Re: [PATCH 3/6] power: max77843_charger: Add Max77843 charger device driver

From: Krzysztof KozÅowski
Date: Fri Jan 23 2015 - 02:04:21 EST

2015-01-23 6:02 GMT+01:00 Jaewon Kim <jaewon02.kim@xxxxxxxxxxx>:
> From: Beomho Seo <beomho.seo@xxxxxxxxxxx>
>
> This patch adds device driver of max77843 charger. This driver provide
> initialize each charging mode(e.g. fast charge, top-off mode and constant
> charging mode so on.). Additionally, control charging paramters to use
> i2c interface.
>
> Cc: Sebastian Reichel <sre@xxxxxxxxxx>
> Signed-off-by: Beomho Seo <beomho.seo@xxxxxxxxxxx>
> ---
> drivers/power/Kconfig | 7 +
> drivers/power/Makefile | 1 +
> drivers/power/max77843_charger.c | 506 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 514 insertions(+)
> create mode 100644 drivers/power/max77843_charger.c
>
> diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
> index 0108c2a..a054a28 100644
> --- a/drivers/power/Kconfig
> +++ b/drivers/power/Kconfig
> @@ -332,6 +332,13 @@ config CHARGER_MAX14577
> Say Y to enable support for the battery charger control sysfs and
> platform data of MAX14577/77836 MUICs.
>
> +config CHARGER_MAX77843
> + tristate "Maxim MAX77843 battery charger driver"
> + depends on MFD_MAX77843
> + help
> + Say Y to enable support for the battery charger control sysfs and
> + platform data of MAX77843
> +
> config CHARGER_MAX8997
> tristate "Maxim MAX8997/MAX8966 PMIC battery charger driver"
> depends on MFD_MAX8997 && REGULATOR_MAX8997
> diff --git a/drivers/power/Makefile b/drivers/power/Makefile
> index dfa8942..212c6a2 100644
> --- a/drivers/power/Makefile
> +++ b/drivers/power/Makefile
> @@ -50,6 +50,7 @@ obj-$(CONFIG_CHARGER_LP8788) += lp8788-charger.o
> obj-$(CONFIG_CHARGER_GPIO) += gpio-charger.o
> obj-$(CONFIG_CHARGER_MANAGER) += charger-manager.o
> obj-$(CONFIG_CHARGER_MAX14577) += max14577_charger.o
> +obj-$(CONFIG_CHARGER_MAX77843) += max77843_charger.o
> obj-$(CONFIG_CHARGER_MAX8997) += max8997_charger.o
> obj-$(CONFIG_CHARGER_MAX8998) += max8998_charger.o
> obj-$(CONFIG_CHARGER_BQ2415X) += bq2415x_charger.o
> diff --git a/drivers/power/max77843_charger.c b/drivers/power/max77843_charger.c
> new file mode 100644
> index 0000000..317b2cc
> --- /dev/null
> +++ b/drivers/power/max77843_charger.c
> @@ -0,0 +1,506 @@
> +/*
> + * Charger driver for Maxim MAX77843
> + *
> + * Copyright (C) 2014 Samsung Electronics, Co., Ltd.
> + * Author: Beomho Seo <beomho.seo@xxxxxxxxxxx>
> + *
> + * 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 bythe Free Software Foundation.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/platform_device.h>
> +#include <linux/power_supply.h>
> +#include <linux/mfd/max77843-private.h>
> +
> +struct max77843_charger_info {
> + u32 fast_charge_uamp;
> + u32 top_off_uamp;
> + u32 input_uamp_limit;
> +};
> +
> +struct max77843_charger {
> + struct device *dev;
> + struct max77843 *max77843;
> + struct i2c_client *client;
> + struct regmap *regmap;
> + struct power_supply psy;
> +
> + struct max77843_charger_info *info;
> +};

Why creating two separate structures?

> +
> +static int max77843_charger_get_max_current(struct max77843_charger *charger)
> +{
> + struct regmap *regmap = charger->regmap;
> + int ret, val = 0;
> + unsigned int reg_data;
> +
> + ret = regmap_read(regmap, MAX77843_CHG_REG_CHG_CNFG_09, &reg_data);
> + if (ret) {
> + dev_err(charger->dev, "Failed to read charger register\n");
> + return ret;
> + }
> +
> + if (reg_data <= 0x03) {
> + val = MAX77843_CHG_INPUT_CURRENT_LIMIT_MIN;
> + } else if (reg_data >= 0x78) {
> + val = MAX77843_CHG_INPUT_CURRENT_LIMIT_MAX;
> + } else {
> + val = reg_data / 3;
> + if (reg_data % 3 == 0)
> + val *= 100000;
> + else if (reg_data % 3 == 1)
> + val = val * 100000 + 33000;
> + else
> + val = val * 100000 + 67000;
> + }
> +
> + return val;
> +}
> +
> +static int max77843_charger_get_now_current(struct max77843_charger *charger)
> +{
> + struct regmap *regmap = charger->regmap;
> + int ret, val = 0;
> + unsigned int reg_data;
> +
> + ret = regmap_read(regmap, MAX77843_CHG_REG_CHG_CNFG_02, &reg_data);
> + if (ret) {
> + dev_err(charger->dev, "Failed to read charger register\n");

This error log shows up in many places. Please print also error code.

Additionally I think it could be useful to print also details about
register which failed. Currently user would not know which register
access failed. Consider adding short description like "Failed to read
current charger register: %d...". However I do not insist on this so
it is up to you.

> + return ret;
> + }
> +
> + reg_data &= MAX77843_CHG_FAST_CHG_CURRENT_MASK;
> +
> + if (reg_data <= 0x02)
> + val = MAX77843_CHG_FAST_CHG_CURRENT_MIN;
> + else if (reg_data >= 0x3f)
> + val = MAX77843_CHG_FAST_CHG_CURRENT_MAX;
> + else
> + val = reg_data * MAX77843_CHG_FAST_CHG_CURRENT_STEP;
> +
> + return val;
> +}
> +
> +static int max77843_charger_get_online(struct max77843_charger *charger)
> +{
> + struct regmap *regmap = charger->regmap;
> + int ret, val = 0;
> + unsigned int reg_data;
> +
> + ret = regmap_read(regmap, MAX77843_CHG_REG_CHG_INT_OK, &reg_data);
> + if (ret) {
> + dev_err(charger->dev, "Failed to read charger register\n");
> + return ret;
> + }
> +
> + if (reg_data & MAX77843_CHG_CHGIN_OK)
> + val = true;
> + else
> + val = false;
> +
> + return val;
> +}
> +
> +static int max77843_charger_get_present(struct max77843_charger *charger)
> +{
> + struct regmap *regmap = charger->regmap;
> + int ret, val = 0;
> + unsigned int reg_data;
> +
> + ret = regmap_read(regmap, MAX77843_CHG_REG_CHG_DTLS_00, &reg_data);
> + if (ret) {
> + dev_err(charger->dev, "Failed to read charger register\n");
> + return ret;
> + }
> +
> + if (reg_data & MAX77843_CHG_BAT_DTLS)
> + val = false;
> + else
> + val = true;
> +
> + return val;
> +}
> +
> +static int max77843_charger_get_health(struct max77843_charger *charger)
> +{
> + struct regmap *regmap = charger->regmap;
> + int ret, val = POWER_SUPPLY_HEALTH_UNKNOWN;
> + unsigned int reg_data;
> +
> + ret = regmap_read(regmap, MAX77843_CHG_REG_CHG_DTLS_01, &reg_data);
> + if (ret) {
> + dev_err(charger->dev, "Failed to read charger register\n");
> + return ret;
> + }
> +
> + reg_data &= MAX77843_CHG_BAT_DTLS_MASK;
> +
> + switch (reg_data) {
> + case MAX77843_CHG_NO_BAT:
> + val = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
> + break;
> + case MAX77843_CHG_LOW_VOLT_BAT:
> + case MAX77843_CHG_OK_BAT:
> + case MAX77843_CHG_OK_LOW_VOLT_BAT:
> + val = POWER_SUPPLY_HEALTH_GOOD;
> + break;
> + case MAX77843_CHG_LONG_BAT_TIME:
> + val = POWER_SUPPLY_HEALTH_DEAD;
> + break;
> + case MAX77843_CHG_OVER_VOLT_BAT:
> + case MAX77843_CHG_OVER_CURRENT_BAT:
> + val = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
> + break;
> + default:
> + val = POWER_SUPPLY_HEALTH_UNKNOWN;
> + break;
> + }
> +
> + return val;
> +}
> +
> +static int max77843_charger_get_status(struct max77843_charger *charger)
> +{
> + struct regmap *regmap = charger->regmap;
> + int ret, val = 0;
> + unsigned int reg_data;
> +
> + ret = regmap_read(regmap, MAX77843_CHG_REG_CHG_DTLS_01, &reg_data);
> + if (ret) {
> + dev_err(charger->dev, "Failed to read charger register\n");
> + return ret;
> + }
> +
> + reg_data &= MAX77843_CHG_DTLS_MASK;
> +
> + switch (reg_data) {
> + case MAX77843_CHG_PQ_MODE:
> + case MAX77843_CHG_CC_MODE:
> + case MAX77843_CHG_CV_MODE:
> + val = POWER_SUPPLY_STATUS_CHARGING;
> + break;
> + case MAX77843_CHG_TO_MODE:
> + case MAX77843_CHG_DO_MODE:
> + val = POWER_SUPPLY_STATUS_FULL;
> + break;
> + case MAX77843_CHG_HT_MODE:
> + case MAX77843_CHG_TF_MODE:
> + case MAX77843_CHG_TS_MODE:
> + val = POWER_SUPPLY_STATUS_NOT_CHARGING;
> + break;
> + case MAX77843_CHG_OFF_MODE:
> + val = POWER_SUPPLY_STATUS_DISCHARGING;
> + break;
> + default:
> + val = POWER_SUPPLY_STATUS_UNKNOWN;
> + break;
> + }
> +
> + return val;
> +}
> +
> +static const char *model_name = "MAX77843";
> +static const char *manufacturer = "Maxim Integrated";
> +
> +static int max77843_charger_get_property(struct power_supply *psy,
> + enum power_supply_property psp,
> + union power_supply_propval *val)
> +{
> + struct max77843_charger *charger = container_of(psy,
> + struct max77843_charger, psy);
> +
> + switch (psp) {
> + case POWER_SUPPLY_PROP_STATUS:
> + val->intval = max77843_charger_get_status(charger);
> + break;
> + case POWER_SUPPLY_PROP_HEALTH:
> + val->intval = max77843_charger_get_health(charger);
> + break;
> + case POWER_SUPPLY_PROP_PRESENT:
> + val->intval = max77843_charger_get_present(charger);
> + break;
> + case POWER_SUPPLY_PROP_ONLINE:
> + val->intval = max77843_charger_get_online(charger);
> + break;
> + case POWER_SUPPLY_PROP_CURRENT_NOW:
> + val->intval = max77843_charger_get_now_current(charger);
> + break;
> + case POWER_SUPPLY_PROP_CURRENT_MAX:
> + val->intval = max77843_charger_get_max_current(charger);
> + break;
> + case POWER_SUPPLY_PROP_MODEL_NAME:
> + val->strval = model_name;
> + break;
> + case POWER_SUPPLY_PROP_MANUFACTURER:
> + val->strval = manufacturer;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static enum power_supply_property max77843_charger_props[] = {
> + POWER_SUPPLY_PROP_STATUS,
> + POWER_SUPPLY_PROP_HEALTH,
> + POWER_SUPPLY_PROP_PRESENT,
> + POWER_SUPPLY_PROP_ONLINE,
> + POWER_SUPPLY_PROP_CURRENT_NOW,
> + POWER_SUPPLY_PROP_CURRENT_MAX,
> + POWER_SUPPLY_PROP_MODEL_NAME,
> + POWER_SUPPLY_PROP_MANUFACTURER,
> +};
> +
> +static int max77843_charger_init_current_limit(struct max77843_charger *charger)
> +{
> + struct regmap *regmap = charger->regmap;
> + struct max77843_charger_info *info = charger->info;
> + unsigned int input_uamp_limit = info->input_uamp_limit;
> + int ret;
> + unsigned int reg_data, val;
> +
> + ret = regmap_update_bits(regmap, MAX77843_CHG_REG_CHG_CNFG_02,
> + MAX77843_CHG_OTG_ILIMIT_MASK,
> + MAX77843_CHG_OTG_ILIMIT_900);
> + if (ret) {
> + dev_err(charger->dev, "Failed to write configure register\n");

Same as in case of "read" operation failures - please print also error code.

> + return ret;
> + }
> +
> + if (input_uamp_limit == MAX77843_CHG_INPUT_CURRENT_LIMIT_MIN) {
> + reg_data = 0x03;
> + } else if (input_uamp_limit == MAX77843_CHG_INPUT_CURRENT_LIMIT_MAX) {
> + reg_data = 0x78;
> + } else {
> + if (input_uamp_limit < MAX77843_CHG_INPUT_CURRENT_LIMIT_REF)
> + val = 0x03;
> + else
> + val = 0x02;
> +
> + input_uamp_limit -= MAX77843_CHG_INPUT_CURRENT_LIMIT_MIN;
> + input_uamp_limit /= MAX77843_CHG_INPUT_CURRENT_LIMIT_STEP;
> + reg_data = val + input_uamp_limit;
> + }
> +
> + ret = regmap_write(regmap, MAX77843_CHG_REG_CHG_CNFG_09, reg_data);
> + if (ret) {
> + dev_err(charger->dev, "Failed to write configure register\n");
> + return ret;
> + }
> +
> + return 0;

Could you merge it into:

ret = regmap_write(regmap, MAX77843_CHG_REG_CHG_CNFG_09, reg_data);
if (ret)
dev_err(charger->dev, "Failed to write configure register\n");
return ret;


> +
> +static int max77843_charger_init_top_off(struct max77843_charger *charger)
> +{
> + struct regmap *regmap = charger->regmap;
> + struct max77843_charger_info *info = charger->info;
> + unsigned int top_off_uamp = info->top_off_uamp;
> + int ret;
> + unsigned int reg_data;
> +
> + if (top_off_uamp == MAX77843_CHG_TOP_OFF_CURRENT_MIN) {
> + reg_data = 0x00;
> + } else if (top_off_uamp == MAX77843_CHG_TOP_OFF_CURRENT_MAX) {
> + reg_data = 0x07;
> + } else {
> + top_off_uamp -= MAX77843_CHG_TOP_OFF_CURRENT_MIN;
> + top_off_uamp /= MAX77843_CHG_TOP_OFF_CURRENT_STEP;
> + reg_data = top_off_uamp;
> + }
> +
> + ret = regmap_update_bits(regmap, MAX77843_CHG_REG_CHG_CNFG_03,
> + MAX77843_CHG_TOP_OFF_CURRENT_MASK, reg_data);
> + if (ret) {
> + dev_err(charger->dev, "Failed to write configure register\n");
> + return ret;
> + }
> +
> + return 0;

Ditto

> +}
> +
> +static int max77843_charger_init_fast_charge(struct max77843_charger *charger)
> +{
> + struct regmap *regmap = charger->regmap;
> + struct max77843_charger_info *info = charger->info;
> + unsigned int fast_charge_uamp = info->fast_charge_uamp;
> + int ret;
> + unsigned int reg_data;
> +
> + if (fast_charge_uamp < info->input_uamp_limit) {
> + reg_data = 0x09;
> + } else if (fast_charge_uamp == MAX77843_CHG_FAST_CHG_CURRENT_MIN) {
> + reg_data = 0x02;
> + } else if (fast_charge_uamp == MAX77843_CHG_FAST_CHG_CURRENT_MAX) {
> + reg_data = 0x3f;
> + } else {
> + fast_charge_uamp -= MAX77843_CHG_FAST_CHG_CURRENT_MIN;
> + fast_charge_uamp /= MAX77843_CHG_FAST_CHG_CURRENT_STEP;
> + reg_data = 0x02 + fast_charge_uamp;
> + }
> +
> + ret = regmap_update_bits(regmap, MAX77843_CHG_REG_CHG_CNFG_02,
> + MAX77843_CHG_FAST_CHG_CURRENT_MASK, reg_data);
> + if (ret) {
> + dev_err(charger->dev, "Failed to write configure register\n");
> + return ret;
> + }
> +
> + return 0;

Ditto

> +}
> +
> +static int max77843_charger_init(struct max77843_charger *charger)
> +{
> + struct regmap *regmap = charger->regmap;
> + int ret;
> +
> + ret = regmap_write(regmap, MAX77843_CHG_REG_CHG_CNFG_06,
> + MAX77843_CHG_WRITE_CAP_UNBLOCK);
> + if (ret) {
> + dev_err(charger->dev, "Failed to write configure register\n");
> + return ret;
> + }
> +
> + ret = regmap_write(regmap, MAX77843_CHG_REG_CHG_CNFG_01,
> + MAX77843_CHG_RESTART_THRESHOLD_DISABLE);
> + if (ret) {
> + dev_err(charger->dev, "Failed to write configure register\n");
> + return ret;
> + }
> +
> + ret = max77843_charger_init_fast_charge(charger);
> + if (ret) {
> + dev_err(charger->dev, "Failed to set fast charge mode.\n");
> + return ret;
> + }
> +
> + ret = max77843_charger_init_top_off(charger);
> + if (ret) {
> + dev_err(charger->dev, "Failed to set top off charge mode.\n");
> + return ret;
> + }
> +
> + ret = max77843_charger_init_current_limit(charger);
> +

Why this return value is ignored?

> + return 0;
> +}
> +
> +static struct max77843_charger_info *max77843_charger_dt_init(
> + struct platform_device *pdev)
> +{
> + struct max77843_charger_info *info;
> + struct device_node *np = pdev->dev.of_node;
> + int ret;
> +
> + if (!np) {
> + dev_err(&pdev->dev, "No charger OF node\n");
> + return ERR_PTR(-EINVAL);
> + }
> +
> + info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
> + if (!info)
> + return ERR_PTR(-ENOMEM);
> +
> + ret = of_property_read_u32(np, "maxim,fast-charge-uamp",
> + &info->fast_charge_uamp);
> + if (ret) {
> + dev_err(&pdev->dev, "Cannot parse fast charge current.\n");
> + return ERR_PTR(ret);
> + }
> +
> + ret = of_property_read_u32(np, "maxim,top-off-uamp",
> + &info->top_off_uamp);
> + if (ret) {
> + dev_err(&pdev->dev,
> + "Cannot parse primary charger termination voltage.\n");
> + return ERR_PTR(ret);
> + }
> +
> + ret = of_property_read_u32(np, "maxim,input-uamp-limit",
> + &info->input_uamp_limit);
> + if (ret) {
> + dev_err(&pdev->dev, "Cannot parse input current limit value\n");
> + return ERR_PTR(ret);
> + }
> +
> + return info;
> +}
> +
> +static int max77843_charger_probe(struct platform_device *pdev)
> +{
> + struct max77843 *max77843 = dev_get_drvdata(pdev->dev.parent);
> + struct max77843_charger *charger;
> + 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->max77843 = max77843;
> + charger->client = max77843->i2c_chg;
> + charger->regmap = max77843->regmap_chg;
> +
> + charger->info = max77843_charger_dt_init(pdev);
> + if (IS_ERR_OR_NULL(charger->info)) {
> + ret = PTR_ERR(charger->info);
> + goto err_i2c;
> + }
> +
> + charger->psy.name = "max77843-charger";
> + charger->psy.type = POWER_SUPPLY_TYPE_MAINS;
> + charger->psy.get_property = max77843_charger_get_property;
> + charger->psy.properties = max77843_charger_props;
> + charger->psy.num_properties = ARRAY_SIZE(max77843_charger_props);
> +
> + ret = max77843_charger_init(charger);
> + if (ret)
> + goto err_i2c;
> +
> + ret = power_supply_register(&pdev->dev, &charger->psy);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to register power supply\n");
> + goto err_i2c;
> + }
> +
> + return 0;
> +
> +err_i2c:
> + i2c_unregister_device(charger->client);

This seems complicated. The MFD registers the i2c dummy for charger...
and sometimes charger driver unregisters it and sometimes not. The
ownership should be in one place: probably in charger driver... but I
asked about this in another thread so lets discuss it there.

Best regards,
Krzysztof
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