| From 482a0893cbe9197987655267d6dd877dca36e845 Mon Sep 17 00:00:00 2001 |
| From: Faiz Abbas <faiz_abbas@ti.com> |
| Date: Thu, 10 Oct 2019 16:22:30 +0530 |
| Subject: [PATCH] mmc: sdhci-omap: Fix Tuning procedure for temperatures < -20C |
| |
| commit feb40824d78eac5e48f56498dca941754dff33d7 upstream. |
| |
| According to the App note[1] detailing the tuning algorithm, for |
| temperatures < -20C, the initial tuning value should be min(largest value |
| in LPW - 24, ceil(13/16 ratio of LPW)). The largest value in LPW is |
| (max_window + 4 * (max_len - 1)) and not (max_window + 4 * max_len) itself. |
| Fix this implementation. |
| |
| [1] http://www.ti.com/lit/an/spraca9b/spraca9b.pdf |
| |
| Fixes: 961de0a856e3 ("mmc: sdhci-omap: Workaround errata regarding SDR104/HS200 tuning failures (i929)") |
| Cc: stable@vger.kernel.org |
| Signed-off-by: Faiz Abbas <faiz_abbas@ti.com> |
| Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c |
| index 41c2677c587f..083e7e053c95 100644 |
| --- a/drivers/mmc/host/sdhci-omap.c |
| +++ b/drivers/mmc/host/sdhci-omap.c |
| @@ -372,7 +372,7 @@ static int sdhci_omap_execute_tuning(struct mmc_host *mmc, u32 opcode) |
| * on temperature |
| */ |
| if (temperature < -20000) |
| - phase_delay = min(max_window + 4 * max_len - 24, |
| + phase_delay = min(max_window + 4 * (max_len - 1) - 24, |
| max_window + |
| DIV_ROUND_UP(13 * max_len, 16) * 4); |
| else if (temperature < 20000) |
| -- |
| 2.7.4 |
| |
