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USDHC tuning circuit should be reset before every time card enumeration or re-enumeration. SD3.0 card need tuning. For SDR104 card, when system suspend in standby mode, and then resume back, the IO timing is still SDR104(tuned) which may result in card re-enumeration fail in low card speed(400khz) for some cards. And we did meet the issue that in certain probability, SDR104 card meet mmc command CRC/Timeout error when send CMD2 during mmc bus resume. This patch reset the tuning circuit when the ios timing is MMC_TIMING_LEGACY/MMC_TIMING_MMC_HS/MMC_TIMING_SD_HS, which means both mmc_power_up() and mmc_power_off() will reset the tuning circuit. Signed-off-by: Haibo Chen <haibo.chen@nxp.com> Acked-by: Dong Aisheng <aisheng.dong@nxp.com> Acked-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.