From 6de468ae2df0ee6fbee668d946811638b57361f6 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Tue, 2 Mar 2010 12:23:46 +0100 Subject: i2c: Hook up runtime PM support Allow I2C drivers to make use of the runtime PM framework by adding bus implementations of the runtime PM operations. These simply immediately suspend when the device is idle. The runtime PM framework provides drivers with off the shelf refcounts for enables and sysfs control for managing runtime suspend from userspace so is useful even without meaningful input from the bus. Signed-off-by: Mark Brown Signed-off-by: Jean Delvare --- drivers/i2c/i2c-core.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) (limited to 'drivers/i2c/i2c-core.c') diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 10be7b5fbe9..4131698008b 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #include "i2c-core.h" @@ -184,6 +185,52 @@ static int i2c_device_pm_resume(struct device *dev) #define i2c_device_pm_resume NULL #endif +#ifdef CONFIG_PM_RUNTIME +static int i2c_device_runtime_suspend(struct device *dev) +{ + const struct dev_pm_ops *pm; + + if (!dev->driver) + return 0; + pm = dev->driver->pm; + if (!pm || !pm->runtime_suspend) + return 0; + return pm->runtime_suspend(dev); +} + +static int i2c_device_runtime_resume(struct device *dev) +{ + const struct dev_pm_ops *pm; + + if (!dev->driver) + return 0; + pm = dev->driver->pm; + if (!pm || !pm->runtime_resume) + return 0; + return pm->runtime_resume(dev); +} + +static int i2c_device_runtime_idle(struct device *dev) +{ + const struct dev_pm_ops *pm = NULL; + int ret; + + if (dev->driver) + pm = dev->driver->pm; + if (pm && pm->runtime_idle) { + ret = pm->runtime_idle(dev); + if (ret) + return ret; + } + + return pm_runtime_suspend(dev); +} +#else +#define i2c_device_runtime_suspend NULL +#define i2c_device_runtime_resume NULL +#define i2c_device_runtime_idle NULL +#endif + static int i2c_device_suspend(struct device *dev, pm_message_t mesg) { struct i2c_client *client = i2c_verify_client(dev); @@ -251,6 +298,9 @@ static const struct attribute_group *i2c_dev_attr_groups[] = { static const struct dev_pm_ops i2c_device_pm_ops = { .suspend = i2c_device_pm_suspend, .resume = i2c_device_pm_resume, + .runtime_suspend = i2c_device_runtime_suspend, + .runtime_resume = i2c_device_runtime_resume, + .runtime_idle = i2c_device_runtime_idle, }; struct bus_type i2c_bus_type = { -- cgit v1.2.3-70-g09d2 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 'drivers/i2c/i2c-core.c') diff --git a/Documentation/i2c/writing-clients b/Documentation/i2c/writing-clients index 0a74603eb67..3219ee0dbfe 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 4131698008b..3202a86f420 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 476abd09c92..0a5da639b32 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 v1.2.3-70-g09d2