From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757382Ab3FSS0W (ORCPT ); Wed, 19 Jun 2013 14:26:22 -0400 Received: from comal.ext.ti.com ([198.47.26.152]:37395 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757362Ab3FSS0T (ORCPT ); Wed, 19 Jun 2013 14:26:19 -0400 Message-ID: <51C1F6C8.30302@ti.com> Date: Wed, 19 Jun 2013 21:22:00 +0300 From: Grygorii Strashko User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130510 Thunderbird/17.0.6 MIME-Version: 1.0 To: Wolfram Sang CC: , , Subject: Re: [RFC] i2c: add deprecation warning for class based instantiation References: <20130607090623.GC3428@katana> <1370596166-12404-1-git-send-email-wsa@the-dreams.de> In-Reply-To: <1370596166-12404-1-git-send-email-wsa@the-dreams.de> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/07/2013 12:09 PM, Wolfram Sang wrote: > Class based instantiation can cause huge delays when booting. This > mechanism was used when it was not possible to describe slaves on I2C > busses. We now have other mechanisms, so most embedded I2C will not need > classes and it was explicitly not recommended to use them. Add a > deprecation warning for drivers who want to disable class based in the > near future to gain boot-up time, so users relying on this technique can > switch to something better. They really should. > > Signed-off-by: Wolfram Sang > --- > drivers/i2c/busses/i2c-omap.c | 2 +- > drivers/i2c/i2c-core.c | 6 ++++++ > include/linux/i2c.h | 1 + > 3 files changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c > index e02f9e3..f06109f 100644 > --- a/drivers/i2c/busses/i2c-omap.c > +++ b/drivers/i2c/busses/i2c-omap.c > @@ -1231,7 +1231,7 @@ omap_i2c_probe(struct platform_device *pdev) > adap = &dev->adapter; > i2c_set_adapdata(adap, dev); > adap->owner = THIS_MODULE; > - adap->class = I2C_CLASS_HWMON; > + adap->class = I2C_CLASS_HWMON | I2C_CLASS_DEPRECATED; > strlcpy(adap->name, "OMAP I2C adapter", sizeof(adap->name)); > adap->algo = &omap_i2c_algo; > adap->dev.parent = &pdev->dev; > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > index 48e31ed..47ea1f0 100644 > --- a/drivers/i2c/i2c-core.c > +++ b/drivers/i2c/i2c-core.c > @@ -999,6 +999,12 @@ static int i2c_register_adapter(struct i2c_adapter *adap) > return -EINVAL; > } > > + if (adap->class & I2C_CLASS_DEPRECATED) > + dev_warn(&adap->dev, "This adapter will soon drop class based " > + "instantiation of slaves\nPlease make sure all its I2C " > + "devices are instantiated by other means.\nCheck " > + "'Documentation/i2c/instantiating-devices' for details\n"); > + Seems, this need to be moved down - after res = device_register(&adap->dev); - or - right before: bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter); > rt_mutex_init(&adap->bus_lock); > mutex_init(&adap->userspace_clients_lock); > INIT_LIST_HEAD(&adap->userspace_clients); > diff --git a/include/linux/i2c.h b/include/linux/i2c.h > index e988fa9..ffab838 100644 > --- a/include/linux/i2c.h > +++ b/include/linux/i2c.h > @@ -473,6 +473,7 @@ void i2c_unlock_adapter(struct i2c_adapter *); > #define I2C_CLASS_HWMON (1<<0) /* lm_sensors, ... */ > #define I2C_CLASS_DDC (1<<3) /* DDC bus on graphics adapters */ > #define I2C_CLASS_SPD (1<<7) /* Memory modules */ > +#define I2C_CLASS_DEPRECATED (1<<8) /* Warn users that adapter will stop using classes */ > > /* Internal numbers to terminate lists */ > #define I2C_CLIENT_END 0xfffeU - grygorii