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Message-ID: <3ec8570e-a730-b572-8246-631b91f46735@gmail.com>
Date:   Sat, 9 Jul 2022 13:56:27 +0300
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Subject: Re: [PATCH v5 4/5] mfd: sm5703: Add support for SM5703 MFD
Content-Language: en-US
To:     Lee Jones <lee.jones@linaro.org>
Cc:     linux-kernel@vger.kernel.org, phone-devel@vger.kernel.org,
        ~postmarketos/upstreaming@lists.sr.ht,
        Matti Vaittinen <mazziesaccount@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        Chanwoo Choi <cw00.choi@samsung.com>,
        devicetree@vger.kernel.org
References: <20220423085319.483524-1-markuss.broks@gmail.com>
 <20220423085319.483524-5-markuss.broks@gmail.com>
 <Yqj+aUNLC00Tcu49@google.com>
From:   Markuss Broks <markuss.broks@gmail.com>
In-Reply-To: <Yqj+aUNLC00Tcu49@google.com>
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Hi Lee,

On 6/15/22 00:32, Lee Jones wrote:
> On Sat, 23 Apr 2022, Markuss Broks wrote:
>
>> Silicon Mitus SM5703 is a multi-function device, meant to be
> Please avoid using the term MFD.
>
> How is the device described in the data-sheet?
I don't have a data-sheet for this device. The only reference I have is 
downstream Linux driver. Maybe a better way to call it would be PMIC?
>
> What do you mean by "meant to be"?
"designed to be", it appears that this part is almost exclusively used 
by Samsung in its mobile phones.
>
>> used in mobile devices. It has several modules: LDO, BUCK regulators,
> Modules or functions?

Some of "modules" are quite separate, so I decided to call it that way. 
How should it be called?

>
>> charger circuit, flash LED driver, a fuel gauge for monitoring the battery
>> and a MUIC USB switcher. The MUIC and fuel gauge parts are separate in that
>> they use separate i2c lines to communicate with the device, while charger
> "I2C"
>
>> circuit, LED driver and regulators are on the main i2c line the device is
>> controlled with.
>>
>> Signed-off-by: Markuss Broks <markuss.broks@gmail.com>
>> ---
>>   MAINTAINERS                |   8 +++
>>   drivers/mfd/Kconfig        |  13 +++++
>>   drivers/mfd/Makefile       |   1 +
>>   drivers/mfd/sm5703.c       |  78 +++++++++++++++++++++++++++
>>   include/linux/mfd/sm5703.h | 105 +++++++++++++++++++++++++++++++++++++
>>   5 files changed, 205 insertions(+)
>>   create mode 100644 drivers/mfd/sm5703.c
>>   create mode 100644 include/linux/mfd/sm5703.h
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 6157e706ed02..6125ed1a3be4 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -18172,6 +18172,14 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git dev
>>   F:	include/linux/srcu*.h
>>   F:	kernel/rcu/srcu*.c
>>   
>> +SM5703 MFD DRIVER
>> +M:	Markuss Broks <markuss.broks@gmail.com>
>> +S:	Maintained
>> +F:	Documentation/devicetree/bindings/mfd/siliconmitus,sm5703.yaml
>> +F:	Documentation/devicetree/bindings/regulator/siliconmitus,sm5703-regulator.yaml
>> +F:	drivers/mfd/sm5703.c
>> +F:	drivers/regulator/sm5703-regulator.c
>> +
>>   SMACK SECURITY MODULE
>>   M:	Casey Schaufler <casey@schaufler-ca.com>
>>   L:	linux-security-module@vger.kernel.org
>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
>> index 3b59456f5545..c13a99ceae99 100644
>> --- a/drivers/mfd/Kconfig
>> +++ b/drivers/mfd/Kconfig
>> @@ -1237,6 +1237,19 @@ config MFD_SM501
>>   	  interface. The device may be connected by PCI or local bus with
>>   	  varying functions enabled.
>>   
>> +config MFD_SM5703
>> +	tristate "Silicon Mitus SM5703 MFD"
>> +	depends on I2C
>> +	depends on OF
>> +	select MFD_CORE
>> +	select REGMAP_I2C
>> +	help
>> +	  This is the core driver for the Silicon Mitus SM5703 multi-function
> Please drop the MFD term, as above.
>
>> +	  device. This device is meant to be used in phones and it has numerous
> "meant to be"?
>
>> +	  modules, including LED controller, regulators, fuel gauge, MUIC and
> Either "an LED controller" or "LED controllers"
>
> Same with "charger circuit" below.
>
>> +	  charger circuit. It also support muxing a serial interface over USB
> "supports"
>
> What kind of serial?
UART as a standard Samsung debug port interface (619K Ohm resistor 
between data lines is Samsung's debug cable).
>
>> +	  data lines.
>> +
>>   config MFD_SM501_GPIO
>>   	bool "Export GPIO via GPIO layer"
>>   	depends on MFD_SM501 && GPIOLIB
>> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
>> index 858cacf659d6..ca8b86736a36 100644
>> --- a/drivers/mfd/Makefile
>> +++ b/drivers/mfd/Makefile
>> @@ -275,3 +275,4 @@ rsmu-i2c-objs			:= rsmu_core.o rsmu_i2c.o
>>   rsmu-spi-objs			:= rsmu_core.o rsmu_spi.o
>>   obj-$(CONFIG_MFD_RSMU_I2C)	+= rsmu-i2c.o
>>   obj-$(CONFIG_MFD_RSMU_SPI)	+= rsmu-spi.o
>> +obj-$(CONFIG_MFD_SM5703)	+= sm5703.o
>> diff --git a/drivers/mfd/sm5703.c b/drivers/mfd/sm5703.c
>> new file mode 100644
>> index 000000000000..7f9838149051
>> --- /dev/null
>> +++ b/drivers/mfd/sm5703.c
>> @@ -0,0 +1,78 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +
>> +#include <linux/err.h>
>> +#include <linux/delay.h>
>> +#include <linux/gpio/consumer.h>
>> +#include <linux/i2c.h>
>> +#include <linux/mfd/core.h>
>> +#include <linux/mfd/sm5703.h>
>> +#include <linux/module.h>
>> +#include <linux/of_device.h>
>> +#include <linux/regmap.h>
>> +
>> +static const struct mfd_cell sm5703_devs[] = {
>> +	{ .name = "sm5703-regulator", },
>> +};
> Where are the rest of the child drivers?
>
>> +static const struct regmap_config sm5703_regmap_config = {
>> +	.reg_bits	= 8,
>> +	.val_bits	= 8,
> Tabbing looks odd.  Just use a space.
>
>> +};
>> +
>> +static int sm5703_i2c_probe(struct i2c_client *i2c,
>> +			    const struct i2c_device_id *id)
>> +{
>> +	struct sm5703_dev *sm5703;
>> +	struct device *dev = &i2c->dev;
>> +	unsigned int dev_id;
>> +	int ret;
>> +
>> +	sm5703 = devm_kzalloc(dev, sizeof(*sm5703), GFP_KERNEL);
>> +	if (!sm5703)
>> +		return -ENOMEM;
>> +
>> +	i2c_set_clientdata(i2c, sm5703);
>> +	sm5703->dev = dev;
>> +
>> +	sm5703->regmap = devm_regmap_init_i2c(i2c, &sm5703_regmap_config);
>> +	if (IS_ERR(sm5703->regmap))
>> +		return dev_err_probe(dev, PTR_ERR(sm5703->regmap),
>> +				     "Failed to allocate the register map\n");
>> +
>> +	sm5703->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
>> +	if (IS_ERR(sm5703->reset_gpio))
>> +		return dev_err_probe(dev, PTR_ERR(sm5703->reset_gpio), "Cannot get reset GPIO\n");
>> +
>> +	gpiod_set_value_cansleep(sm5703->reset_gpio, 1);
>> +	msleep(20);
>> +
>> +	ret = regmap_read(sm5703->regmap, SM5703_DEVICE_ID, &dev_id);
>> +	if (ret)
>> +		return dev_err_probe(dev, -ENODEV, "Device not found\n");
>> +
>> +	ret = devm_mfd_add_devices(sm5703->dev, -1, sm5703_devs,
> Not -1.  Please use the defines provided.
>
>> +				   ARRAY_SIZE(sm5703_devs), NULL, 0, NULL);
>> +	if (ret)
>> +		return dev_err_probe(dev, ret, "Failed to add child devices\n");
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct of_device_id sm5703_of_match[] = {
>> +	{ .compatible = "siliconmitus,sm5703", },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(of, sm5703_of_match);
>> +
>> +static struct i2c_driver sm5703_driver = {
>> +	.driver = {
>> +		.name = "sm5703",
>> +		.of_match_table = sm5703_of_match,
>> +	},
>> +	.probe = sm5703_i2c_probe,
>> +};
>> +module_i2c_driver(sm5703_driver);
>> +
>> +MODULE_DESCRIPTION("Silicon Mitus SM5703 multi-function device driver");
> There is no such thing as an MFD.
>
>> +MODULE_AUTHOR("Markuss Broks <markuss.broks@gmail.com>");
>> +MODULE_LICENSE("GPL");
>> diff --git a/include/linux/mfd/sm5703.h b/include/linux/mfd/sm5703.h
>> new file mode 100644
>> index 000000000000..c62affa0d3f1
>> --- /dev/null
>> +++ b/include/linux/mfd/sm5703.h
>> @@ -0,0 +1,105 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +
>> +#ifndef _SM5703_H
>> +#define _SM5703_H
>> +
>> +struct sm5703_dev {
>> +	struct device *dev;
>> +	struct regmap *regmap;
>> +	struct gpio_desc *reset_gpio;
>> +};
>> +
>> +// Regulator-related defines
> No C++ style comments.
>
>> +#define SM5703_REG_LDO1				0x1A
> I'd drop the REG parts from these.
>
> What are these registers called in the data-sheet?
No data-sheet, sadly.
>
>> +#define SM5703_REG_LDO2				0x1B
>> +#define SM5703_REG_LDO3				0x1C
>> +#define SM5703_LDO_EN				BIT(3)
> Some people like to space out the bits to differentiate them from the
> register addresses.
>
>> +#define SM5703_LDO_VOLT_MASK			0x7
> Please keep the bit length consistent, so 0x07 here if these are Byte
> length registers.
>
>> +#define SM5703_BUCK_VOLT_MASK			0x1F
>> +#define SM5703_REG_USBLDO12			0x1C
>> +#define SM5703_REG_EN_USBLDO1			BIT(6)
>> +#define SM5703_REG_EN_USBLDO2			BIT(7)
>> +#define SM5703_REG_BUCK				0x1D
> Please place these in order.
>
>> +#define SM5703_REG_EN_BUCK			BIT(6)
>> +#define SM5703_USBLDO_MICROVOLT			4800000
>> +#define SM5703_VBUS_MICROVOLT			5000000
>> +
>> +// Fuel-Gauge-related defines
>> +
>> +#define SM5703_FG_REG_DEVICE_ID			0x00
>> +#define SM5703_FG_REG_CNTL			0x01
>> +#define SM5703_FG_REG_INTFG			0x02
>> +#define SM5703_FG_REG_INTFG_MASK		0x03
>> +#define SM5703_FG_REG_STATUS			0x04
>> +#define SM5703_FG_REG_SOC			0x05
>> +#define SM5703_FG_REG_OCV			0x06
>> +#define SM5703_FG_REG_VOLTAGE			0x07
>> +#define SM5703_FG_REG_CURRENT			0x08
>> +#define SM5703_FG_REG_TEMPERATURE		0x09
>> +#define SM5703_FG_REG_CURRENT_EST		0x85
>> +#define SM5703_FG_REG_FG_OP_STATUS		0x10
>> +
>> +// Flash LED driver-related defines
>> +
>> +#define SM5703_FLEDCNTL1			0x14
>> +#define SM5703_FLEDCNTL2			0x15
>> +#define SM5703_FLEDCNTL3			0x16
>> +#define SM5703_FLEDCNTL4			0x17
>> +#define SM5703_FLEDCNTL5			0x18
>> +#define SM5703_FLEDCNTL6			0x19
>> +
>> +#define SM5703_FLEDEN_MASK			0x03
>> +#define SM5703_FLEDEN_DISABLE			0x00
>> +#define SM5703_FLEDEN_MOVIE_MODE		0x01
>> +#define SM5703_FLEDEN_FLASH_MODE		0x02
>> +#define SM5703_FLEDEN_EXTERNAL			0x03
>> +
>> +#define SM5703_IFLED_MASK			0x1F
>> +#define SM5703_IMLED_MASK			0x1F
>> +
>> +// Charger-related, IRQ and device ID defines
>> +
>> +#define SM5703_REG_CNTL				0x0C
>> +#define SM5703_VBUSCNTL				0x0D
>> +#define SM5703_CHGCNTL1				0x0E
>> +#define SM5703_CHGCNTL2				0x0F
>> +#define SM5703_CHGCNTL3				0x10
>> +#define SM5703_CHGCNTL4				0x11
>> +#define SM5703_CHGCNTL5				0x12
>> +#define SM5703_CHGCNTL6				0x13
>> +#define SM5703_OTGCURRENTCNTL			0x60
>> +#define SM5703_Q3LIMITCNTL			0x66
>> +#define SM5703_DEVICE_ID			0x1E
>> +#define SM5703_OPERATION_MODE			0x07
>> +#define SM5703_OPERATION_MODE_MASK		0x07
>> +
>> +#define SM5703_OPERATION_MODE_SUSPEND		0x00
>> +#define SM5703_OPERATION_MODE_CHARGING_OFF	0x04
>> +#define SM5703_OPERATION_MODE_CHARGING_ON	0x05
>> +#define SM5703_OPERATION_MODE_FLASH_BOOST_MODE	0x06
>> +#define SM5703_OPERATION_MODE_USB_OTG_MODE	0x07
>> +
>> +#define SM5703_BSTOUT				0x0F
>> +#define SM5703_BSTOUT_MASK			0x0F
>> +#define SM5703_BSTOUT_SHIFT			0
>> +
>> +#define SM5703_BSTOUT_4P5			0x05
>> +#define SM5703_BSTOUT_5P0			0x0A
>> +#define SM5703_BSTOUT_5P1			0x0B
>> +
>> +#define SM5703_IRQ_STATUS1			0x08
>> +#define SM5703_IRQ_STATUS2			0x09
>> +#define SM5703_IRQ_STATUS3			0x0A
>> +#define SM5703_IRQ_STATUS4			0x0B
>> +#define SM5703_IRQ_STATUS5			0x6B
>> +
>> +#define SM5703_STATUS1_OTGFAIL			0x80
>> +#define SM5703_STATUS3_DONE			0x08
>> +#define SM5703_STATUS3_TOPOFF			0x04
>> +#define SM5703_STATUS3_CHGON			0x01
>> +#define SM5703_STATUS5_VBUSOVP			0x80
>> +#define SM5703_STATUS5_VBUSUVLO			0x40
>> +#define SM5703_STATUS5_VBUSOK			0x20
>> +
>> +#endif
- Markuss