Hi Wolfram,
On Mon, 26 Jan 2015 12:33:29 +0100, Wolfram Sang wrote:
> > I find it confusing that I2C slave support is included even when
> > CONFIG_I2C_SLAVE is not set. I don't know if this was discussed before?
>
> I was thinking about it but was undecided between "size of code added
> unconditionally" and "ugly #ifdeffing the code".
>
> > I am considering adding ifdefs around the code to only include it when
> > CONFIG_I2C_SLAVE is set. Alternatively the code could be moved to a
> > separate module altogether. What do you think?
>
> Own module: Again, undecided. On the one hand it makes for a nice
> encapsulation, on the other hand there is overhead for having another
> module. I am very happy that the core code for slave support is so slim.
I gave a try to the separate module approach and I have to agree that
it seems overkill given the small amount of code.
> Mabye #ifdef is a good start. I could do it as well, I don't mind.
Something like this?
From: Jean Delvare <jdelvare@xxxxxxx>
Subject: i2c: Only include slave support if selected
Make the slave support depend on CONFIG_I2C_SLAVE. Otherwise it gets
included unconditionally, even when it is not needed.
Signed-off-by: Jean Delvare <jdelvare@xxxxxxx>
Cc: Wolfram Sang <wsa@xxxxxxxxxxxxx>
---
drivers/i2c/i2c-core.c | 2 ++
include/linux/i2c.h | 4 ++++
2 files changed, 6 insertions(+)
--- linux-3.19-rc6.orig/drivers/i2c/i2c-core.c 2015-01-26 12:47:26.467671896 +0100
+++ linux-3.19-rc6/drivers/i2c/i2c-core.c 2015-01-26 12:50:23.541420438 +0100
@@ -2962,6 +2962,7 @@ trace:
}
EXPORT_SYMBOL(i2c_smbus_xfer);
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
{drivers/i2c/i2c-smbus.c
int ret;
@@ -3009,6 +3010,7 @@ int i2c_slave_unregister(struct i2c_clie
return ret;
}
EXPORT_SYMBOL_GPL(i2c_slave_unregister);
+#endif
MODULE_AUTHOR("Simon G. Vogl <simon@xxxxxxxxxxxxxxxxx>");
MODULE_DESCRIPTION("I2C-Bus main module");
--- linux-3.19-rc6.orig/include/linux/i2c.h 2015-01-26 12:47:26.470671959 +0100
+++ linux-3.19-rc6/include/linux/i2c.h 2015-01-26 12:52:00.027462551 +0100
@@ -222,7 +222,9 @@ struct i2c_client {
struct device dev; /* the device structure */
int irq; /* irq issued by device */
struct list_head detected;
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
i2c_slave_cb_t slave_cb; /* callback for slave mode */
+#endif
};
#define to_i2c_client(d) container_of(d, struct i2c_client, dev)
@@ -247,6 +249,7 @@ static inline void i2c_set_clientdata(st
/* I2C slave support */
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
enum i2c_slave_event {
I2C_SLAVE_REQ_READ_START,
I2C_SLAVE_REQ_READ_END,
@@ -263,6 +266,7 @@ static inline int i2c_slave_event(struct
{
return client->slave_cb(client, event, val);
}
+#endif
/**
* struct i2c_board_info - template for device creation
--
Jean Delvare
SUSE L3 Support
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