On Sat, Jan 9, 2010 at 6:42 AM, Khasim Syed Mohammed <kha...@beagleboard.org> wrote: > From cc1b24cb290d428f2e1aefec9c7878b46380f592 Mon Sep 17 00:00:00 2001 > From: Syed Mohammed Khasim <kha...@ti.com> > Date: Sat, 9 Jan 2010 09:28:03 +0530 > Subject: [PATCH] API to select twl4030 voltage and dev group > > Adds a new API "twl4030_pmrecv_vsel_cfg" to select voltage > and its device group > > Signed-off-by: Syed Mohammed Khasim <kha...@ti.com> > ---
<snip> > @@ -113,3 +104,18 @@ void twl4030_power_mmc_init(void) > twl4030_i2c_write_u8(TWL4030_CHIP_PM_RECEIVER, byte, > TWL4030_PM_RECEIVER_VMMC1_DEDICATED); > } > + > +/* > + * Generic function to select Device Group and Voltage > + */ > +void twl4030_pmrecv_vsel_cfg(u8 vsel_reg, u8 vsel_val, > + u8 dev_grp, u8 dev_grp_sel) > +{ > + /* Select the Device Group */ > + twl4030_i2c_write_u8(TWL4030_CHIP_PM_RECEIVER, dev_grp_sel, > + dev_grp); > + > + /* Select the Voltage */ > + twl4030_i2c_write_u8(TWL4030_CHIP_PM_RECEIVER, vsel_val, > + vsel_reg); > +} I was always wondering why TI code first sets the device group (which effectively enables the supply), and configures voltage after that. Doesn't that cause wrong voltage output for a short interval of time (knowing that i2c transfers take some time to complete)? What happens if second write fails due to some i2c error? _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot