From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shawn Lin Subject: [RESEND PATCH v2 2/4] mmc: core: changes frequency to hs_max_dtr when selecting hs400es Date: Fri, 23 Sep 2016 08:12:55 +0800 Message-ID: <1474589577-11193-2-git-send-email-shawn.lin@rock-chips.com> References: <1474589577-11193-1-git-send-email-shawn.lin@rock-chips.com> Return-path: In-Reply-To: <1474589577-11193-1-git-send-email-shawn.lin@rock-chips.com> Sender: linux-kernel-owner@vger.kernel.org To: Ulf Hansson Cc: Adrian Hunter , Jaehoon Chung , linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, Shawn Lin List-Id: linux-rockchip.vger.kernel.org Per JESD84-B51 P69, Host need to change frequency to <=52MHz after setting HS_TIMING to 0x1, and host may changes frequency to <= 200MHz after setting HS_TIMING to 0x3. That means the card expects the clock rate to increase from the current used f_init (which is less than 400KHz, but still being less than 52MHz) to 52MHz, otherwise we find some eMMC devices significantly report failure when sending status. Reported-by: Xiao Yao Signed-off-by: Shawn Lin --- Changes in v2: - improve the changelog drivers/mmc/core/mmc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index f4ed5ac..39fc5b2 100644 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -1282,6 +1282,8 @@ static int mmc_select_hs400es(struct mmc_card *card) if (err) goto out_err; + mmc_set_clock(host, card->ext_csd.hs_max_dtr); + err = mmc_switch_status(card); if (err) goto out_err; -- 2.3.7