On Sun, 21 Jun 2020, Jonathan Neuschäfer wrote:

Description of the device here please.

Third-party hardware documentation is available at

'\n'

https://github.com/neuschaefer/linux/wiki/Netronix-MSP430-embedded-controller

Indent this with a couple of spaces.

s/of certain/found in certain/.

Only the SPDX line should contain C++ style comments.

Description at the top, copyright after.

An "MFD driver" isn't really a thing.  Please describe the device.

+#include <asm/unaligned.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/mfd/ntxec.h>
+#include <linux/of_platform.h>
+#include <linux/pm.h>
+#include <linux/reboot.h>
+#include <linux/types.h>
+
+

No need for double line spacing.

+#define NTXEC_VERSION		0x00
+#define NTXEC_POWEROFF		0x50
+#define NTXEC_POWERKEEP		0x70
+#define NTXEC_RESET		0x90

Are these registers?  Might be worth pre/post-fixing with _REG.

+/* Register access */
+
+int ntxec_read16(struct ntxec *ec, u8 addr)
+{
+	u8 request[1] = { addr };
+	u8 response[2];
+	int res;
+
+	struct i2c_msg msgs[] = {
+		{
+			.addr = ec->client->addr,
+			.flags = ec->client->flags,
+			.len = sizeof(request),
+			.buf = request
+		}, {
+			.addr = ec->client->addr,
+			.flags = ec->client->flags | I2C_M_RD,
+			.len = sizeof(response),
+			.buf = response
+		}
+	};
+
+	res = i2c_transfer(ec->client->adapter, msgs, ARRAY_SIZE(msgs));
+	if (res < 0)
+		return res;
+	if (res != ARRAY_SIZE(msgs))
+		return -EIO;
+
+	return get_unaligned_be16(response);
+}
+EXPORT_SYMBOL(ntxec_read16);
+
+int ntxec_write16(struct ntxec *ec, u8 addr, u16 value)
+{
+	u8 request[3] = { addr, };
+	int res;
+
+	put_unaligned_be16(value, request + 1);
+
+	res = i2c_transfer_buffer_flags(ec->client, request, sizeof(request),
+					ec->client->flags);
+	if (res < 0)
+		return res;
+
+	return 0;
+}
+EXPORT_SYMBOL(ntxec_write16);
+
+int ntxec_read8(struct ntxec *ec, u8 addr)
+{
+	int res = ntxec_read16(ec, addr);
+
+	if (res < 0)
+		return res;
+
+	return (res >> 8) & 0xff;
+}
+EXPORT_SYMBOL(ntxec_read8);
+
+int ntxec_write8(struct ntxec *ec, u8 addr, u8 value)
+{
+	return ntxec_write16(ec, addr, value << 8);
+}
+EXPORT_SYMBOL(ntxec_write8);

Why are you hand-rolling your own accessors?

+
+
+/* Reboot/poweroff handling */

These comments seem to be stating the obvious.

Please remove them.

+static struct ntxec *poweroff_restart_instance;
+
+static void ntxec_poweroff(void)
+{
+	ntxec_write8(poweroff_restart_instance, NTXEC_POWEROFF, 0x01);

All magic numbers should be defined?

+	msleep(5000);

Why 5000?

+}
+
+static int ntxec_restart(struct notifier_block *nb,
+		unsigned long action, void *data)
+{
+	/* FIXME: The I2C driver sleeps, but restart handlers may not sleep */

Then this is not allowed.

You need to fix this *before* submitting upstream.

+	ntxec_write8(poweroff_restart_instance, NTXEC_RESET, 0xff);
+	/* TODO: delay? */

TODO *before* submitting upstream.  This is not a development branch.

+	return NOTIFY_DONE;
+}
+
+static struct notifier_block ntxec_restart_handler = {
+	.notifier_call = ntxec_restart,
+	.priority = 128
+};
+
+
+/* Driver setup */
+
+static int ntxec_probe(struct i2c_client *client,
+			    const struct i2c_device_id *ids)
+{
+	struct ntxec *ec;
+	int res;

What does 'res' mean?

+	ec = devm_kmalloc(&client->dev, sizeof(*ec), GFP_KERNEL);
+	if (!ec)
+		return -ENOMEM;
+
+	ec->dev = &client->dev;
+	ec->client = client;

You don't need both (if any).

+	/* Determine the firmware version */
+	res = ntxec_read16(ec, NTXEC_VERSION);
+	if (res < 0) {
+		dev_dbg(ec->dev, "Failed to read firmware version number\n");

Why dbg?

+		return res;
+	}
+	ec->version = res;
+
+	dev_info(ec->dev,
+		 "Netronix embedded controller version %04x detected.\n",
+		 ec->version);
+
+	/* For now, we don't support the new register layout. */
+	if (ntxec_has_new_layout(ec))
+		return -EOPNOTSUPP;

What is the new layout?

Why don't you support it?

+	if (of_device_is_system_power_controller(ec->dev->of_node)) {
+		/*
+		 * Set the 'powerkeep' bit. This is necessary on some boards
+		 * in order to keep the system running.
+		 */
+		res = ntxec_write8(ec, NTXEC_POWERKEEP, 0x08);
+		if (res < 0)
+			return res;
+
+		/* Install poweroff handler */
+		WARN_ON(poweroff_restart_instance);

Why WARN?

+		poweroff_restart_instance = ec;
+		if (pm_power_off != NULL)

if (pm_power_off)

+			/* TODO: Refactor among all poweroff drivers */

Nope.

+			dev_err(ec->dev, "pm_power_off already assigned\n");

Error, but execution carries on anyway?

+		else
+			pm_power_off = ntxec_poweroff;
+
+		/* Install board reset handler */
+		res = register_restart_handler(&ntxec_restart_handler);
+		if (res < 0)

Is >0 valid?

+			dev_err(ec->dev,
+				"Failed to register restart handler: %d\n", res);
+	}
+
+	i2c_set_clientdata(client, ec);

Where do you use this?

+	return devm_of_platform_populate(ec->dev);
+}
+
+static const struct of_device_id of_ntxec_match_table[] = {
+	{ .compatible = "netronix,ntxec", },
+	{}
+};

Use .probe_new() and drop this.

+static struct i2c_driver ntxec_driver = {
+	.driver	= {
+		.name	= "ntxec",
+		.of_match_table = of_ntxec_match_table,
+	},
+	.probe		= ntxec_probe,

Nothing to .remove()?

+};
+builtin_i2c_driver(ntxec_driver);

Only built-in?

No such thing as an MFD.

"Embedded Controller"

+ */
+
+#ifndef NTXEC_H
+#define NTXEC_H
+
+#include <linux/types.h>
+
+struct ntxec {
+	struct device *dev;
+	struct i2c_client *client;
+	u16 version;
+	/* TODO: Add a mutex to protect actions consisting of multiple accesses? */

No TODOs.  Please fix before upstreaming.

+};
+
+static inline bool ntxec_has_new_layout(struct ntxec *ec)
+{
+	return ec->version == 0xe916;

Why don't you just check for the devices you *do* support?

+}
+
+int ntxec_read16(struct ntxec *ec, u8 addr);
+int ntxec_write16(struct ntxec *ec, u8 addr, u16 value);
+int ntxec_read8(struct ntxec *ec, u8 addr);
+int ntxec_write8(struct ntxec *ec, u8 addr, u8 value);
+
+#endif

#endif /* NTXEC_H */

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