Re: [PATCH 2/6] mfd: Initial commit of sy7636a

From: Lee Jones
Date: Thu Feb 04 2021 - 05:34:03 EST

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On Sat, 16 Jan 2021, Alistair Francis wrote:

> Initial support for the Silergy SY7636A Power Management chip
> driver.

Please remove "driver", as this is not support for the driver, it *is*
the driver which supports the chip.

> Signed-off-by: Alistair Francis <alistair@xxxxxxxxxxxxx>
> ---
> drivers/mfd/Kconfig | 10 ++
> drivers/mfd/Makefile | 2 +
> drivers/mfd/sy7636a.c | 252 ++++++++++++++++++++++++++++++++++++
> include/linux/mfd/sy7636a.h | 50 +++++++
> 4 files changed, 314 insertions(+)
> create mode 100644 drivers/mfd/sy7636a.c
> create mode 100644 include/linux/mfd/sy7636a.h
>
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index bdfce7b15621..c8c62d92433c 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -1360,6 +1360,16 @@ config MFD_SYSCON
> Select this option to enable accessing system control registers
> via regmap.
>
> +config MFD_SY7636A
> + tristate "Silergy SY7636A Power Management chip driver"

Again, please remove the word "driver" here.

> + select MFD_CORE
> + select REGMAP_I2C
> + select REGMAP_IRQ
> + depends on I2C=y
> + help
> + Select this option to enable support for the Silergy SY7636A
> + Power Management chip driver.

And again.

> config MFD_DAVINCI_VOICECODEC
> tristate
> select MFD_CORE
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 14fdb188af02..1fa1e635f506 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -265,6 +265,8 @@ obj-$(CONFIG_MFD_ROHM_BD718XX) += rohm-bd718x7.o
> obj-$(CONFIG_MFD_STMFX) += stmfx.o
> obj-$(CONFIG_MFD_KHADAS_MCU) += khadas-mcu.o
>
> +obj-$(CONFIG_MFD_SY7636A) += sy7636a.o
> +

Why does this have to be segregated?

> obj-$(CONFIG_SGI_MFD_IOC3) += ioc3.o
> obj-$(CONFIG_MFD_SIMPLE_MFD_I2C) += simple-mfd-i2c.o
> obj-$(CONFIG_MFD_INTEL_M10_BMC) += intel-m10-bmc.o
> diff --git a/drivers/mfd/sy7636a.c b/drivers/mfd/sy7636a.c
> new file mode 100644
> index 000000000000..39aac965d854
> --- /dev/null
> +++ b/drivers/mfd/sy7636a.c
> @@ -0,0 +1,252 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * MFD driver for SY7636A chip

"Parent driver".

> + * Copyright (C) 2019 reMarkable AS - http://www.remarkable.com/

This is quite out of date. Please update.

> + * Author: Lars Ivar Miljeteig <lars.ivar.miljeteig@xxxxxxxxxxxxxx>
> + *
> + * 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 version 2.
> + *
> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
> + * kind, whether express or implied; without even the implied warranty
> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.

This test is replaced by the SPDX header above.

> + * Based on the lp87565 driver by Keerthy <j-keerthy@xxxxxx>
> + */
> +
> +#include <linux/interrupt.h>
> +#include <linux/mfd/core.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/regmap.h>
> +#include <linux/sysfs.h>
> +
> +#include <linux/mfd/sy7636a.h>
> +
> +static const struct regmap_config sy7636a_regmap_config = {
> + .reg_bits = 8,
> + .val_bits = 8,
> +};
> +
> +static const struct mfd_cell sy7636a_cells[] = {
> + { .name = "sy7636a-regulator", },
> + { .name = "sy7636a-temperature", },
> + { .name = "sy7636a-thermal", },
> +};
> +
> +static const struct of_device_id of_sy7636a_match_table[] = {
> + { .compatible = "silergy,sy7636a", },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, of_sy7636a_match_table);

Please move this to where it is used i.e. at the bottom of the file.

> +static const char * const states[] = {
> + "no fault event",
> + "UVP at VP rail",
> + "UVP at VN rail",
> + "UVP at VPOS rail",
> + "UVP at VNEG rail",
> + "UVP at VDDH rail",
> + "UVP at VEE rail",
> + "SCP at VP rail",
> + "SCP at VN rail",
> + "SCP at VPOS rail",
> + "SCP at VNEG rail",
> + "SCP at VDDH rail",
> + "SCP at VEE rail",
> + "SCP at V COM rail",
> + "UVLO",
> + "Thermal shutdown",
> +};
> +
> +int get_vcom_voltage_mv(struct regmap *regmap)
> +{
> + int ret;
> + unsigned int val, val_h;
> +
> + ret = regmap_read(regmap, SY7636A_REG_VCOM_ADJUST_CTRL_L, &val);
> + if (ret)
> + return ret;
> +
> + ret = regmap_read(regmap, SY7636A_REG_VCOM_ADJUST_CTRL_H, &val_h);
> + if (ret)
> + return ret;
> +
> + val |= (val_h << 8);

Please define the shifts and masks.

> + return (val & 0x1FF) * 10;

What's 10?

> +}
> +
> +int set_vcom_voltage_mv(struct regmap *regmap, unsigned int vcom)
> +{
> + int ret;
> + unsigned int val;
> +
> + if (vcom < 0 || vcom > 5000)

Please define min/max values.

> + return -EINVAL;
> +
> + val = (unsigned int)(vcom / 10) & 0x1ff;

As above.

> + ret = regmap_write(regmap, SY7636A_REG_VCOM_ADJUST_CTRL_L, val);
> + if (ret)
> + return ret;
> +
> + ret = regmap_write(regmap, SY7636A_REG_VCOM_ADJUST_CTRL_H, val >> 8);
> + if (ret)
> + return ret;
> +
> + return 0;
> +}

Who calls these?

> +static ssize_t state_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + int ret;
> + unsigned int val;
> + struct sy7636a *sy7636a = dev_get_drvdata(dev);
> +
> + ret = regmap_read(sy7636a->regmap, SY7636A_REG_FAULT_FLAG, &val);
> + if (ret) {
> + dev_err(sy7636a->dev, "Failed to read from device\n");
> + return ret;
> + }
> +
> + val = val >> 1;

Why 1?

> + if (val >= ARRAY_SIZE(states)) {
> + dev_err(sy7636a->dev, "Unexpected value read from device: %u\n", val);
> + return -EINVAL;
> + }
> +
> + return snprintf(buf, PAGE_SIZE, "%s\n", states[val]);
> +}
> +static DEVICE_ATTR(state, 0444, state_show, NULL);

You need to document new sysfs entries.

> +static ssize_t power_good_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + int ret;
> + unsigned int val;
> + struct sy7636a *sy7636a = dev_get_drvdata(dev);
> +
> + ret = regmap_read(sy7636a->regmap, SY7636A_REG_FAULT_FLAG, &val);
> + if (ret) {
> + dev_err(sy7636a->dev, "Failed to read from device\n");
> + return ret;
> + }
> +
> + val &= 0x01;
> +
> + return snprintf(buf, PAGE_SIZE, "%s\n", val ? "ON" : "OFF");

Doesn't 0 just mean "no fault event"?

> +}
> +static DEVICE_ATTR(power_good, 0444, power_good_show, NULL);
> +
> +static ssize_t vcom_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + int ret;
> + struct sy7636a *sy7636a = dev_get_drvdata(dev);
> +
> + ret = get_vcom_voltage_mv(sy7636a->regmap);
> + if (ret < 0)
> + return ret;
> +
> + return snprintf(buf, PAGE_SIZE, "%d\n", -ret);
> +}
> +

Remove this line please.

> +static ssize_t vcom_store(struct device *dev,
> + struct device_attribute *attr, const char *buf, size_t count)
> +{
> + int ret;
> + int vcom;
> + struct sy7636a *sy7636a = dev_get_drvdata(dev);
> +
> + ret = kstrtoint(buf, 0, &vcom);
> + if (ret)
> + return ret;
> +
> + if (vcom > 0 || vcom < -5000)
> + return -EINVAL;
> +
> + ret = set_vcom_voltage_mv(sy7636a->regmap, (unsigned int)(-vcom));
> + if (ret)
> + return ret;
> +
> + return count;
> +}
> +static DEVICE_ATTR(vcom, 0644, vcom_show, vcom_store);
> +
> +static struct attribute *sy7636a_sysfs_attrs[] = {
> + &dev_attr_state.attr,
> + &dev_attr_power_good.attr,
> + &dev_attr_vcom.attr,
> + NULL,
> +};

These all look like power options? Do they really belong here?

> +static const struct attribute_group sy7636a_sysfs_attr_group = {
> + .attrs = sy7636a_sysfs_attrs,
> +};
> +
> +static int sy7636a_probe(struct i2c_client *client,
> + const struct i2c_device_id *ids)
> +{
> + struct sy7636a *sy7636a;
> + int ret;
> +
> + sy7636a = devm_kzalloc(&client->dev, sizeof(struct sy7636a), GFP_KERNEL);

sizeof(*sy7636a)

> + if (sy7636a == NULL)

if (!sy7636a)

> + return -ENOMEM;
> +
> + sy7636a->dev = &client->dev;
> +
> + sy7636a->regmap = devm_regmap_init_i2c(client, &sy7636a_regmap_config);
> + if (IS_ERR(sy7636a->regmap)) {
> + ret = PTR_ERR(sy7636a->regmap);
> + dev_err(sy7636a->dev,
> + "Failed to initialize register map: %d\n", ret);
> + return ret;
> + }
> +
> + i2c_set_clientdata(client, sy7636a);
> +
> + ret = sysfs_create_group(&client->dev.kobj, &sy7636a_sysfs_attr_group);
> + if (ret) {
> + dev_err(sy7636a->dev, "Failed to create sysfs attributes\n");
> + return ret;
> + }
> +
> + ret = devm_mfd_add_devices(sy7636a->dev, PLATFORM_DEVID_AUTO,
> + sy7636a_cells, ARRAY_SIZE(sy7636a_cells),
> + NULL, 0, NULL);
> + if (ret) {
> + dev_err(sy7636a->dev, "Failed to add mfd devices\n");

"Failed to add child devices"

> + sysfs_remove_group(&client->dev.kobj, &sy7636a_sysfs_attr_group);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static const struct i2c_device_id sy7636a_id_table[] = {
> + { "sy7636a", 0 },
> + { },
> +};
> +MODULE_DEVICE_TABLE(i2c, sy7636a_id_table);

If you use .probe2, you can omit this table.

> +static struct i2c_driver sy7636a_driver = {
> + .driver = {
> + .name = "sy7636a",
> + .of_match_table = of_sy7636a_match_table,
> + },
> + .probe = sy7636a_probe,
> + .id_table = sy7636a_id_table,
> +};
> +module_i2c_driver(sy7636a_driver);
> +
> +MODULE_AUTHOR("Lars Ivar Miljeteig <lars.ivar.miljeteig@xxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Silergy SY7636A Multi-Function Device Driver");

s/Multi-Function Device Driver/Power Management Chip/

> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/mfd/sy7636a.h b/include/linux/mfd/sy7636a.h
> new file mode 100644
> index 000000000000..642789c4d0a9
> --- /dev/null
> +++ b/include/linux/mfd/sy7636a.h
> @@ -0,0 +1,50 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Functions to access SY3686A power management chip.
> + *
> + * Copyright (C) 2019 reMarkable AS - http://www.remarkable.com/
> + *
> + * 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 version 2.
> + *
> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
> + * kind, whether express or implied; without even the implied warranty
> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */

Same issues as mentioned above.

> +#ifndef __LINUX_MFD_SY7636A_H
> +#define __LINUX_MFD_SY7636A_H

Just MFD is fine.

> +#include <linux/i2c.h>
> +#include <linux/regulator/driver.h>
> +#include <linux/regulator/machine.h>
> +#include <linux/regmap.h>

Alphabetical.

> +#define SY7636A_REG_OPERATION_MODE_CRL 0x00
> +#define SY7636A_OPERATION_MODE_CRL_VCOMCTL (1 << 6)
> +#define SY7636A_OPERATION_MODE_CRL_ONOFF (1 << 7)
> +#define SY7636A_REG_VCOM_ADJUST_CTRL_L 0x01
> +#define SY7636A_REG_VCOM_ADJUST_CTRL_H 0x02
> +#define SY7636A_REG_VCOM_ADJUST_CTRL_MASK 0x01ff
> +#define SY7636A_REG_VLDO_VOLTAGE_ADJULST_CTRL 0x03
> +#define SY7636A_REG_POWER_ON_DELAY_TIME 0x06
> +#define SY7636A_REG_FAULT_FLAG 0x07
> +#define SY7636A_FAULT_FLAG_PG (1 << 0)
> +#define SY7636A_REG_TERMISTOR_READOUT 0x08

Tab out the values please.

Use BIT()

> +#define SY7636A_REG_MAX 0x08
> +
> +struct sy7636a {
> + struct device *dev;
> + struct regmap *regmap;
> + unsigned int vcom;

Where is this used?

> + struct gpio_desc *pgood_gpio;

Where is this used?

> + struct mutex reglock;

Where is this used?

> +};
> +
> +int get_vcom_voltage_mv(struct regmap *regmap);
> +int set_vcom_voltage_mv(struct regmap *regmap, unsigned int vcom);

What calls these?

> +#endif /* __LINUX_MFD_SY7636A_H */

--
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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