Hi John, On Wed, Feb 11, 2015 at 10:24 PM, John Tobias <john.tobias.ph@xxxxxxxxx> wrote: > Hello All, > > We interface the WiLink8 (http://www.ti.com/lit/gpn/wl1807mod) in iMX6 > custom board. The VIO is 1.8v and the kernel detect the chip in high > speed mode with a signal voltage of 3.3v. > > Is there a way to force the kernel to use a 1.8v signal voltage?. In drivers/mmc/core/sdio.c, function mmc_sdio_init_card() has: /* * If the host and card support UHS-I mode request the card * to switch to 1.8V signaling level. No 1.8v signalling if * UHS mode is not enabled to maintain compatibility and some * systems that claim 1.8v signalling in fact do not support * it. */ if (!powered_resume && (rocr & ocr & R4_18V_PRESENT)) { err = mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_180, ocr); Can you add a printk to check if mmc_set_signal_voltage() is getting called? -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
