Message-ID: <20230508065014.xfftu6vorxgqdh7h@mercury.elektranox.org>
Date:   Mon, 8 May 2023 08:50:14 +0200
From:   Sebastian Reichel <sebastian.reichel@...labora.com>
To:     Jakob Hauser <jahau@...ketmail.com>
Cc:     Lee Jones <lee@...nel.org>, Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Beomho Seo <beomho.seo@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Stephan Gerhold <stephan@...hold.net>,
        Raymond Hackley <raymondhackley@...tonmail.com>,
        Pavel Machek <pavel@....cz>, Axel Lin <axel.lin@...ics.com>,
        ChiYuan Huang <cy_huang@...htek.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Henrik Grimler <henrik@...mler.se>, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        phone-devel@...r.kernel.org, ~postmarketos/upstreaming@...ts.sr.ht
Subject: Re: [PATCH v4 5/8] power: supply: rt5033_charger: Add RT5033 charger
 device driver

Hi,

On Sat, May 06, 2023 at 05:54:32PM +0200, Jakob Hauser wrote:
> This patch adds device driver of Richtek RT5033 PMIC. The driver supports
> switching charger. rt5033 charger provides three charging modes. The charging
> modes are pre-charge mode, fast charge mode and constant voltage mode. They
> vary in charge rate, the charge parameters can be controlled by i2c interface.
> 
> Cc: Beomho Seo <beomho.seo@...sung.com>
> Cc: Chanwoo Choi <cw00.choi@...sung.com>
> Tested-by: Raymond Hackley <raymondhackley@...tonmail.com>
> Signed-off-by: Jakob Hauser <jahau@...ketmail.com>
> Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
> ---

Driver looks mostly good. I still found a couple of small things
though. Please find them inline.

>  drivers/power/supply/Kconfig          |   8 +
>  drivers/power/supply/Makefile         |   1 +
>  drivers/power/supply/rt5033_charger.c | 464 ++++++++++++++++++++++++++
>  3 files changed, 473 insertions(+)
>  create mode 100644 drivers/power/supply/rt5033_charger.c
> 
> diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
> index c78be9f322e6..ea11797670ca 100644
> --- a/drivers/power/supply/Kconfig
> +++ b/drivers/power/supply/Kconfig
> @@ -766,6 +766,14 @@ config BATTERY_RT5033
>  	  The fuelgauge calculates and determines the battery state of charge
>  	  according to battery open circuit voltage.
>  
> +config CHARGER_RT5033
> +	tristate "RT5033 battery charger support"
> +	depends on MFD_RT5033
> +	help
> +	  This adds support for battery charger in Richtek RT5033 PMIC.
> +	  The device supports pre-charge mode, fast charge mode and
> +	  constant voltage mode.
> +
>  config CHARGER_RT9455
>  	tristate "Richtek RT9455 battery charger driver"
>  	depends on I2C
> diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
> index 4adbfba02d05..dfc624bbcf1d 100644
> --- a/drivers/power/supply/Makefile
> +++ b/drivers/power/supply/Makefile
> @@ -54,6 +54,7 @@ obj-$(CONFIG_BATTERY_MAX17040)	+= max17040_battery.o
>  obj-$(CONFIG_BATTERY_MAX17042)	+= max17042_battery.o
>  obj-$(CONFIG_BATTERY_MAX1721X)	+= max1721x_battery.o
>  obj-$(CONFIG_BATTERY_RT5033)	+= rt5033_battery.o
> +obj-$(CONFIG_CHARGER_RT5033)	+= rt5033_charger.o
>  obj-$(CONFIG_CHARGER_RT9455)	+= rt9455_charger.o
>  obj-$(CONFIG_CHARGER_RT9467)	+= rt9467-charger.o
>  obj-$(CONFIG_CHARGER_RT9471)	+= rt9471.o
> diff --git a/drivers/power/supply/rt5033_charger.c b/drivers/power/supply/rt5033_charger.c
> new file mode 100644
> index 000000000000..038530d2f0a0
> --- /dev/null
> +++ b/drivers/power/supply/rt5033_charger.c
> @@ -0,0 +1,464 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Battery charger driver for RT5033
> + *
> + * Copyright (C) 2014 Samsung Electronics, Co., Ltd.
> + * Author: Beomho Seo <beomho.seo@...sung.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */

no need for the GPL2 text with SPDX license header

> +
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/power_supply.h>
> +#include <linux/mfd/rt5033-private.h>
> +#include <linux/mfd/rt5033.h>
> +
> +static int rt5033_get_charger_state(struct rt5033_charger *charger)
> +{
> +	struct regmap *regmap = charger->rt5033->regmap;
> +	unsigned int reg_data;
> +	int state;
> +
> +	if (!regmap)
> +		return POWER_SUPPLY_STATUS_UNKNOWN;
> +
> +	regmap_read(regmap, RT5033_REG_CHG_STAT, &reg_data);
> +
> +	switch (reg_data & RT5033_CHG_STAT_MASK) {
> +	case RT5033_CHG_STAT_DISCHARGING:
> +		state = POWER_SUPPLY_STATUS_DISCHARGING;
> +		break;
> +	case RT5033_CHG_STAT_CHARGING:
> +		state = POWER_SUPPLY_STATUS_CHARGING;
> +		break;
> +	case RT5033_CHG_STAT_FULL:
> +		state = POWER_SUPPLY_STATUS_FULL;
> +		break;
> +	case RT5033_CHG_STAT_NOT_CHARGING:
> +		state = POWER_SUPPLY_STATUS_NOT_CHARGING;
> +		break;
> +	default:
> +		state = POWER_SUPPLY_STATUS_UNKNOWN;
> +	}
> +
> +	return state;
> +}
> +
> +static int rt5033_get_charger_type(struct rt5033_charger *charger)
> +{
> +	struct regmap *regmap = charger->rt5033->regmap;
> +	unsigned int reg_data;
> +	int state;
> +
> +	regmap_read(regmap, RT5033_REG_CHG_STAT, &reg_data);
> +
> +	switch (reg_data & RT5033_CHG_STAT_TYPE_MASK) {
> +	case RT5033_CHG_STAT_TYPE_FAST:
> +		state = POWER_SUPPLY_CHARGE_TYPE_FAST;
> +		break;
> +	case RT5033_CHG_STAT_TYPE_PRE:
> +		state = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
> +		break;
> +	default:
> +		state = POWER_SUPPLY_CHARGE_TYPE_NONE;
> +	}
> +
> +	return state;
> +}
> +
> +static int rt5033_get_charger_current_limit(struct rt5033_charger *charger)
> +{
> +	struct regmap *regmap = charger->rt5033->regmap;
> +	unsigned int state, reg_data, data;
> +
> +	regmap_read(regmap, RT5033_REG_CHG_CTRL5, &reg_data);
> +
> +	state = (reg_data & RT5033_CHGCTRL5_ICHG_MASK)
> +		 >> RT5033_CHGCTRL5_ICHG_SHIFT;
> +
> +	data = RT5033_CHARGER_FAST_CURRENT_MIN +
> +		RT5033_CHARGER_FAST_CURRENT_STEP_NUM * state;
> +
> +	return data;
> +}
> +
> +static int rt5033_get_charger_const_voltage(struct rt5033_charger *charger)
> +{
> +	struct regmap *regmap = charger->rt5033->regmap;
> +	unsigned int state, reg_data, data;
> +
> +	regmap_read(regmap, RT5033_REG_CHG_CTRL2, &reg_data);
> +
> +	state = (reg_data & RT5033_CHGCTRL2_CV_MASK)
> +		 >> RT5033_CHGCTRL2_CV_SHIFT;
> +
> +	data = RT5033_CHARGER_CONST_VOLTAGE_LIMIT_MIN +
> +		RT5033_CHARGER_CONST_VOLTAGE_STEP_NUM * state;
> +
> +	return data;
> +}
> +
> +static inline int rt5033_init_const_charge(struct rt5033_charger *charger)
> +{
> +	struct rt5033_charger_data *chg = charger->chg;
> +	int ret;
> +	unsigned int val;
> +	u8 reg_data;
> +
> +	/* Set constant voltage mode */
> +	if (chg->const_uvolt < RT5033_CHARGER_CONST_VOLTAGE_LIMIT_MIN ||
> +	    chg->const_uvolt > RT5033_CHARGER_CONST_VOLTAGE_LIMIT_MAX) {
> +		dev_err(charger->dev,
> +			"Value 'constant-charge-voltage-max-microvolt' out of range\n");
> +		return -EINVAL;
> +	}
> +
> +	if (chg->const_uvolt == RT5033_CHARGER_CONST_VOLTAGE_LIMIT_MIN)
> +		reg_data = 0x00;
> +	else if (chg->const_uvolt == RT5033_CHARGER_CONST_VOLTAGE_LIMIT_MAX)
> +		reg_data = RT5033_CV_MAX_VOLTAGE;
> +	else {
> +		val = chg->const_uvolt;
> +		val -= RT5033_CHARGER_CONST_VOLTAGE_LIMIT_MIN;
> +		val /= RT5033_CHARGER_CONST_VOLTAGE_STEP_NUM;
> +		reg_data = val;
> +	}
> +
> +	ret = regmap_update_bits(charger->rt5033->regmap, RT5033_REG_CHG_CTRL2,
> +			RT5033_CHGCTRL2_CV_MASK,
> +			reg_data << RT5033_CHGCTRL2_CV_SHIFT);
> +	if (ret) {
> +		dev_err(charger->dev, "Failed regmap update\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Set end of charge current */
> +	if (chg->eoc_uamp < RT5033_CHARGER_EOC_MIN ||
> +	    chg->eoc_uamp > RT5033_CHARGER_EOC_MAX) {
> +		dev_err(charger->dev,
> +			"Value 'charge-term-current-microamp' out of range\n");
> +		return -EINVAL;
> +	}
> +
> +	if (chg->eoc_uamp == RT5033_CHARGER_EOC_MIN)
> +		reg_data = 0x01;
> +	else if (chg->eoc_uamp == RT5033_CHARGER_EOC_MAX)
> +		reg_data = 0x07;
> +	else {
> +		val = chg->eoc_uamp;
> +		if (val < RT5033_CHARGER_EOC_REF) {
> +			val -= RT5033_CHARGER_EOC_MIN;
> +			val /= RT5033_CHARGER_EOC_STEP_NUM1;
> +			reg_data = 0x01 + val;
> +		} else if (val > RT5033_CHARGER_EOC_REF) {
> +			val -= RT5033_CHARGER_EOC_REF;
> +			val /= RT5033_CHARGER_EOC_STEP_NUM2;
> +			reg_data = 0x04 + val;
> +		} else {
> +			reg_data = 0x04;
> +		}
> +	}
> +
> +	ret = regmap_update_bits(charger->rt5033->regmap, RT5033_REG_CHG_CTRL4,
> +			RT5033_CHGCTRL4_EOC_MASK, reg_data);
> +	if (ret) {
> +		dev_err(charger->dev, "Failed regmap update\n");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static inline int rt5033_init_fast_charge(struct rt5033_charger *charger)
> +{
> +	struct rt5033_charger_data *chg = charger->chg;
> +	int ret;
> +	unsigned int val;
> +	u8 reg_data;
> +
> +	/* Set limit input current */
> +	ret = regmap_update_bits(charger->rt5033->regmap, RT5033_REG_CHG_CTRL1,
> +			RT5033_CHGCTRL1_IAICR_MASK, RT5033_AICR_2000_MODE);
> +	if (ret) {
> +		dev_err(charger->dev, "Failed regmap update\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Set fast-charge mode charging current */
> +	if (chg->fast_uamp < RT5033_CHARGER_FAST_CURRENT_MIN ||
> +	    chg->fast_uamp > RT5033_CHARGER_FAST_CURRENT_MAX) {
> +		dev_err(charger->dev,
> +			"Value 'constant-charge-current-max-microamp' out of range\n");
> +		return -EINVAL;
> +	}
> +
> +	if (chg->fast_uamp == RT5033_CHARGER_FAST_CURRENT_MIN)
> +		reg_data = 0x00;
> +	else if (chg->fast_uamp == RT5033_CHARGER_FAST_CURRENT_MAX)
> +		reg_data = RT5033_CHG_MAX_CURRENT;
> +	else {
> +		val = chg->fast_uamp;
> +		val -= RT5033_CHARGER_FAST_CURRENT_MIN;
> +		val /= RT5033_CHARGER_FAST_CURRENT_STEP_NUM;
> +		reg_data = val;
> +	}
> +
> +	ret = regmap_update_bits(charger->rt5033->regmap, RT5033_REG_CHG_CTRL5,
> +			RT5033_CHGCTRL5_ICHG_MASK,
> +			reg_data << RT5033_CHGCTRL5_ICHG_SHIFT);
> +	if (ret) {
> +		dev_err(charger->dev, "Failed regmap update\n");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static inline int rt5033_init_pre_charge(struct rt5033_charger *charger)
> +{
> +	struct rt5033_charger_data *chg = charger->chg;
> +	int ret;
> +	unsigned int val;
> +	u8 reg_data;
> +
> +	/* Set pre-charge threshold voltage */
> +	if (chg->pre_uvolt < RT5033_CHARGER_PRE_THRESHOLD_LIMIT_MIN ||
> +	    chg->pre_uvolt > RT5033_CHARGER_PRE_THRESHOLD_LIMIT_MAX) {
> +		dev_err(charger->dev,
> +			"Value 'precharge-upper-limit-microvolt' out of range\n");
> +		return -EINVAL;
> +	}
> +
> +	if (chg->pre_uvolt == RT5033_CHARGER_PRE_THRESHOLD_LIMIT_MIN)
> +		reg_data = 0x00;
> +	else if (chg->pre_uvolt == RT5033_CHARGER_PRE_THRESHOLD_LIMIT_MAX)
> +		reg_data = 0x0f;
> +	else {
> +		val = chg->pre_uvolt;
> +		val -= RT5033_CHARGER_PRE_THRESHOLD_LIMIT_MIN;
> +		val /= RT5033_CHARGER_PRE_THRESHOLD_STEP_NUM;
> +		reg_data = val;
> +	}
> +
> +	ret = regmap_update_bits(charger->rt5033->regmap, RT5033_REG_CHG_CTRL5,
> +			RT5033_CHGCTRL5_VPREC_MASK, reg_data);
> +	if (ret) {
> +		dev_err(charger->dev, "Failed regmap update\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Set pre-charge mode charging current */
> +	if (chg->pre_uamp < RT5033_CHARGER_PRE_CURRENT_LIMIT_MIN ||
> +	    chg->pre_uamp > RT5033_CHARGER_PRE_CURRENT_LIMIT_MAX) {
> +		dev_err(charger->dev,
> +			"Value 'precharge-current-microamp' out of range\n");
> +		return -EINVAL;
> +	}
> +
> +	if (chg->pre_uamp == RT5033_CHARGER_PRE_CURRENT_LIMIT_MIN)
> +		reg_data = 0x00;
> +	else if (chg->pre_uamp == RT5033_CHARGER_PRE_CURRENT_LIMIT_MAX)
> +		reg_data = RT5033_CHG_MAX_PRE_CURRENT;
> +	else {
> +		val = chg->pre_uamp;
> +		val -= RT5033_CHARGER_PRE_CURRENT_LIMIT_MIN;
> +		val /= RT5033_CHARGER_PRE_CURRENT_STEP_NUM;
> +		reg_data = val;
> +	}
> +
> +	ret = regmap_update_bits(charger->rt5033->regmap, RT5033_REG_CHG_CTRL4,
> +			RT5033_CHGCTRL4_IPREC_MASK,
> +			reg_data << RT5033_CHGCTRL4_IPREC_SHIFT);
> +	if (ret) {
> +		dev_err(charger->dev, "Failed regmap update\n");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int rt5033_charger_reg_init(struct rt5033_charger *charger)
> +{
> +	int ret = 0;
> +
> +	/* Enable charging termination */
> +	ret = regmap_update_bits(charger->rt5033->regmap, RT5033_REG_CHG_CTRL1,
> +			RT5033_CHGCTRL1_TE_EN_MASK, RT5033_TE_ENABLE);
> +	if (ret) {
> +		dev_err(charger->dev, "Failed to enable charging termination.\n");
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * Disable minimum input voltage regulation (MIVR), this improves
> +	 * the charging performance.
> +	 */
> +	ret = regmap_update_bits(charger->rt5033->regmap, RT5033_REG_CHG_CTRL4,
> +			RT5033_CHGCTRL4_MIVR_MASK, RT5033_CHARGER_MIVR_DISABLE);
> +	if (ret) {
> +		dev_err(charger->dev, "Failed to disable MIVR.\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = rt5033_init_pre_charge(charger);
> +	if (ret)
> +		return ret;
> +
> +	ret = rt5033_init_fast_charge(charger);
> +	if (ret)
> +		return ret;
> +
> +	ret = rt5033_init_const_charge(charger);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static enum power_supply_property rt5033_charger_props[] = {
> +	POWER_SUPPLY_PROP_STATUS,
> +	POWER_SUPPLY_PROP_CHARGE_TYPE,
> +	POWER_SUPPLY_PROP_CURRENT_MAX,
> +	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
> +	POWER_SUPPLY_PROP_MODEL_NAME,
> +	POWER_SUPPLY_PROP_MANUFACTURER,
> +	POWER_SUPPLY_PROP_ONLINE,
> +};
> +
> +static int rt5033_charger_get_property(struct power_supply *psy,
> +			enum power_supply_property psp,
> +			union power_supply_propval *val)
> +{
> +	struct rt5033_charger *charger = power_supply_get_drvdata(psy);
> +	int ret = 0;

ret is unused.

> +
> +	switch (psp) {
> +	case POWER_SUPPLY_PROP_STATUS:
> +		val->intval = rt5033_get_charger_state(charger);
> +		break;
> +	case POWER_SUPPLY_PROP_CHARGE_TYPE:
> +		val->intval = rt5033_get_charger_type(charger);
> +		break;
> +	case POWER_SUPPLY_PROP_CURRENT_MAX:
> +		val->intval = rt5033_get_charger_current_limit(charger);
> +		break;
> +	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
> +		val->intval = rt5033_get_charger_const_voltage(charger);
> +		break;
> +	case POWER_SUPPLY_PROP_MODEL_NAME:
> +		val->strval = RT5033_CHARGER_MODEL;
> +		break;
> +	case POWER_SUPPLY_PROP_MANUFACTURER:
> +		val->strval = RT5033_MANUFACTURER;
> +		break;
> +	case POWER_SUPPLY_PROP_ONLINE:
> +		val->intval = (rt5033_get_charger_state(charger) ==
> +				POWER_SUPPLY_STATUS_CHARGING);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +static struct rt5033_charger_data *rt5033_charger_dt_init(
> +						struct rt5033_charger *charger)
> +{
> +	struct rt5033_charger_data *chg;
> +	struct power_supply_battery_info *info;
> +	int ret;
> +
> +	chg = devm_kzalloc(charger->dev, sizeof(*chg), GFP_KERNEL);
> +	if (!chg)
> +		return ERR_PTR(-ENOMEM);
> +
> +	ret = power_supply_get_battery_info(charger->psy, &info);
> +	if (ret) {
> +		dev_err(charger->dev, "failed to get battery info\n");
> +		return ERR_PTR(-EINVAL);
> +	}

You can use the battery_info from the power-supply core:

info = charger->psy->battery_info;
if (!info)
    return dev_err_probe(charger->dev, -EINVAL, "missing battery info\n");

> +	/* Assign data. Validity will be checked in the init functions. */
> +	chg->pre_uamp = info->precharge_current_ua;
> +	chg->fast_uamp = info->constant_charge_current_max_ua;
> +	chg->eoc_uamp = info->charge_term_current_ua;
> +	chg->pre_uvolt = info->precharge_voltage_max_uv;
> +	chg->const_uvolt = info->constant_charge_voltage_max_uv;
> +
> +	return chg;
> +}
> +
> +static const struct power_supply_desc rt5033_charger_desc = {
> +	.name = "rt5033-charger",
> +	.type = POWER_SUPPLY_TYPE_USB,
> +	.properties = rt5033_charger_props,
> +	.num_properties = ARRAY_SIZE(rt5033_charger_props),
> +	.get_property = rt5033_charger_get_property,
> +};
> +
> +static int rt5033_charger_probe(struct platform_device *pdev)
> +{
> +	struct rt5033_charger *charger;
> +	struct rt5033_dev *rt5033 = dev_get_drvdata(pdev->dev.parent);
> +	struct power_supply_config psy_cfg = {};
> +	int ret;
> +
> +	charger = devm_kzalloc(&pdev->dev, sizeof(*charger), GFP_KERNEL);
> +	if (!charger)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, charger);
> +	charger->dev = &pdev->dev;
> +	charger->rt5033 = rt5033;

You are only using the regmap, so just get and store that:

charger->regmap = dev_get_regmap(pdev->dev.parent);

> +	psy_cfg.of_node = pdev->dev.of_node;
> +	psy_cfg.drv_data = charger;
> +
> +	charger->psy = devm_power_supply_register(&pdev->dev,
> +						  &rt5033_charger_desc,
> +						  &psy_cfg);
> +	if (IS_ERR(charger->psy)) {
> +		dev_err(&pdev->dev, "failed: power supply register\n");
> +		return PTR_ERR(charger->psy);
> +	}

dev_err_probe()

> +
> +	charger->chg = rt5033_charger_dt_init(charger);
> +	if (IS_ERR_OR_NULL(charger->chg))
> +		return -ENODEV;
> +
> +	ret = rt5033_charger_reg_init(charger);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static const struct platform_device_id rt5033_charger_id[] = {
> +	{ "rt5033-charger", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(platform, rt5033_charger_id);
> +
> +static const struct of_device_id rt5033_charger_of_match[] = {
> +	{ .compatible = "richtek,rt5033-charger", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, rt5033_charger_of_match);
> +
> +static struct platform_driver rt5033_charger_driver = {
> +	.driver = {
> +		.name = "rt5033-charger",
> +		.of_match_table = rt5033_charger_of_match,
> +	},
> +	.probe = rt5033_charger_probe,
> +	.id_table = rt5033_charger_id,
> +};
> +module_platform_driver(rt5033_charger_driver);
> +
> +MODULE_DESCRIPTION("Richtek RT5033 charger driver");
> +MODULE_AUTHOR("Beomho Seo <beomho.seo@...sung.com>");
> +MODULE_LICENSE("GPL v2");

Thanks,

-- Sebastian

Download attachment "signature.asc" of type "application/pgp-signature" (834 bytes)

Powered by blists - more mailing lists