From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935614AbdAEIzG (ORCPT ); Thu, 5 Jan 2017 03:55:06 -0500 Received: from mail-wm0-f66.google.com ([74.125.82.66]:32834 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758281AbdAEIyX (ORCPT ); Thu, 5 Jan 2017 03:54:23 -0500 Date: Thu, 5 Jan 2017 09:54:19 +0100 From: Pali =?utf-8?B?Um9ow6Fy?= To: Dmitry Torokhov Cc: Wolfram Sang , Benjamin Tissoires , =?utf-8?B?TWljaGHFgiBLxJlwaWXFhA==?= , Jean Delvare , Steven Honeyman , Valdis.Kletnieks@vt.edu, Jochen Eisinger , Gabriele Mazzotta , Andy Lutomirski , Mario_Limonciello@dell.com, Alex Hung , Takashi Iwai , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, platform-driver-x86@vger.kernel.org Subject: Re: [PATCH] i2c: i801: Register optional lis3lv02d i2c device on Dell machines Message-ID: <20170105085419.GB31083@pali> References: <20170104101306.GR5767@mail.corp.redhat.com> <20170104102118.GD3499@pali> <20170104103233.GT5767@mail.corp.redhat.com> <20170104112223.GE3499@pali> <20170104120031.GG3499@pali> <20170104130252.GV5767@mail.corp.redhat.com> <20170104160643.GH3499@pali> <20170104173928.GW5767@mail.corp.redhat.com> <20170104174619.feke27q3ehwkylfs@ninjato> <20170104175456.GA40341@dtor-ws> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20170104175456.GA40341@dtor-ws> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 04 January 2017 09:54:56 Dmitry Torokhov wrote: > On Wed, Jan 04, 2017 at 06:46:19PM +0100, Wolfram Sang wrote: > > > > > How about: > > > --- > > > From daa7571bbf337704332c0cfeec9b8fd5aeae596f Mon Sep 17 00:00:00 2001 > > > From: Benjamin Tissoires > > > Date: Wed, 4 Jan 2017 18:26:54 +0100 > > > Subject: [PATCH] I2C: add the source of the IRQ in struct i2c_client > > > > > > With commit 4d5538f5882a ("i2c: use an IRQ to report Host Notify events, > > > not alert"), the IRQ provided in struct i2c_client might be assigned while > > > it has not been explicitly declared by either the platform information > > > or OF or ACPI. > > > Some drivers (lis3lv02d) rely on the fact that the IRQ gets assigned or > > > not to trigger a different behavior (exposing /dev/freefall in this case). > > > > > > Provide a way for others to know who set the IRQ and so they can behave > > > accordingly. > > > > > > Signed-off-by: Benjamin Tissoires > > > --- > > > drivers/i2c/i2c-core.c | 7 +++++++ > > > include/linux/i2c.h | 11 +++++++++++ > > > 2 files changed, 18 insertions(+) > > > > > > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > > > index cf9e396..226c75d 100644 > > > --- a/drivers/i2c/i2c-core.c > > > +++ b/drivers/i2c/i2c-core.c > > > @@ -935,8 +935,12 @@ static int i2c_device_probe(struct device *dev) > > > irq = of_irq_get_byname(dev->of_node, "irq"); > > > if (irq == -EINVAL || irq == -ENODATA) > > > irq = of_irq_get(dev->of_node, 0); > > > + if (irq > 0) > > > + client->irq_source = I2C_IRQ_SOURCE_OF; > > > } else if (ACPI_COMPANION(dev)) { > > > irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0); > > > + if (irq > 0) > > > + client->irq_source = I2C_IRQ_SOURCE_ACPI; > > > } > > > if (irq == -EPROBE_DEFER) > > > return irq; > > > @@ -947,6 +951,8 @@ static int i2c_device_probe(struct device *dev) > > > if (irq < 0) { > > > dev_dbg(dev, "Using Host Notify IRQ\n"); > > > irq = i2c_smbus_host_notify_to_irq(client); > > > + if (irq > 0) > > > + client->irq_source = I2C_IRQ_SOURCE_HOST_NOTIFY; > > > } > > > if (irq < 0) > > > irq = 0; > > > @@ -1317,6 +1323,7 @@ i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info) > > > client->flags = info->flags; > > > client->addr = info->addr; > > > client->irq = info->irq; > > > + client->irq_source = I2C_IRQ_SOURCE_PLATFORM; > > > > > > strlcpy(client->name, info->type, sizeof(client->name)); > > > > > > diff --git a/include/linux/i2c.h b/include/linux/i2c.h > > > index b2109c5..7d0368d 100644 > > > --- a/include/linux/i2c.h > > > +++ b/include/linux/i2c.h > > > @@ -213,6 +213,13 @@ struct i2c_driver { > > > }; > > > #define to_i2c_driver(d) container_of(d, struct i2c_driver, driver) > > > > > > +enum i2c_irq_source { > > > + I2C_IRQ_SOURCE_PLATFORM, > > > + I2C_IRQ_SOURCE_OF, > > > + I2C_IRQ_SOURCE_ACPI, > > > + I2C_IRQ_SOURCE_HOST_NOTIFY, > > > +}; > > > + > > > /** > > > * struct i2c_client - represent an I2C slave device > > > * @flags: I2C_CLIENT_TEN indicates the device uses a ten bit chip address; > > > @@ -227,6 +234,9 @@ struct i2c_driver { > > > * userspace_devices list > > > * @slave_cb: Callback when I2C slave mode of an adapter is used. The adapter > > > * calls it to pass on slave events to the slave driver. > > > + * @irq_source: Enum which provides the source of the IRQ. Useful to know > > > + * if the IRQ was issued from Host Notify or if it was provided by an other > > > + * component. > > > > I'd think some documentation somewhere makes sense why we need to > > distinguish this in some cases? > > I'd rather drivers be oblivious of the source of interrupt. If they need > to distinguish between them that means that our IRQ abstration failed. > > > > > > * > > > * An i2c_client identifies a single device (i.e. chip) connected to an > > > * i2c bus. The behaviour exposed to Linux is defined by the driver > > > @@ -245,6 +255,7 @@ struct i2c_client { > > > #if IS_ENABLED(CONFIG_I2C_SLAVE) > > > i2c_slave_cb_t slave_cb; /* callback for slave mode */ > > > #endif > > > + enum i2c_irq_source irq_source; /* which component assigned the irq */ > > > }; > > > #define to_i2c_client(d) container_of(d, struct i2c_client, dev) > > > > > > Dmitry, Wolfram, Jean, would this be acceptable for you? > > > > Adding something to i2c_driver is not exactly cheap, but from what I > > glimpsed from this thread, this is one of the cleanest solution to this > > problem? > > > > As Benjamin said, it is really property of device [instance], not > driver. I.e. driver could handle both wired IRQ and HostNotify-based > scheme similarly, it is device (and board) that knows how stuff is > connected. > > Maybe we could do something like this (untested): > > > From e362a0277fd1bd6112f258664d8831d9bc6b78da Mon Sep 17 00:00:00 2001 > From: Dmitry Torokhov > Date: Wed, 4 Jan 2017 09:33:43 -0800 > Subject: [PATCH] i2c: do not enable fall back to Host Notify by default > > Falling back unconditionally to HostNotify as primary client's interrupt > breaks some drivers which alter their functionality depending on whether > interrupt is present or not, so let's introduce a board flag telling I2C > core explicitly if we want wired interrupt or HostNotify-based one: > I2C_CLIENT_HOST_NOTIFY. > > For DT-based systems we introduce "host-notofy" property that we convert > to I2C_CLIENT_HOST_NOTIFY board flag. > > Signed-off-by: Dmitry Torokhov > --- > Documentation/devicetree/bindings/i2c/i2c.txt | 8 ++++++++ > drivers/i2c/i2c-core.c | 17 ++++++++--------- > include/linux/i2c.h | 1 + > 3 files changed, 17 insertions(+), 9 deletions(-) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt > index 5fa691e6f638..cee9d5055fa2 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c.txt > @@ -62,6 +62,9 @@ wants to support one of the below features, it should adapt the bindings below. > "irq" and "wakeup" names are recognized by I2C core, other names are > left to individual drivers. > > +- host-notify > + device uses SMBus host notify protocol instead of interrupt line. > + > - multi-master > states that there is another master active on this bus. The OS can use > this information to adapt power management to keep the arbitration awake > @@ -81,6 +84,11 @@ Binding may contain optional "interrupts" property, describing interrupts > used by the device. I2C core will assign "irq" interrupt (or the very first > interrupt if not using interrupt names) as primary interrupt for the slave. > > +Alternatively, devices supporting SMbus Host Notify, and connected to > +adapters that support this feature, may use "host-notify" property. I2C > +core will create a virtual interrupt for Host Notify and assign it as > +primary interrupt for the slave. > + > Also, if device is marked as a wakeup source, I2C core will set up "wakeup" > interrupt for the device. If "wakeup" interrupt name is not present in the > binding, then primary interrupt will be used as wakeup interrupt. > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c > index cf9e396d7702..250969fa7670 100644 > --- a/drivers/i2c/i2c-core.c > +++ b/drivers/i2c/i2c-core.c > @@ -931,7 +931,10 @@ static int i2c_device_probe(struct device *dev) > if (!client->irq) { > int irq = -ENOENT; > > - if (dev->of_node) { > + if (client->flags & I2C_CLIENT_HOST_HOTIFY) { > + dev_dbg(dev, "Using Host Notify IRQ\n"); > + irq = i2c_smbus_host_notify_to_irq(client); > + } else if (dev->of_node) { > irq = of_irq_get_byname(dev->of_node, "irq"); > if (irq == -EINVAL || irq == -ENODATA) > irq = of_irq_get(dev->of_node, 0); > @@ -940,14 +943,7 @@ static int i2c_device_probe(struct device *dev) > } > if (irq == -EPROBE_DEFER) > return irq; > - /* > - * ACPI and OF did not find any useful IRQ, try to see > - * if Host Notify can be used. > - */ > - if (irq < 0) { > - dev_dbg(dev, "Using Host Notify IRQ\n"); > - irq = i2c_smbus_host_notify_to_irq(client); > - } > + > if (irq < 0) > irq = 0; > > @@ -1716,6 +1712,9 @@ static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap, > info.of_node = of_node_get(node); > info.archdata = &dev_ad; > > + if (of_read_property_bool(node, "host-notify")) > + info.flags |= I2C_CLIENT_HOST_NOTIFY; > + > if (of_get_property(node, "wakeup-source", NULL)) > info.flags |= I2C_CLIENT_WAKE; > > diff --git a/include/linux/i2c.h b/include/linux/i2c.h > index b2109c522dec..4b45ec46161f 100644 > --- a/include/linux/i2c.h > +++ b/include/linux/i2c.h > @@ -665,6 +665,7 @@ i2c_unlock_adapter(struct i2c_adapter *adapter) > #define I2C_CLIENT_TEN 0x10 /* we have a ten bit chip address */ > /* Must equal I2C_M_TEN below */ > #define I2C_CLIENT_SLAVE 0x20 /* we are the slave */ > +#define I2C_CLIENT_HOST_NOTIFY 0x40 /* We want to use I2C host notify */ > #define I2C_CLIENT_WAKE 0x80 /* for board_info; true iff can wake */ > #define I2C_CLIENT_SCCB 0x9000 /* Use Omnivision SCCB protocol */ > /* Must match I2C_M_STOP|IGNORE_NAK */ > -- > 2.11.0.390.gc69c2f50cf-goog > > Looks good, this seems to be elegant solution to our problem. But then it is needed to patch those touchpad drivers to add that I2C_CLIENT_HOST_NOTIFY flag, right? -- Pali Rohár pali.rohar@gmail.com