From: Sarthak Garg Date: Mon, 8 Sep 2025 10:41:21 +0000 (+0530) Subject: mmc: core: Parse and use the new max-sd-hs-hz DT property X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=f338529ca9279e3bea392cb53cec8bd292909cb1;p=users%2Fhch%2Fmisc.git mmc: core: Parse and use the new max-sd-hs-hz DT property Introduce a new device tree flag to cap the maximum High-Speed (HS) mode frequency for SD cards, accommodating board-specific electrical limitations which cannot support the default 50Mhz HS frequency and others. Signed-off-by: Sarthak Garg Signed-off-by: Ulf Hansson --- diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c index 5f0ec23aeff5..88c95dbfd9cf 100644 --- a/drivers/mmc/core/host.c +++ b/drivers/mmc/core/host.c @@ -302,6 +302,8 @@ int mmc_of_parse(struct mmc_host *host) /* f_max is obtained from the optional "max-frequency" property */ device_property_read_u32(dev, "max-frequency", &host->f_max); + device_property_read_u32(dev, "max-sd-hs-hz", &host->max_sd_hs_hz); + /* * Configure CD and WP pins. They are both by default active low to * match the SDHCI spec. If GPIOs are provided for CD and / or WP, the diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c index ec02067f03c5..67cd63004829 100644 --- a/drivers/mmc/core/sd.c +++ b/drivers/mmc/core/sd.c @@ -359,7 +359,7 @@ static int mmc_read_switch(struct mmc_card *card) } if (status[13] & SD_MODE_HIGH_SPEED) - card->sw_caps.hs_max_dtr = HIGH_SPEED_MAX_DTR; + card->sw_caps.hs_max_dtr = card->host->max_sd_hs_hz ?: HIGH_SPEED_MAX_DTR; if (card->scr.sda_spec3) { card->sw_caps.sd3_bus_mode = status[13]; diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index e0d935a4ac1d..e0e2c265e5d1 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -576,6 +576,7 @@ struct mmc_host { int hsq_depth; u32 err_stats[MMC_ERR_MAX]; + u32 max_sd_hs_hz; unsigned long private[] ____cacheline_aligned; };