ARM: OMAP3: Disable broken omap3_set_off_timings function

Commit c589eb3869a8 (ARM: OMAP3: VC: calculate ramp times)
started using regulator slew rates for calculating the idle
mode start-up times. This works fine for I2C4 controlled
regulator scaling as the regulators are never completely
turned off.

For sys_off_mode pin controlled PMIC scripts, the slew rate
based calculations won't work at all as the regulators are
completely turned off and the start-up time is much longer.

This means currently omap3_set_off_timings currently has
zero chance of working on any real hardare. The current code
is broken in at least the following ways:

1. It attempts to use the default ULONG_MAX value for the
   oscillator start-up value as we're currently never
   initializing the start-up value.

2. It relies on a magic number potentially set by the
   bootloader for volsetup2 register.

3. If no magic value is passed, it attempts to calculate
   voltsetup2 register based on the regulator slew rate.
   This won't work as there is roughly at least five
   times the delay needed for turning on vdd1 and vdd2
   regulators.

4. It does duplicate register write to OMAP3_PRM_VOLTOFFSET

5. It duplicates the code for omap_usec_to_32k unnecessarily

6. It initialized global registers twice, once for each channel

Let's just remove the broken code and call omap3_set_i2c_timings
directly, we're better off with this function doing nothing until
it's fixed. And otherwise further fixes to omap3_set_off_timings
will be unreadable.

And let's get rid of omap3_set_clksetup as that's not needed
for off-idle controlled by I2C4 as in that case the oscillator
is never shut down.

Cc: Kevin Hilman <khilman@linaro.org>
Cc: Nishanth Menon <nm@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/vc.c

@@ -301,12 +301,6 @@ static void __init omap3_vc_init_pmic_signaling(struct voltagedomain *voltdm)
 	omap3_vc_set_pmic_signaling(PWRDM_POWER_ON);
 }
 
-/* Set oscillator setup time for omap3 */
-static void omap3_set_clksetup(u32 usec, struct voltagedomain *voltdm)
-{
-	voltdm->write(omap_usec_to_32k(usec), OMAP3_PRM_CLKSETUP_OFFSET);
-}
-
 /**
  * omap3_set_i2c_timings - sets i2c sleep timings for a channel
  * @voltdm: channel to configure
@@ -323,12 +317,6 @@ static void omap3_set_i2c_timings(struct voltagedomain *voltdm, bool off_mode)
 	unsigned long voltsetup1;
 	u32 tgt_volt;
 
-	/*
-	 * Oscillator is shut down only if we are using sys_off_mode pad,
-	 * thus we set a minimal setup time here
-	 */
-	omap3_set_clksetup(1, voltdm);
-
 	if (off_mode)
 		tgt_volt = voltdm->vc_param->off;
 	else
@@ -365,61 +353,13 @@ static void omap3_set_i2c_timings(struct voltagedomain *voltdm, bool off_mode)
  */
 static void omap3_set_off_timings(struct voltagedomain *voltdm)
 {
-	unsigned long clksetup;
-	unsigned long voltsetup2;
-	unsigned long voltsetup2_old;
-	u32 val;
-	u32 tstart, tshut;
-
-	/* check if sys_off_mode is used to control off-mode voltages */
-	val = voltdm->read(OMAP3_PRM_VOLTCTRL_OFFSET);
-	if (!(val & OMAP3430_PRM_VOLTCTRL_SEL_OFF)) {
-		/* No, omap is controlling them over I2C */
-		omap3_set_i2c_timings(voltdm, true);
-		return;
-	}
-
-	omap_pm_get_oscillator(&tstart, &tshut);
-	omap3_set_clksetup(tstart, voltdm);
-
-	clksetup = voltdm->read(OMAP3_PRM_CLKSETUP_OFFSET);
-
-	/* voltsetup 2 in us */
-	voltsetup2 = voltdm->vc_param->on / voltdm->pmic->slew_rate;
-
-	/* convert to 32k clk cycles */
-	voltsetup2 = DIV_ROUND_UP(voltsetup2 * 32768, 1000000);
-
-	voltsetup2_old = voltdm->read(OMAP3_PRM_VOLTSETUP2_OFFSET);
-
-	/*
-	 * Update voltsetup2 if higher than current value (needed because
-	 * we have multiple channels with different ramp times), also
-	 * update voltoffset always to value recommended by TRM
-	 */
-	if (voltsetup2 > voltsetup2_old) {
-		voltdm->write(voltsetup2, OMAP3_PRM_VOLTSETUP2_OFFSET);
-		voltdm->write(clksetup - voltsetup2,
-			OMAP3_PRM_VOLTOFFSET_OFFSET);
-	} else
-		voltdm->write(clksetup - voltsetup2_old,
-			OMAP3_PRM_VOLTOFFSET_OFFSET);
-
-	/*
-	 * omap is not controlling voltage scaling during off-mode,
-	 * thus set voltsetup1 to 0
-	 */
-	voltdm->rmw(voltdm->vfsm->voltsetup_mask, 0,
-		voltdm->vfsm->voltsetup_reg);
-
-	/* voltoffset must be clksetup minus voltsetup2 according to TRM */
-	voltdm->write(clksetup - voltsetup2, OMAP3_PRM_VOLTOFFSET_OFFSET);
 }
 
 static void __init omap3_vc_init_channel(struct voltagedomain *voltdm)
 {
 	omap3_vc_init_pmic_signaling(voltdm);
 	omap3_set_off_timings(voltdm);
+	omap3_set_i2c_timings(voltdm, true);
 }
 
 /**