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SubjectRe: [PATCH 2/2] hwmon (pmbus): cffps: Add debugfs entries
On Thu, Dec 07, 2017 at 01:50:38PM -0600, Eddie James wrote:
> From: "Edward A. James" <eajames@us.ibm.com>
>
> Add debugfs entries for additional power supply data, including part
> number, serial number, FRU number, firmware revision, ccin, and the
> input history of the power supply. The input history is 10 minutes of
> input power data in the form of twenty 30-second packets. Each packet
> contains average and maximum power for that 30 second period.
>
> Signed-off-by: Edward A. James <eajames@us.ibm.com>
> ---
> drivers/hwmon/pmbus/ibm-cffps.c | 199 +++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 198 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hwmon/pmbus/ibm-cffps.c b/drivers/hwmon/pmbus/ibm-cffps.c
> index cb56da6..6d19399 100644
> --- a/drivers/hwmon/pmbus/ibm-cffps.c
> +++ b/drivers/hwmon/pmbus/ibm-cffps.c
> @@ -8,12 +8,26 @@
> */
>
> #include <linux/bitops.h>
> +#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_FRU_CMD 0x9A
> +#define CFFPS_PN_CMD 0x9B
> +#define CFFPS_SN_CMD 0x9E
> +#define CFFPS_CCIN_CMD 0xBD
> +#define CFFPS_FW_CMD_START 0xFA
> +#define CFFPS_FW_NUM_BYTES 4
> +
> +#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 +38,144 @@
> #define CFFPS_MFR_VAUX_FAULT BIT(6)
> #define CFFPS_MFR_CURRENT_SHARE_WARNING BIT(7)
>
> +enum {
> + CFFPS_DEBUGFS_INPUT_HISTORY = 0,
> + CFFPS_DEBUGFS_FRU,
> + CFFPS_DEBUGFS_PN,
> + CFFPS_DEBUGFS_SN,
> + CFFPS_DEBUGFS_CCIN,
> + CFFPS_DEBUGFS_FW,
> + CFFPS_DEBUGFS_NUM_ENTRIES
> +};
> +
> +struct ibm_cffps_input_history {
> + struct mutex update_lock;
> + unsigned long last_update;
> +
> + u8 byte_count;
> + u8 data[CFFPS_INPUT_HISTORY_SIZE];
> +};
> +
> +struct ibm_cffps {
> + struct i2c_client *client;
> +
> + struct ibm_cffps_input_history input_history;
> +
> + int debugfs_entries[CFFPS_DEBUGFS_NUM_ENTRIES];
> +};
> +
> +#define to_psu(x, y) container_of((x), struct ibm_cffps, debugfs_entries[(y)])
> +
> +static ssize_t ibm_cffps_read_input_history(struct ibm_cffps *psu,
> + char __user *buf, size_t count,
> + loff_t *ppos)
> +{
> + int rc;
> + 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->input_history.update_lock);
> + if (time_after(jiffies, psu->input_history.last_update + 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->input_history.update_lock);
> + return rc;
> + }
> +
> + psu->input_history.byte_count = msgbuf1[0];
> + memcpy(psu->input_history.data, &msgbuf1[1],
> + CFFPS_INPUT_HISTORY_SIZE);
> + psu->input_history.last_update = jiffies;
> + }
> +
> + mutex_unlock(&psu->input_history.update_lock);
> + }
> +
> + return simple_read_from_buffer(buf, count, ppos,
> + psu->input_history.data,
> + psu->input_history.byte_count);
> +}
> +
> +static ssize_t ibm_cffps_debugfs_op(struct file *file, char __user *buf,
> + size_t count, loff_t *ppos)
> +{
> + u8 cmd;
> + int i, rc;
> + int *idxp = file->private_data;
> + int idx = *idxp;
> + struct ibm_cffps *psu = to_psu(idxp, idx);
> + char data[I2C_SMBUS_BLOCK_MAX] = { 0 };
> +
> + switch (idx) {
> + case CFFPS_DEBUGFS_INPUT_HISTORY:
> + return ibm_cffps_read_input_history(psu, buf, count, ppos);
> + case CFFPS_DEBUGFS_FRU:
> + cmd = CFFPS_FRU_CMD;
> + break;
> + case CFFPS_DEBUGFS_PN:
> + cmd = CFFPS_PN_CMD;
> + break;
> + case CFFPS_DEBUGFS_SN:
> + cmd = CFFPS_SN_CMD;
> + break;
> + case CFFPS_DEBUGFS_CCIN:
> + rc = i2c_smbus_read_word_data(psu->client, CFFPS_CCIN_CMD);
> + if (rc < 0)
> + return rc;
> +
> + rc = snprintf(data, 5, "%04X", rc);
> + goto done;
> + case CFFPS_DEBUGFS_FW:
> + for (i = 0; i < CFFPS_FW_NUM_BYTES; ++i) {
> + rc = i2c_smbus_read_byte_data(psu->client,
> + CFFPS_FW_CMD_START + i);
> + if (rc < 0)
> + return rc;
> +
> + snprintf(&data[i * 2], 3, "%02X", rc);
> + }
> +
> + rc = i * 2;
> + goto done;
> + default:
> + return -EINVAL;
> + }
> +
> + rc = i2c_smbus_read_block_data(psu->client, cmd, data);
> + if (rc < 0)
> + return rc;
> +
> +done:
> + data[rc] = '\n';
> + rc += 2;
> +
> + return simple_read_from_buffer(buf, count, ppos, data, rc);
> +}
> +
> +static const struct file_operations ibm_cffps_fops = {
> + .llseek = noop_llseek,
> + .read = ibm_cffps_debugfs_op,
> + .open = simple_open,
> +};
> +
> static int ibm_cffps_read_byte_data(struct i2c_client *client, int page,
> int reg)
> {
> @@ -119,7 +271,52 @@ 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 i, 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->input_history.update_lock);
> + if (jiffies > HZ)
> + /* time_after wouldn't succeed with last_update = 0 in test */

... but you are setting it to 'jiffies' elsewhere, so it can still end up
being 0 at some point, especially since 'jiffies' starts with a large number
and wraps a few minutes after boot. Not sure I understand the problem,
actually. Can you elaborate ?

> + psu->input_history.last_update = jiffies - HZ;
> +
> + debugfs = pmbus_get_debugfs_dir(client);
> + if (!debugfs)
> + return 0;
> +
It might be better to do that first, to avoid allocating memory unnecessarily.
That memory would only be freed when the driver is unloaded.

> + for (i = 0; i < CFFPS_DEBUGFS_NUM_ENTRIES; ++i)
> + psu->debugfs_entries[i] = i;
> +
> + debugfs_create_file("ibm_cffps_input_history", 0444, debugfs,
> + &psu->debugfs_entries[CFFPS_DEBUGFS_INPUT_HISTORY],
> + &ibm_cffps_fops);
> + debugfs_create_file("ibm_cffps_fru", 0444, debugfs,
> + &psu->debugfs_entries[CFFPS_DEBUGFS_FRU],
> + &ibm_cffps_fops);
> + debugfs_create_file("ibm_cffps_pn", 0444, debugfs,
> + &psu->debugfs_entries[CFFPS_DEBUGFS_PN],
> + &ibm_cffps_fops);
> + debugfs_create_file("ibm_cffps_sn", 0444, debugfs,
> + &psu->debugfs_entries[CFFPS_DEBUGFS_SN],
> + &ibm_cffps_fops);
> + debugfs_create_file("ibm_cffps_ccin", 0444, debugfs,
> + &psu->debugfs_entries[CFFPS_DEBUGFS_CCIN],
> + &ibm_cffps_fops);
> + debugfs_create_file("ibm_cffps_fw", 0444, debugfs,
> + &psu->debugfs_entries[CFFPS_DEBUGFS_FW],
> + &ibm_cffps_fops);

Can you put those into their own subdirectory ?

.../ibm_cffps/input_history
.../ibm_cffps/fru

and so on. Also, consider using ibm_cffps1 (or client->name) to align
with the the hwmon 'name' attribute.

Thanks,
Guenter

> +
> + return 0;
> }
>
> static const struct i2c_device_id ibm_cffps_id[] = {
> --
> 1.8.3.1
>

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