Re: [PATCH V2] regulators: anatop: add set_voltage_time_sel interface

[Shawn Guo]

On Thu, Jan 31, 2013 at 10:57:06AM -0500, Anson Huang wrote:
> 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 <b20788@xxxxxxxxxxxxx>
> ---
>  .../bindings/regulator/anatop-regulator.txt        |    8 ++++
>  drivers/regulator/anatop-regulator.c               |   42 ++++++++++++++++++++
>  2 files changed, 50 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/regulator/anatop-regulator.txt b/Documentation/devicetree/bindings/regulator/anatop-regulator.txt
> index 357758c..758eae2 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 8f39cac..fe79d24 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_bit_width) {

I would agree with Troy Kisky that the check of (new_sel > old_sel)
could be done in "if" statement,  as the whole "if" block is only
needed in case that we are increasing the voltage.

Shawn

> +		/*
> +		 * 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
> 
> 

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