From 9ee417c07479b9a87d0808dd3c8b4ce3925983f1 Mon Sep 17 00:00:00 2001 From: Anson Huang Date: Thu, 31 Jan 2013 11:23:53 -0500 Subject: [PATCH 1/2] regulators: anatop: add set_voltage_time_sel interface some of anatop's regulators(cpu, 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]: cpu 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 Acked-by: Shawn Guo Signed-off-by: Mark Brown --- .../bindings/regulator/anatop-regulator.txt | 8 ++++ drivers/regulator/anatop-regulator.c | 41 +++++++++++++++++++ 2 files changed, 49 insertions(+) diff --git a/Documentation/devicetree/bindings/regulator/anatop-regulator.txt b/Documentation/devicetree/bindings/regulator/anatop-regulator.txt index 357758cb6e92..758eae24082a 100644 --- a/Documentation/devicetree/bindings/regulator/anatop-regulator.txt +++ b/Documentation/devicetree/bindings/regulator/anatop-regulator.txt @@ -9,6 +9,11 @@ Required properties: - anatop-min-voltage: Minimum voltage of this regulator - anatop-max-voltage: Maximum voltage of this regulator +Optional properties: +- anatop-delay-reg-offset: Anatop MFD step time register offset +- anatop-delay-bit-shift: Bit shift for the step time register +- anatop-delay-bit-width: Number of bits used in the step time register + Any property defined as part of the core regulator binding, defined in regulator.txt, can also be used. @@ -23,6 +28,9 @@ Example: anatop-reg-offset = <0x140>; anatop-vol-bit-shift = <9>; anatop-vol-bit-width = <5>; + anatop-delay-reg-offset = <0x170>; + anatop-delay-bit-shift = <24>; + anatop-delay-bit-width = <2>; anatop-min-bit-val = <1>; anatop-min-voltage = <725000>; anatop-max-voltage = <1300000>; diff --git a/drivers/regulator/anatop-regulator.c b/drivers/regulator/anatop-regulator.c index 8f39cac661d2..0df9c6a97604 100644 --- a/drivers/regulator/anatop-regulator.c +++ b/drivers/regulator/anatop-regulator.c @@ -31,12 +31,18 @@ #include #include +#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 +61,32 @@ 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_bit_width && new_sel > old_sel) { + /* + * 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) * ((LDO_RAMP_UP_UNIT_IN_CYCLES << + val) / LDO_RAMP_UP_FREQ_IN_MHZ + 1); + } + + return ret; +} + static int anatop_regmap_get_voltage_sel(struct regulator_dev *reg) { struct anatop_regulator *anatop_reg = rdev_get_drvdata(reg); @@ -67,6 +99,7 @@ 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 +176,14 @@ 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; From ff1ce0571eb98b21f5a9221b2fdc3bd010840b1a Mon Sep 17 00:00:00 2001 From: Shawn Guo Date: Mon, 4 Feb 2013 10:21:32 +0800 Subject: [PATCH 2/2] regulator: anatop: improve precision of delay time For cpufreq example, it takes 13 steps (25 mV for one step) to increase vddcore from 0.95 V to 1.275 V, and the time of 64 clock cycles at 24 MHz for one step is ~2.67 uS, so the total delay time would be ~34.71 uS. But the current calculation in the driver gives 39 uS. Change the formula to have the addition of 1 be the last step, so that we can get a more precise delay time. For example above, the new formula will give 35 uS. Signed-off-by: Shawn Guo Signed-off-by: Mark Brown --- drivers/regulator/anatop-regulator.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/regulator/anatop-regulator.c b/drivers/regulator/anatop-regulator.c index 0df9c6a97604..0d4a8ccbb536 100644 --- a/drivers/regulator/anatop-regulator.c +++ b/drivers/regulator/anatop-regulator.c @@ -80,8 +80,8 @@ static int anatop_regmap_set_voltage_time_sel(struct regulator_dev *reg, 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) * ((LDO_RAMP_UP_UNIT_IN_CYCLES << - val) / LDO_RAMP_UP_FREQ_IN_MHZ + 1); + ret = (new_sel - old_sel) * (LDO_RAMP_UP_UNIT_IN_CYCLES << + val) / LDO_RAMP_UP_FREQ_IN_MHZ + 1; } return ret;