes in v2:
* s/i2chid/i2c_hid/
* remove i2c_hid_print_buffer function and use "%*ph" instead
* define i2c_hid_dbg macro
* remove retries in __i2c_hid_command
* fix return values
* fix imports (I hope)
* drop hiddev and pidff_init support as the used functions were usb only
* make memory allocation more static
* remove spinlock
* don't use an array for the commands, but static const declarations instead
* move i2c-hid into drivers/hid
* remove HID_MAX_BUFFER_SIZE test
* implement missing output reports sending (not tested)
* typos, spacing, and many small thinks that appeared in the previous review
Cheers,
Benjamin
drivers/hid/Kconfig | 2 +
drivers/hid/Makefile | 1 +
drivers/hid/i2c-hid/Kconfig | 21 +
drivers/hid/i2c-hid/Makefile | 5 +
drivers/hid/i2c-hid/i2c-hid.c | 974 ++++++++++++++++++++++++++++++++++++++++++
include/linux/i2c/i2c-hid.h | 35 ++
6 files changed, 1038 insertions(+)
create mode 100644 drivers/hid/i2c-hid/Kconfig
create mode 100644 drivers/hid/i2c-hid/Makefile
create mode 100644 drivers/hid/i2c-hid/i2c-hid.c
create mode 100644 include/linux/i2c/i2c-hid.h
diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index f0ac277..e7d6a13 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -737,4 +737,6 @@ endif # HID
source "drivers/hid/usbhid/Kconfig"
+source "drivers/hid/i2c-hid/Kconfig"
+
endmenu
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 78eae69..b622157 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -119,3 +119,4 @@ obj-$(CONFIG_USB_HID) += usbhid/
obj-$(CONFIG_USB_MOUSE) += usbhid/
obj-$(CONFIG_USB_KBD) += usbhid/
+obj-$(CONFIG_I2C_HID) += i2c-hid/
diff --git a/drivers/hid/i2c-hid/Kconfig b/drivers/hid/i2c-hid/Kconfig
new file mode 100644
index 0000000..5b7d4d8
--- /dev/null
+++ b/drivers/hid/i2c-hid/Kconfig
@@ -0,0 +1,21 @@
+menu "I2C HID support"
+ depends on I2C
+
+config I2C_HID
+ tristate "HID over I2C transport layer"
+ default n
+ depends on I2C && INPUT
+ select HID
+ ---help---
+ Say Y here if you want to use the HID over i2c protocol
+ implementation.
+
+ If unsure, say N.
+
+ This support is also available as a module. If so, the module
+ will be called i2c-hid.
+
+comment "Input core support is needed for HID over I2C input layer"
+ depends on I2C_HID && INPUT=n
+
+endmenu
diff --git a/drivers/hid/i2c-hid/Makefile b/drivers/hid/i2c-hid/Makefile
new file mode 100644
index 0000000..832d8f9
--- /dev/null
+++ b/drivers/hid/i2c-hid/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for the I2C input drivers
+#
+
+obj-$(CONFIG_I2C_HID) += i2c-hid.o
diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
new file mode 100644
index 0000000..11140bd
--- /dev/null
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -0,0 +1,974 @@
+/*
+ * HID over I2C protocol implementation
+ *
+ * Copyright (c) 2012 Benjamin Tissoires <[email protected]>
+ * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France
+ * Copyright (c) 2012 Red Hat, Inc
+ *
+ * This code is partly based on "USB HID support for Linux":
+ *
+ * Copyright (c) 1999 Andreas Gal
+ * Copyright (c) 2000-2005 Vojtech Pavlik <[email protected]>
+ * Copyright (c) 2005 Michael Haboustak <[email protected]> for Concept2, Inc
+ * Copyright (c) 2007-2008 Oliver Neukum
+ * Copyright (c) 2006-2010 Jiri Kosina
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of this archive for
+ * more details.
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/input.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/pm.h>
+#include <linux/device.h>
+#include <linux/wait.h>
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/list.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/bug.h>
+#include <linux/hid.h>
+
+#include <linux/i2c/i2c-hid.h>
+
+/* flags */
+#define I2C_HID_STARTED (1 << 0)
+#define I2C_HID_RESET_PENDING (1 << 1)
+#define I2C_HID_READ_PENDING (1 << 2)
+
+#define I2C_HID_PWR_ON 0x00
+#define I2C_HID_PWR_SLEEP 0x01
+
+/* debug option */
+static bool debug = false;
+module_param(debug, bool, 0444);
+MODULE_PARM_DESC(debug, "print a lot of debug information");
+
+#define i2c_hid_dbg(ihid, fmt, arg...) \
+ if (debug) \
+ dev_printk(KERN_DEBUG, &(ihid)->client->dev, fmt, ##arg)
+
+struct i2c_hid_desc {
+ __le16 wHIDDescLength;
+ __le16 bcdVersion;
+ __le16 wReportDescLength;
+ __le16 wReportDescRegister;
+ __le16 wInputRegister;
+ __le16 wMaxInputLength;
+ __le16 wOutputRegister;
+ __le16 wMaxOutputLength;
+ __le16 wCommandRegister;
+ __le16 wDataRegister;
+ __le16 wVendorID;
+ __le16 wProductID;
+ __le16 wVersionID;
+} __packed;
+
+struct i2c_hid_cmd {
+ unsigned int registerIndex;
+ __u8 opcode;
+ unsigned int length;
+ bool wait;
+};
+
+union command {
+ u8 data[0];
+ struct cmd {
+ __le16 reg;
+ __u8 reportTypeID;
+ __u8 opcode;
+ } __packed c;
+};
+
+#define I2C_HID_CMD(opcode_) \
+ .opcode = opcode_, .length = 4, \
+ .registerIndex = offsetof(struct i2c_hid_desc, wCommandRegister)
+
+/* fetch HID descriptor */
+static const struct i2c_hid_cmd hid_descr_cmd = { .length = 2 };
+/* fetch report descriptors */
+static const struct i2c_hid_cmd hid_report_descr_cmd = {
+ .registerIndex = offsetof(struct i2c_hid_desc,
+ wReportDescRegister),
+ .opcode = 0x00,
+ .length = 2 };
+/* commands */
+static const struct i2c_hid_cmd hid_reset_cmd = { I2C_HID_CMD(0x01),
+ .wait = true };
+static const struct i2c_hid_cmd hid_get_report_cmd = { I2C_HID_CMD(0x02) };
+static const struct i2c_hid_cmd hid_set_report_cmd = { I2C_HID_CMD(0x03) };
+static const struct i2c_hid_cmd hid_get_idle_cmd = { I2C_HID_CMD(0x04) };
+static const struct i2c_hid_cmd hid_set_idle_cmd = { I2C_HID_CMD(0x05) };
+static const struct i2c_hid_cmd hid_get_protocol_cmd = { I2C_HID_CMD(0x06) };
+static const struct i2c_hid_cmd hid_set_protocol_cmd = { I2C_HID_CMD(0x07) };
+static const struct i2c_hid_cmd hid_set_power_cmd = { I2C_HID_CMD(0x08) };
+/* read/write data register */
+static const struct i2c_hid_cmd hid_data_cmd = {
+ .registerIndex = offsetof(struct i2c_hid_desc, wDataRegister),
+ .opcode = 0x00,
+ .length = 2 };
+/* write output reports */
+static const struct i2c_hid_cmd hid_out_cmd = {
+ .registerIndex = offsetof(struct i2c_hid_desc,
+ wOutputRegister),
+ .opcode = 0x00,
+ .length = 2 };
+
+/* The main device structure */
+struct i2c_hid {
+ struct i2c_client *client; /* i2c client */
+ struct hid_device *hid; /* pointer to corresponding HID dev */
+ union {
+ __u8 hdesc_buffer[sizeof(struct i2c_hid_desc)];
+ struct i2c_hid_desc hdesc; /* the HID Descriptor */
+ };
+ __le16 wHIDDescRegister; /* location of the i2c
+ * register of the HID
+ * descriptor. */
+ unsigned int bufsize; /* i2c buffer size */
+ char *inbuf; /* Input buffer */
+ char *cmdbuf; /* Command buffer */
+ char *argsbuf; /* Command arguments buffer */
+
+ unsigned long flags; /* device flags */
+
+ int irq; /* the interrupt line irq */
+
+ wait_queue_head_t wait; /* For waiting the interrupt */
+};
+
+static int __i2c_hid_command(struct i2c_client *client,
+ const struct i2c_hid_cmd *command, u8 reportID,
+ u8 reportType, u8 *args, int args_len,
+ unsigned char *buf_recv, int data_len)
+{
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+ union command *cmd = (union command *)ihid->cmdbuf;
+ int ret;
+ struct i2c_msg msg[2];
+ int msg_num = 1;
+
+ int length = command->length;
+ bool wait = command->wait;
+ unsigned int registerIndex = command->registerIndex;
+
+ /* special case for hid_descr_cmd */
+ if (command == &hid_descr_cmd) {
+ cmd->c.reg = ihid->wHIDDescRegister;
+ } else {
+ cmd->data[0] = ihid->hdesc_buffer[registerIndex];
+ cmd->data[1] = ihid->hdesc_buffer[registerIndex + 1];
+ }
+
+ if (length > 2) {
+ cmd->c.opcode = command->opcode;
+ cmd->c.reportTypeID = reportID | reportType << 4;
+ }
+
+ memcpy(cmd->data + length, args, args_len);
+ length += args_len;
+
+ i2c_hid_dbg(ihid, "%s: cmd=%*ph\n", __func__, length, cmd->data);
+
+ msg[0].addr = client->addr;
+ msg[0].flags = client->flags & I2C_M_TEN;
+ msg[0].len = length;
+ msg[0].buf = cmd->data;
+ if (data_len > 0) {
+ msg[1].addr = client->addr;
+ msg[1].flags = client->flags & I2C_M_TEN;
+ msg[1].flags |= I2C_M_RD;
+ msg[1].len = data_len;
+ msg[1].buf = buf_recv;
+ msg_num = 2;
+ set_bit(I2C_HID_READ_PENDING, &ihid->flags);
+ }
+
+ if (wait)
+ set_bit(I2C_HID_RESET_PENDING, &ihid->flags);
+
+ ret = i2c_transfer(client->adapter, msg, msg_num);
+
+ if (data_len > 0)
+ clear_bit(I2C_HID_READ_PENDING, &ihid->flags);
+
+ if (ret != msg_num)
+ return ret < 0 ? ret : -EIO;
+
+ ret = 0;
+
+ if (wait) {
+ i2c_hid_dbg(ihid, "%s: waiting...\n", __func__);
+ if (!wait_event_timeout(ihid->wait,
+ !test_bit(I2C_HID_RESET_PENDING, &ihid->flags),
+ msecs_to_jiffies(5000)))
+ ret = -ENODATA;
+ i2c_hid_dbg(ihid, "%s: finished.\n", __func__);
+ }
+
+ return ret;
+}
+
+static int i2c_hid_command(struct i2c_client *client,
+ const struct i2c_hid_cmd *command,
+ unsigned char *buf_recv, int data_len)
+{
+ return __i2c_hid_command(client, command, 0, 0, NULL, 0,
+ buf_recv, data_len);
+}
+
+static int i2c_hid_get_report(struct i2c_client *client, u8 reportType,
+ u8 reportID, unsigned char *buf_recv, int data_len)
+{
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+ u8 args[3];
+ int ret;
+ int args_len = 0;
+ u16 readRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
+
+ i2c_hid_dbg(ihid, "%s\n", __func__);
+
+ if (reportID >= 0x0F) {
+ args[args_len++] = reportID;
+ reportID = 0x0F;
+ }
+
+ args[args_len++] = readRegister & 0xFF;
+ args[args_len++] = readRegister >> 8;
+
+ ret = __i2c_hid_command(client, &hid_get_report_cmd, reportID,
+ reportType, args, args_len, buf_recv, data_len);
+ if (ret) {
+ dev_err(&client->dev,
+ "failed to retrieve report from device.\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int i2c_hid_set_report(struct i2c_client *client, u8 reportType,
+ u8 reportID, unsigned char *buf, size_t data_len)
+{
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+ u8 *args = ihid->argsbuf;
+ int ret;
+ u16 dataRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
+
+ /* hidraw already checked that data_len < HID_MAX_BUFFER_SIZE */
+ u16 size = 2 /* size */ +
+ (reportID ? 1 : 0) /* reportID */ +
+ data_len /* buf */;
+ int args_len = (reportID >= 0x0F ? 1 : 0) /* optional third byte */ +
+ 2 /* dataRegister */ +
+ size /* args */;
+ int index = 0;
+
+ i2c_hid_dbg(ihid, "%s\n", __func__);
+
+ if (reportID >= 0x0F) {
+ args[index++] = reportID;
+ reportID = 0x0F;
+ }
+
+ args[index++] = dataRegister & 0xFF;
+ args[index++] = dataRegister >> 8;
+
+ args[index++] = size & 0xFF;
+ args[index++] = size >> 8;
+
+ if (reportID)
+ args[index++] = reportID;
+
+ memcpy(&args[index], buf, data_len);
+
+ ret = __i2c_hid_command(client, &hid_set_report_cmd, reportID,
+ reportType, args, args_len, NULL, 0);
+ if (ret) {
+ dev_err(&client->dev, "failed to set a report to device.\n");
+ return -EINVAL;
+ }
+
+ return data_len;
+}
+
+static int i2c_hid_set_power(struct i2c_client *client, int power_state)
+{
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+ int ret;
+
+ i2c_hid_dbg(ihid, "%s\n", __func__);
+
+ ret = __i2c_hid_command(client, &hid_set_power_cmd, power_state,
+ 0, NULL, 0, NULL, 0);
+ if (ret)
+ dev_err(&client->dev, "failed to change power setting.\n");
+
+ return ret;
+}
+
+static int i2c_hid_hwreset(struct i2c_client *client)
+{
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+ int ret;
+
+ i2c_hid_dbg(ihid, "%s\n", __func__);
+
+ ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
+ if (ret)
+ return ret;
+
+ i2c_hid_dbg(ihid, "resetting...\n");
+
+ ret = i2c_hid_command(client, &hid_reset_cmd, NULL, 0);
+ if (ret) {
+ dev_err(&client->dev, "failed to reset device.\n");
+ i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int i2c_hid_get_input(struct i2c_hid *ihid)
+{
+ int ret, ret_size;
+ int size = le16_to_cpu(ihid->hdesc.wMaxInputLength);
+
+ ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
+ if (ret != size) {
+ if (ret < 0)
+ return ret;
+
+ dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
+ __func__, ret, size);
+ return ret;
+ }
+
+ ret_size = ihid->inbuf[0] | ihid->inbuf[1] << 8;
+
+ if (!ret_size) {
+ /* host or device initiated RESET completed */
+ if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags))
+ wake_up(&ihid->wait);
+ return 0;
+ }
+
+ if (ret_size > size) {
+ dev_err(&ihid->client->dev, "%s: incomplete report (%d/%d)\n",
+ __func__, size, ret_size);
+ return -EIO;
+ }
+
+ i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->inbuf);
+
+ if (test_bit(I2C_HID_STARTED, &ihid->flags))
+ hid_input_report(ihid->hid, HID_INPUT_REPORT, ihid->inbuf + 2,
+ ret_size - 2, 1);
+
+ return 0;
+}
+
+static irqreturn_t i2c_hid_irq(int irq, void *dev_id)
+{
+ struct i2c_hid *ihid = dev_id;
+
+ if (test_bit(I2C_HID_READ_PENDING, &ihid->flags))
+ return IRQ_HANDLED;
+
+ i2c_hid_get_input(ihid);
+
+ return IRQ_HANDLED;
+}
+
+static int i2c_hid_get_report_length(struct hid_report *report)
+{
+ return ((report->size - 1) >> 3) + 1 +
+ report->device->report_enum[report->type].numbered + 2;
+}
+
+static void i2c_hid_init_report(struct hid_report *report, u8 *buffer,
+ size_t bufsize)
+{
+ struct hid_device *hid = report->device;
+ struct i2c_client *client = hid->driver_data;
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+ unsigned int size, ret_size;
+
+ size = i2c_hid_get_report_length(report);
+ i2c_hid_get_report(client,
+ report->type == HID_FEATURE_REPORT ? 0x03 : 0x01,
+ report->id, buffer, size);
+
+ i2c_hid_dbg(ihid, "report (len=%d): %*ph\n", size, size, ihid->inbuf);
+
+ ret_size = buffer[0] | (buffer[1] << 8);
+
+ if (ret_size != size) {
+ dev_err(&client->dev, "error in %s size:%d / ret_size:%d\n",
+ __func__, size, ret_size);
+ return;
+ }
+
+ /* hid->driver_lock is held as we are in probe function,
+ * we just need to setup the input fields, so using
+ * hid_report_raw_event is safe. */
+ hid_report_raw_event(hid, report->type, buffer + 2, size - 2, 1);
+}
+
+/*
+ * Initialize all reports
+ */
+static void i2c_hid_init_reports(struct hid_device *hid)
+{
+ struct hid_report *report;
+ struct i2c_client *client = hid->driver_data;
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+ u8 *inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);
+
+ if (!inbuf)
+ return;
+
+ list_for_each_entry(report,
+ &hid->report_enum[HID_INPUT_REPORT].report_list, list)
+ i2c_hid_init_report(report, inbuf, ihid->bufsize);
+
+ list_for_each_entry(report,
+ &hid->report_enum[HID_FEATURE_REPORT].report_list, list)
+ i2c_hid_init_report(report, inbuf, ihid->bufsize);
+
+ kfree(inbuf);
+}
+
+/*
+ * Traverse the supplied list of reports and find the longest
+ */
+static void i2c_hid_find_max_report(struct hid_device *hid, unsigned int type,
+ unsigned int *max)
+{
+ struct hid_report *report;
+ unsigned int size;
+
+ /* We should not rely on wMaxInputLength, as some devices may set it to
+ * a wrong length. */
+ list_for_each_entry(report, &hid->report_enum[type].report_list, list) {
+ size = i2c_hid_get_report_length(report);
+ if (*max < size)
+ *max = size;
+ }
+}
+
+static int i2c_hid_alloc_buffers(struct i2c_hid *ihid)
+{
+ /* the worst case is computed from the set_report command with a
+ * reportID > 15 and the maximum report length */
+ int args_len = sizeof(__u8) + /* optional ReportID byte */
+ sizeof(__u16) + /* data register */
+ sizeof(__u16) + /* size of the report */
+ ihid->bufsize; /* report */
+
+ ihid->inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);
+
+ if (!ihid->inbuf)
+ return -ENOMEM;
+
+ ihid->argsbuf = kzalloc(args_len, GFP_KERNEL);
+
+ if (!ihid->argsbuf) {
+ kfree(ihid->inbuf);
+ return -ENOMEM;
+ }
+
+ ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL);
+
+ if (!ihid->cmdbuf) {
+ kfree(ihid->inbuf);
+ kfree(ihid->argsbuf);
+ ihid->inbuf = NULL;
+ ihid->argsbuf = NULL;
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static void i2c_hid_free_buffers(struct i2c_hid *ihid)
+{
+ kfree(ihid->inbuf);
+ kfree(ihid->argsbuf);
+ kfree(ihid->cmdbuf);
+ ihid->inbuf = NULL;
+ ihid->cmdbuf = NULL;
+ ihid->argsbuf = NULL;
+}
+
+static int i2c_hid_get_raw_report(struct hid_device *hid,
+ unsigned char report_number, __u8 *buf, size_t count,
+ unsigned char report_type)
+{
+ struct i2c_client *client = hid->driver_data;
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+ int ret;
+
+ if (report_type == HID_OUTPUT_REPORT)
+ return -EINVAL;
+
+ if (count > ihid->bufsize)
+ count = ihid->bufsize;
+
+ ret = i2c_hid_get_report(client,
+ report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
+ report_number, ihid->inbuf, count);
+
+ if (ret < 0)
+ return ret;
+
+ count = ihid->inbuf[0] | (ihid->inbuf[1] << 8);
+
+ memcpy(buf, ihid->inbuf + 2, count);
+
+ return count;
+}
+
+static int i2c_hid_output_raw_report(struct hid_device *hid, __u8 *buf,
+ size_t count, unsigned char report_type)
+{
+ struct i2c_client *client = hid->driver_data;
+ int report_id = buf[0];
+
+ if (report_type == HID_INPUT_REPORT)
+ return -EINVAL;
+
+ return i2c_hid_set_report(client,
+ report_type == HID_FEATURE_REPORT ? 0x03 : 0x02,
+ report_id, buf, count);
+}
+
+static int i2c_hid_parse(struct hid_device *hid)
+{
+ struct i2c_client *client = hid->driver_data;
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+ struct i2c_hid_desc *hdesc = &ihid->hdesc;
+ unsigned int rsize;
+ char *rdesc;
+ int ret;
+ int tries = 3;
+
+ i2c_hid_dbg(ihid, "entering %s\n", __func__);
+
+ rsize = le16_to_cpu(hdesc->wReportDescLength);
+ if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
+ dbg_hid("weird size of report descriptor (%u)\n", rsize);
+ return -EINVAL;
+ }
+
+ do {
+ ret = i2c_hid_hwreset(client);
+ if (ret)
+ msleep(1000);
+ } while (tries-- > 0 && ret);
+
+ if (ret)
+ return ret;
+
+ rdesc = kzalloc(rsize, GFP_KERNEL);
+
+ if (!rdesc) {
+ dbg_hid("couldn't allocate rdesc memory\n");
+ return -ENOMEM;
+ }
+
+ i2c_hid_dbg(ihid, "asking HID report descriptor\n");
+
+ ret = i2c_hid_command(client, &hid_report_descr_cmd, rdesc, rsize);
+ if (ret) {
+ hid_err(hid, "reading report descriptor failed\n");
+ kfree(rdesc);
+ return -EIO;
+ }
+
+ i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
+
+ ret = hid_parse_report(hid, rdesc, rsize);
+ kfree(rdesc);
+ if (ret) {
+ dbg_hid("parsing report descriptor failed\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int i2c_hid_start(struct hid_device *hid)
+{
+ struct i2c_client *client = hid->driver_data;
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+ int ret;
+ int old_bufsize = ihid->bufsize;
+
+ ihid->bufsize = HID_MIN_BUFFER_SIZE;
+ i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &ihid->bufsize);
+ i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &ihid->bufsize);
+ i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &ihid->bufsize);
+
+ if (ihid->bufsize > old_bufsize || !ihid->inbuf || !ihid->cmdbuf) {
+ i2c_hid_free_buffers(ihid);
+
+ ret = i2c_hid_alloc_buffers(ihid);
+
+ if (ret) {
+ ihid->bufsize = old_bufsize;
+ return ret;
+ }
+ }
+
+ if (!(hid->quirks & HID_QUIRK_NO_INIT_REPORTS))
+ i2c_hid_init_reports(hid);
+
+ return 0;
+}
+
+static void i2c_hid_stop(struct hid_device *hid)
+{
+ struct i2c_client *client = hid->driver_data;
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+
+ hid->claimed = 0;
+
+ i2c_hid_free_buffers(ihid);
+}
+
+static int i2c_hid_open(struct hid_device *hid)
+{
+ struct i2c_client *client = hid->driver_data;
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+ int ret;
+
+ if (!hid->open++) {
+ ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
+ if (ret) {
+ hid->open--;
+ return -EIO;
+ }
+ set_bit(I2C_HID_STARTED, &ihid->flags);
+ }
+ return 0;
+}
+
+static void i2c_hid_close(struct hid_device *hid)
+{
+ struct i2c_client *client = hid->driver_data;
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+
+ /* protecting hid->open to make sure we don't restart
+ * data acquistion due to a resumption we no longer
+ * care about
+ */
+ if (!--hid->open) {
+ clear_bit(I2C_HID_STARTED, &ihid->flags);
+
+ /* Save some power */
+ i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
+ }
+}
+
+static int i2c_hid_power(struct hid_device *hid, int lvl)
+{
+ struct i2c_client *client = hid->driver_data;
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+ int ret = 0;
+
+ i2c_hid_dbg(ihid, "%s lvl:%d\n", __func__, lvl);
+
+ switch (lvl) {
+ case PM_HINT_FULLON:
+ ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
+ break;
+ case PM_HINT_NORMAL:
+ ret = i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
+ break;
+ }
+ return ret;
+}
+
+static int i2c_hid_hidinput_input_event(struct input_dev *dev,
+ unsigned int type, unsigned int code, int value)
+{
+ struct hid_device *hid = input_get_drvdata(dev);
+ struct hid_field *field;
+ int offset;
+
+ if (type == EV_FF)
+ return input_ff_event(dev, type, code, value);
+
+ if (type != EV_LED)
+ return -1;
+
+ offset = hidinput_find_field(hid, type, code, &field);
+
+ if (offset == -1) {
+ hid_warn(dev, "event field not found\n");
+ return -1;
+ }
+
+ hid_set_field(field, offset, value);
+
+ return 0;
+}
+
+static struct hid_ll_driver i2c_hid_ll_driver = {
+ .parse = i2c_hid_parse,
+ .start = i2c_hid_start,
+ .stop = i2c_hid_stop,
+ .open = i2c_hid_open,
+ .close = i2c_hid_close,
+ .power = i2c_hid_power,
+ .hidinput_input_event = i2c_hid_hidinput_input_event,
+};
+
+static int __devinit i2c_hid_init_irq(struct i2c_client *client)
+{
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+ int ret;
+
+ dev_dbg(&client->dev, "Requesting IRQ: %d\n", client->irq);
+
+ ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
+ IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+ client->name, ihid);
+ if (ret < 0) {
+ dev_dbg(&client->dev,
+ "Could not register for %s interrupt, irq = %d,"
+ " ret = %d\n",
+ client->name, client->irq, ret);
+
+ return ret;
+ }
+
+ ihid->irq = client->irq;
+
+ return 0;
+}
+
+static int __devinit i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
+{
+ struct i2c_client *client = ihid->client;
+ struct i2c_hid_desc *hdesc = &ihid->hdesc;
+ unsigned int dsize;
+ int ret;
+
+ /* Fetch the length of HID description, retrieve the 4 first bytes:
+ * bytes 0-1 -> length
+ * bytes 2-3 -> bcdVersion (has to be 1.00) */
+ ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer, 4);
+
+ i2c_hid_dbg(ihid, "%s, ihid->hdesc_buffer: %*ph\n",
+ __func__, 4, ihid->hdesc_buffer);
+
+ if (ret) {
+ dev_err(&client->dev, "HID_DESCR_LENGTH_CMD Fail (ret=%d)\n",
+ ret);
+ return -ENODEV;
+ }
+
+ dsize = le16_to_cpu(hdesc->wHIDDescLength);
+ if (!dsize || dsize > HID_MAX_DESCRIPTOR_SIZE) {
+ dev_err(&client->dev, "weird size of HID descriptor (%u)\n",
+ dsize);
+ return -ENODEV;
+ }
+
+ /* check bcdVersion == 1.0 */
+ if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
+ dev_err(&client->dev,
+ "unexpected HID descriptor bcdVersion (0x%04x)\n",
+ le16_to_cpu(hdesc->bcdVersion));
+ return -ENODEV;
+ }
+
+ i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
+
+ ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer,
+ dsize);
+ if (ret) {
+ dev_err(&client->dev, "hid_descr_cmd Fail\n");
+ return -ENODEV;
+ }
+
+ i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, ihid->hdesc_buffer);
+
+ return 0;
+}
+
+static int __devinit i2c_hid_probe(struct i2c_client *client,
+ const struct i2c_device_id *dev_id)
+{
+ int ret;
+ struct i2c_hid *ihid;
+ struct hid_device *hid;
+ __u16 hidRegister;
+ struct i2c_hid_platform_data *platform_data = client->dev.platform_data;
+
+ dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);
+
+ if (!platform_data) {
+ dev_err(&client->dev, "HID register address not provided\n");
+ return -EINVAL;
+ }
+
+ if (!client->irq) {
+ dev_err(&client->dev,
+ "HID over i2c has not been provided an Int IRQ\n");
+ return -EINVAL;
+ }
+
+ ihid = kzalloc(sizeof(struct i2c_hid), GFP_KERNEL);
+ if (!ihid)
+ return -ENOMEM;
+
+ i2c_set_clientdata(client, ihid);
+
+ ihid->client = client;
+
+ hidRegister = platform_data->hid_descriptor_address;
+ ihid->wHIDDescRegister = cpu_to_le16(hidRegister);
+
+ init_waitqueue_head(&ihid->wait);
+
+ /* we need to allocate the command buffer without knowing the maximum
+ * size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the
+ * real computation later. */
+ ihid->bufsize = HID_MIN_BUFFER_SIZE;
+ i2c_hid_alloc_buffers(ihid);
+
+ ret = i2c_hid_fetch_hid_descriptor(ihid);
+ if (ret < 0)
+ goto err;
+
+ ret = i2c_hid_init_irq(client);
+ if (ret < 0)
+ goto err;
+
+ hid = hid_allocate_device();
+ if (IS_ERR(hid)) {
+ ret = PTR_ERR(hid);
+ goto err;
+ }
+
+ ihid->hid = hid;
+
+ hid->driver_data = client;
+ hid->ll_driver = &i2c_hid_ll_driver;
+ hid->hid_get_raw_report = i2c_hid_get_raw_report;
+ hid->hid_output_raw_report = i2c_hid_output_raw_report;
+ hid->dev.parent = &client->dev;
+ hid->bus = BUS_I2C;
+ hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
+ hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
+ hid->product = le16_to_cpu(ihid->hdesc.wProductID);
+
+ snprintf(hid->name, sizeof(hid->name), "%s %04X:%04X",
+ client->name, hid->vendor, hid->product);
+
+ ret = hid_add_device(hid);
+ if (ret) {
+ if (ret != -ENODEV)
+ hid_err(client, "can't add hid device: %d\n", ret);
+ goto err_mem_free;
+ }
+
+ return 0;
+
+err_mem_free:
+ hid_destroy_device(hid);
+
+err:
+ if (ihid->irq)
+ free_irq(ihid->irq, ihid);
+
+ kfree(ihid);
+ return ret;
+}
+
+static int __devexit i2c_hid_remove(struct i2c_client *client)
+{
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+ struct hid_device *hid;
+
+ if (WARN_ON(!ihid))
+ return -1;
+
+ hid = ihid->hid;
+ hid_destroy_device(hid);
+
+ free_irq(client->irq, ihid);
+
+ kfree(ihid);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int i2c_hid_suspend(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct i2c_hid *ihid = i2c_get_clientdata(client);
+
+ if (device_may_wakeup(&client->dev))
+ enable_irq_wake(ihid->irq);
+
+ /* Save some power */
+ i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
+
+ return 0;
+}
+
+static int i2c_hid_resume(struct device *dev)
+{
+ int ret;
+ struct i2c_client *client = to_i2c_client(dev);
+
+ ret = i2c_hid_hwreset(client);
+ if (ret)
+ return ret;
+
+ if (device_may_wakeup(&client->dev))
+ disable_irq_wake(client->irq);
+
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(i2c_hid_pm, i2c_hid_suspend, i2c_hid_resume);
+
+static const struct i2c_device_id i2c_hid_id_table[] = {
+ { "i2c_hid", 0 },
+ { },
+};
+MODULE_DEVICE_TABLE(i2c, i2c_hid_id_table);
+
+
+static struct i2c_driver i2c_hid_driver = {
+ .driver = {
+ .name = "i2c_hid",
+ .owner = THIS_MODULE,
+ .pm = &i2c_hid_pm,
+ },
+
+ .probe = i2c_hid_probe,
+ .remove = __devexit_p(i2c_hid_remove),
+
+ .id_table = i2c_hid_id_table,
+};
+
+module_i2c_driver(i2c_hid_driver);
+
+MODULE_DESCRIPTION("HID over I2C core driver");
+MODULE_AUTHOR("Benjamin Tissoires <[email protected]>");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/i2c/i2c-hid.h b/include/linux/i2c/i2c-hid.h
new file mode 100644
index 0000000..60e411d
--- /dev/null
+++ b/include/linux/i2c/i2c-hid.h
@@ -0,0 +1,35 @@
+/*
+ * HID over I2C protocol implementation
+ *
+ * Copyright (c) 2012 Benjamin Tissoires <[email protected]>
+ * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file COPYING in the main directory of this archive for
+ * more details.
+ */
+
+#ifndef __LINUX_I2C_HID_H
+#define __LINUX_I2C_HID_H
+
+#include <linux/types.h>
+
+/**
+ * struct i2chid_platform_data - used by hid over i2c implementation.
+ * @hid_descriptor_address: i2c register where the HID descriptor is stored.
+ *
+ * Note that it is the responsibility of the platform driver (or the acpi 5.0
+ * driver) to setup the irq related to the gpio in the struct i2c_board_info.
+ * The platform driver should also setup the gpio according to the device:
+ *
+ * A typical example is the following:
+ * irq = gpio_to_irq(intr_gpio);
+ * hkdk4412_i2c_devs5[0].irq = irq; // store the irq in i2c_board_info
+ * gpio_request(intr_gpio, "elan-irq");
+ * s3c_gpio_setpull(intr_gpio, S3C_GPIO_PULL_UP);
+ */
+struct i2c_hid_platform_data {
+ u16 hid_descriptor_address;
+};
+
+#endif /* __LINUX_I2C_HID_H */
--
1.8.0
On Mon, 12 Nov 2012, Benjamin Tissoires wrote:
> Microsoft published the protocol specification of HID over i2c:
> http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx
>
> This patch introduces an implementation of this protocol.
>
> This implementation does not includes the ACPI part of the specification.
> This will come when ACPI 5.0 devices enumeration will be available.
>
> Once the ACPI part is done, OEM will not have to declare HID over I2C
> devices in their platform specific driver.
>
> Signed-off-by: Benjamin Tissoires <[email protected]>
Out of curiosity -- has this been tested on a real device (is there any
such device available anyway?), or is that just the implementation of the
defined protocol?
Thanks,
--
Jiri Kosina
SUSE Labs
On Thu, Nov 15, 2012 at 2:51 PM, Jiri Kosina <[email protected]> wrote:
> On Mon, 12 Nov 2012, Benjamin Tissoires wrote:
>
>> Microsoft published the protocol specification of HID over i2c:
>> http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx
>>
>> This patch introduces an implementation of this protocol.
>>
>> This implementation does not includes the ACPI part of the specification.
>> This will come when ACPI 5.0 devices enumeration will be available.
>>
>> Once the ACPI part is done, OEM will not have to declare HID over I2C
>> devices in their platform specific driver.
>>
>> Signed-off-by: Benjamin Tissoires <[email protected]>
>
> Out of curiosity -- has this been tested on a real device (is there any
> such device available anyway?), or is that just the implementation of the
> defined protocol?
It has been tested on an ELAN microelectronics device (a prototype),
on an odroid-x board. That's how we figure out the bug in the
set_report command.
I think we manage to test all main features of the protocol
(get_report, irqs, hid descriptor, report descriptors, set_report).
I'm currently waiting for a Synaptics touchpad to check if it's also
working with their devices.
The thing is that HID over i2c for x86 platform will presumably
require the Haswell platform from Intel (we need ACPI 5 for
enumeration), but it would be very nice to get this in the kernel just
before hardware arrive on the market :)
However, I won't be surprise if android OEMs also start using this
specification because it won't force them to write kernel drivers...
Cheers,
Benjamin
>
> Thanks,
>
> --
> Jiri Kosina
> SUSE Labs
On Thu, Nov 15, 2012 at 3:04 PM, Benjamin Tissoires
<[email protected]> wrote:
> On Thu, Nov 15, 2012 at 2:51 PM, Jiri Kosina <[email protected]> wrote:
>> On Mon, 12 Nov 2012, Benjamin Tissoires wrote:
>>
>>> Microsoft published the protocol specification of HID over i2c:
>>> http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx
>>>
>>> This patch introduces an implementation of this protocol.
>>>
>>> This implementation does not includes the ACPI part of the specification.
>>> This will come when ACPI 5.0 devices enumeration will be available.
>>>
>>> Once the ACPI part is done, OEM will not have to declare HID over I2C
>>> devices in their platform specific driver.
>>>
>>> Signed-off-by: Benjamin Tissoires <[email protected]>
>>
>> Out of curiosity -- has this been tested on a real device (is there any
>> such device available anyway?), or is that just the implementation of the
>> defined protocol?
>
> It has been tested on an ELAN microelectronics device (a prototype),
> on an odroid-x board. That's how we figure out the bug in the
> set_report command.
> I think we manage to test all main features of the protocol
> (get_report, irqs, hid descriptor, report descriptors, set_report).
>
> I'm currently waiting for a Synaptics touchpad to check if it's also
> working with their devices.
>
> The thing is that HID over i2c for x86 platform will presumably
> require the Haswell platform from Intel (we need ACPI 5 for
> enumeration), but it would be very nice to get this in the kernel just
> before hardware arrive on the market :)
> However, I won't be surprise if android OEMs also start using this
> specification because it won't force them to write kernel drivers...
And as a complement, Ramalingam tested it for Nvidia on an early
NVIDIA's Tegra reference board for PISMO which is registered at
http://www.arm.linux.org.uk/developer/machines/list.php?id=4439 , with
a HID over i2c keyboard.
He is up to test also his Synaptics touchpad.
Cheers,
Benjamin
>
> Cheers,
> Benjamin
>
>>
>> Thanks,
>>
>> --
>> Jiri Kosina
>> SUSE Labs
On Mon, 12 Nov 2012, Benjamin Tissoires wrote:
> Microsoft published the protocol specification of HID over i2c:
> http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx
>
> This patch introduces an implementation of this protocol.
>
> This implementation does not includes the ACPI part of the specification.
> This will come when ACPI 5.0 devices enumeration will be available.
>
> Once the ACPI part is done, OEM will not have to declare HID over I2C
> devices in their platform specific driver.
>
> Signed-off-by: Benjamin Tissoires <[email protected]>
> ---
>
> Hi Guys,
>
> here is the v3 of the HID over I2C driver.
>
> Changes in v3:
> * fix i2c_hid_alloc_buffers when allocation failed
> * fix error messages to be more "human"
> * fix i2c_hid_set_report as it didn't followed the protocol
> * remove i2c_hid_write_out_report (hid-core doesn't present the callback that
> could use this feature of the protocol)
> * reject HID_OUTPUT_REPORT in i2c_hid_get_raw_report
> * fix output report id in i2c_hid_output_raw_report and reject HID_INPUT_REPORT
Benjamin,
I am now queuing this in for-3.8/i2c-hid branch, so please send any
potential followup patches on top of that.
Thanks a lot for all your work on this so far.
--
Jiri Kosina
SUSE Labs
On Mon, Nov 19, 2012 at 11:06 AM, Jiri Kosina <[email protected]> wrote:
> On Mon, 12 Nov 2012, Benjamin Tissoires wrote:
>
>> Microsoft published the protocol specification of HID over i2c:
>> http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx
>>
>> This patch introduces an implementation of this protocol.
>>
>> This implementation does not includes the ACPI part of the specification.
>> This will come when ACPI 5.0 devices enumeration will be available.
>>
>> Once the ACPI part is done, OEM will not have to declare HID over I2C
>> devices in their platform specific driver.
>>
>> Signed-off-by: Benjamin Tissoires <[email protected]>
>> ---
>>
>> Hi Guys,
>>
>> here is the v3 of the HID over I2C driver.
>>
>> Changes in v3:
>> * fix i2c_hid_alloc_buffers when allocation failed
>> * fix error messages to be more "human"
>> * fix i2c_hid_set_report as it didn't followed the protocol
>> * remove i2c_hid_write_out_report (hid-core doesn't present the callback that
>> could use this feature of the protocol)
>> * reject HID_OUTPUT_REPORT in i2c_hid_get_raw_report
>> * fix output report id in i2c_hid_output_raw_report and reject HID_INPUT_REPORT
>
> Benjamin,
>
> I am now queuing this in for-3.8/i2c-hid branch, so please send any
> potential followup patches on top of that.
Ok, thanks a lot Jiri.
Cheers,
Benjamin
>
> Thanks a lot for all your work on this so far.
>
> --
> Jiri Kosina
> SUSE Labs
Hi,
> -----Original Message-----
> From: Benjamin Tissoires [mailto:[email protected]]
> Sent: Friday, November 16, 2012 8:26 PM
> To: Jiri Kosina; Ramalingam C
> Cc: Dmitry Torokhov; Stephane Chatty; [email protected];
> [email protected]; Jean Delvare; JJ Ding; Jiri Slaby; Shubhrajyoti Datta;
> [email protected]; [email protected]; linux-
> [email protected]
> Subject: Re: [PATCH v3] i2c-hid: introduce HID over i2c specification
> implementation
>
> On Thu, Nov 15, 2012 at 3:04 PM, Benjamin Tissoires
> <[email protected]> wrote:
> > On Thu, Nov 15, 2012 at 2:51 PM, Jiri Kosina <[email protected]> wrote:
> >> On Mon, 12 Nov 2012, Benjamin Tissoires wrote:
> >>
> >>> Microsoft published the protocol specification of HID over i2c:
> >>> http://msdn.microsoft.com/en-
> us/library/windows/hardware/hh852380.as
> >>> px
> >>>
> >>> This patch introduces an implementation of this protocol.
> >>>
> >>> This implementation does not includes the ACPI part of the specification.
> >>> This will come when ACPI 5.0 devices enumeration will be available.
> >>>
> >>> Once the ACPI part is done, OEM will not have to declare HID over
> >>> I2C devices in their platform specific driver.
> >>>
> >>> Signed-off-by: Benjamin Tissoires <[email protected]>
> >>
> >> Out of curiosity -- has this been tested on a real device (is there
> >> any such device available anyway?), or is that just the
> >> implementation of the defined protocol?
> >
> > It has been tested on an ELAN microelectronics device (a prototype),
> > on an odroid-x board. That's how we figure out the bug in the
> > set_report command.
> > I think we manage to test all main features of the protocol
> > (get_report, irqs, hid descriptor, report descriptors, set_report).
> >
> > I'm currently waiting for a Synaptics touchpad to check if it's also
> > working with their devices.
> >
> > The thing is that HID over i2c for x86 platform will presumably
> > require the Haswell platform from Intel (we need ACPI 5 for
> > enumeration), but it would be very nice to get this in the kernel just
> > before hardware arrive on the market :) However, I won't be surprise
> > if android OEMs also start using this specification because it won't
> > force them to write kernel drivers...
>
> And as a complement, Ramalingam tested it for Nvidia on an early NVIDIA's
> Tegra reference board for PISMO which is registered at
> http://www.arm.linux.org.uk/developer/machines/list.php?id=4439 , with a
> HID over i2c keyboard.
> He is up to test also his Synaptics touchpad.
I have tested with Synaptics trackpad. It is working fine. Thank you Benjamin.
Thanks and Regards,
Ramalingam C
>
> Cheers,
> Benjamin
>
> >
> > Cheers,
> > Benjamin
> >
> >>
> >> Thanks,
> >>
> >> --
> >> Jiri Kosina
> >> SUSE Labs
Hi Benjamin, Jiri,
Sorry for the late review. But better late than never I guess...
On Mon, 12 Nov 2012 15:42:59 +0100, Benjamin Tissoires wrote:
> Microsoft published the protocol specification of HID over i2c:
> http://msdn.microsoft.com/en-us/library/windows/hardware/hh852380.aspx
>
> This patch introduces an implementation of this protocol.
>
> This implementation does not includes the ACPI part of the specification.
> This will come when ACPI 5.0 devices enumeration will be available.
>
> Once the ACPI part is done, OEM will not have to declare HID over I2C
> devices in their platform specific driver.
>
> Signed-off-by: Benjamin Tissoires <[email protected]>
> ---
> (..)
> drivers/hid/Kconfig | 2 +
> drivers/hid/Makefile | 1 +
> drivers/hid/i2c-hid/Kconfig | 21 +
> drivers/hid/i2c-hid/Makefile | 5 +
> drivers/hid/i2c-hid/i2c-hid.c | 974 ++++++++++++++++++++++++++++++++++++++++++
> include/linux/i2c/i2c-hid.h | 35 ++
> 6 files changed, 1038 insertions(+)
> create mode 100644 drivers/hid/i2c-hid/Kconfig
> create mode 100644 drivers/hid/i2c-hid/Makefile
> create mode 100644 drivers/hid/i2c-hid/i2c-hid.c
> create mode 100644 include/linux/i2c/i2c-hid.h
Looks much better. I still have several random comments which you may
be interested in.
> (...)
> diff --git a/drivers/hid/i2c-hid/Kconfig b/drivers/hid/i2c-hid/Kconfig
> new file mode 100644
> index 0000000..5b7d4d8
> --- /dev/null
> +++ b/drivers/hid/i2c-hid/Kconfig
> @@ -0,0 +1,21 @@
> +menu "I2C HID support"
> + depends on I2C
> +
> +config I2C_HID
> + tristate "HID over I2C transport layer"
> + default n
> + depends on I2C && INPUT
> + select HID
> + ---help---
> + Say Y here if you want to use the HID over i2c protocol
> + implementation.
s/i2c/I2C/
The USB equivalent lists a number of examples, maybe you could do the
same here so that the reader knows if he/she needs this driver.
> +
> + If unsure, say N.
> +
> + This support is also available as a module. If so, the module
> + will be called i2c-hid.
> +
> +comment "Input core support is needed for HID over I2C input layer"
> + depends on I2C_HID && INPUT=n
Given that the HID menu itself depends on INPUT, I fail to see how this
comment would ever be displayed. Same question holds for the USB
equivalent.
> +
> +endmenu
> (...)
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> new file mode 100644
> index 0000000..11140bd
> --- /dev/null
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> (...)
> +/* flags */
> +#define I2C_HID_STARTED (1 << 0)
> +#define I2C_HID_RESET_PENDING (1 << 1)
> +#define I2C_HID_READ_PENDING (1 << 2)
> +
> +#define I2C_HID_PWR_ON 0x00
> +#define I2C_HID_PWR_SLEEP 0x01
> +
> +/* debug option */
> +static bool debug = false;
Whether you like it or not, that's still an error for checkpatch:
ERROR: do not initialise statics to 0 or NULL
#240: FILE: drivers/hid/i2c-hid/i2c-hid.c:49:
+static bool debug = false;
The rationale is that the compiler can write more efficient code if
initializations to 0 or NULL are implicit.
> +module_param(debug, bool, 0444);
> +MODULE_PARM_DESC(debug, "print a lot of debug information");
> +
> +#define i2c_hid_dbg(ihid, fmt, arg...) \
> + if (debug) \
> + dev_printk(KERN_DEBUG, &(ihid)->client->dev, fmt, ##arg)
This is considered an error by checkpatch too:
ERROR: Macros with complex values should be enclosed in parenthesis
#244: FILE: drivers/hid/i2c-hid/i2c-hid.c:53:
+#define i2c_hid_dbg(ihid, fmt, arg...) \
+ if (debug) \
+ dev_printk(KERN_DEBUG, &(ihid)->client->dev, fmt, ##arg)
And I wouldn't disagree, as the construct above can lead to bugs which
are hard to see... Consider the following piece of code:
if (condition)
i2c_hid_dbg(ihid, "Blah blah %d\n", i);
else
do_something_very_important();
It looks correct, however with the macro definition above, this expands
to the unexpected:
if (condition) {
if (debug) \
dev_printk(KERN_DEBUG, &ihid->client->dev,
"Blah blah %d\n", i);
else
do_something_very_important();
}
That is, the condition to call do_something_very_important() is
condition && !debug, and not !condition as the code suggests. This is
only an example and your driver doesn't currently use any such
construct. Still I believe this should be fixed.
> (...)
> +#define I2C_HID_CMD(opcode_) \
> + .opcode = opcode_, .length = 4, \
> + .registerIndex = offsetof(struct i2c_hid_desc, wCommandRegister)
> +
> +/* fetch HID descriptor */
> +static const struct i2c_hid_cmd hid_descr_cmd = { .length = 2 };
> +/* fetch report descriptors */
> +static const struct i2c_hid_cmd hid_report_descr_cmd = {
> + .registerIndex = offsetof(struct i2c_hid_desc,
> + wReportDescRegister),
> + .opcode = 0x00,
> + .length = 2 };
> +/* commands */
> +static const struct i2c_hid_cmd hid_reset_cmd = { I2C_HID_CMD(0x01),
> + .wait = true };
> +static const struct i2c_hid_cmd hid_get_report_cmd = { I2C_HID_CMD(0x02) };
> +static const struct i2c_hid_cmd hid_set_report_cmd = { I2C_HID_CMD(0x03) };
> +static const struct i2c_hid_cmd hid_get_idle_cmd = { I2C_HID_CMD(0x04) };
> +static const struct i2c_hid_cmd hid_set_idle_cmd = { I2C_HID_CMD(0x05) };
> +static const struct i2c_hid_cmd hid_get_protocol_cmd = { I2C_HID_CMD(0x06) };
> +static const struct i2c_hid_cmd hid_set_protocol_cmd = { I2C_HID_CMD(0x07) };
The previous four are never used.
> +static const struct i2c_hid_cmd hid_set_power_cmd = { I2C_HID_CMD(0x08) };
> +/* read/write data register */
> +static const struct i2c_hid_cmd hid_data_cmd = {
> + .registerIndex = offsetof(struct i2c_hid_desc, wDataRegister),
> + .opcode = 0x00,
> + .length = 2 };
> +/* write output reports */
> +static const struct i2c_hid_cmd hid_out_cmd = {
> + .registerIndex = offsetof(struct i2c_hid_desc,
> + wOutputRegister),
> + .opcode = 0x00,
> + .length = 2 };
These two are never used either.
> (...)
> +static int i2c_hid_get_report(struct i2c_client *client, u8 reportType,
> + u8 reportID, unsigned char *buf_recv, int data_len)
> +{
> + struct i2c_hid *ihid = i2c_get_clientdata(client);
> + u8 args[3];
> + int ret;
> + int args_len = 0;
> + u16 readRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
> +
> + i2c_hid_dbg(ihid, "%s\n", __func__);
> +
> + if (reportID >= 0x0F) {
> + args[args_len++] = reportID;
> + reportID = 0x0F;
> + }
> +
> + args[args_len++] = readRegister & 0xFF;
> + args[args_len++] = readRegister >> 8;
> +
> + ret = __i2c_hid_command(client, &hid_get_report_cmd, reportID,
> + reportType, args, args_len, buf_recv, data_len);
> + if (ret) {
> + dev_err(&client->dev,
> + "failed to retrieve report from device.\n");
> + return -EINVAL;
Why don't you pass the error value from __i2c_hid_command to the
caller? -EINVAL is for invalid input parameters, which isn't the case
here.
> + }
> +
> + return 0;
> +}
> +
> +static int i2c_hid_set_report(struct i2c_client *client, u8 reportType,
> + u8 reportID, unsigned char *buf, size_t data_len)
> +{
> + struct i2c_hid *ihid = i2c_get_clientdata(client);
> + u8 *args = ihid->argsbuf;
> + int ret;
> + u16 dataRegister = le16_to_cpu(ihid->hdesc.wDataRegister);
> +
> + /* hidraw already checked that data_len < HID_MAX_BUFFER_SIZE */
> + u16 size = 2 /* size */ +
> + (reportID ? 1 : 0) /* reportID */ +
> + data_len /* buf */;
> + int args_len = (reportID >= 0x0F ? 1 : 0) /* optional third byte */ +
> + 2 /* dataRegister */ +
> + size /* args */;
> + int index = 0;
> +
> + i2c_hid_dbg(ihid, "%s\n", __func__);
> +
> + if (reportID >= 0x0F) {
> + args[index++] = reportID;
> + reportID = 0x0F;
> + }
> +
> + args[index++] = dataRegister & 0xFF;
> + args[index++] = dataRegister >> 8;
> +
> + args[index++] = size & 0xFF;
> + args[index++] = size >> 8;
> +
> + if (reportID)
> + args[index++] = reportID;
> +
> + memcpy(&args[index], buf, data_len);
> +
> + ret = __i2c_hid_command(client, &hid_set_report_cmd, reportID,
> + reportType, args, args_len, NULL, 0);
> + if (ret) {
> + dev_err(&client->dev, "failed to set a report to device.\n");
> + return -EINVAL;
Same here, returning "ret" would be more informative than hard-coding
an arbitrary error code.
> + }
> +
> + return data_len;
> +}
> + (...)
> +static int i2c_hid_get_input(struct i2c_hid *ihid)
The caller never checks the return value. If there is nothing useful
the caller can do with the value then you should consider making
i2c_hid_get_input return void.
> +{
> + int ret, ret_size;
> + int size = le16_to_cpu(ihid->hdesc.wMaxInputLength);
> +
> + ret = i2c_master_recv(ihid->client, ihid->inbuf, size);
> + if (ret != size) {
> + if (ret < 0)
> + return ret;
> +
> + dev_err(&ihid->client->dev, "%s: got %d data instead of %d\n",
> + __func__, ret, size);
> + return ret;
If you don't change this function to return void, you should return
-Esomething instead of ret here, so that the caller doesn't get an
unexpected positive number.
> + }
> +
> + ret_size = ihid->inbuf[0] | ihid->inbuf[1] << 8;
> +
> + if (!ret_size) {
> + /* host or device initiated RESET completed */
> + if (test_and_clear_bit(I2C_HID_RESET_PENDING, &ihid->flags))
> + wake_up(&ihid->wait);
> + return 0;
> + }
> +
> + if (ret_size > size) {
> + dev_err(&ihid->client->dev, "%s: incomplete report (%d/%d)\n",
> + __func__, size, ret_size);
> + return -EIO;
> + }
> +
> + i2c_hid_dbg(ihid, "input: %*ph\n", ret_size, ihid->inbuf);
> +
> + if (test_bit(I2C_HID_STARTED, &ihid->flags))
> + hid_input_report(ihid->hid, HID_INPUT_REPORT, ihid->inbuf + 2,
> + ret_size - 2, 1);
> +
> + return 0;
> +}
> +
> +static irqreturn_t i2c_hid_irq(int irq, void *dev_id)
> +{
> + struct i2c_hid *ihid = dev_id;
> +
> + if (test_bit(I2C_HID_READ_PENDING, &ihid->flags))
> + return IRQ_HANDLED;
> +
> + i2c_hid_get_input(ihid);
> +
> + return IRQ_HANDLED;
> +}
> + (...)
> +static void i2c_hid_init_report(struct hid_report *report, u8 *buffer,
> + size_t bufsize)
> +{
> + struct hid_device *hid = report->device;
> + struct i2c_client *client = hid->driver_data;
> + struct i2c_hid *ihid = i2c_get_clientdata(client);
> + unsigned int size, ret_size;
> +
> + size = i2c_hid_get_report_length(report);
> + i2c_hid_get_report(client,
> + report->type == HID_FEATURE_REPORT ? 0x03 : 0x01,
> + report->id, buffer, size);
This can fail.
> +
> + i2c_hid_dbg(ihid, "report (len=%d): %*ph\n", size, size, ihid->inbuf);
> +
> + ret_size = buffer[0] | (buffer[1] << 8);
> +
> + if (ret_size != size) {
> + dev_err(&client->dev, "error in %s size:%d / ret_size:%d\n",
> + __func__, size, ret_size);
> + return;
> + }
> +
> + /* hid->driver_lock is held as we are in probe function,
> + * we just need to setup the input fields, so using
> + * hid_report_raw_event is safe. */
> + hid_report_raw_event(hid, report->type, buffer + 2, size - 2, 1);
> +}
> +
> +/*
> + * Initialize all reports
> + */
> +static void i2c_hid_init_reports(struct hid_device *hid)
> +{
> + struct hid_report *report;
> + struct i2c_client *client = hid->driver_data;
> + struct i2c_hid *ihid = i2c_get_clientdata(client);
> + u8 *inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);
> +
> + if (!inbuf)
> + return;
No error logged, no error reported to the caller?
> +
> + list_for_each_entry(report,
> + &hid->report_enum[HID_INPUT_REPORT].report_list, list)
> + i2c_hid_init_report(report, inbuf, ihid->bufsize);
> +
> + list_for_each_entry(report,
> + &hid->report_enum[HID_FEATURE_REPORT].report_list, list)
> + i2c_hid_init_report(report, inbuf, ihid->bufsize);
> +
> + kfree(inbuf);
> +}
> (...)
> +static int i2c_hid_alloc_buffers(struct i2c_hid *ihid)
> +{
> + /* the worst case is computed from the set_report command with a
> + * reportID > 15 and the maximum report length */
> + int args_len = sizeof(__u8) + /* optional ReportID byte */
> + sizeof(__u16) + /* data register */
> + sizeof(__u16) + /* size of the report */
> + ihid->bufsize; /* report */
> +
> + ihid->inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);
> +
> + if (!ihid->inbuf)
> + return -ENOMEM;
> +
> + ihid->argsbuf = kzalloc(args_len, GFP_KERNEL);
> +
> + if (!ihid->argsbuf) {
> + kfree(ihid->inbuf);
If it is important to set ihid->inbuf and ihid->argsbuf back to NULL in
the error path below, then I suppose it is equally important to set
ihid->inbuf back to NULL here. BTW, I would like to suggest an easier
and more efficient way to handle this, see below.
> + return -ENOMEM;
> + }
> +
> + ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL);
> +
> + if (!ihid->cmdbuf) {
> + kfree(ihid->inbuf);
> + kfree(ihid->argsbuf);
> + ihid->inbuf = NULL;
> + ihid->argsbuf = NULL;
> + return -ENOMEM;
> + }
> +
> + return 0;
> +}
> +
With proper function ordering, the above could be simplified to:
static int i2c_hid_alloc_buffers(struct i2c_hid *ihid)
{
/* the worst case is computed from the set_report command with a
* reportID > 15 and the maximum report length */
int args_len = sizeof(__u8) + /* optional ReportID byte */
sizeof(__u16) + /* data register */
sizeof(__u16) + /* size of the report */
ihid->bufsize; /* report */
ihid->inbuf = kzalloc(ihid->bufsize, GFP_KERNEL);
ihid->argsbuf = kzalloc(args_len, GFP_KERNEL);
ihid->cmdbuf = kzalloc(sizeof(union command) + args_len, GFP_KERNEL);
if (!ihid->inbuf || !ihid->argsbuf || !ihid->cmdbuf) {
i2c_hid_free_buffers(hid);
return -ENOMEM;
}
return 0;
}
> +static void i2c_hid_free_buffers(struct i2c_hid *ihid)
> +{
> + kfree(ihid->inbuf);
> + kfree(ihid->argsbuf);
> + kfree(ihid->cmdbuf);
> + ihid->inbuf = NULL;
> + ihid->cmdbuf = NULL;
> + ihid->argsbuf = NULL;
> +}
> +
> +static int i2c_hid_get_raw_report(struct hid_device *hid,
> + unsigned char report_number, __u8 *buf, size_t count,
> + unsigned char report_type)
> +{
> + struct i2c_client *client = hid->driver_data;
> + struct i2c_hid *ihid = i2c_get_clientdata(client);
> + int ret;
> +
> + if (report_type == HID_OUTPUT_REPORT)
> + return -EINVAL;
> +
> + if (count > ihid->bufsize)
> + count = ihid->bufsize;
> +
> + ret = i2c_hid_get_report(client,
> + report_type == HID_FEATURE_REPORT ? 0x03 : 0x01,
> + report_number, ihid->inbuf, count);
> +
> + if (ret < 0)
> + return ret;
> +
> + count = ihid->inbuf[0] | (ihid->inbuf[1] << 8);
> +
> + memcpy(buf, ihid->inbuf + 2, count);
What guarantee do you have that count is not larger than buf's length?
I hope you don't just count on all hardware out there being nice and
sane, do you? ;)
> +
> + return count;
> +}
> + (...)
> +static int i2c_hid_parse(struct hid_device *hid)
> +{
> + struct i2c_client *client = hid->driver_data;
> + struct i2c_hid *ihid = i2c_get_clientdata(client);
> + struct i2c_hid_desc *hdesc = &ihid->hdesc;
> + unsigned int rsize;
> + char *rdesc;
> + int ret;
> + int tries = 3;
> +
> + i2c_hid_dbg(ihid, "entering %s\n", __func__);
> +
> + rsize = le16_to_cpu(hdesc->wReportDescLength);
> + if (!rsize || rsize > HID_MAX_DESCRIPTOR_SIZE) {
> + dbg_hid("weird size of report descriptor (%u)\n", rsize);
> + return -EINVAL;
> + }
> +
> + do {
> + ret = i2c_hid_hwreset(client);
> + if (ret)
> + msleep(1000);
> + } while (tries-- > 0 && ret);
> +
> + if (ret)
> + return ret;
> +
> + rdesc = kzalloc(rsize, GFP_KERNEL);
> +
> + if (!rdesc) {
> + dbg_hid("couldn't allocate rdesc memory\n");
hid_err() would suit better IMHO.
> + return -ENOMEM;
> + }
> +
> + i2c_hid_dbg(ihid, "asking HID report descriptor\n");
> +
> + ret = i2c_hid_command(client, &hid_report_descr_cmd, rdesc, rsize);
> + if (ret) {
> + hid_err(hid, "reading report descriptor failed\n");
> + kfree(rdesc);
> + return -EIO;
> + }
> +
> + i2c_hid_dbg(ihid, "Report Descriptor: %*ph\n", rsize, rdesc);
> +
> + ret = hid_parse_report(hid, rdesc, rsize);
> + kfree(rdesc);
> + if (ret) {
> + dbg_hid("parsing report descriptor failed\n");
Here too, if this is an unexpected event hid_warn() or hid_err() would
be better.
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int i2c_hid_start(struct hid_device *hid)
> +{
> + struct i2c_client *client = hid->driver_data;
> + struct i2c_hid *ihid = i2c_get_clientdata(client);
> + int ret;
> + int old_bufsize = ihid->bufsize;
> +
> + ihid->bufsize = HID_MIN_BUFFER_SIZE;
> + i2c_hid_find_max_report(hid, HID_INPUT_REPORT, &ihid->bufsize);
> + i2c_hid_find_max_report(hid, HID_OUTPUT_REPORT, &ihid->bufsize);
> + i2c_hid_find_max_report(hid, HID_FEATURE_REPORT, &ihid->bufsize);
> +
> + if (ihid->bufsize > old_bufsize || !ihid->inbuf || !ihid->cmdbuf) {
I don't quite get this condition. As far as I can see, either all 3
buffers are allocated, or none is. A single test should tell you. If
you set ihid->bufsize to 0 on memory allocation failure, testing for
ihid->bufsize > old_bufsize should be sufficient.
> + i2c_hid_free_buffers(ihid);
> +
> + ret = i2c_hid_alloc_buffers(ihid);
> +
> + if (ret) {
> + ihid->bufsize = old_bufsize;
Not really... If we fail here, this means that all 3 buffers have been
freed, so ihid->bufsize is more like 0.
> + return ret;
> + }
> + }
> +
> + if (!(hid->quirks & HID_QUIRK_NO_INIT_REPORTS))
> + i2c_hid_init_reports(hid);
> +
> + return 0;
> +}
> +
> +static void i2c_hid_stop(struct hid_device *hid)
> +{
> + struct i2c_client *client = hid->driver_data;
> + struct i2c_hid *ihid = i2c_get_clientdata(client);
> +
> + hid->claimed = 0;
> +
> + i2c_hid_free_buffers(ihid);
> +}
> +
> +static int i2c_hid_open(struct hid_device *hid)
> +{
> + struct i2c_client *client = hid->driver_data;
> + struct i2c_hid *ihid = i2c_get_clientdata(client);
> + int ret;
> +
> + if (!hid->open++) {
This looks racy. The usbhid driver protects hid->open with a mutex and
I suspect you should do the same.
> + ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
> + if (ret) {
> + hid->open--;
> + return -EIO;
> + }
> + set_bit(I2C_HID_STARTED, &ihid->flags);
> + }
> + return 0;
> +}
> +
> +static void i2c_hid_close(struct hid_device *hid)
> +{
> + struct i2c_client *client = hid->driver_data;
> + struct i2c_hid *ihid = i2c_get_clientdata(client);
> +
> + /* protecting hid->open to make sure we don't restart
> + * data acquistion due to a resumption we no longer
> + * care about
> + */
> + if (!--hid->open) {
> + clear_bit(I2C_HID_STARTED, &ihid->flags);
> +
> + /* Save some power */
> + i2c_hid_set_power(client, I2C_HID_PWR_SLEEP);
> + }
> +}
> (...)
> +static int i2c_hid_hidinput_input_event(struct input_dev *dev,
> + unsigned int type, unsigned int code, int value)
> +{
> + struct hid_device *hid = input_get_drvdata(dev);
> + struct hid_field *field;
> + int offset;
> +
> + if (type == EV_FF)
> + return input_ff_event(dev, type, code, value);
> +
> + if (type != EV_LED)
> + return -1;
> +
> + offset = hidinput_find_field(hid, type, code, &field);
> +
> + if (offset == -1) {
> + hid_warn(dev, "event field not found\n");
> + return -1;
> + }
> +
> + hid_set_field(field, offset, value);
> +
> + return 0;
hid_set_field() can fail, so maybe
return hid_set_field(field, offset, value);
> +}
> + (...)
> +static int __devinit i2c_hid_init_irq(struct i2c_client *client)
> +{
> + struct i2c_hid *ihid = i2c_get_clientdata(client);
> + int ret;
> +
> + dev_dbg(&client->dev, "Requesting IRQ: %d\n", client->irq);
> +
> + ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
> + IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> + client->name, ihid);
> + if (ret < 0) {
> + dev_dbg(&client->dev,
> + "Could not register for %s interrupt, irq = %d,"
> + " ret = %d\n",
> + client->name, client->irq, ret);
dev_warn()? Indentation is broken too.
> +
> + return ret;
> + }
> +
> + ihid->irq = client->irq;
I don't think you need this. Everywhere you use ihid->irq, you have
client at hand so you could as well use client->irq. This would avoid
inconsistencies like free_irq(ihid->irq, ihid) in probing error path
vs. free_irq(client->irq, ihid) in removal path, or
enable_irq_wake(ihid->irq) vs. disable_irq_wake(client->irq) in
suspend/resume.
> +
> + return 0;
> +}
> +
> +static int __devinit i2c_hid_fetch_hid_descriptor(struct i2c_hid *ihid)
> +{
> + struct i2c_client *client = ihid->client;
> + struct i2c_hid_desc *hdesc = &ihid->hdesc;
> + unsigned int dsize;
> + int ret;
> +
> + /* Fetch the length of HID description, retrieve the 4 first bytes:
> + * bytes 0-1 -> length
> + * bytes 2-3 -> bcdVersion (has to be 1.00) */
> + ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer, 4);
> +
> + i2c_hid_dbg(ihid, "%s, ihid->hdesc_buffer: %*ph\n",
> + __func__, 4, ihid->hdesc_buffer);
> +
> + if (ret) {
> + dev_err(&client->dev, "HID_DESCR_LENGTH_CMD Fail (ret=%d)\n",
> + ret);
This message is a little confusing as HID_DESCR_LENGTH_CMD no longer
exists.
> + return -ENODEV;
> + }
> +
> + dsize = le16_to_cpu(hdesc->wHIDDescLength);
> + if (!dsize || dsize > HID_MAX_DESCRIPTOR_SIZE) {
> + dev_err(&client->dev, "weird size of HID descriptor (%u)\n",
> + dsize);
> + return -ENODEV;
> + }
> +
> + /* check bcdVersion == 1.0 */
> + if (le16_to_cpu(hdesc->bcdVersion) != 0x0100) {
> + dev_err(&client->dev,
> + "unexpected HID descriptor bcdVersion (0x%04x)\n",
Should be 0x%04hx.
> + le16_to_cpu(hdesc->bcdVersion));
> + return -ENODEV;
> + }
> +
> + i2c_hid_dbg(ihid, "Fetching the HID descriptor\n");
> +
> + ret = i2c_hid_command(client, &hid_descr_cmd, ihid->hdesc_buffer,
> + dsize);
> + if (ret) {
> + dev_err(&client->dev, "hid_descr_cmd Fail\n");
> + return -ENODEV;
> + }
> +
> + i2c_hid_dbg(ihid, "HID Descriptor: %*ph\n", dsize, ihid->hdesc_buffer);
> +
> + return 0;
> +}
> +
> +static int __devinit i2c_hid_probe(struct i2c_client *client,
> + const struct i2c_device_id *dev_id)
> +{
> + int ret;
> + struct i2c_hid *ihid;
> + struct hid_device *hid;
> + __u16 hidRegister;
> + struct i2c_hid_platform_data *platform_data = client->dev.platform_data;
> +
> + dbg_hid("HID probe called for i2c 0x%02x\n", client->addr);
> +
> + if (!platform_data) {
> + dev_err(&client->dev, "HID register address not provided\n");
> + return -EINVAL;
> + }
> +
> + if (!client->irq) {
> + dev_err(&client->dev,
> + "HID over i2c has not been provided an Int IRQ\n");
> + return -EINVAL;
> + }
> +
> + ihid = kzalloc(sizeof(struct i2c_hid), GFP_KERNEL);
> + if (!ihid)
> + return -ENOMEM;
> +
> + i2c_set_clientdata(client, ihid);
> +
> + ihid->client = client;
> +
> + hidRegister = platform_data->hid_descriptor_address;
> + ihid->wHIDDescRegister = cpu_to_le16(hidRegister);
> +
> + init_waitqueue_head(&ihid->wait);
> +
> + /* we need to allocate the command buffer without knowing the maximum
> + * size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the
> + * real computation later. */
> + ihid->bufsize = HID_MIN_BUFFER_SIZE;
> + i2c_hid_alloc_buffers(ihid);
This could fail, yet you don't check for an error.
> +
> + ret = i2c_hid_fetch_hid_descriptor(ihid);
> + if (ret < 0)
> + goto err;
> +
> + ret = i2c_hid_init_irq(client);
> + if (ret < 0)
> + goto err;
> +
> + hid = hid_allocate_device();
> + if (IS_ERR(hid)) {
> + ret = PTR_ERR(hid);
> + goto err;
> + }
> +
> + ihid->hid = hid;
> +
> + hid->driver_data = client;
> + hid->ll_driver = &i2c_hid_ll_driver;
> + hid->hid_get_raw_report = i2c_hid_get_raw_report;
> + hid->hid_output_raw_report = i2c_hid_output_raw_report;
> + hid->dev.parent = &client->dev;
> + hid->bus = BUS_I2C;
> + hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
> + hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
> + hid->product = le16_to_cpu(ihid->hdesc.wProductID);
> +
> + snprintf(hid->name, sizeof(hid->name), "%s %04X:%04X",
Should be %04hX:%04hX.
> + client->name, hid->vendor, hid->product);
> +
> + ret = hid_add_device(hid);
> + if (ret) {
> + if (ret != -ENODEV)
> + hid_err(client, "can't add hid device: %d\n", ret);
> + goto err_mem_free;
> + }
> +
> + return 0;
> +
> +err_mem_free:
> + hid_destroy_device(hid);
> +
> +err:
> + if (ihid->irq)
> + free_irq(ihid->irq, ihid);
> +
> + kfree(ihid);
> + return ret;
> +}
> +
> +static int __devexit i2c_hid_remove(struct i2c_client *client)
> +{
> + struct i2c_hid *ihid = i2c_get_clientdata(client);
> + struct hid_device *hid;
> +
> + if (WARN_ON(!ihid))
> + return -1;
This just can't happen...?
> +
> + hid = ihid->hid;
> + hid_destroy_device(hid);
> +
> + free_irq(client->irq, ihid);
> +
Is there any guarantee that i2c_hid_stop() has been called before
i2c_hid_remove() is? If not, you're missing a call to
i2c_hid_free_buffers() here. BTW I'm not quite sure why
i2c_hid_remove() frees the buffers in the first place, but then again I
don't know a thing about the HID infrastructure.
> + kfree(ihid);
> +
> + return 0;
> +}
> +(...)
> +static const struct i2c_device_id i2c_hid_id_table[] = {
> + { "i2c_hid", 0 },
I am just realizing "i2c_hid" is a little redundant as an i2c device
name. Can we make this just "hid"?
> + { },
> +};
> +MODULE_DEVICE_TABLE(i2c, i2c_hid_id_table);
--
Jean Delvare