linux-kernel - Re: [PATCHv2 12/13] regulator: rk808: add rk806 support

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Date:   Thu, 8 Sep 2022 10:45:40 +0300
From:   Matti Vaittinen <mazziesaccount@...il.com>
To:     Sebastian Reichel <sebastian.reichel@...labora.com>,
        Heiko Stuebner <heiko@...ech.de>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Lee Jones <lee@...nel.org>
Cc:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        linux-rockchip@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel@...labora.com,
        shengfei Xu <xsf@...k-chips.com>
Subject: Re: [PATCHv2 12/13] regulator: rk808: add rk806 support

On 9/8/22 03:31, Sebastian Reichel wrote:
> Add rk806 support to the existing rk808 regulator
> driver.
> 
> This has been implemented using shengfei Xu's rk806
> specific driver from the vendor tree as reference.
> 
> Co-Developed-by: shengfei Xu <xsf@...k-chips.com>
> Signed-off-by: shengfei Xu <xsf@...k-chips.com>
> Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>
> ---
>   drivers/regulator/rk808-regulator.c | 482 ++++++++++++++++++++++++++++
>   1 file changed, 482 insertions(+)
> 
> diff --git a/drivers/regulator/rk808-regulator.c b/drivers/regulator/rk808-regulator.c
> index fa9fc1aa1ae3..cd1a2cff4a37 100644
> --- a/drivers/regulator/rk808-regulator.c
> +++ b/drivers/regulator/rk808-regulator.c

Thanks for upstreaming the downstream stuff! :)
I wonder if we could drop some code by using the existing helpers? Or 
maybe I am missreading some code. Wouldn't be the first (and probably 
not the last) time...

//snip

>   struct rk808_regulator_data {
>   	struct gpio_desc *dvs_gpio[2];
>   };
> @@ -216,6 +271,223 @@ static const unsigned int rk817_buck1_4_ramp_table[] = {
>   	3000, 6300, 12500, 25000
>   };
>   
> +static int rk806_get_voltage_sel_regmap(struct regulator_dev *rdev)
> +{
> +	unsigned int val;
> +	int vsel_reg, ret;
> +
> +	vsel_reg = rdev->desc->vsel_reg;
> +
> +	ret = regmap_read(rdev->regmap, vsel_reg, &val);
> +	if (ret != 0)
> +		return ret;
> +
> +	val &= rdev->desc->vsel_mask;
> +	val >>= ffs(rdev->desc->vsel_mask) - 1;
> +
> +	return val;
> +}

Could we just use the regulator_get_voltage_sel_regmap()?

> +
> +static int rk806_set_voltage(struct regulator_dev *rdev,
> +			     int req_min_uV, int req_max_uV,
> +			     unsigned int *selector)
> +{
> +	int vsel_reg, ret, sel;
> +
> +	ret = regulator_map_voltage_linear_range(rdev, req_min_uV, req_max_uV);
> +	if (ret >= 0) {
> +		*selector = ret;
> +		sel = ret;
> +	} else {
> +		return -EINVAL;
> +	}
> +
> +	vsel_reg = rdev->desc->vsel_reg;
> +
> +	sel <<= ffs(rdev->desc->vsel_mask) - 1;
> +
> +	ret = regmap_update_bits(rdev->regmap, vsel_reg,
> +				 rdev->desc->vsel_mask, sel);
> +
> +	return ret;
> +}

Hmm. Maybe this is not necessary? I wonder if we could get away just 
with the .map and .set_voltage_sel (regulator_get_voltage_sel_regmap() 
and regulator_map_voltage_linear_range()).

// snip
> +
> +static int rk806_set_ramp_delay_ldo(struct regulator_dev *rdev, int ramp_delay)
> +{
> +	unsigned int ramp_value = RK806_RAMP_RATE_2LSB_PER_1CLK;
> +	int regval;
> +
> +	switch (ramp_delay) {
> +	case 1 ... 780:
> +		ramp_value = RK806_RAMP_RATE_1LSB_PER_32CLK;
> +		break;
> +	case 781 ... 1900:
> +		ramp_value = RK806_RAMP_RATE_1LSB_PER_13CLK;
> +		break;
> +	case 1901 ... 3120:
> +		ramp_value = RK806_RAMP_RATE_1LSB_PER_8CLK;
> +		break;
> +	case 3121 ... 6280:
> +		ramp_value = RK806_RAMP_RATE_1LSB_PER_4CLK;
> +		break;
> +	case 6281 ... 12500:
> +		ramp_value = RK806_RAMP_RATE_1LSB_PER_2CLK;
> +		break;
> +	case 12501 ... 25000:
> +		ramp_value = RK806_RAMP_RATE_1LSB_PER_1CLK;
> +		break;
> +	case 25001 ... 50000:
> +		ramp_value = RK806_RAMP_RATE_2LSB_PER_1CLK;
> +		break;
> +	case 50001 ... 100000:
> +		ramp_value = RK806_RAMP_RATE_4LSB_PER_1CLK;
> +		break;
> +	default:
> +		pr_warn("%s ramp_delay: %d not supported, setting 10000\n",
> +			rdev->desc->name, ramp_delay);
> +	}
> +
> +	regval = ramp_value << (ffs(rdev->desc->ramp_mask) - 1);
> +	return regmap_update_bits(rdev->regmap, rdev->desc->ramp_reg,
> +				  rdev->desc->ramp_mask, regval);
> +}

Do you think we could get rid of this function by populating a 
ramp-delay table and using regulator_set_ramp_delay_regmap()?

Best Regards
	-- Matti

-- 
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~