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dbe68bc9e8
With commitc709135e57("pinctrl: at91-pio4: add support for slew-rate") and commitcbde6c823b("pinctrl: at91-pio4: Fix slew rate disablement") the slew-rate is enabled by default for each configured pin. The datasheet specifies at chapter "Output Driver AC Characteristics" that HSIO drivers (use in SDMMCx and QSPI0 peripherals), don't have a slewrate setting but are rather calibrated against an external 1% resistor mounted on the SDMMCx_CAL or QSPI0_CAL pins. Depending on the target signal frequency and the external load, it is possible to adjust their target output impedance. Thus set slew-rate = <0> for SDMMC (QSPI is not enabled at the moment in device tree). Fixes:7540629e2f("ARM: dts: at91: add sama7g5 SoC DT and sama7g5-ek") Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com> Link: https://lore.kernel.org/r/20210915074836.6574-3-claudiu.beznea@microchip.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.