[PATCH 2/2] regulators: anatop: add set_voltage_time_sel interface

Anson Huang
2013-01-30T09:38:14Z

some of anatop's regulators(vppcpu, vddpu and vddsoc) have
register settings about LDO's step time, which will impact
the LDO ramp up speed, need to use set_voltage_time_sel
interface to add necessary delay everytime LDOs' voltage
is increased.

offset 0x170:
bit [24-25]: vddcpu
bit [26-27]: vddpu
bit [28-29]: vddsoc

field definition:
0'b00: 64 cycles of 24M clock;
0'b01: 128 cycles of 24M clock;
0'b02: 256 cycles of 24M clock;
0'b03: 512 cycles of 24M clock;

Signed-off-by: Anson Huang <b20788@freescale.com>
---
drivers/regulator/anatop-regulator.c | 42 ++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)

diff --git a/drivers/regulator/anatop-regulator.c b/drivers/regulator/anatop-regulator.c
index 8f39cac..a857b9c 100644
--- a/drivers/regulator/anatop-regulator.c
+++ b/drivers/regulator/anatop-regulator.c
@@ -31,12 +31,18 @@
#include <linux/regulator/driver.h>
#include <linux/regulator/of_regulator.h>

+#define LDO_RAMP_UP_UNIT_IN_CYCLES 64 /* 64 cycles per step */
+#define LDO_RAMP_UP_FREQ_IN_MHZ 24 /* cycle based on 24M OSC */
+
struct anatop_regulator {
const char *name;
u32 control_reg;
struct regmap *anatop;
int vol_bit_shift;
int vol_bit_width;
+ u32 delay_reg;
+ int delay_bit_shift;
+ int delay_bit_width;
int min_bit_val;
int min_voltage;
int max_voltage;
@@ -55,6 +61,33 @@ static int anatop_regmap_set_voltage_sel(struct regulator_dev *reg,
return regulator_set_voltage_sel_regmap(reg, selector);
}

+static int anatop_regmap_set_voltage_time_sel(struct regulator_dev *reg,
+ unsigned int old_sel,
+ unsigned int new_sel)
+{
+ struct anatop_regulator *anatop_reg = rdev_get_drvdata(reg);
+ u32 val;
+ int ret = 0;
+
+ /* check whether need to care about LDO ramp up speed */
+ if (anatop_reg->delay_reg) {
+ /*
+ * the delay 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 needed. (us)
+ */
+ regmap_read(anatop_reg->anatop, anatop_reg->delay_reg, &val);
+ val = (val >> anatop_reg->delay_bit_shift) &
+ ((1 << anatop_reg->delay_bit_width) - 1);
+ ret = new_sel > old_sel ? (new_sel - old_sel) *
+ ((LDO_RAMP_UP_UNIT_IN_CYCLES << val) /
+ LDO_RAMP_UP_FREQ_IN_MHZ + 1) : 0;
+ }
+
+ return ret;
+}
+
static int anatop_regmap_get_voltage_sel(struct regulator_dev *reg)
{
struct anatop_regulator *anatop_reg = rdev_get_drvdata(reg);
@@ -67,6 +100,7 @@ static int anatop_regmap_get_voltage_sel(struct regulator_dev *reg)

static struct regulator_ops anatop_rops = {
.set_voltage_sel = anatop_regmap_set_voltage_sel,
+ .set_voltage_time_sel = anatop_regmap_set_voltage_time_sel,
.get_voltage_sel = anatop_regmap_get_voltage_sel,
.list_voltage = regulator_list_voltage_linear,
.map_voltage = regulator_map_voltage_linear,
@@ -143,6 +177,14 @@ static int anatop_regulator_probe(struct platform_device *pdev)
goto anatop_probe_end;
}

+ /* read LDO ramp up setting, only for core reg */
+ of_property_read_u32(np, "anatop-delay-reg-offset",
+ &sreg->delay_reg);
+ of_property_read_u32(np, "anatop-delay-bit-width",
+ &sreg->delay_bit_width);
+ of_property_read_u32(np, "anatop-delay-bit-shift",
+ &sreg->delay_bit_shift);
+
rdesc->n_voltages = (sreg->max_voltage - sreg->min_voltage) / 25000 + 1
+ sreg->min_bit_val;
rdesc->min_uV = sreg->min_voltage;
--
1.7.9.5