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32 lines
1.1 KiB
32 lines
1.1 KiB
6 years ago
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From 9cd69b8f61edc246563741cd11d01fa911cd7e91 Mon Sep 17 00:00:00 2001
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From: Phil Elwell <phil@raspberrypi.org>
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Date: Mon, 22 Jan 2018 12:22:01 +0000
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Subject: [PATCH 167/454] mmc: bcm2835-mmc: Support underclocking
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Support underclocking of the SD bus using the max-frequency DT property
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(which currently has no DT parameter). The sd_overclock parameter
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already provides another way to achieve the same thing which should be
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equivalent in end result, but it is a bug not to support max-frequency
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as well.
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See: https://github.com/raspberrypi/linux/issues/2350
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Signed-off-by: Phil Elwell <phil@raspberrypi.org>
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---
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drivers/mmc/host/bcm2835-mmc.c | 4 ++--
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1 file changed, 2 insertions(+), 2 deletions(-)
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--- a/drivers/mmc/host/bcm2835-mmc.c
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+++ b/drivers/mmc/host/bcm2835-mmc.c
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@@ -1310,8 +1310,8 @@ static int bcm2835_mmc_add_host(struct b
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host->clk_mul = 0;
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- mmc->f_max = host->max_clk;
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- mmc->f_max = host->max_clk;
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+ if (!mmc->f_max || mmc->f_max > host->max_clk)
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+ mmc->f_max = host->max_clk;
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mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_300;
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/* SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK */
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