From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mika Westerberg Subject: Re: [PATCH v2 4/4] spi: Use Apple device properties in absence of ACPI resources Date: Thu, 29 Jun 2017 10:54:18 +0300 Message-ID: <20170629075418.GB629@lahna.fi.intel.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Lukas Wunner Cc: "Rafael J. Wysocki" , Mark Brown , Ronald Tschalaer , Federico Lorenzi , Andy Shevchenko , Leif Liddy , Daniel Roschka , linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-acpi@vger.kernel.org On Wed, Jun 28, 2017 at 07:20:19PM +0200, Lukas Wunner wrote: > MacBooks and MacBook Pros introduced since 2015 return empty _CRS data > for SPI slaves, causing device initialization to fail. Most of the > information that would normally be conveyed via _CRS is available > through ACPI device properties instead, so take advantage of them. > > The meaning and appropriate usage of the device properties was reverse > engineered by Ronald Tschalär and carried over from these commits > authored by him: > > https://github.com/cb22/macbook12-spi-driver/commit/9a416d699ef4 > https://github.com/cb22/macbook12-spi-driver/commit/0c34936ed9a1 > > According to Ronald, the device properties have the following meaning: > > spiSclkPeriod /* period in ns */ > spiWordSize /* in number of bits */ > spiBitOrder /* 1 = MSB_FIRST, 0 = LSB_FIRST */ > spiSPO /* clock polarity: 0 = low, 1 = high */ > spiSPH /* clock phase: 0 = first, 1 = second */ > spiCSDelay /* delay between cs and receive on reads in 10 us */ > resetA2RUsec /* active-to-receive delay? */ > resetRecUsec /* receive delay? */ > > Cc: Mark Brown > Cc: Federico Lorenzi > Reported-by: Leif Liddy > Tested-by: Ronald Tschalär > Signed-off-by: Lukas Wunner Acked-by: Mika Westerberg -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html