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Date: Wed, 3 Jun 2015 12:27:41 +0100
From: Lee Jones <lee.jones@...aro.org>
To: Javier Martinez Canillas <javier.martinez@...labora.co.uk>
Cc: Samuel Ortiz <sameo@...ux.intel.com>,
Olof Johansson <olof@...om.net>,
Doug Anderson <dianders@...omium.org>,
Bill Richardson <wfrichar@...omium.org>,
Simon Glass <sjg@...gle.com>,
Gwendal Grignou <gwendal@...gle.com>,
Stephen Barber <smbarber@...omium.org>,
Filipe Brandenburger <filbranden@...gle.com>,
Todd Broch <tbroch@...omium.org>,
Alexandru M Stan <amstan@...omium.org>,
Heiko Stuebner <heiko@...ech.de>,
linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
devicetree@...r.kernel.org, Gwendal Grignou <gwendal@...omium.org>
Subject: Re: [PATCH v4 6/8] mfd: cros_ec: Support multiple EC in a system
On Wed, 03 Jun 2015, Javier Martinez Canillas wrote:
> Hello Lee,
>
> Thanks a lot for your feedback.
>
> On 06/03/2015 10:53 AM, Lee Jones wrote:
> > On Tue, 02 Jun 2015, Javier Martinez Canillas wrote:
> >
> >> From: Gwendal Grignou <gwendal@...omium.org>
> >>
> >> Chromebooks can have more than one Embedded Controller so the
> >> cros_ec device id has to be incremented for each EC registered.
> >>
> >> Add code to handle multiple EC. First ec found is cros-ec0,
> >> second cros-ec1 and so on.
> >>
> >> Add a new structure to represent multiple EC as different char
> >> devices (e.g: /dev/cros_ec, /dev/cros_pd). It connects to
> >> cros_ec_device and allows sysfs inferface for cros_pd.
> >>
> >> Also reduce number of allocated objects, make chromeos sysfs
> >> class object a static and add refcounting to prevent object
> >> deletion while command is in progress.
> >>
> >> Signed-off-by: Gwendal Grignou <gwendal@...omium.org>
> >> Reviewed-by: Dmitry Torokhov <dtor@...omium.org>
> >> Signed-off-by: Javier Martinez Canillas <javier.martinez@...labora.co.uk>
> >> ---
> >>
> >> Changes since v3:
> >> - Add defines for the EC and PD index constants.
> >> - Remove cros_ec_dev_register() and declare the mfd_cells as static structs.
> >> Suggested by Lee Jones.
> >> - Add a new line before the return statement in cros_ec_dev_register().
> >> Suggested by Lee Jones.
> >>
> >> Changes since v2: None
> >>
> >> Changes since v1:
> >> - Squash patch that adds support to represent EC's as different
> >> char devices (e.g: /dev/cros_ec, /dev/cros_pd):
> >> https://chromium-review.googlesource.com/#/c/217297/
> >> Suggested by Gwendal Grignou
> >> - Use cros_ec instead of cros-ec in the subject line to be consistent.
> >> Suggested by Gwendal Grignou
> >> ---
> >> drivers/input/keyboard/cros_ec_keyb.c | 2 +-
> >> drivers/mfd/cros_ec.c | 59 +++++++++++--
> >> drivers/mfd/cros_ec_i2c.c | 1 -
> >> drivers/mfd/cros_ec_spi.c | 1 -
> >> drivers/platform/chrome/cros_ec_dev.c | 128 ++++++++++++++++++++---------
> >> drivers/platform/chrome/cros_ec_dev.h | 7 --
> >> drivers/platform/chrome/cros_ec_lightbar.c | 75 +++++++++--------
> >> drivers/platform/chrome/cros_ec_lpc.c | 1 -
> >> drivers/platform/chrome/cros_ec_sysfs.c | 48 +++++------
> >> include/linux/mfd/cros_ec.h | 44 ++++++++--
> >> 10 files changed, 240 insertions(+), 126 deletions(-)
> >>
> >> diff --git a/drivers/input/keyboard/cros_ec_keyb.c b/drivers/input/keyboard/cros_ec_keyb.c
> >> index 974154a74505..b01966dc7eb3 100644
> >> --- a/drivers/input/keyboard/cros_ec_keyb.c
> >> +++ b/drivers/input/keyboard/cros_ec_keyb.c
> >> @@ -275,7 +275,7 @@ static int cros_ec_keyb_probe(struct platform_device *pdev)
> >> ckdev->dev = dev;
> >> dev_set_drvdata(&pdev->dev, ckdev);
> >>
> >> - idev->name = ec->ec_name;
> >> + idev->name = CROS_EC_DEV_NAME;
> >> idev->phys = ec->phys_name;
> >> __set_bit(EV_REP, idev->evbit);
> >>
> >> diff --git a/drivers/mfd/cros_ec.c b/drivers/mfd/cros_ec.c
> >> index 08d82bfc5268..4fbb4ce8f81e 100644
> >> --- a/drivers/mfd/cros_ec.c
> >> +++ b/drivers/mfd/cros_ec.c
> >> @@ -24,11 +24,29 @@
> >> #include <linux/mfd/core.h>
> >> #include <linux/mfd/cros_ec.h>
> >>
> >> -static const struct mfd_cell cros_devs[] = {
> >> - {
> >> - .name = "cros-ec-ctl",
> >> - .id = PLATFORM_DEVID_AUTO,
> >> - },
> >> +#define CROS_EC_DEV_EC_INDEX 0
> >> +#define CROS_EC_DEV_PD_INDEX 1
> >> +
> >> +struct cros_ec_platform ec_p = {
> >> + .cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_EC_INDEX),
> >> +};
> >> +
> >> +struct cros_ec_platform pd_p = {
> >> + .cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_PD_INDEX),
> >> +};
> >> +
> >> +struct mfd_cell ec_cell = {
> >> + .name = "cros-ec-ctl",
> >> + .id = PLATFORM_DEVID_AUTO,
> >> + .platform_data = &ec_p,
> >> + .pdata_size = sizeof(ec_p),
> >> +};
> >> +
> >> +struct mfd_cell ec_pd_cell = {
> >> + .name = "cros-ec-ctl",
> >> + .id = PLATFORM_DEVID_AUTO,
> >> + .platform_data = &pd_p,
> >> + .pdata_size = sizeof(pd_p),
> >> };
> >>
> >> int cros_ec_register(struct cros_ec_device *ec_dev)
> >> @@ -52,14 +70,39 @@ int cros_ec_register(struct cros_ec_device *ec_dev)
> >>
> >> cros_ec_query_all(ec_dev);
> >>
> >> - err = mfd_add_devices(dev, 0, cros_devs,
> >> - ARRAY_SIZE(cros_devs),
> >> + if (IS_ENABLED(CONFIG_OF) && dev->of_node)
> >> + ec_p.ec_name = of_get_property(dev->of_node, "devname",
> >> + NULL);
> >
> > Has this binding already been accepted? We don't normally allow
> > "device name"properties in DT.
> >
>
> Sigh, I now noticed that I missed the DT binding change when originally
> forward porting the patches from the downstream ChromiumOS tree. I'm so
> sorry about that.
>
> ChromiumOS tree has in Documentation/devicetree/bindings/mfd/cros-ec.txt:
>
> Optional properties (All):
> - devname: name of the EC. Can be based on its function: for instance,
> for Sensor Hub, 'cros_sh', for Power Delivery MCU 'cros_pd'.
> If not present, 'cros_ec' can be assumed.
>
> When you say that normally device names are not allowed in DT, do you mean
> that "devname" is a too generic property name? (which I totally agree) or
> that DT bindings shouldn't have a property to change a device's name for
> something more descriptive?
>
> Because for example, the regulator bindings has a "regulator-name" property.
> If you agree I can change the property to "google,cros-ec-name" which should
> be more precise.
I mean, no names of devices are allowed in Device Tree:
`git grep name -- arch/arm/boot/dts/ | grep dev`
> >> + if (!ec_p.ec_name)
> >> + ec_p.ec_name = CROS_EC_DEV_NAME;
> >> +
> >> + err = mfd_add_devices(ec_dev->dev, CROS_EC_DEV_EC_INDEX, &ec_cell, 1,
> >> NULL, ec_dev->irq, NULL);
> >
> > Take a look at how 'id' (second argument) is handled in mfd-core, then
> > try to figure out why what you're doing is not correct.
> >
>
> I see, so I should not set the struct mfd_cell .id to PLATFORM_DEVID_AUTO and
> just pass PLATFORM_DEVID_AUTO to mfd_add_devices() so platform_device_add()
> automatically allocates a device ID and sets pdev->id_auto = true.
>
> It was only working because CROS_EC_DEV_EC_INDEX was zero so id + cell->id
> was still PLATFORM_DEVID_AUTO but for CROS_EC_DEV_PD_INDEX, it was set to
> PLATFORM_DEVID_NONE...
>
> I'll change that, thanks for pointing it out.
No problem
--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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