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

On Thu, Feb 4, 2021 at 5:31 AM Lee Jones [off-list ref] wrote:

On Sat, 16 Jan 2021, Alistair Francis wrote:

quoted

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.

Sorry for the long delay here.

I have addressed your comments.

quoted

Signed-off-by: Alistair Francis <redacted>
---
 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.

quoted

+     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.

I removed "driver" from all of these.

quoted

 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?

Fixed

quoted

 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".

quoted

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

This is quite out of date.  Please update.

I don't own this copyright, so I would rather not change it.

quoted

+ * 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.

Removed.

quoted

+ * 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.

Done.

quoted

+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.

quoted

+     return (val & 0x1FF) * 10;

What's 10?

quoted

+}
+
+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.

quoted

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

As above.

I have used defines for all of these.

quoted

+     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?

They sysfs store and show functions.

quoted

+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?

I used a define here to make it clearer

quoted

+     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.

I'm not sure how to document this. Do you mind pointing out an example
I can use?

quoted

+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"?

The LSB is reserved, so we don't clear that.

quoted

+}
+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.

quoted

+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?

From what I can tell I think they do. Let me know if you don't think so.

quoted

+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)

quoted

+     if (sy7636a == NULL)

if (!sy7636a)

quoted

+             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"

quoted

+             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.

quoted

+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/

quoted

+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.

quoted

+#ifndef __LINUX_MFD_SY7636A_H
+#define __LINUX_MFD_SY7636A_H

Just MFD is fine.

quoted

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

Alphabetical.

quoted

+#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()

quoted

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

Where is this used?

quoted

+     struct gpio_desc *pgood_gpio;

Where is this used?

quoted

+     struct mutex reglock;

Where is this used?

I have removed these.

quoted

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

What calls these?

I have just made these internal to the driver.


Alistair

quoted

+#endif /* __LINUX_MFD_SY7636A_H */

--
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog