Re: [PATCH v2 4/5] regulator: max14577: Add regulator driver for Maxim14577

From: Bartlomiej Zolnierkiewicz
Date: Wed Nov 20 2013 - 12:59:03 EST

On Wednesday, November 20, 2013 06:54:34 PM Bartlomiej Zolnierkiewicz wrote:
>
> Hi Krzysztof,
>
> On Wednesday, November 20, 2013 03:12:11 PM Krzysztof Kozlowski wrote:
> > MAX14577 chip is a multi-function device which includes MUIC,
> > charger and voltage regulator. The driver is located in drivers/mfd.
> >
> > This patch adds regulator driver for MAX14577 chip. There are two
> > regulators in this chip:
> > 1. Safeout LDO with constant voltage output of 4.9V. It can be only
> > enabled or disabled.
> > 2. Current regulator for the charger. It provides current from 90mA up
> > to 950mA.
> > Driver supports Device Tree.
> >
> > Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
> > Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> > ---
> > drivers/regulator/Kconfig | 7 ++
> > drivers/regulator/Makefile | 1 +
> > drivers/regulator/max14577.c | 282 ++++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 290 insertions(+)
> > create mode 100644 drivers/regulator/max14577.c
> >
> > diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
> > index ce785f4..11ee053 100644
> > --- a/drivers/regulator/Kconfig
> > +++ b/drivers/regulator/Kconfig
> > @@ -249,6 +249,13 @@ config REGULATOR_LP8788
> > help
> > This driver supports LP8788 voltage regulator chip.
> >
> > +config REGULATOR_MAX14577
> > + tristate "Maxim 14577 regulator"
> > + depends on MFD_MAX14577
> > + help
> > + This driver controls a Maxim 14577 regulator via I2C bus.
> > + The regulators include safeout LDO and current regulator 'CHARGER'.
> > +
> > config REGULATOR_MAX1586
> > tristate "Maxim 1586/1587 voltage regulator"
> > depends on I2C
> > diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
> > index 01c597e..654bd43 100644
> > --- a/drivers/regulator/Makefile
> > +++ b/drivers/regulator/Makefile
> > @@ -35,6 +35,7 @@ obj-$(CONFIG_REGULATOR_LP872X) += lp872x.o
> > obj-$(CONFIG_REGULATOR_LP8788) += lp8788-buck.o
> > obj-$(CONFIG_REGULATOR_LP8788) += lp8788-ldo.o
> > obj-$(CONFIG_REGULATOR_LP8755) += lp8755.o
> > +obj-$(CONFIG_REGULATOR_MAX14577) += max14577.o
> > obj-$(CONFIG_REGULATOR_MAX1586) += max1586.o
> > obj-$(CONFIG_REGULATOR_MAX8649) += max8649.o
> > obj-$(CONFIG_REGULATOR_MAX8660) += max8660.o
> > diff --git a/drivers/regulator/max14577.c b/drivers/regulator/max14577.c
> > new file mode 100644
> > index 0000000..f449e57
> > --- /dev/null
> > +++ b/drivers/regulator/max14577.c
> > @@ -0,0 +1,282 @@
> > +/*
> > + * max14577.c - Regulator driver for the Maxim 14577
> > + *
> > + * Copyright (C) 2013 Samsung Electronics
> > + * Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
> > + *
> > + * This program is free software; you can redistribute it and/or modify
> > + * it under the terms of the GNU General Public License as published by
> > + * the Free Software Foundation; either version 2 of the License, or
> > + * (at your option) any later version.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> > + * GNU General Public License for more details.
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regulator/driver.h>
> > +#include <linux/mfd/max14577.h>
> > +#include <linux/mfd/max14577-private.h>
> > +#include <linux/regulator/of_regulator.h>
> > +
> > +struct max14577_regulator {
> > + struct device *dev;
> > + struct max14577 *max14577;
> > + int num_regulators;
> > + struct regulator_dev **regulators;
> > +};
> > +
> > +static int max14577_reg_is_enabled(struct regulator_dev *rdev)
> > +{
> > + int rid = rdev_get_id(rdev);
> > + struct regmap *rmap = rdev->regmap;
> > + u8 reg_data;
> > +
> > + switch (rid) {
> > + case MAX14577_CHARGER:
> > + max14577_read_reg(rmap, MAX14577_CHG_REG_CHG_CTRL2, &reg_data);
> > + if ((reg_data & CHGCTRL2_MBCHOSTEN_MASK) == 0)
> > + return 0;
> > + max14577_read_reg(rmap, MAX14577_CHG_REG_STATUS3, &reg_data);
> > + if ((reg_data & STATUS3_CGMBC_MASK) == 0)
> > + return 0;
> > + /* MBCHOSTEN and CGMBC are on */
> > + return 1;
> > + default:
> > + return -EINVAL;
> > + }
> > +}
> > +
> > +static int max14577_reg_get_current_limit(struct regulator_dev *rdev)
> > +{
> > + u8 reg_data;
> > + struct regmap *rmap = rdev->regmap;
> > +
> > + if (rdev_get_id(rdev) != MAX14577_CHARGER)
> > + return -EINVAL;
> > +
> > + max14577_read_reg(rmap, MAX14577_CHG_REG_CHG_CTRL4, &reg_data);
> > +
> > + if ((reg_data & CHGCTRL4_MBCICHWRCL_MASK) == 0)
> > + return MAX14577_REGULATOR_CURRENT_LIMIT_MIN;
> > +
> > + reg_data = ((reg_data & CHGCTRL4_MBCICHWRCH_MASK) >>
> > + CHGCTRL4_MBCICHWRCH_SHIFT);
> > + return MAX14577_REGULATOR_CURRENT_LIMIT_HIGH_START +
> > + reg_data * MAX14577_REGULATOR_CURRENT_LIMIT_HIGH_STEP;
> > +}
> > +
> > +static int max14577_reg_set_current_limit(struct regulator_dev *rdev,
> > + int min_uA, int max_uA)
> > +{
> > + int i, current_bits = 0xf;
> > + u8 reg_data;
> > +
> > + if (rdev_get_id(rdev) != MAX14577_CHARGER)
> > + return -EINVAL;
> > +
> > + if (min_uA > MAX14577_REGULATOR_CURRENT_LIMIT_MAX ||
> > + max_uA < MAX14577_REGULATOR_CURRENT_LIMIT_MIN)
> > + return -EINVAL;
> > +
> > + if (max_uA < MAX14577_REGULATOR_CURRENT_LIMIT_HIGH_START) {
> > + /* Less than 200 mA, so set 90mA (turn only Low Bit off) */
> > + u8 reg_data = 0x0 << CHGCTRL4_MBCICHWRCL_SHIFT;
> > + return max14577_update_reg(rdev->regmap,
> > + MAX14577_CHG_REG_CHG_CTRL4,
> > + CHGCTRL4_MBCICHWRCL_MASK, reg_data);
> > + }
> > +
> > + /* max_uA is in range: <LIMIT_HIGH_START, inifinite>, so search for
> > + * valid current starting from LIMIT_MAX. */
> > + for (i = MAX14577_REGULATOR_CURRENT_LIMIT_MAX;
> > + i >= MAX14577_REGULATOR_CURRENT_LIMIT_HIGH_START;
> > + i -= MAX14577_REGULATOR_CURRENT_LIMIT_HIGH_STEP) {
> > + if (i <= max_uA)
> > + break;
> > + current_bits--;
> > + }
> > + BUG_ON(current_bits < 0); /* Cannot happen */
> > + /* Turn Low Bit on (use range 200mA-950 mA) */
> > + reg_data = 0x1 << CHGCTRL4_MBCICHWRCL_SHIFT;
> > + /* and set proper High Bits */
> > + reg_data |= current_bits << CHGCTRL4_MBCICHWRCH_SHIFT;
> > +
> > + return max14577_update_reg(rdev->regmap, MAX14577_CHG_REG_CHG_CTRL4,
> > + CHGCTRL4_MBCICHWRCL_MASK | CHGCTRL4_MBCICHWRCH_MASK,
> > + reg_data);
> > +}
> > +
> > +static struct regulator_ops max14577_safeout_ops = {
> > + .is_enabled = regulator_is_enabled_regmap,
> > + .enable = regulator_enable_regmap,
> > + .disable = regulator_disable_regmap,
> > + .list_voltage = regulator_list_voltage_linear,
> > +};
> > +
> > +static struct regulator_ops max14577_charger_ops = {
> > + .is_enabled = max14577_reg_is_enabled,
> > + .enable = regulator_enable_regmap,
> > + .disable = regulator_disable_regmap,
> > + .get_current_limit = max14577_reg_get_current_limit,
> > + .set_current_limit = max14577_reg_set_current_limit,
> > +};
> > +
> > +static struct regulator_desc supported_regulators[] = {
> > + {
> > + .name = "SAFEOUT",
> > + .id = MAX14577_SAFEOUT,
> > + .ops = &max14577_safeout_ops,
> > + .type = REGULATOR_VOLTAGE,
> > + .owner = THIS_MODULE,
> > + .n_voltages = 1,
> > + .min_uV = MAX14577_REGULATOR_SAFEOUT_VOLTAGE,
> > + .enable_reg = MAX14577_REG_CONTROL2,
> > + .enable_mask = CTRL2_SFOUTORD_MASK,
> > + }, {
> > + .name = "CHARGER",
> > + .id = MAX14577_CHARGER,
> > + .ops = &max14577_charger_ops,
> > + .type = REGULATOR_CURRENT,
> > + .owner = THIS_MODULE,
> > + .enable_reg = MAX14577_CHG_REG_CHG_CTRL2,
> > + .enable_mask = CHGCTRL2_MBCHOSTEN_MASK,
> > + }
> > +};
> > +
> > +#ifdef CONFIG_OF
> > +static int max14577_regulator_dt_parse_pdata(struct platform_device *pdev,
> > + struct max14577_platform_data *pdata)
> > +{
> > + struct max14577 *max14577 = dev_get_drvdata(pdev->dev.parent);
> > + struct device_node *np;
> > + struct max14577_regulator_platform_data *reg_pdata;
> > + struct of_regulator_match rmatch;
> > + int i, ret, cnt = 0;
> > +
> > + np = of_get_child_by_name(max14577->dev->of_node, "regulators");
> > + if (!np)
> > + return -EINVAL;
> > +
> > + reg_pdata = devm_kzalloc(&pdev->dev, sizeof(*reg_pdata) *
> > + ARRAY_SIZE(supported_regulators), GFP_KERNEL);
> > + if (!reg_pdata)
> > + return -ENOMEM;
> > +
> > + for (i = 0; i < ARRAY_SIZE(supported_regulators); i++) {
> > + rmatch.name = supported_regulators[i].name;
> > + ret = of_regulator_match(&pdev->dev, np, &rmatch, 1);
> > + if (ret != 1)
> > + continue;
> > + dev_dbg(&pdev->dev, "Found regulator %d/%s\n",
> > + supported_regulators[i].id,
> > + supported_regulators[i].name);
> > + reg_pdata[cnt].id = supported_regulators[i].id;
> > + reg_pdata[cnt].initdata = rmatch.init_data;
> > + reg_pdata[cnt].of_node = rmatch.of_node;
> > + cnt++;
> > + }
> > +
> > + pdata->num_regulators = cnt;
> > + pdata->regulators = reg_pdata;
> > +
> > + return 0;
> > +}
> > +#else
> > +static int max14577_regulator_dt_parse_pdata(struct platform_device *pdev,
> > + struct max14577_platform_data *pdata)
> > +{
> > + return 0;
> > +}
> > +#endif
> > +
> > +static int max14577_regulator_probe(struct platform_device *pdev)
> > +{
> > + struct max14577_regulator *info;
> > + struct max14577 *max14577 = dev_get_drvdata(pdev->dev.parent);
> > + struct max14577_platform_data *pdata = dev_get_platdata(max14577->dev);
> > + int i, size;
> > + struct regulator_config config = {};
> > +
> > + if (!pdata) {
> > + /* Parent must provide pdata */
> > + dev_err(&pdev->dev, "No MFD driver platform data found.\n");
> > + return -ENODEV;
> > + }
> > +
> > + if (max14577->dev->of_node) {
> > + int ret = max14577_regulator_dt_parse_pdata(pdev, pdata);
> > + if (ret)
> > + return ret;
> > + }
> > +
> > + info = devm_kzalloc(&pdev->dev, sizeof(struct max14577_regulator),
> > + GFP_KERNEL);
> > + if (!info)
> > + return -ENOMEM;
> > +
> > + size = sizeof(struct regulator_dev *) * pdata->num_regulators;
> > + info->regulators = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
> > + if (!info->regulators) {
> > + dev_err(&pdev->dev, "Cannot allocate memory for regulators\n");
> > + return -ENOMEM;
> > + }
> > +
> > + info->dev = &pdev->dev;
> > + info->max14577 = max14577;
> > + info->num_regulators = pdata->num_regulators;
> > +
> > + config.dev = &pdev->dev;
> > + config.regmap = max14577->regmap;
> > + config.driver_data = info;
> > + platform_set_drvdata(pdev, info);
>
> I don't see any code in this driver that reads from "info" so unless

Err..

> I'm missing something obvious "info" is redundant and can be removed
> altogether.
>
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
>
> > + for (i = 0; i < pdata->num_regulators; i++) {
> > + int id = pdata->regulators[i].id;
> > +
> > + config.init_data = pdata->regulators[i].initdata;
> > + config.of_node = pdata->regulators[i].of_node;
> > +
> > + info->regulators[i] = devm_regulator_register(&pdev->dev,
> > + &supported_regulators[id], &config);
> > + if (IS_ERR(info->regulators[i])) {

This code actually reads from "info" but it can be fixed trivially
to not require "info".

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

> > + int ret = PTR_ERR(info->regulators[i]);
> > + dev_err(&pdev->dev,
> > + "Regulator init failed for ID %d with error: %d\n",
> > + id, ret);
> > + return ret;
> > + }
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static struct platform_driver max14577_regulator_driver = {
> > + .driver = {
> > + .owner = THIS_MODULE,
> > + .name = "max14577-regulator",
> > + },
> > + .probe = max14577_regulator_probe,
> > +};
> > +
> > +static int __init max14577_regulator_init(void)
> > +{
> > + BUILD_BUG_ON(MAX14577_REGULATOR_CURRENT_LIMIT_HIGH_START +
> > + MAX14577_REGULATOR_CURRENT_LIMIT_HIGH_STEP * 0xf !=
> > + MAX14577_REGULATOR_CURRENT_LIMIT_MAX);
> > + return platform_driver_register(&max14577_regulator_driver);
> > +}
> > +subsys_initcall(max14577_regulator_init);
> > +
> > +static void __exit max14577_regulator_exit(void)
> > +{
> > + platform_driver_unregister(&max14577_regulator_driver);
> > +}
> > +module_exit(max14577_regulator_exit);
> > +
> > +MODULE_AUTHOR("Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>");
> > +MODULE_DESCRIPTION("MAXIM 14577 regulator driver");
> > +MODULE_LICENSE("GPL");

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