On Wed, Aug 31, 2016 at 1:54 PM, Stephen Boyd <sboyd@xxxxxxxxxxxxxx> wrote: > On 08/31/2016 03:52 AM, Archit Taneja wrote: >> On the APQ8016 SBC, the LDO2 PM8916 regulator feeds 1.2V to the following: >> >> - VDDA_1P2_MIPI_DSI and VDDA_MIPI_CSI pins on APQ8016. >> - VCCCAD pins on the LPDDR3 chip. >> - VDDPX_1 pins on APQ8016. >> >> The LDO6 regulator feeds 1.8V to: >> - VDAA_MIPI_DSI0_PLL pin on APQ8016. >> - QFPROM_BLOW_VDD pin on PM8916. >> - The AVDD, A2VDD and DVDD pins on ADV7533 bridge. >> >> The LDO17 regulator feeds 3.3V to: >> - The V3P3 pin on ADV7533 bridge. >> >> Currently, the regulator min/max voltages for all the LDOs are set to the >> range of what the PMIC supports. Set the ranges for L2, L6 and L17 to what >> we need, i.e. 1.2V, 1.8V and 3.3V respectively. > > Why doesn't the consuming driver request a particular voltage on these > LDOs? It doesn't seem correct to modify board constraints to satisfy a > consumer (even if that consumer is on the board). > The devicetree should accurately describe the voltage constraints for each regulator on this board, rather than the constraints of the PMIC. As such the board designer will have to provide a single value for supplies of single-voltage consumers. This then saves us the trouble of only sometimes being allowed to "change voltage", depending on the supply being a LDO, LVS or just some fixed voltage source. Regards, Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
