Re: [PATCH] hwmon: (pmbus/acbel-fsg032) Add firmware version debugfs attribute

From: Guenter Roeck
Date: Tue Jun 27 2023 - 18:19:33 EST


On 6/27/23 11:40, Eddie James wrote:
Like the IBM CFFPS driver, export the PSU's firmware version to a
debugfs attribute as reported in the manufacturer register.

Signed-off-by: Eddie James <eajames@xxxxxxxxxxxxx>
---
drivers/hwmon/pmbus/acbel-fsg032.c | 48 ++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)

diff --git a/drivers/hwmon/pmbus/acbel-fsg032.c b/drivers/hwmon/pmbus/acbel-fsg032.c
index 0a0ef4ce3493..4b97f108cfe3 100644
--- a/drivers/hwmon/pmbus/acbel-fsg032.c
+++ b/drivers/hwmon/pmbus/acbel-fsg032.c
@@ -3,6 +3,7 @@
* Copyright 2023 IBM Corp.
*/
+#include <linux/debugfs.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/i2c.h>
@@ -11,6 +12,52 @@
#include <linux/hwmon-sysfs.h>
#include "pmbus.h"
+#define ACBEL_MFR_FW_REVISION 0xd9
+
+static ssize_t acbel_fsg032_debugfs_read(struct file *file, char __user *buf, size_t count,
+ loff_t *ppos)
+{
+ struct i2c_client *client = file->private_data;
+ char data[I2C_SMBUS_BLOCK_MAX + 2] = { 0 };
+ char out[8];
+ int rc;
+ int i;
+
+ rc = pmbus_lock_interruptible(client);

Is that needed here ?

+ if (rc)
+ return rc;
+
+ rc = i2c_smbus_read_block_data(client, ACBEL_MFR_FW_REVISION, data);
+ pmbus_unlock(client);
+ if (rc < 0)
+ return rc;
+
+ for (i = 0; i < rc && i < 3; ++i)
+ snprintf(&out[i * 2], 3, "%02X", data[i]);
+
+ rc = i * 2;
+ out[rc++] = '\n';
+ out[rc++] = 0;

Any reason for not using one of the %*ph variants ?

Thanks,
Guenter

+ return simple_read_from_buffer(buf, count, ppos, out, rc);
+}
+
+static const struct file_operations acbel_debugfs_ops = {
+ .llseek = noop_llseek,
+ .read = acbel_fsg032_debugfs_read,
+ .write = NULL,
+ .open = simple_open,
+};
+
+static void acbel_fsg032_init_debugfs(struct i2c_client *client)
+{
+ struct dentry *debugfs = pmbus_get_debugfs_dir(client);
+
+ if (!debugfs)
+ return;
+
+ debugfs_create_file("fw_version", 0444, debugfs, client, &acbel_debugfs_ops);
+}
+
static const struct i2c_device_id acbel_fsg032_id[] = {
{ "acbel_fsg032" },
{}
@@ -59,6 +106,7 @@ static int acbel_fsg032_probe(struct i2c_client *client)
if (rc)
return rc;
+ acbel_fsg032_init_debugfs(client);
return 0;
}