From 65b3ac3a8cc329f1e725f17ff9fe6103150b5e50 Mon Sep 17 00:00:00 2001 From: xiaoyao Date: Thu, 22 Sep 2016 17:24:59 +0800 Subject: [PATCH] mmc: sdhci-of-arasan: add sdhci_arasan_voltage_switch for arasan,5.1 Per the vendor's requirement, we shouldn't do any setting for 1.8V Signaling Enable, otherwise the interaction/behaviour between phy and controller will be undefined. Mostly it works fine if we do that, but we still see failures. Anyway, let's fix it to meet the vendor's requirement. The error log looks like: [ 93.405085] mmc1: unexpected status 0x800900 after switch [ 93.408474] mmc1: switch to bus width 1 failed [ 93.408482] mmc1: mmc_select_hs200 failed, error -110 [ 93.408492] mmc1: error -110 during resume (card was removed?) [ 93.408705] PM: resume of devices complete after 213.453 msecs Change-Id: Icc5457355c3f57b84bd6073f0c4e01350bcc9ee6 Signed-off-by: Shawn Lin Signed-off-by: xiaoyao --- drivers/mmc/host/sdhci-of-arasan.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c index 243d49e41632..bce72df47967 100644 --- a/drivers/mmc/host/sdhci-of-arasan.c +++ b/drivers/mmc/host/sdhci-of-arasan.c @@ -245,6 +245,28 @@ static void sdhci_arasan_hs400_enhanced_strobe(struct mmc_host *mmc, writel(vendor, host->ioaddr + SDHCI_ARASAN_VENDOR_REGISTER); } +static int sdhci_arasan_voltage_switch(struct mmc_host *mmc, + struct mmc_ios *ios) +{ + switch (ios->signal_voltage) { + case MMC_SIGNAL_VOLTAGE_180: + /* + * Plese don't switch to 1V8 as arasan,5.1 doesn't + * actually refer to this setting to indicate the + * signal voltage and the state machine will be broken + * actually if we force to enable 1V8. That's something + * like broken quirk but we could work around here. + */ + return 0; + case MMC_SIGNAL_VOLTAGE_330: + case MMC_SIGNAL_VOLTAGE_120: + /* We don't support 3V3 and 1V2 */ + break; + } + + return -EINVAL; +} + static struct sdhci_ops sdhci_arasan_ops = { .set_clock = sdhci_arasan_set_clock, .get_max_clock = sdhci_pltfm_clk_get_max_clock, @@ -636,6 +658,8 @@ static int sdhci_arasan_probe(struct platform_device *pdev) host->mmc_host_ops.hs400_enhanced_strobe = sdhci_arasan_hs400_enhanced_strobe; + host->mmc_host_ops.start_signal_voltage_switch = + sdhci_arasan_voltage_switch; } ret = sdhci_add_host(host); -- 2.34.1