From 393764340beb595c1ad7dd2d2243c2b6551aaa71 Mon Sep 17 00:00:00 2001 From: Seth Heasley Date: Tue, 2 Mar 2010 12:23:39 +0100 Subject: i2c-i801: Add Intel Cougar Point device IDs Add the Intel Cougar Point (PCH) SMBus controller device IDs. Signed-off-by: Seth Heasley Signed-off-by: Jean Delvare --- Documentation/i2c/busses/i2c-i801 | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/i2c/busses/i2c-i801 b/Documentation/i2c/busses/i2c-i801 index 81c0c59a60ea..e1bb5b261693 100644 --- a/Documentation/i2c/busses/i2c-i801 +++ b/Documentation/i2c/busses/i2c-i801 @@ -15,7 +15,8 @@ Supported adapters: * Intel 82801I (ICH9) * Intel EP80579 (Tolapai) * Intel 82801JI (ICH10) - * Intel PCH + * Intel 3400/5 Series (PCH) + * Intel Cougar Point (PCH) Datasheets: Publicly available at the Intel website Authors: -- cgit v1.2.3 From b5527a7766f0505dc72efe3cefe5e9dea826f611 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Tue, 2 Mar 2010 12:23:42 +0100 Subject: i2c: Add SMBus alert support SMBus alert support. The SMBus alert protocol allows several SMBus slave devices to share a single interrupt pin on the SMBus master, while still allowing the master to know which slave triggered the interrupt. This is based on preliminary work by David Brownell. The key difference between David's implementation and mine is that his was part of i2c-core, while mine is split into a separate, standalone module named i2c-smbus. The i2c-smbus module is meant to include support for all SMBus extensions to the I2C protocol in the future. The benefit of this approach is a zero cost for I2C bus segments which do not need SMBus alert support. Where David's implementation increased the size of struct i2c_adapter by 7% (40 bytes on i386), mine doesn't touch it. Where David's implementation added over 150 lines of code to i2c-core (+10%), mine doesn't touch it. The only change that touches all the users of the i2c subsystem is a new callback in struct i2c_driver (common to both implementations.) I seem to remember Trent was worried about the footprint of David'd implementation, hopefully mine addresses the issue. Signed-off-by: Jean Delvare Acked-by: Jonathan Cameron Cc: David Brownell Cc: Trent Piepho --- Documentation/i2c/smbus-protocol | 16 +++ drivers/i2c/Makefile | 2 +- drivers/i2c/i2c-smbus.c | 263 +++++++++++++++++++++++++++++++++++++++ include/linux/i2c-smbus.h | 50 ++++++++ include/linux/i2c.h | 7 ++ 5 files changed, 337 insertions(+), 1 deletion(-) create mode 100644 drivers/i2c/i2c-smbus.c create mode 100644 include/linux/i2c-smbus.h (limited to 'Documentation') diff --git a/Documentation/i2c/smbus-protocol b/Documentation/i2c/smbus-protocol index 9df47441f0e7..7c19d1a2bea0 100644 --- a/Documentation/i2c/smbus-protocol +++ b/Documentation/i2c/smbus-protocol @@ -185,6 +185,22 @@ the protocol. All ARP communications use slave address 0x61 and require PEC checksums. +SMBus Alert +=========== + +SMBus Alert was introduced in Revision 1.0 of the specification. + +The SMBus alert protocol allows several SMBus slave devices to share a +single interrupt pin on the SMBus master, while still allowing the master +to know which slave triggered the interrupt. + +This is implemented the following way in the Linux kernel: +* I2C bus drivers which support SMBus alert should call + i2c_setup_smbus_alert() to setup SMBus alert support. +* I2C drivers for devices which can trigger SMBus alerts should implement + the optional alert() callback. + + I2C Block Transactions ====================== diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile index ba26e6cbe74e..7111c93bd3e6 100644 --- a/drivers/i2c/Makefile +++ b/drivers/i2c/Makefile @@ -3,7 +3,7 @@ # obj-$(CONFIG_I2C_BOARDINFO) += i2c-boardinfo.o -obj-$(CONFIG_I2C) += i2c-core.o +obj-$(CONFIG_I2C) += i2c-core.o i2c-smbus.o obj-$(CONFIG_I2C_CHARDEV) += i2c-dev.o obj-y += busses/ chips/ algos/ diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c new file mode 100644 index 000000000000..421278221243 --- /dev/null +++ b/drivers/i2c/i2c-smbus.c @@ -0,0 +1,263 @@ +/* + * i2c-smbus.c - SMBus extensions to the I2C protocol + * + * Copyright (C) 2008 David Brownell + * Copyright (C) 2010 Jean Delvare + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include +#include +#include +#include +#include +#include +#include +#include + +struct i2c_smbus_alert { + unsigned int alert_edge_triggered:1; + int irq; + struct work_struct alert; + struct i2c_client *ara; /* Alert response address */ +}; + +struct alert_data { + unsigned short addr; + u8 flag:1; +}; + +/* If this is the alerting device, notify its driver */ +static int smbus_do_alert(struct device *dev, void *addrp) +{ + struct i2c_client *client = i2c_verify_client(dev); + struct alert_data *data = addrp; + + if (!client || client->addr != data->addr) + return 0; + if (client->flags & I2C_CLIENT_TEN) + return 0; + + /* + * Drivers should either disable alerts, or provide at least + * a minimal handler. Lock so client->driver won't change. + */ + down(&dev->sem); + if (client->driver) { + if (client->driver->alert) + client->driver->alert(client, data->flag); + else + dev_warn(&client->dev, "no driver alert()!\n"); + } else + dev_dbg(&client->dev, "alert with no driver\n"); + up(&dev->sem); + + /* Stop iterating after we find the device */ + return -EBUSY; +} + +/* + * The alert IRQ handler needs to hand work off to a task which can issue + * SMBus calls, because those sleeping calls can't be made in IRQ context. + */ +static void smbus_alert(struct work_struct *work) +{ + struct i2c_smbus_alert *alert; + struct i2c_client *ara; + unsigned short prev_addr = 0; /* Not a valid address */ + + alert = container_of(work, struct i2c_smbus_alert, alert); + ara = alert->ara; + + for (;;) { + s32 status; + struct alert_data data; + + /* + * Devices with pending alerts reply in address order, low + * to high, because of slave transmit arbitration. After + * responding, an SMBus device stops asserting SMBALERT#. + * + * Note that SMBus 2.0 reserves 10-bit addresess for future + * use. We neither handle them, nor try to use PEC here. + */ + status = i2c_smbus_read_byte(ara); + if (status < 0) + break; + + data.flag = status & 1; + data.addr = status >> 1; + + if (data.addr == prev_addr) { + dev_warn(&ara->dev, "Duplicate SMBALERT# from dev " + "0x%02x, skipping\n", data.addr); + break; + } + dev_dbg(&ara->dev, "SMBALERT# from dev 0x%02x, flag %d\n", + data.addr, data.flag); + + /* Notify driver for the device which issued the alert */ + device_for_each_child(&ara->adapter->dev, &data, + smbus_do_alert); + prev_addr = data.addr; + } + + /* We handled all alerts; re-enable level-triggered IRQs */ + if (!alert->alert_edge_triggered) + enable_irq(alert->irq); +} + +static irqreturn_t smbalert_irq(int irq, void *d) +{ + struct i2c_smbus_alert *alert = d; + + /* Disable level-triggered IRQs until we handle them */ + if (!alert->alert_edge_triggered) + disable_irq_nosync(irq); + + schedule_work(&alert->alert); + return IRQ_HANDLED; +} + +/* Setup SMBALERT# infrastructure */ +static int smbalert_probe(struct i2c_client *ara, + const struct i2c_device_id *id) +{ + struct i2c_smbus_alert_setup *setup = ara->dev.platform_data; + struct i2c_smbus_alert *alert; + struct i2c_adapter *adapter = ara->adapter; + int res; + + alert = kzalloc(sizeof(struct i2c_smbus_alert), GFP_KERNEL); + if (!alert) + return -ENOMEM; + + alert->alert_edge_triggered = setup->alert_edge_triggered; + alert->irq = setup->irq; + INIT_WORK(&alert->alert, smbus_alert); + alert->ara = ara; + + if (setup->irq > 0) { + res = devm_request_irq(&ara->dev, setup->irq, smbalert_irq, + 0, "smbus_alert", alert); + if (res) { + kfree(alert); + return res; + } + } + + i2c_set_clientdata(ara, alert); + dev_info(&adapter->dev, "supports SMBALERT#, %s trigger\n", + setup->alert_edge_triggered ? "edge" : "level"); + + return 0; +} + +/* IRQ resource is managed so it is freed automatically */ +static int smbalert_remove(struct i2c_client *ara) +{ + struct i2c_smbus_alert *alert = i2c_get_clientdata(ara); + + cancel_work_sync(&alert->alert); + + i2c_set_clientdata(ara, NULL); + kfree(alert); + return 0; +} + +static const struct i2c_device_id smbalert_ids[] = { + { "smbus_alert", 0 }, + { /* LIST END */ } +}; +MODULE_DEVICE_TABLE(i2c, smbalert_ids); + +static struct i2c_driver smbalert_driver = { + .driver = { + .name = "smbus_alert", + }, + .probe = smbalert_probe, + .remove = smbalert_remove, + .id_table = smbalert_ids, +}; + +/** + * i2c_setup_smbus_alert - Setup SMBus alert support + * @adapter: the target adapter + * @setup: setup data for the SMBus alert handler + * Context: can sleep + * + * Setup handling of the SMBus alert protocol on a given I2C bus segment. + * + * Handling can be done either through our IRQ handler, or by the + * adapter (from its handler, periodic polling, or whatever). + * + * NOTE that if we manage the IRQ, we *MUST* know if it's level or + * edge triggered in order to hand it to the workqueue correctly. + * If triggering the alert seems to wedge the system, you probably + * should have said it's level triggered. + * + * This returns the ara client, which should be saved for later use with + * i2c_handle_smbus_alert() and ultimately i2c_unregister_device(); or NULL + * to indicate an error. + */ +struct i2c_client *i2c_setup_smbus_alert(struct i2c_adapter *adapter, + struct i2c_smbus_alert_setup *setup) +{ + struct i2c_board_info ara_board_info = { + I2C_BOARD_INFO("smbus_alert", 0x0c), + .platform_data = setup, + }; + + return i2c_new_device(adapter, &ara_board_info); +} +EXPORT_SYMBOL_GPL(i2c_setup_smbus_alert); + +/** + * i2c_handle_smbus_alert - Handle an SMBus alert + * @ara: the ARA client on the relevant adapter + * Context: can't sleep + * + * Helper function to be called from an I2C bus driver's interrupt + * handler. It will schedule the alert work, in turn calling the + * corresponding I2C device driver's alert function. + * + * It is assumed that ara is a valid i2c client previously returned by + * i2c_setup_smbus_alert(). + */ +int i2c_handle_smbus_alert(struct i2c_client *ara) +{ + struct i2c_smbus_alert *alert = i2c_get_clientdata(ara); + + return schedule_work(&alert->alert); +} +EXPORT_SYMBOL_GPL(i2c_handle_smbus_alert); + +static int __init i2c_smbus_init(void) +{ + return i2c_add_driver(&smbalert_driver); +} + +static void __exit i2c_smbus_exit(void) +{ + i2c_del_driver(&smbalert_driver); +} + +module_init(i2c_smbus_init); +module_exit(i2c_smbus_exit); + +MODULE_AUTHOR("Jean Delvare "); +MODULE_DESCRIPTION("SMBus protocol extensions support"); +MODULE_LICENSE("GPL"); diff --git a/include/linux/i2c-smbus.h b/include/linux/i2c-smbus.h new file mode 100644 index 000000000000..63f57a8c8b31 --- /dev/null +++ b/include/linux/i2c-smbus.h @@ -0,0 +1,50 @@ +/* + * i2c-smbus.h - SMBus extensions to the I2C protocol + * + * Copyright (C) 2010 Jean Delvare + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#ifndef _LINUX_I2C_SMBUS_H +#define _LINUX_I2C_SMBUS_H + +#include + + +/** + * i2c_smbus_alert_setup - platform data for the smbus_alert i2c client + * @alert_edge_triggered: whether the alert interrupt is edge (1) or level (0) + * triggered + * @irq: IRQ number, if the smbus_alert driver should take care of interrupt + * handling + * + * If irq is not specified, the smbus_alert driver doesn't take care of + * interrupt handling. In that case it is up to the I2C bus driver to either + * handle the interrupts or to poll for alerts. + * + * If irq is specified then it it crucial that alert_edge_triggered is + * properly set. + */ +struct i2c_smbus_alert_setup { + unsigned int alert_edge_triggered:1; + int irq; +}; + +struct i2c_client *i2c_setup_smbus_alert(struct i2c_adapter *adapter, + struct i2c_smbus_alert_setup *setup); +int i2c_handle_smbus_alert(struct i2c_client *ara); + +#endif /* _LINUX_I2C_SMBUS_H */ diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 02fc617782ef..476abd09c921 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -152,6 +152,13 @@ struct i2c_driver { int (*suspend)(struct i2c_client *, pm_message_t mesg); int (*resume)(struct i2c_client *); + /* Alert callback, for example for the SMBus alert protocol. + * The format and meaning of the data value depends on the protocol. + * For the SMBus alert protocol, there is a single bit of data passed + * as the alert response's low bit ("event flag"). + */ + void (*alert)(struct i2c_client *, unsigned int data); + /* a ioctl like command that can be used to perform specific functions * with the device. */ -- cgit v1.2.3 From 35859254483bce479024781885bc02d860552995 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Tue, 2 Mar 2010 12:23:44 +0100 Subject: i2c-parport: Add SMBus alert support Add support for the SMBus alert mechanism to the i2c-parport driver. The ADM1032 evaluation board at least is properly wired for this. Signed-off-by: Jean Delvare Cc: David Brownell Cc: Trent Piepho --- Documentation/i2c/busses/i2c-parport | 3 +++ drivers/i2c/busses/Kconfig | 1 + drivers/i2c/busses/i2c-parport.c | 37 ++++++++++++++++++++++++++++++++++-- drivers/i2c/busses/i2c-parport.h | 4 +++- 4 files changed, 42 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/i2c/busses/i2c-parport b/Documentation/i2c/busses/i2c-parport index dceaba1ad930..2461c7b53b2c 100644 --- a/Documentation/i2c/busses/i2c-parport +++ b/Documentation/i2c/busses/i2c-parport @@ -29,6 +29,9 @@ can be easily added when needed. Earlier kernels defaulted to type=0 (Philips). But now, if the type parameter is missing, the driver will simply fail to initialize. +SMBus alert support is available on adapters which have this line properly +connected to the parallel port's interrupt pin. + Building your own adapter ------------------------- diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 7c382f9d81c3..4d65546ede44 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -581,6 +581,7 @@ config I2C_PARPORT tristate "Parallel port adapter" depends on PARPORT select I2C_ALGOBIT + select I2C_SMBUS help This supports parallel port I2C adapters such as the ones made by Philips or Velleman, Analog Devices evaluation boards, and more. diff --git a/drivers/i2c/busses/i2c-parport.c b/drivers/i2c/busses/i2c-parport.c index 056af1820993..220fca7f23a6 100644 --- a/drivers/i2c/busses/i2c-parport.c +++ b/drivers/i2c/busses/i2c-parport.c @@ -1,7 +1,7 @@ /* ------------------------------------------------------------------------ * * i2c-parport.c I2C bus over parallel port * * ------------------------------------------------------------------------ * - Copyright (C) 2003-2007 Jean Delvare + Copyright (C) 2003-2010 Jean Delvare Based on older i2c-philips-par.c driver Copyright (C) 1995-2000 Simon G. Vogl @@ -31,6 +31,7 @@ #include #include #include +#include #include "i2c-parport.h" /* ----- Device list ------------------------------------------------------ */ @@ -39,6 +40,8 @@ struct i2c_par { struct pardevice *pdev; struct i2c_adapter adapter; struct i2c_algo_bit_data algo_data; + struct i2c_smbus_alert_setup alert_data; + struct i2c_client *ara; struct i2c_par *next; }; @@ -144,6 +147,19 @@ static struct i2c_algo_bit_data parport_algo_data = { /* ----- I2c and parallel port call-back functions and structures --------- */ +void i2c_parport_irq(void *data) +{ + struct i2c_par *adapter = data; + struct i2c_client *ara = adapter->ara; + + if (ara) { + dev_dbg(&ara->dev, "SMBus alert received\n"); + i2c_handle_smbus_alert(ara); + } else + dev_dbg(&adapter->adapter.dev, + "SMBus alert received but no ARA client!\n"); +} + static void i2c_parport_attach (struct parport *port) { struct i2c_par *adapter; @@ -155,8 +171,9 @@ static void i2c_parport_attach (struct parport *port) } pr_debug("i2c-parport: attaching to %s\n", port->name); + parport_disable_irq(port); adapter->pdev = parport_register_device(port, "i2c-parport", - NULL, NULL, NULL, PARPORT_FLAG_EXCL, NULL); + NULL, NULL, i2c_parport_irq, PARPORT_FLAG_EXCL, adapter); if (!adapter->pdev) { printk(KERN_ERR "i2c-parport: Unable to register with parport\n"); goto ERROR0; @@ -197,6 +214,18 @@ static void i2c_parport_attach (struct parport *port) goto ERROR1; } + /* Setup SMBus alert if supported */ + if (adapter_parm[type].smbus_alert) { + adapter->alert_data.alert_edge_triggered = 1; + adapter->ara = i2c_setup_smbus_alert(&adapter->adapter, + &adapter->alert_data); + if (adapter->ara) + parport_enable_irq(port); + else + printk(KERN_WARNING "i2c-parport: Failed to register " + "ARA client\n"); + } + /* Add the new adapter to the list */ adapter->next = adapter_list; adapter_list = adapter; @@ -217,6 +246,10 @@ static void i2c_parport_detach (struct parport *port) for (prev = NULL, adapter = adapter_list; adapter; prev = adapter, adapter = adapter->next) { if (adapter->pdev->port == port) { + if (adapter->ara) { + parport_disable_irq(port); + i2c_unregister_device(adapter->ara); + } i2c_del_adapter(&adapter->adapter); /* Un-init if needed (power off...) */ diff --git a/drivers/i2c/busses/i2c-parport.h b/drivers/i2c/busses/i2c-parport.h index ed69d846cb95..a9f66816546c 100644 --- a/drivers/i2c/busses/i2c-parport.h +++ b/drivers/i2c/busses/i2c-parport.h @@ -1,7 +1,7 @@ /* ------------------------------------------------------------------------ * * i2c-parport.h I2C bus over parallel port * * ------------------------------------------------------------------------ * - Copyright (C) 2003-2004 Jean Delvare + Copyright (C) 2003-2010 Jean Delvare This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -38,6 +38,7 @@ struct adapter_parm { struct lineop getsda; struct lineop getscl; struct lineop init; + unsigned int smbus_alert:1; }; static struct adapter_parm adapter_parm[] = { @@ -73,6 +74,7 @@ static struct adapter_parm adapter_parm[] = { .setscl = { 0x01, DATA, 1 }, .getsda = { 0x10, STAT, 1 }, .init = { 0xf0, DATA, 0 }, + .smbus_alert = 1, }, /* type 5: ADM1025, ADM1030 and ADM1031 evaluation boards */ { -- cgit v1.2.3 From 927ab2f80745ec26f1e83e6ca15a5b29e134c8e5 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Tue, 2 Mar 2010 12:23:45 +0100 Subject: i2c-parport-light: Add SMBus alert support Add support for the SMBus alert mechanism to the i2c-parport-light driver. The ADM1032 evaluation board at least is properly wired for this. Signed-off-by: Jean Delvare Cc: David Brownell Cc: Trent Piepho --- Documentation/i2c/busses/i2c-parport-light | 11 ++++++++ drivers/i2c/busses/Kconfig | 1 + drivers/i2c/busses/i2c-parport-light.c | 42 +++++++++++++++++++++++++++--- 3 files changed, 51 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/i2c/busses/i2c-parport-light b/Documentation/i2c/busses/i2c-parport-light index 287436478520..bdc9cbb2e0f2 100644 --- a/Documentation/i2c/busses/i2c-parport-light +++ b/Documentation/i2c/busses/i2c-parport-light @@ -9,3 +9,14 @@ parport handling is not an option. The drawback is a reduced portability and the impossibility to daisy-chain other parallel port devices. Please see i2c-parport for documentation. + +Module parameters: + +* type: type of adapter (see i2c-parport or modinfo) + +* base: base I/O address + Default is 0x378 which is fairly common for parallel ports, at least on PC. + +* irq: optional IRQ + This must be passed if you want SMBus alert support, assuming your adapter + actually supports this. diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index 4d65546ede44..4cc3807bd31c 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -605,6 +605,7 @@ config I2C_PARPORT config I2C_PARPORT_LIGHT tristate "Parallel port adapter (light)" select I2C_ALGOBIT + select I2C_SMBUS help This supports parallel port I2C adapters such as the ones made by Philips or Velleman, Analog Devices evaluation boards, and more. diff --git a/drivers/i2c/busses/i2c-parport-light.c b/drivers/i2c/busses/i2c-parport-light.c index 5383f64c5372..5f41ec0f72d2 100644 --- a/drivers/i2c/busses/i2c-parport-light.c +++ b/drivers/i2c/busses/i2c-parport-light.c @@ -1,7 +1,7 @@ /* ------------------------------------------------------------------------ * * i2c-parport-light.c I2C bus over parallel port * * ------------------------------------------------------------------------ * - Copyright (C) 2003-2007 Jean Delvare + Copyright (C) 2003-2010 Jean Delvare Based on older i2c-velleman.c driver Copyright (C) 1995-2000 Simon G. Vogl @@ -32,6 +32,7 @@ #include #include #include +#include #include #include "i2c-parport.h" @@ -44,6 +45,10 @@ static u16 base; module_param(base, ushort, 0); MODULE_PARM_DESC(base, "Base I/O address"); +static int irq; +module_param(irq, int, 0); +MODULE_PARM_DESC(irq, "IRQ (optional)"); + /* ----- Low-level parallel port access ----------------------------------- */ static inline void port_write(unsigned char p, unsigned char d) @@ -120,6 +125,16 @@ static struct i2c_adapter parport_adapter = { .name = "Parallel port adapter (light)", }; +/* SMBus alert support */ +static struct i2c_smbus_alert_setup alert_data = { + .alert_edge_triggered = 1, +}; +static struct i2c_client *ara; +static struct lineop parport_ctrl_irq = { + .val = (1 << 4), + .port = CTRL, +}; + static int __devinit i2c_parport_probe(struct platform_device *pdev) { int err; @@ -136,13 +151,31 @@ static int __devinit i2c_parport_probe(struct platform_device *pdev) parport_adapter.dev.parent = &pdev->dev; err = i2c_bit_add_bus(&parport_adapter); - if (err) + if (err) { dev_err(&pdev->dev, "Unable to register with I2C\n"); - return err; + return err; + } + + /* Setup SMBus alert if supported */ + if (adapter_parm[type].smbus_alert && irq) { + alert_data.irq = irq; + ara = i2c_setup_smbus_alert(&parport_adapter, &alert_data); + if (ara) + line_set(1, &parport_ctrl_irq); + else + dev_warn(&pdev->dev, "Failed to register ARA client\n"); + } + + return 0; } static int __devexit i2c_parport_remove(struct platform_device *pdev) { + if (ara) { + line_set(0, &parport_ctrl_irq); + i2c_unregister_device(ara); + ara = NULL; + } i2c_del_adapter(&parport_adapter); /* Un-init if needed (power off...) */ @@ -209,6 +242,9 @@ static int __init i2c_parport_init(void) if (!request_region(base, 3, DRVNAME)) return -EBUSY; + if (irq != 0) + pr_info(DRVNAME ": using irq %d\n", irq); + if (!adapter_parm[type].getscl.val) parport_algo_data.getscl = NULL; -- cgit v1.2.3 From 0c43ea544c1086fbbed5a6c99ea58eb64674ea8f Mon Sep 17 00:00:00 2001 From: Zhangfei Gao Date: Tue, 2 Mar 2010 12:23:49 +0100 Subject: i2c: Document the message size limit i2c_master_send & i2c_master_recv do not support more than 64 kb transfer, since msg.len is u16. Signed-off-by: Zhangfei Gao Signed-off-by: Jean Delvare --- Documentation/i2c/writing-clients | 5 +++-- drivers/i2c/i2c-core.c | 4 ++-- include/linux/i2c.h | 1 + 3 files changed, 6 insertions(+), 4 deletions(-) (limited to 'Documentation') diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients index 0a74603eb671..3219ee0dbfef 100644 --- a/Documentation/i2c/writing-clients +++ b/Documentation/i2c/writing-clients @@ -318,8 +318,9 @@ Plain I2C communication These routines read and write some bytes from/to a client. The client contains the i2c address, so you do not have to include it. The second parameter contains the bytes to read/write, the third the number of bytes -to read/write (must be less than the length of the buffer.) Returned is -the actual number of bytes read/written. +to read/write (must be less than the length of the buffer, also should be +less than 64k since msg.len is u16.) Returned is the actual number of bytes +read/written. int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num); diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 4131698008b9..3202a86f420e 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -1183,7 +1183,7 @@ EXPORT_SYMBOL(i2c_transfer); * i2c_master_send - issue a single I2C message in master transmit mode * @client: Handle to slave device * @buf: Data that will be written to the slave - * @count: How many bytes to write + * @count: How many bytes to write, must be less than 64k since msg.len is u16 * * Returns negative errno, or else the number of bytes written. */ @@ -1210,7 +1210,7 @@ EXPORT_SYMBOL(i2c_master_send); * i2c_master_recv - issue a single I2C message in master receive mode * @client: Handle to slave device * @buf: Where to store data read from slave - * @count: How many bytes to read + * @count: How many bytes to read, must be less than 64k since msg.len is u16 * * Returns negative errno, or else the number of bytes read. */ diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 476abd09c921..0a5da639b327 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -53,6 +53,7 @@ struct i2c_board_info; * on a bus (or read from them). Apart from two basic transfer functions to * transmit one message at a time, a more complex version can be used to * transmit an arbitrary number of messages without interruption. + * @count must be be less than 64k since msg.len is u16. */ extern int i2c_master_send(struct i2c_client *client, const char *buf, int count); -- cgit v1.2.3