[PATCH linux dev-4.10 2/2] hwmon: (pmbus): cffps: Add input_history debugfs file

[Matt Spinler]

Reviewed-by: Matt Spinler mspinler at linux.vnet.ibm.com


On 11/2/2017 3:59 PM, Eddie James wrote:
> From: "Edward A. James" <eajames at us.ibm.com>
>
> Provide binary data of the powers supply input history to debugfs.
>
> Signed-off-by: Edward A. James <eajames at us.ibm.com>
> ---
>   drivers/hwmon/pmbus/ibm-cffps.c | 97 ++++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 96 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hwmon/pmbus/ibm-cffps.c b/drivers/hwmon/pmbus/ibm-cffps.c
> index 1a6294c..0570c12 100644
> --- a/drivers/hwmon/pmbus/ibm-cffps.c
> +++ b/drivers/hwmon/pmbus/ibm-cffps.c
> @@ -7,13 +7,19 @@
>    * (at your option) any later version.
>    */
>
> +#include <linux/debugfs.h>
>   #include <linux/device.h>
> +#include <linux/fs.h>
>   #include <linux/i2c.h>
>   #include <linux/jiffies.h>
>   #include <linux/module.h>
> +#include <linux/mutex.h>
>
>   #include "pmbus.h"
>
> +#define CFFPS_INPUT_HISTORY_CMD			0xD6
> +#define CFFPS_INPUT_HISTORY_SIZE		100
> +
>   /* STATUS_MFR_SPECIFIC bits */
>   #define CFFPS_MFR_FAN_FAULT			BIT(0)
>   #define CFFPS_MFR_THERMAL_FAULT			BIT(1)
> @@ -24,6 +30,70 @@
>   #define CFFPS_MFR_VAUX_FAULT			BIT(6)
>   #define CFFPS_MFR_CURRENT_SHARE_WARNING		BIT(7)
>
> +struct ibm_cffps {
> +	struct i2c_client *client;
> +
> +	struct mutex update_lock;
> +	unsigned long last_updated;
> +
> +	u8 byte_count;
> +	u8 input_history[CFFPS_INPUT_HISTORY_SIZE];
> +};
> +
> +static ssize_t ibm_cffps_read_input_history(struct file *file,
> +					    char __user *buf, size_t count,
> +					    loff_t *ppos)
> +{
> +	int rc;
> +	struct ibm_cffps *psu = file->private_data;
> +	u8 msgbuf0[1] = { CFFPS_INPUT_HISTORY_CMD };
> +	u8 msgbuf1[CFFPS_INPUT_HISTORY_SIZE + 1] = { 0 };
> +	struct i2c_msg msg[2] = {
> +		{
> +			.addr = psu->client->addr,
> +			.flags = psu->client->flags,
> +			.len = 1,
> +			.buf = msgbuf0,
> +		}, {
> +			.addr = psu->client->addr,
> +			.flags = psu->client->flags | I2C_M_RD,
> +			.len = CFFPS_INPUT_HISTORY_SIZE + 1,
> +			.buf = msgbuf1,
> +		},
> +	};
> +
> +	if (!*ppos) {
> +		mutex_lock(&psu->update_lock);
> +		if (time_after(jiffies, psu->last_updated + HZ)) {
> +			/*
> +			 * Use a raw i2c transfer, since we need more bytes
> +			 * than Linux I2C supports through smbus xfr (only 32).
> +			 */
> +			rc = i2c_transfer(psu->client->adapter, msg, 2);
> +			if (rc < 0) {
> +				mutex_unlock(&psu->update_lock);
> +				return rc;
> +			}
> +
> +			psu->byte_count = msgbuf1[0];
> +			memcpy(psu->input_history, &msgbuf1[1],
> +			       CFFPS_INPUT_HISTORY_SIZE);
> +			psu->last_updated = jiffies;
> +		}
> +
> +		mutex_unlock(&psu->update_lock);
> +	}
> +
> +	return simple_read_from_buffer(buf, count, ppos, psu->input_history,
> +				       psu->byte_count);
> +}
> +
> +static const struct file_operations ibm_cffps_fops = {
> +	.llseek = noop_llseek,
> +	.read = ibm_cffps_read_input_history,
> +	.open = simple_open,
> +};
> +
>   static int ibm_cffps_read_byte_data(struct i2c_client *client, int page,
>   				    int reg)
>   {
> @@ -119,7 +189,32 @@ static int ibm_cffps_read_word_data(struct i2c_client *client, int page,
>   static int ibm_cffps_probe(struct i2c_client *client,
>   			   const struct i2c_device_id *id)
>   {
> -	return pmbus_do_probe(client, id, &ibm_cffps_info);
> +	int rc;
> +	struct dentry *debugfs;
> +	struct ibm_cffps *psu;
> +
> +	rc = pmbus_do_probe(client, id, &ibm_cffps_info);
> +	if (rc)
> +		return rc;
> +
> +	/* Don't fail the probe if we can't create debugfs */
> +	psu = devm_kzalloc(&client->dev, sizeof(*psu), GFP_KERNEL);
> +	if (!psu)
> +		return 0;
> +
> +	psu->client = client;
> +	mutex_init(&psu->update_lock);
> +	if (jiffies > HZ)
> +		psu->last_updated = jiffies - HZ;
> +
> +	debugfs = pmbus_get_debugfs_dir(client);
> +	if (!debugfs)
> +		return 0;
> +
> +	debugfs_create_file("ibm_cffps_input_history", 0444, debugfs, psu,
> +			    &ibm_cffps_fops);
> +
> +	return 0;
>   }
>
>   static const struct i2c_device_id ibm_cffps_id[] = {

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