From: Wolfram Sang <wsa@the-dreams.de>
To: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Cc: linux-i2c@vger.kernel.org,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
Weifeng Voon <weifeng.voon@intel.com>
Subject: Re: [PATCH 2/3] i2c: core: Add function for finding the bus speed from ACPI
Date: Tue, 19 Jul 2016 06:33:59 +0200 [thread overview]
Message-ID: <20160719043359.GF1640@katana> (raw)
In-Reply-To: <20160714133540.GG4149@tetsubishi>
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On Thu, Jul 14, 2016 at 10:35:41PM +0900, Wolfram Sang wrote:
> On Mon, Jun 06, 2016 at 02:26:22PM +0300, Jarkko Nikula wrote:
> > ACPI 5 specification doesn't have property for the I2C bus speed but
> > I2cSerialBus resource descriptors which define each controller-slave
> > connection define the maximum speed supported by that connection.
> >
> > Thus finding the maximum safe speed for the bus is to walk all
> > I2cSerialBus resources that are associated to I2C controller and use
> > the speed of slowest connection.
> >
> > Add function i2c_acpi_find_bus_speed() to the i2c-core that adapter
> > drivers can call prior registering itself to core.
> >
> > This implies two-step walk through the I2cSerialBus resources: call to
> > i2c_acpi_find_bus_speed() does the first scan and finds the safe bus
> > speed that adapter drivers can set up. Adapter driver registration does
> > the second scan when i2c-core creates the I2C slaves by calling the
> > i2c_acpi_register_devices(). In that way the bus speed is set in case
> > slave device probe gets called during registration and does
> > communication.
> >
> > Implement this by reusing the existing ACPI I2C walk routines in the
> > i2c-core. Extend them so that slowest connection speed is saved during
> > the walk and I2C slaves are registered only when calling through the
> > i2c_acpi_register_devices() with the i2c_adapter pointer.
> >
> > Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
>
> Applied to for-next, thanks!
And reverted due to merge problems and 3/3 not being in shape currently.
Please rebase on v4.8-rc1 and resubmit.
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next prev parent reply other threads:[~2016-07-19 4:34 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-06 11:26 [PATCH 0/3] i2c: core/designware: Find bus speed from ACPI Jarkko Nikula
2016-06-06 11:26 ` [PATCH 1/3] i2c: core: Cleanup I2C ACPI namespace Jarkko Nikula
2016-07-14 13:35 ` Wolfram Sang
2016-07-19 4:33 ` Wolfram Sang
2016-06-06 11:26 ` [PATCH 2/3] i2c: core: Add function for finding the bus speed from ACPI Jarkko Nikula
2016-07-14 13:35 ` Wolfram Sang
2016-07-19 4:33 ` Wolfram Sang [this message]
2016-06-06 11:26 ` [PATCH 3/3] i2c: designware: Find " Jarkko Nikula
2016-07-14 13:36 ` Wolfram Sang
2016-08-02 14:03 ` Jarkko Nikula
2016-08-02 14:43 ` Wolfram Sang
2016-06-06 13:24 ` [PATCH 0/3] i2c: core/designware: " Andy Shevchenko
2016-06-06 16:06 ` Mika Westerberg
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