2012/11/14 Mark Brown <broo...@opensource.wolfsonmicro.com>: > On Wed, Nov 14, 2012 at 03:11:37PM +0800, Kevin Liu wrote: > >> - ret = regulator_set_voltage(host->vqmmc, 3300000, 3300000); >> + ret = regulator_set_voltage(host->vqmmc, 2700000, 3600000); > > Should this be regulator_set_voltage_tol()? Otherwise it'd be good to > explain where the numbers come from. In SD physical layer spec 3.01 chapter 6.6.1, the threshold level for voltage range is defined as below: Vdd(min) = 2.7V while Vdd(max) = 3.6V. The card should work within the voltage range.
If you are afraid the voltage value is too aggressive, maybe we can use regulator_set_voltage_tol() to set a smaller range. But which range should be reasonable? >> + ret = regulator_is_supported_voltage(host->vmmc, 1700000, >> + 1950000); > > We should really add a regulator_is_supported_voltage_tol... let me > just do that. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
