ENGR00241003-1 mx6: need to add delay in LDO voltage setting

1.LDO ramp up time may be modified by ROM code
according to fuse setting, cpu freq driver use
fixed delay time which assume the LDO ramp up time
is the reset value of ANATOP register, need to set
it to reset value in regulator init.

2.The regulator set voltage should take care of
the ramp up time, calculate the ramp up time based
of register setting and to the delay, make sure that
when the set voltage function return, the voltage is
stable enough.

3.CPUFreq no need to use delay, it is already taken
care by regulator voltage setting.

Signed-off-by: Anson Huang <b20788@freescale.com>

4 files changed, 118 insertions, 31 deletions

diff --git a/arch/arm/mach-mx6/cpu_regulator-mx6.c b/arch/arm/mach-mx6/cpu_regulator-mx6.c
index d905132e98b1..59bc3832d00f 100644
--- a/arch/arm/mach-mx6/cpu_regulator-mx6.c
+++ b/arch/arm/mach-mx6/cpu_regulator-mx6.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright (C) 2012-2013 Freescale Semiconductor, Inc. All Rights Reserved.
  */
 
 /*
@@ -97,12 +97,32 @@ void mx6_cpu_regulator_init(void)
 		} else {
 			curr_cpu = clk_get_rate(cpu_clk);
 			cpu_op_tbl = get_cpu_op(&cpu_op_nr);
-			/* Set the core to max frequency requested. */
+
+			soc_regulator = regulator_get(NULL, soc_reg_id);
+			if (IS_ERR(soc_regulator))
+				printk(KERN_ERR "%s: failed to get soc regulator\n",
+					__func__);
+			else
+				/* set soc to highest setpoint voltage. */
+				regulator_set_voltage(soc_regulator,
+					      cpu_op_tbl[0].soc_voltage,
+					      cpu_op_tbl[0].soc_voltage);
+
+			pu_regulator = regulator_get(NULL, pu_reg_id);
+			if (IS_ERR(pu_regulator))
+				printk(KERN_ERR "%s: failed to get pu regulator\n",
+					__func__);
+			else
+				/* set pu to higheset setpoint voltage. */
+				regulator_set_voltage(pu_regulator,
+					      cpu_op_tbl[0].pu_voltage,
+					      cpu_op_tbl[0].pu_voltage);
+			/* set the core to higheset setpoint voltage. */
 			regulator_set_voltage(cpu_regulator,
 					      cpu_op_tbl[0].cpu_voltage,
 					      cpu_op_tbl[0].cpu_voltage);
 			if (enable_ldo_mode == LDO_MODE_BYPASSED) {
-				/*digital bypass VDDPU/VDDSOC/VDDARM*/
+				/* digital bypass VDDPU/VDDSOC/VDDARM */
 				reg = __raw_readl(ANADIG_REG_CORE);
 				reg &= ~BM_ANADIG_REG_CORE_REG0_TRG;
 				reg |= BF_ANADIG_REG_CORE_REG0_TRG(0x1f);
@@ -111,14 +131,15 @@ void mx6_cpu_regulator_init(void)
 				reg &= ~BM_ANADIG_REG_CORE_REG2_TRG;
 				reg |= BF_ANADIG_REG_CORE_REG2_TRG(0x1f);
 				__raw_writel(reg, ANADIG_REG_CORE);
-				/* Mask the ANATOP brown out interrupt in the GPC. */
+				/* mask the ANATOP brown out irq in the GPC. */
 				reg = __raw_readl(gpc_base + 0x14);
 				reg |= 0x80000000;
 				__raw_writel(reg, gpc_base + 0x14);
 			}
+
 			clk_set_rate(cpu_clk, cpu_op_tbl[0].cpu_rate);
 
-			/*Fix loops-per-jiffy */
+			/* fix loops-per-jiffy */
 #ifdef CONFIG_SMP
 			for_each_online_cpu(cpu)
 				per_cpu(cpu_data, cpu).loops_per_jiffy =
@@ -141,27 +162,24 @@ void mx6_cpu_regulator_init(void)
 #endif
 		}
 	}
-	soc_regulator = regulator_get(NULL, soc_reg_id);
-	if (IS_ERR(soc_regulator))
-		printk(KERN_ERR "%s: failed to get soc regulator\n", __func__);
-	pu_regulator = regulator_get(NULL, pu_reg_id);
-	if (IS_ERR(pu_regulator))
-		printk(KERN_ERR "%s: failed to get pu regulator\n", __func__);
-	/*If use ldo bypass and VDDPU_IN is single supplied
-	*by external pmic, it means VDDPU_IN can be turned off if GPU/VPU driver
-	*not running.In this case we should set external_pureg which can be used
-	*in pu_enable/pu_disable of arch/arm/mach-mx6/mx6_anatop_regulator.c to
-	*enable or disable external VDDPU regulator from pmic. But for FSL
-	*reference boards, VDDSOC_IN connect with VDDPU_IN, so we didn't set
-	*pu_reg_id to the external pmic regulator supply name in the board file.
-	*In this case external_pureg should be 0 and can't turn off extern pmic
-	*regulator, but can turn off VDDPU by internal anatop power gate.
-	*
-	*If enable internal ldo , external_pureg will be 0, and
-	*VDDPU can be turned off by internal anatop anatop power gate.
-	*
-	*/
-	else if (!IS_ERR(pu_regulator) && strcmp(pu_reg_id, "cpu_vddgpu"))
+	/*
+	 * if use ldo bypass and VDDPU_IN is single supplied
+	 * by external pmic, it means VDDPU_IN can be turned off
+	 * if GPU/VPU driver not running.In this case we should set
+	 * external_pureg which can be used in pu_enable/pu_disable of
+	 * arch/arm/mach-mx6/mx6_anatop_regulator.c to
+	 * enable or disable external VDDPU regulator from pmic. But for FSL
+	 * reference boards, VDDSOC_IN connect with VDDPU_IN, so we didn't set
+	 * pu_reg_id to the external pmic regulator supply name in the board
+	 * file. In this case external_pureg should be 0 and can't turn off
+	 * extern pmic regulator, but can turn off VDDPU by internal anatop
+	 * power gate.
+	 *
+	 * if enable internal ldo , external_pureg will be 0, and
+	 * VDDPU can be turned off by internal anatop anatop power gate.
+	 *
+	 */
+	if (!IS_ERR(pu_regulator) && strcmp(pu_reg_id, "cpu_vddgpu"))
 		external_pureg = 1;
 }
 
diff --git a/arch/arm/mach-mx6/crm_regs.h b/arch/arm/mach-mx6/crm_regs.h
index 5e03312b7fce..43fcb4d0d466 100644
--- a/arch/arm/mach-mx6/crm_regs.h
+++ b/arch/arm/mach-mx6/crm_regs.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2008-2012 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2008-2013 Freescale Semiconductor, Inc. All Rights Reserved.
  *
  * The code contained herein is licensed under the GNU General Public
  * License. You may obtain a copy of the GNU General Public License
@@ -55,6 +55,7 @@
 #define PFD_528_BASE_ADDR		(MXC_PLL_BASE + 0x100)
 #define ANADIG_REG_CORE		(MXC_PLL_BASE + 0x140)
 #define ANADIG_MISC1_REG		(MXC_PLL_BASE + 0x160)
+#define ANADIG_MISC2_REG		(MXC_PLL_BASE + 0x170)
 #define ANATOP_LVDS_CLK1_SRC_SATA	0xB
 #define ANATOP_LVDS_CLK1_OBEN_MASK	0x400
 #define ANATOP_LVDS_CLK1_IBEN_MASK	0x1000
@@ -154,6 +155,9 @@
 #define ANADIG_ANA_MISC2_REG1_BO_EN			(1 << 13)
 #define ANADIG_ANA_MISC2_CONTROL3_MASK		0xC0000000
 #define ANADIG_ANA_MISC2_CONTROL3_OFFSET	30
+#define ANADIG_ANA_MISC2_REG0_STEP_TIME_MASK		0x30000000
+#define ANADIG_ANA_MISC2_REG1_STEP_TIME_MASK		0xC000000
+#define ANADIG_ANA_MISC2_REG2_STEP_TIME_MASK		0x3000000
 
 #define MXC_CCM_BASE		MX6_IO_ADDRESS(CCM_BASE_ADDR)
 /* CCM Register Offsets. */
diff --git a/arch/arm/mach-mx6/mx6_anatop_regulator.c b/arch/arm/mach-mx6/mx6_anatop_regulator.c
index 02ee982964ed..83bd363dc3e3 100644
--- a/arch/arm/mach-mx6/mx6_anatop_regulator.c
+++ b/arch/arm/mach-mx6/mx6_anatop_regulator.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2011-2012 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright (C) 2011-2013 Freescale Semiconductor, Inc. All Rights Reserved.
  */
 
 /*
@@ -42,6 +42,9 @@
 #define GPC_PGC_GPU_PGCR_OFFSET	0x260
 #define GPC_CNTR_OFFSET		0x0
 
+#define LDO_RAMP_UP_UNIT_IN_CYCLES	64 /* 64 cycles per step */
+#define LDO_RAMP_UP_FREQ_IN_MHZ		24 /* time base on 24M OSC */
+
 extern struct platform_device sgtl5000_vdda_reg_devices;
 extern struct platform_device sgtl5000_vddio_reg_devices;
 extern struct platform_device sgtl5000_vddd_reg_devices;
@@ -79,6 +82,7 @@ static int get_voltage(struct anatop_regulator *sreg)
 static int set_voltage(struct anatop_regulator *sreg, int uv)
 {
 	u32 val, reg;
+	u32 delay, steps, old_val;
 
 	pr_debug("%s: uv %d, min %d, max %d\n", __func__,
 		uv, sreg->rdata->min_voltage, sreg->rdata->max_voltage);
@@ -94,8 +98,56 @@ static int set_voltage(struct anatop_regulator *sreg, int uv)
 			~(sreg->rdata->vol_bit_mask <<
 			sreg->rdata->vol_bit_shift));
 		pr_debug("%s: calculated val %d\n", __func__, val);
+
+		old_val = (__raw_readl(sreg->rdata->control_reg) >>
+			sreg->rdata->vol_bit_shift) & sreg->rdata->vol_bit_mask;
+
 		__raw_writel((val << sreg->rdata->vol_bit_shift) | reg,
 			     sreg->rdata->control_reg);
+
+		if (sreg->rdata->control_reg == (unsigned int)(MXC_PLL_BASE +
+			HW_ANADIG_REG_CORE)) {
+			/* calculate how many steps to ramp up */
+			steps = (val > old_val) ? val - old_val : 0;
+			if (steps) {
+				switch (sreg->rdata->vol_bit_shift) {
+				case BP_ANADIG_REG_CORE_REG0_TRG:
+				reg = (__raw_readl(MXC_PLL_BASE +
+					HW_ANADIG_ANA_MISC2) &
+					BM_ANADIG_ANA_MISC2_REG0_STEP_TIME) >>
+					BP_ANADIG_ANA_MISC2_REG0_STEP_TIME;
+					break;
+				case BP_ANADIG_REG_CORE_REG1_TRG:
+				reg = (__raw_readl(MXC_PLL_BASE +
+					HW_ANADIG_ANA_MISC2) &
+					BM_ANADIG_ANA_MISC2_REG1_STEP_TIME) >>
+					BP_ANADIG_ANA_MISC2_REG1_STEP_TIME;
+					break;
+				case BP_ANADIG_REG_CORE_REG2_TRG:
+				reg = (__raw_readl(MXC_PLL_BASE +
+					HW_ANADIG_ANA_MISC2) &
+					BM_ANADIG_ANA_MISC2_REG2_STEP_TIME) >>
+					BP_ANADIG_ANA_MISC2_REG2_STEP_TIME;
+					break;
+				default:
+					break;
+				}
+
+				/*
+				 * the delay time for LDO ramp up time is
+				 * based on the register setting, we need
+				 * to calculate how many steps LDO need to
+				 * ramp up, and how much delay needs. (us)
+				 */
+				delay = steps * ((LDO_RAMP_UP_UNIT_IN_CYCLES <<
+					reg) / LDO_RAMP_UP_FREQ_IN_MHZ + 1);
+				udelay(delay);
+				pr_debug("%s: %s: delay %d, steps %d, uv %d\n",
+					__func__, sreg->rdata->name, delay,
+					steps, uv);
+			}
+		}
+
 		return 0;
 	} else {
 		pr_debug("Regulator not supported.\n");
@@ -532,6 +584,8 @@ static struct anatop_regulator vdd3p0_reg = {
 
 static int __init regulators_init(void)
 {
+	unsigned int reg;
+
 	anatop_register_regulator(&vddpu_reg, ANATOP_VDDPU, &vddpu_init);
 	anatop_register_regulator(&vddcore_reg, ANATOP_VDDCORE, &vddcore_init);
 	anatop_register_regulator(&vddsoc_reg, ANATOP_VDDSOC, &vddsoc_init);
@@ -539,7 +593,19 @@ static int __init regulators_init(void)
 	anatop_register_regulator(&vdd1p1_reg, ANATOP_VDD1P1, &vdd1p1_init);
 	anatop_register_regulator(&vdd3p0_reg, ANATOP_VDD3P0, &vdd3p0_init);
 
-	/* clear flag in boot*/
+	/* Set the REGx step time back to reset value,
+	 * as ROM may modify it according to fuse setting,
+	 * so we need to set it back, otherwise, the delay
+	 * time in cpu freq change will be impacted, the reset
+	 * value is 0'b00, 64 cycles of 24M clock.
+	 */
+	reg = __raw_readl(ANADIG_MISC2_REG);
+	reg &= ~ANADIG_ANA_MISC2_REG0_STEP_TIME_MASK;
+	reg &= ~ANADIG_ANA_MISC2_REG1_STEP_TIME_MASK;
+	reg &= ~ANADIG_ANA_MISC2_REG2_STEP_TIME_MASK;
+	__raw_writel(reg, ANADIG_MISC2_REG);
+
+	/* clear flag in boot */
 	pu_is_enabled = 0;
 	get_clk = 0;
 	return 0;
diff --git a/arch/arm/plat-mxc/cpufreq.c b/arch/arm/plat-mxc/cpufreq.c
index 0f036e2040c7..bf34bf79ceea 100755
--- a/arch/arm/plat-mxc/cpufreq.c
+++ b/arch/arm/plat-mxc/cpufreq.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2010-2012 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright (C) 2010-2013 Freescale Semiconductor, Inc. All Rights Reserved.
  */
 
 /*
@@ -115,7 +115,6 @@ int set_cpu_freq(int freq)
 			printk(KERN_ERR "COULD NOT SET GP VOLTAGE!!!!\n");
 			goto err3;
 		}
-		udelay(50);
 	}
 	ret = clk_set_rate(cpu_clk, freq);
 	if (ret != 0) {