[PATCH 05/16] i2c: i2c-davinci: Drop class based scanning to improve bootup time

[Wolfram Sang]

This driver has been flagged to drop class based instantiation. The removal
improves boot-up time and is unneeded for embedded controllers. Users have been
warned to switch for some time now, so we can actually do the removal. Keep the
DEPRECATED flag, so the core can inform users that the behaviour finally
changed now. After another transition period, this flag can go, too.

Signed-off-by: Wolfram Sang <wsa at the-dreams.de>
---
drivers/i2c/busses/i2c-davinci.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 389bc68c55ad..4d9614719128 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -712,7 +712,7 @@ static int davinci_i2c_probe(struct platform_device *pdev)
adap = &dev->adapter;
i2c_set_adapdata(adap, dev);
adap->owner = THIS_MODULE;
- adap->class = I2C_CLASS_HWMON | I2C_CLASS_DEPRECATED;
+ adap->class = I2C_CLASS_DEPRECATED;
strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
adap->algo = &i2c_davinci_algo;
adap->dev.parent = &pdev->dev;

[Wolfram Sang]

+ /* Warn that the adapter lost class based instantiation */
+ if (adapter->class == I2C_CLASS_DEPRECATED) {
+ dev_dbg(&adapter->dev,
+ "This adapter dropped support for I2C classes and "
+ "won't auto-detect %s devices anymore. If you need it, check "
+ "'Documentation/i2c/instantiating-devices' for alternatives.\n",

It's usually a bad idea to split kernel messages across source lines

Yes, "usually". Not for this message, though, it's specific. The lines
would have been quite long.

You could at least do the split at the sentence boundary.

OK, this would have been a compromise.

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[Wolfram Sang]

Some drivers were flagged to remove class based instantiation soon to improve
boot-up time. Originally, I was planning for a longer deprecation time so users
could switch over to some other kind of instantiation. However, the demand for
the speed up is high enough and class based instantiation is used rarely, so
the removal takes place now. To make up for the deprecation time, another
warning is added to the i2c core pointing out that the behaviour has now
+ /* Warn that the adapter lost class based instantiation */
+ if (adapter->class == I2C_CLASS_DEPRECATED) {
+ dev_dbg(&adapter->dev,
+ "This adapter dropped support for I2C classes and "
+ "won't auto-detect %s devices anymore. If you need it, check "
+ "'Documentation/i2c/instantiating-devices' for alternatives.\n",
+ driver->driver.name);
+ return 0;
+ }
git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git i2c/deprecate_stuff
I hope this meets all the needs. Please comment, ack, test...
Thanks,
Wolfram
i2c: add debug info when class instantiation was dropped
i2c: i2c-at91: Drop class based scanning to improve bootup time
i2c: i2c-bcm2835: Drop class based scanning to improve bootup time
i2c: i2c-bfin-twi: Drop class based scanning to improve bootup time
i2c: i2c-davinci: Drop class based scanning to improve bootup time
i2c: i2c-designware-platdrv: Drop class based scanning to improve
bootup time
i2c: i2c-mv64xxx: Drop class based scanning to improve bootup time
i2c: i2c-nomadik: Drop class based scanning to improve bootup time
i2c: i2c-ocores: Drop class based scanning to improve bootup time
i2c: i2c-omap: Drop class based scanning to improve bootup time
i2c: i2c-rcar: Drop class based scanning to improve bootup time
i2c: i2c-s3c2410: Drop class based scanning to improve bootup time
i2c: i2c-sirf: Drop class based scanning to improve bootup time
i2c: i2c-stu300: Drop class based scanning to improve bootup time
i2c: i2c-tegra: Drop class based scanning to improve bootup time
i2c: i2c-xiic: Drop class based scanning to improve bootup time
drivers/i2c/busses/i2c-at91.c | 2 +-
drivers/i2c/busses/i2c-bcm2835.c | 2 +-
drivers/i2c/busses/i2c-bfin-twi.c | 2 +-
drivers/i2c/busses/i2c-davinci.c | 2 +-
drivers/i2c/busses/i2c-designware-platdrv.c | 2 +-
drivers/i2c/busses/i2c-mv64xxx.c | 2 +-

Applied to for-next, thanks!

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[Lothar Waßmann]

Hi,

Some drivers were flagged to remove class based instantiation soon to improve
boot-up time. Originally, I was planning for a longer deprecation time so users
could switch over to some other kind of instantiation. However, the demand for
the speed up is high enough and class based instantiation is used rarely, so
the removal takes place now. To make up for the deprecation time, another
warning is added to the i2c core pointing out that the behaviour has now
+ /* Warn that the adapter lost class based instantiation */
+ if (adapter->class == I2C_CLASS_DEPRECATED) {
+ dev_dbg(&adapter->dev,
+ "This adapter dropped support for I2C classes and "
+ "won't auto-detect %s devices anymore. If you need it, check "
+ "'Documentation/i2c/instantiating-devices' for alternatives.\n",

It's usually a bad idea to split kernel messages across source lines
because it makes searching for the corresponding source line for a
message found in the log difficult.
You could at least do the split at the sentence boundary.


Lothar Wa?mann
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