Hi Benjamin, I have one little question about __i2chid_command(), please see below. "benjamin.tissoires" <benjamin.tissoires@xxxxxxxxx> writes: > From: Benjamin Tissoires <benjamin.tissoires@xxxxxxx> > > 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 will be available. > > Once the ACPI part will be done, OEM will not have to declare HID over I2C > devices in their platform specific driver. > > Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxx> > --- > > Hi, > > this is finally my first implementation of HID over I2C. > > This has been tested on an Elan Microelectronics HID over I2C device, with > a Samsung Exynos 4412 board. > > Any comments are welcome. > > Cheers, > Benjamin > > drivers/i2c/Kconfig | 8 + > drivers/i2c/Makefile | 1 + > drivers/i2c/i2c-hid.c | 1027 +++++++++++++++++++++++++++++++++++++++++++ > include/linux/i2c/i2c-hid.h | 35 ++ > 4 files changed, 1071 insertions(+) > create mode 100644 drivers/i2c/i2c-hid.c > create mode 100644 include/linux/i2c/i2c-hid.h > > diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig > index 5a3bb3d..5adf65a 100644 > --- a/drivers/i2c/Kconfig > +++ b/drivers/i2c/Kconfig > @@ -47,6 +47,14 @@ config I2C_CHARDEV > This support is also available as a module. If so, the module > will be called i2c-dev. > > +config I2C_HID > + tristate "HID over I2C bus" > + help > + Say Y here to use the HID over i2c protocol implementation. > + > + This support is also available as a module. If so, the module > + will be called i2c-hid. > + > config I2C_MUX > tristate "I2C bus multiplexing support" > help > diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile > index beee6b2..8f38116 100644 > --- a/drivers/i2c/Makefile > +++ b/drivers/i2c/Makefile > @@ -6,6 +6,7 @@ obj-$(CONFIG_I2C_BOARDINFO) += i2c-boardinfo.o > obj-$(CONFIG_I2C) += i2c-core.o > obj-$(CONFIG_I2C_SMBUS) += i2c-smbus.o > obj-$(CONFIG_I2C_CHARDEV) += i2c-dev.o > +obj-$(CONFIG_I2C_HID) += i2c-hid.o > obj-$(CONFIG_I2C_MUX) += i2c-mux.o > obj-y += algos/ busses/ muxes/ > > diff --git a/drivers/i2c/i2c-hid.c b/drivers/i2c/i2c-hid.c > new file mode 100644 > index 0000000..eb17d8c > --- /dev/null > +++ b/drivers/i2c/i2c-hid.c > @@ -0,0 +1,1027 @@ > +/* > + * HID over I2C protocol implementation > + * > + * Copyright (c) 2012 Benjamin Tissoires <benjamin.tissoires@xxxxxxxxx> > + * Copyright (c) 2012 Ecole Nationale de l'Aviation Civile, France > + * > + * This code is partly based on "USB HID support for Linux": > + * > + * Copyright (c) 1999 Andreas Gal > + * Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@xxxxxxx> > + * Copyright (c) 2005 Michael Haboustak <mike-@xxxxxxxxxxxx> 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/irq.h> > +#include <linux/gpio.h> > +#include <linux/interrupt.h> > +#include <linux/input.h> > +#include <linux/delay.h> > +#include <linux/slab.h> > +#include <linux/pm.h> > + > +#include <linux/i2c/i2c-hid.h> > + > +#include <linux/hid.h> > +#include <linux/hiddev.h> > +#include <linux/hidraw.h> > + > +#define DRIVER_NAME "i2chid" > +#define DRIVER_DESC "HID over I2C core driver" > + > +#define I2C_HID_COMMAND_TRIES 3 > + > +/* flags */ > +#define I2C_HID_STARTED (1 << 0) > +#define I2C_HID_OUT_RUNNING (1 << 1) > +#define I2C_HID_IN_RUNNING (1 << 2) > +#define I2C_HID_RESET_PENDING (1 << 3) > +#define I2C_HID_SUSPENDED (1 << 4) > + > +#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 informations"); > + > +struct i2chid_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 i2chid_cmd { > + enum { > + /* fecth HID descriptor */ > + HID_DESCR_CMD, > + > + /* fetch report descriptors */ > + HID_REPORT_DESCR_CMD, > + > + /* commands */ > + HID_RESET_CMD, > + HID_GET_REPORT_CMD, > + HID_SET_REPORT_CMD, > + HID_GET_IDLE_CMD, > + HID_SET_IDLE_CMD, > + HID_GET_PROTOCOL_CMD, > + HID_SET_PROTOCOL_CMD, > + HID_SET_POWER_CMD, > + > + /* read/write data register */ > + HID_DATA_CMD, > + } name; > + 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(name_, opcode_) \ > + .name = name_, .opcode = opcode_, .length = 4, \ > + .registerIndex = offsetof(struct i2chid_desc, wCommandRegister) > + > +static const struct i2chid_cmd cmds[] = { > + { I2C_HID_CMD(HID_RESET_CMD, 0x01), .wait = true }, > + { I2C_HID_CMD(HID_GET_REPORT_CMD, 0x02) }, > + { I2C_HID_CMD(HID_SET_REPORT_CMD, 0x03) }, > + { I2C_HID_CMD(HID_GET_IDLE_CMD, 0x04) }, > + { I2C_HID_CMD(HID_SET_IDLE_CMD, 0x05) }, > + { I2C_HID_CMD(HID_GET_PROTOCOL_CMD, 0x06) }, > + { I2C_HID_CMD(HID_SET_PROTOCOL_CMD, 0x07) }, > + { I2C_HID_CMD(HID_SET_POWER_CMD, 0x08) }, > + > + {.name = HID_DESCR_CMD, > + .length = 2}, > + > + {.name = HID_REPORT_DESCR_CMD, > + .registerIndex = offsetof(struct i2chid_desc, wReportDescRegister), > + .opcode = 0x00, > + .length = 2}, > + > + {.name = HID_DATA_CMD, > + .registerIndex = offsetof(struct i2chid_desc, wDataRegister), > + .opcode = 0x00, > + .length = 2}, > + > + {}, /* terminating */ > +}; > + > +/* The main device structure */ > +struct i2chid { > + struct i2c_client *client; /* i2c client */ > + struct hid_device *hid; /* pointer to corresponding HID dev */ > + union { > + __u8 hdesc_buffer[sizeof(struct i2chid_desc)]; > + struct i2chid_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 */ > + > + spinlock_t flock; /* flags spinlock */ > + unsigned long flags; /* device flags */ > + > + int irq; /* the interrupt line irq */ > + > + wait_queue_head_t wait; /* For waiting the interrupt */ > +}; > + > +void i2chid_print_buffer(struct i2chid *ihid, u8 *buf, unsigned int n) > +{ > + int i; > + char *string = kzalloc((n*3+1)*sizeof(char), GFP_KERNEL); > + char tmpbuf[4] = ""; > + > + for (i = 0; i < n; ++i) { > + sprintf(tmpbuf, "%02x ", buf[i] & 0xFF); > + strcat(string, tmpbuf); > + } > + > + dev_err(&ihid->client->dev, "%s\n", string); > + kfree(string); > +} > + > +static int __i2chid_command(struct i2c_client *client, int command, u8 reportID, > + u8 reportType, u8 *args, int args_len, > + unsigned char *buf_recv, int data_len) > +{ > + struct i2chid *ihid = i2c_get_clientdata(client); > + union command *cmd; > + unsigned char *rec_buf = buf_recv; > + int ret; > + int tries = I2C_HID_COMMAND_TRIES; > + int length = 0; > + struct i2c_msg msg[2]; > + int msg_num = 0; > + int i; > + bool wait = false; > + > + if (WARN_ON(!ihid)) > + return -ENODEV; > + > + cmd = kmalloc(args_len + sizeof(union command), GFP_KERNEL); > + if (!cmd) > + return -ENOMEM; > + > + for (i = 0; cmds[i].length; i++) { > + unsigned int registerIndex; > + > + if (cmds[i].name != command) > + continue; > + > + registerIndex = cmds[i].registerIndex; > + cmd->data[0] = ihid->hdesc_buffer[registerIndex]; > + cmd->data[1] = ihid->hdesc_buffer[registerIndex + 1]; > + cmd->c.opcode = cmds[i].opcode; > + length = cmds[i].length; > + wait = cmds[i].wait; > + } > + > + /* special case for HID_DESCR_CMD */ > + if (command == HID_DESCR_CMD) > + cmd->c.reg = ihid->wHIDDescRegister; > + > + cmd->c.reportTypeID = reportID | reportType << 4; > + > + memcpy(cmd->data + length, args, args_len); > + length += args_len; > + > + if (debug) { > + char tmpstr[4] = ""; > + char strbuf[50] = ""; > + int i; > + for (i = 0; i < length; i++) { > + sprintf(tmpstr, "%02x ", cmd->data[i] & 0xFF); > + strcat(strbuf, tmpstr); > + } > + dev_err(&client->dev, "%s, cmd=%s\n", __func__, strbuf); > + } > + > + msg[0].addr = client->addr; > + msg[0].flags = client->flags & I2C_M_TEN; > + msg[0].len = length; > + msg[0].buf = (char *) cmd->data; > + 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 = rec_buf; > + > + msg_num = data_len > 0 ? 2 : 1; > + > + if (wait) { > + spin_lock_irq(&ihid->flock); > + set_bit(I2C_HID_RESET_PENDING, &ihid->flags); > + spin_unlock_irq(&ihid->flock); > + } > + > + do { > + ret = i2c_transfer(client->adapter, msg, msg_num); > + if (ret > 0) > + break; > + tries--; > + dev_dbg(&client->dev, "retrying i2chid_command:%d (%d)\n", > + command, tries); > + } while (tries > 0); Do we have to do this retry here? In i2c_transfer() it already does retry automatically on arbitration loss (please see __i2c_transfer() in drivers/i2c/i2c-core.c) that's defined by individual bus driver. Maybe we don't have to retry here and make the code a bit simpler. Thanks, JJ > + if (wait && ret > 0) { > + if (debug) > + dev_err(&client->dev, "%s: waiting....\n", __func__); > + if (!wait_event_timeout(ihid->wait, > + !test_bit(I2C_HID_RESET_PENDING, &ihid->flags), > + msecs_to_jiffies(5000))) > + ret = -ENODATA; > + if (debug) > + dev_err(&client->dev, "%s: finished.\n", __func__); > + } > + > + kfree(cmd); > + > + return ret > 0 ? ret != msg_num : ret; > +} > + > +static int i2chid_command(struct i2c_client *client, int command, > + unsigned char *buf_recv, int data_len) > +{ > + return __i2chid_command(client, command, 0, 0, NULL, 0, > + buf_recv, data_len); > +} -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
