linux-kernel - Re: [PATCH v3 4/6] hwmon: pmbus: adm1266: add debugfs attr for states

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Message-ID: <877a42cb-2b22-ccb6-5c2a-15c6067401cc@roeck-us.net>
Date:   Fri, 29 May 2020 11:43:09 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     alexandru.tachici@...log.com, linux-hwmon@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Cc:     robh+dt@...nel.org
Subject: Re: [PATCH v3 4/6] hwmon: pmbus: adm1266: add debugfs attr for states

On 5/29/20 6:05 AM, alexandru.tachici@...log.com wrote:
> From: Alexandru Tachici <alexandru.tachici@...log.com>
> 
> Add debugfs files for go_command and read_state.
> 
> Signed-off-by: Alexandru Tachici <alexandru.tachici@...log.com>
> ---
>  drivers/hwmon/pmbus/adm1266.c | 47 +++++++++++++++++++++++++++++++++++
>  1 file changed, 47 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/adm1266.c b/drivers/hwmon/pmbus/adm1266.c
> index 190170300ef1..85d6795b79d3 100644
> --- a/drivers/hwmon/pmbus/adm1266.c
> +++ b/drivers/hwmon/pmbus/adm1266.c
> @@ -19,6 +19,8 @@
>  #include "pmbus.h"
>  
>  #define ADM1266_PDIO_CONFIG	0xD4
> +#define ADM1266_GO_COMMAND	0xD8
> +#define ADM1266_READ_STATE	0xD9
>  #define ADM1266_GPIO_CONFIG	0xE1
>  #define ADM1266_PDIO_STATUS	0xE9
>  #define ADM1266_GPIO_STATUS	0xEA
> @@ -41,6 +43,7 @@ struct adm1266_data {
>  	struct gpio_chip gc;
>  	const char *gpio_names[ADM1266_GPIO_NR + ADM1266_PDIO_NR];
>  	struct i2c_client *client;
> +	struct dentry *debugfs_dir;
>  };
>  
>  #if IS_ENABLED(CONFIG_GPIOLIB)
> @@ -234,6 +237,48 @@ static inline int adm1266_config_gpio(struct adm1266_data *data)
>  }
>  #endif
>  
> +static int adm1266_get_state_op(void *pdata, u64 *state)
> +{
> +	struct adm1266_data *data = pdata;
> +	int ret;
> +
> +	ret = i2c_smbus_read_word_data(data->client, ADM1266_READ_STATE);
> +	if (ret < 0)
> +		return ret;
> +
> +	*state = ret;
> +
> +	return 0;
> +}
> +
> +static int adm1266_set_go_command_op(void *pdata, u64 val)
> +{
> +	struct adm1266_data *data = pdata;
> +	u8 reg;
> +
> +	reg = FIELD_GET(GENMASK(4, 0), val);
> +
> +	return i2c_smbus_write_word_data(data->client, ADM1266_GO_COMMAND, reg);
> +}
> +
> +DEFINE_DEBUGFS_ATTRIBUTE(go_command_fops, NULL, adm1266_set_go_command_op,
> +			 "%llu\n");
> +DEFINE_DEBUGFS_ATTRIBUTE(read_state_fops, adm1266_get_state_op, NULL, "%llu\n");
> +
> +static void adm1266_debug_init(struct adm1266_data *data)
> +{
> +	struct dentry *root;
> +	char dir_name[30];
> +
> +	sprintf(dir_name, "adm1266-%x_debugfs", data->client->addr);
> +	root = debugfs_create_dir(dir_name, NULL);
> +	data->debugfs_dir = root;
> +	debugfs_create_file_unsafe("go_command", 0200, root, data,
> +				   &go_command_fops);

I am not entirely sure what this does, but from the description in the datasheet
it is way too critical to support as debugfs command. Anyone believing this
is needed should use ioctl commands instead.


> +	debugfs_create_file_unsafe("read_state", 0400, root, data,
> +				   &read_state_fops);
> +}
> +

We have standard pmbus debug functions. Please use it.

>  static int adm1266_probe(struct i2c_client *client,
>  			 const struct i2c_device_id *id)
>  {
> @@ -254,6 +299,8 @@ static int adm1266_probe(struct i2c_client *client,
>  	if (ret < 0)
>  		return ret;
>  
> +	adm1266_debug_init(data);
> +
>  	info = &data->info;
>  	info->pages = 17;
>  	info->format[PSC_VOLTAGE_OUT] = linear;
>