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

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.

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.

Why does this have to be segregated?

"Parent driver".

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

This is quite out of date.  Please update.

+ * Author: Lars Ivar Miljeteig [off-list ref]
+ *
+ * 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 [off-list ref]
+ */
+
+#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 [off-list ref]");
+MODULE_DESCRIPTION("Silergy SY7636A Multi-Function Device Driver");

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

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
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