[3/3] regulator: palmas: add support for LDO8 tracking mode

LDO8 of Palma device like tps65913 support the tracking mode
on which LDO8 track the SMPS45 voltage when SMPS45 is ON
and use the LDO8.VOLTAGE_SEL register when SMPS45 is OFF.

On track mode, the steps of voltage change for LDO8 is 25mV
where in non-tracking mode it is 50mV. Set the steps accordingly.
Number of voltage count is still same for both the cases.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
---
 drivers/regulator/palmas-regulator.c |   53 ++++++++++++++++++++++++++++++++++
 include/linux/mfd/palmas.h           |    3 ++
 2 files changed, 56 insertions(+), 0 deletions(-)

Looks good to me, I don't actually know the use case for this feature!

Acked-by: Graeme Gregory <gg@slimlogic.co.uk>

On 17/04/13 10:43, Laxman Dewangan wrote:
> LDO8 of Palma device like tps65913 support the tracking mode
> on which LDO8 track the SMPS45 voltage when SMPS45 is ON
> and use the LDO8.VOLTAGE_SEL register when SMPS45 is OFF.
>
> On track mode, the steps of voltage change for LDO8 is 25mV
> where in non-tracking mode it is 50mV. Set the steps accordingly.
> Number of voltage count is still same for both the cases.
>
> Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
> ---
>  drivers/regulator/palmas-regulator.c |   53 ++++++++++++++++++++++++++++++++++
>  include/linux/mfd/palmas.h           |    3 ++
>  2 files changed, 56 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/regulator/palmas-regulator.c b/drivers/regulator/palmas-regulator.c
> index 28080a7..d6efaf1 100644
> --- a/drivers/regulator/palmas-regulator.c
> +++ b/drivers/regulator/palmas-regulator.c
> @@ -572,6 +572,46 @@ static int palmas_extreg_init(struct palmas *palmas, int id,
>  	return 0;
>  }
>  
> +static void palmas_enable_ldo8_track(struct palmas *palmas)
> +{
> +	unsigned int reg;
> +	unsigned int addr;
> +	int ret;
> +
> +	addr = palmas_regs_info[PALMAS_REG_LDO8].ctrl_addr;
> +
> +	ret = palmas_ldo_read(palmas, addr, &reg);
> +	if (ret) {
> +		dev_err(palmas->dev, "Error in reading ldo8 control reg\n");
> +		return;
> +	}
> +
> +	reg |= PALMAS_LDO8_CTRL_LDO_TRACKING_EN;
> +	ret = palmas_ldo_write(palmas, addr, reg);
> +	if (ret < 0) {
> +		dev_err(palmas->dev, "Error in enabling tracking mode\n");
> +		return;
> +	}
> +	/*
> +	 * When SMPS45 is set to off and LDO8 tracking is enabled, the LDO8
> +	 * output is defined by the LDO8_VOLTAGE.VSEL register divided by two,
> +	 * and can be set from 0.45 to 1.65 V.
> +	 */
> +	addr = palmas_regs_info[PALMAS_REG_LDO8].vsel_addr;
> +	ret = palmas_ldo_read(palmas, addr, &reg);
> +	if (ret) {
> +		dev_err(palmas->dev, "Error in reading ldo8 voltage reg\n");
> +		return;
> +	}
> +
> +	reg = (reg << 1) & PALMAS_LDO8_VOLTAGE_VSEL_MASK;
> +	ret = palmas_ldo_write(palmas, addr, reg);
> +	if (ret < 0)
> +		dev_err(palmas->dev, "Error in setting ldo8 voltage reg\n");
> +
> +	return;
> +}
> +
>  static struct of_regulator_match palmas_matches[] = {
>  	{ .name = "smps12", },
>  	{ .name = "smps123", },
> @@ -657,6 +697,11 @@ static void palmas_dt_to_pdata(struct device *dev,
>  		if (ret)
>  			pdata->reg_init[idx]->vsel =
>  				PALMAS_SMPS12_VOLTAGE_RANGE;
> +
> +		if (idx == PALMAS_REG_LDO8)
> +			pdata->enable_ldo8_tracking = of_property_read_bool(
> +						palmas_matches[idx].of_node,
> +						"ti,enable-ldo8-tracking");
>  	}
>  
>  	pdata->ldo6_vibrator = of_property_read_bool(node, "ti,ldo6-vibrator");
> @@ -836,6 +881,13 @@ static int palmas_regulators_probe(struct platform_device *pdev)
>  						palmas_regs_info[id].ctrl_addr);
>  			pmic->desc[id].enable_mask =
>  					PALMAS_LDO1_CTRL_MODE_ACTIVE;
> +
> +			/* Check if LDO8 is in tracking mode or not */
> +			if (pdata && (id == PALMAS_REG_LDO8) &&
> +					pdata->enable_ldo8_tracking) {
> +				palmas_enable_ldo8_track(palmas);
> +				pmic->desc[id].uV_step = 25000;
> +			}
>  		} else {
>  			pmic->desc[id].n_voltages = 1;
>  			pmic->desc[id].ops = &palmas_ops_extreg;
> @@ -884,6 +936,7 @@ static int palmas_regulators_probe(struct platform_device *pdev)
>  		}
>  	}
>  
> +
>  	return 0;
>  
>  err_unregister_regulator:
> diff --git a/include/linux/mfd/palmas.h b/include/linux/mfd/palmas.h
> index fb04d07..12d8a62 100644
> --- a/include/linux/mfd/palmas.h
> +++ b/include/linux/mfd/palmas.h
> @@ -187,6 +187,9 @@ struct palmas_pmic_platform_data {
>  
>  	/* use LDO6 for vibrator control */
>  	int ldo6_vibrator;
> +
> +	/* Enable tracking mode of LDO8 */
> +	bool enable_ldo8_tracking;
>  };
>  
>  struct palmas_usb_platform_data {

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On Wed, Apr 17, 2013 at 03:13:13PM +0530, Laxman Dewangan wrote:
> LDO8 of Palma device like tps65913 support the tracking mode
> on which LDO8 track the SMPS45 voltage when SMPS45 is ON
> and use the LDO8.VOLTAGE_SEL register when SMPS45 is OFF.

Applied, thanks.

On Wednesday 17 April 2013 07:24 PM, Graeme Gregory wrote:
> Looks good to me, I don't actually know the use case for this feature!
>
> Acked-by: Graeme Gregory <gg@slimlogic.co.uk>
>

This is require for Tegra.
The always ON section of Tegra (say vdd_ao) need to be same as the core 
voltage(vdd_core) when system is active/idle. Hence the vdd_ao should be 
track to vdd_core and for this we need to configure the rail in tracking 
mode.
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