[PATCH 0/2] hwmon: (ucd9000) Add gpio and debugfs interfaces

[PATCH 0/2] hwmon: (ucd9000) Add gpio and debugfs interfaces

[Eddie James]

The ucd9000 series chips have gpio pins. Add a gpio chip interface to the ucd
device so that users can query and set the state of the gpio pins.

Add a debugfs interface using the existing pmbus debugfs directory to provide
MFR_STATUS and the status of the gpi faults to users.

Christopher Bostic (2):
  hwmon: (ucd9000) Add gpio chip interface
  hwmon: (ucd9000) Add debugfs attributes to provide mfr_status

 drivers/hwmon/pmbus/ucd9000.c | 392 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 391 insertions(+), 1 deletion(-)

-- 
1.8.3.1

[PATCH 1/2] hwmon: (ucd9000) Add gpio chip interface

[Eddie James]

From: Christopher Bostic <cbostic@linux.vnet.ibm.com>

Add a struct gpio_chip and define some methods so that this device's
I/O can be accessed via /sys/class/gpio.

Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Eddie James <eajames@linux.vnet.ibm.com>
---
 drivers/hwmon/pmbus/ucd9000.c | 220 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 220 insertions(+)

diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
index b74dbec..e3a507f 100644
--- a/drivers/hwmon/pmbus/ucd9000.c
+++ b/drivers/hwmon/pmbus/ucd9000.c
@@ -27,6 +27,7 @@
 #include <linux/slab.h>
 #include <linux/i2c.h>
 #include <linux/pmbus.h>
+#include <linux/gpio.h>
 #include "pmbus.h"
 
 enum chips { ucd9000, ucd90120, ucd90124, ucd90160, ucd9090, ucd90910 };
@@ -35,8 +36,18 @@
 #define UCD9000_NUM_PAGES		0xd6
 #define UCD9000_FAN_CONFIG_INDEX	0xe7
 #define UCD9000_FAN_CONFIG		0xe8
+#define UCD9000_GPIO_SELECT		0xfa
+#define UCD9000_GPIO_CONFIG		0xfb
 #define UCD9000_DEVICE_ID		0xfd
 
+/* GPIO CONFIG bits */
+#define UCD9000_GPIO_CONFIG_ENABLE	BIT(0)
+#define UCD9000_GPIO_CONFIG_OUT_ENABLE	BIT(1)
+#define UCD9000_GPIO_CONFIG_OUT_VALUE	BIT(2)
+#define UCD9000_GPIO_CONFIG_STATUS	BIT(3)
+#define UCD9000_GPIO_INPUT		0
+#define UCD9000_GPIO_OUTPUT		1
+
 #define UCD9000_MON_TYPE(x)	(((x) >> 5) & 0x07)
 #define UCD9000_MON_PAGE(x)	((x) & 0x0f)
 
@@ -47,9 +58,15 @@
 
 #define UCD9000_NUM_FAN		4
 
+#define UCD9000_GPIO_NAME_LEN	16
+#define UCD9090_NUM_GPIOS	23
+#define UCD901XX_NUM_GPIOS	26
+#define UCD90910_NUM_GPIOS	26
+
 struct ucd9000_data {
 	u8 fan_data[UCD9000_NUM_FAN][I2C_SMBUS_BLOCK_MAX];
 	struct pmbus_driver_info info;
+	struct gpio_chip gpio;
 };
 #define to_ucd9000_data(_info) container_of(_info, struct ucd9000_data, info)
 
@@ -149,6 +166,168 @@ static int ucd9000_read_byte_data(struct i2c_client *client, int page, int reg)
 };
 MODULE_DEVICE_TABLE(of, ucd9000_of_match);
 
+static int ucd9000_gpio_read_config(struct i2c_client *client,
+				    unsigned int offset)
+{
+	int ret;
+
+	/* No page set required */
+	ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_SELECT, offset);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to select GPIO %d: %d\n", offset,
+			ret);
+
+		return ret;
+	}
+
+	return i2c_smbus_read_byte_data(client, UCD9000_GPIO_CONFIG);
+}
+
+static int ucd9000_gpio_get(struct gpio_chip *gc, unsigned int offset)
+{
+	struct i2c_client *client  = gpiochip_get_data(gc);
+	int ret;
+
+	ret = ucd9000_gpio_read_config(client, offset);
+	if (ret < 0) {
+		dev_err(&client->dev, "failed to read GPIO %d config: %d\n",
+			offset, ret);
+
+		return ret;
+	}
+
+	return !!(ret & UCD9000_GPIO_CONFIG_STATUS);
+}
+
+static void ucd9000_gpio_set(struct gpio_chip *gc, unsigned int offset,
+			     int value)
+{
+	struct i2c_client *client = gpiochip_get_data(gc);
+	int ret;
+
+	ret = ucd9000_gpio_read_config(client, offset);
+	if (ret < 0) {
+		dev_err(&client->dev, "failed to read GPIO %d config: %d\n",
+			offset, ret);
+
+		return;
+	}
+
+	if (value) {
+		if (ret & UCD9000_GPIO_CONFIG_STATUS)
+			return;
+
+		ret |= UCD9000_GPIO_CONFIG_STATUS;
+	} else {
+		if (!(ret & UCD9000_GPIO_CONFIG_STATUS))
+			return;
+
+		ret &= ~UCD9000_GPIO_CONFIG_STATUS;
+	}
+
+	ret |= UCD9000_GPIO_CONFIG_ENABLE;
+
+	/* Page set not required */
+	ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, ret);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to write GPIO %d config: %d\n",
+			offset, ret);
+
+		return;
+	}
+
+	ret &= ~UCD9000_GPIO_CONFIG_ENABLE;
+
+	ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, ret);
+	if (ret < 0)
+		dev_err(&client->dev, "Failed to write GPIO %d config: %d\n",
+			offset, ret);
+}
+
+static int ucd9000_gpio_get_direction(struct gpio_chip *gc,
+				      unsigned int offset)
+{
+	struct i2c_client *client = gpiochip_get_data(gc);
+	int ret;
+
+	ret = ucd9000_gpio_read_config(client, offset);
+	if (ret < 0) {
+		dev_err(&client->dev, "failed to read GPIO %d config: %d\n",
+			offset, ret);
+
+		return ret;
+	}
+
+	return !(ret & UCD9000_GPIO_CONFIG_OUT_ENABLE);
+}
+
+static int ucd9000_gpio_set_direction(struct gpio_chip *gc,
+				      unsigned int offset, bool direction_out,
+				      int requested_out)
+{
+	struct i2c_client *client = gpiochip_get_data(gc);
+	int ret, config, out_val;
+
+	ret = ucd9000_gpio_read_config(client, offset);
+	if (ret < 0) {
+		dev_err(&client->dev, "failed to read GPIO %d config: %d\n",
+			offset, ret);
+
+		return ret;
+	}
+
+	if (direction_out) {
+		out_val = requested_out ? UCD9000_GPIO_CONFIG_OUT_VALUE : 0;
+
+		if (ret & UCD9000_GPIO_CONFIG_OUT_ENABLE) {
+			if ((ret & UCD9000_GPIO_CONFIG_OUT_VALUE) == out_val)
+				return 0;
+		} else {
+			ret |= UCD9000_GPIO_CONFIG_OUT_ENABLE;
+		}
+
+		if (out_val)
+			ret |= UCD9000_GPIO_CONFIG_OUT_VALUE;
+		else
+			ret &= ~UCD9000_GPIO_CONFIG_OUT_VALUE;
+
+	} else {
+		if (!(ret & UCD9000_GPIO_CONFIG_OUT_ENABLE))
+			return 0;
+
+		ret &= ~UCD9000_GPIO_CONFIG_OUT_ENABLE;
+	}
+
+	ret |= UCD9000_GPIO_CONFIG_ENABLE;
+	config = ret;
+
+	/* Page set not required */
+	ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, config);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to write GPIO %d config: %d\n",
+			offset, ret);
+
+		return ret;
+	}
+
+	config &= ~UCD9000_GPIO_CONFIG_ENABLE;
+
+	return i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, config);
+}
+
+static int ucd9000_gpio_direction_input(struct gpio_chip *gc,
+					unsigned int offset)
+{
+	return ucd9000_gpio_set_direction(gc, offset, UCD9000_GPIO_INPUT, 0);
+}
+
+static int ucd9000_gpio_direction_output(struct gpio_chip *gc,
+					 unsigned int offset, int val)
+{
+	return ucd9000_gpio_set_direction(gc, offset, UCD9000_GPIO_OUTPUT,
+					  val);
+}
+
 static int ucd9000_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
@@ -263,6 +442,47 @@ static int ucd9000_probe(struct i2c_client *client,
 		  | PMBUS_HAVE_FAN34 | PMBUS_HAVE_STATUS_FAN34;
 	}
 
+	/*
+	 * Note:
+	 *
+	 * Pinmux support has not been added to the new gpio_chip.
+	 * This support should be added when possible given the mux
+	 * behavior of these IO devices.
+	 */
+	data->gpio.label = (const char *)&client->name;
+	data->gpio.get_direction = ucd9000_gpio_get_direction;
+	data->gpio.direction_input = ucd9000_gpio_direction_input;
+	data->gpio.direction_output = ucd9000_gpio_direction_output;
+	data->gpio.get = ucd9000_gpio_get;
+	data->gpio.set = ucd9000_gpio_set;
+	data->gpio.can_sleep = 1;
+	data->gpio.base = -1;
+
+	/* No default case. No data available for ucd9000. */
+	switch (mid->driver_data) {
+	case ucd9090:
+		data->gpio.ngpio = UCD9090_NUM_GPIOS;
+		break;
+	case ucd90120:
+	case ucd90124:
+	case ucd90160:
+		data->gpio.ngpio = UCD901XX_NUM_GPIOS;
+		break;
+	case ucd90910:
+		data->gpio.ngpio = UCD90910_NUM_GPIOS;
+		break;
+	}
+
+	data->gpio.parent = &client->dev;
+	data->gpio.owner = THIS_MODULE;
+
+	ret = devm_gpiochip_add_data(&client->dev, &data->gpio, client);
+	if (ret) {
+		data->gpio.parent = NULL;
+		dev_warn(&client->dev, "Could not add gpiochip: %d\n", ret);
+		return ret;
+	}
+
 	return pmbus_do_probe(client, mid, info);
 }
 
-- 
1.8.3.1

[PATCH 2/2] hwmon: (ucd9000) Add debugfs attributes to provide mfr_status

[Eddie James]

From: Christopher Bostic <cbostic@linux.vnet.ibm.com>

Expose the gpiN_fault fields of mfr_status as individual debugfs
attributes. This provides a way for users to be easily notified of gpi
faults. Also provide the whole mfr_status register in debugfs.

Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Eddie James <eajames@linux.vnet.ibm.com>
---
 drivers/hwmon/pmbus/ucd9000.c | 172 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 171 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
index e3a507f..297da0e 100644
--- a/drivers/hwmon/pmbus/ucd9000.c
+++ b/drivers/hwmon/pmbus/ucd9000.c
@@ -19,6 +19,7 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+#include <linux/debugfs.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
@@ -36,6 +37,7 @@
 #define UCD9000_NUM_PAGES		0xd6
 #define UCD9000_FAN_CONFIG_INDEX	0xe7
 #define UCD9000_FAN_CONFIG		0xe8
+#define UCD9000_MFR_STATUS		0xf3
 #define UCD9000_GPIO_SELECT		0xfa
 #define UCD9000_GPIO_CONFIG		0xfb
 #define UCD9000_DEVICE_ID		0xfd
@@ -63,13 +65,22 @@
 #define UCD901XX_NUM_GPIOS	26
 #define UCD90910_NUM_GPIOS	26
 
+#define UCD9000_DEBUGFS_NAME_LEN	24
+#define UCD9000_GPI_COUNT		8
+
 struct ucd9000_data {
 	u8 fan_data[UCD9000_NUM_FAN][I2C_SMBUS_BLOCK_MAX];
 	struct pmbus_driver_info info;
 	struct gpio_chip gpio;
+	struct dentry *debugfs;
 };
 #define to_ucd9000_data(_info) container_of(_info, struct ucd9000_data, info)
 
+struct ucd9000_debugfs_entry {
+	struct i2c_client *client;
+	u8 index;
+};
+
 static int ucd9000_get_fan_config(struct i2c_client *client, int fan)
 {
 	int fan_config = 0;
@@ -328,6 +339,156 @@ static int ucd9000_gpio_direction_output(struct gpio_chip *gc,
 					  val);
 }
 
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+static int ucd9000_get_mfr_status(struct i2c_client *client, u8 *buffer)
+{
+	int ret = pmbus_set_page(client, 0);
+
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * With the ucd90120 and ucd90124 devices, this command [MFR_STATUS]
+	 * is 2 bytes long (bits 0-15).  With the ucd90240 this command is 5
+	 * bytes long.  With all other devices, it is 4 bytes long.
+	 */
+	return i2c_smbus_read_block_data(client, UCD9000_MFR_STATUS, buffer);
+}
+
+static int ucd9000_debugfs_show_mfr_status_bit(void *data, u64 *val)
+{
+	struct ucd9000_debugfs_entry *entry = data;
+	struct i2c_client *client = entry->client;
+	u8 buffer[4];
+	int ret;
+
+	/*
+	 * This attribute is only created for devices that return 4 bytes for
+	 * status_mfr, so it's safe to call with 4-byte buffer.
+	 */
+	ret = ucd9000_get_mfr_status(client, buffer);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
+			ret);
+
+		return ret;
+	}
+
+	/*
+	 * Attribute only created for devices with gpi fault bits at bits
+	 * 16-23, which is the second byte of the response.
+	 */
+	*val = !!(buffer[1] & BIT(entry->index));
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_bit,
+			 ucd9000_debugfs_show_mfr_status_bit, NULL, "%1lld\n");
+
+static int ucd9000_debugfs_show_mfr_status_word2(void *data, u64 *val)
+{
+	struct i2c_client *client = data;
+	__be16 buffer;
+	int ret;
+
+	ret = ucd9000_get_mfr_status(client, (u8 *)&buffer);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
+			ret);
+
+		return ret;
+	}
+
+	*val = be16_to_cpu(buffer);
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_word2,
+			 ucd9000_debugfs_show_mfr_status_word2, NULL,
+			 "%04llx\n");
+
+static int ucd9000_debugfs_show_mfr_status_word4(void *data, u64 *val)
+{
+	struct i2c_client *client = data;
+	__be32 buffer;
+	int ret;
+
+	ret = ucd9000_get_mfr_status(client, (u8 *)&buffer);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
+			ret);
+
+		return ret;
+	}
+
+	*val = be32_to_cpu(buffer);
+
+	return 0;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_word4,
+			 ucd9000_debugfs_show_mfr_status_word4, NULL,
+			 "%08llx\n");
+
+static int ucd9000_init_debugfs(struct i2c_client *client,
+				const struct i2c_device_id *mid,
+				struct ucd9000_data *data)
+{
+	struct dentry *debugfs;
+	struct ucd9000_debugfs_entry *entries;
+	int i;
+	char name[UCD9000_DEBUGFS_NAME_LEN];
+
+	debugfs = pmbus_get_debugfs_dir(client);
+	if (!debugfs)
+		return -ENOENT;
+
+	data->debugfs = debugfs_create_dir(client->name, debugfs);
+	if (!data->debugfs)
+		return -ENOENT;
+
+	/*
+	 * Of the chips this driver supports, only the UCD9090, UCD90160,
+	 * and UCD90910 report GPI faults in their MFR_STATUS register, so only
+	 * create the GPI fault debugfs attributes for those chips.
+	 */
+	if (mid->driver_data == ucd9090 || mid->driver_data == ucd90160 ||
+	    mid->driver_data == ucd90910) {
+		entries = devm_kzalloc(&client->dev,
+				       sizeof(*entries) * UCD9000_GPI_COUNT,
+				       GFP_KERNEL);
+		if (!entries)
+			return -ENOMEM;
+
+		for (i = 0; i < UCD9000_GPI_COUNT; i++) {
+			entries[i].client = client;
+			entries[i].index = i;
+			scnprintf(name, UCD9000_DEBUGFS_NAME_LEN,
+				  "gpi%d_alarm", i + 1);
+			debugfs_create_file(name, 0444, data->debugfs,
+					    &entries[i],
+					    &ucd9000_debugfs_mfr_status_bit);
+		}
+
+		scnprintf(name, UCD9000_DEBUGFS_NAME_LEN, "mfr_status");
+		debugfs_create_file(name, 0444, data->debugfs, client,
+				    &ucd9000_debugfs_mfr_status_word4);
+	} else if (mid->driver_data == ucd90120 ||
+		   mid->driver_data == ucd90124) {
+		scnprintf(name, UCD9000_DEBUGFS_NAME_LEN, "mfr_status");
+		debugfs_create_file(name, 0444, data->debugfs, client,
+				    &ucd9000_debugfs_mfr_status_word2);
+	}
+
+	return 0;
+}
+#else
+static int ucd9000_init_debugfs(struct i2c_client *client,
+				struct ucd9000_data *data)
+{
+	return 0;
+}
+#endif /* IS_ENABLED(CONFIG_DEBUG_FS) */
+
 static int ucd9000_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
@@ -483,7 +644,16 @@ static int ucd9000_probe(struct i2c_client *client,
 		return ret;
 	}
 
-	return pmbus_do_probe(client, mid, info);
+	ret = pmbus_do_probe(client, mid, info);
+	if (ret)
+		return ret;
+
+	ret = ucd9000_init_debugfs(client, mid, data);
+	if (ret)
+		dev_warn(&client->dev, "Failed to register debugfs: %d\n",
+			 ret);
+
+	return 0;
 }
 
 /* This is the driver that will be inserted */
-- 
1.8.3.1

Re: [PATCH 1/2] hwmon: (ucd9000) Add gpio chip interface

[Guenter Roeck]

On 03/09/2018 11:19 AM, Eddie James wrote:
> From: Christopher Bostic <cbostic@linux.vnet.ibm.com>
> 
> Add a struct gpio_chip and define some methods so that this device's
> I/O can be accessed via /sys/class/gpio.
> 
> Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> Signed-off-by: Eddie James <eajames@linux.vnet.ibm.com>
> ---
>   drivers/hwmon/pmbus/ucd9000.c | 220 ++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 220 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
> index b74dbec..e3a507f 100644
> --- a/drivers/hwmon/pmbus/ucd9000.c
> +++ b/drivers/hwmon/pmbus/ucd9000.c
> @@ -27,6 +27,7 @@
>   #include <linux/slab.h>
>   #include <linux/i2c.h>
>   #include <linux/pmbus.h>
> +#include <linux/gpio.h>
>   #include "pmbus.h"
>   
>   enum chips { ucd9000, ucd90120, ucd90124, ucd90160, ucd9090, ucd90910 };
> @@ -35,8 +36,18 @@
>   #define UCD9000_NUM_PAGES		0xd6
>   #define UCD9000_FAN_CONFIG_INDEX	0xe7
>   #define UCD9000_FAN_CONFIG		0xe8
> +#define UCD9000_GPIO_SELECT		0xfa
> +#define UCD9000_GPIO_CONFIG		0xfb
>   #define UCD9000_DEVICE_ID		0xfd
>   
> +/* GPIO CONFIG bits */
> +#define UCD9000_GPIO_CONFIG_ENABLE	BIT(0)
> +#define UCD9000_GPIO_CONFIG_OUT_ENABLE	BIT(1)
> +#define UCD9000_GPIO_CONFIG_OUT_VALUE	BIT(2)
> +#define UCD9000_GPIO_CONFIG_STATUS	BIT(3)
> +#define UCD9000_GPIO_INPUT		0
> +#define UCD9000_GPIO_OUTPUT		1
> +
>   #define UCD9000_MON_TYPE(x)	(((x) >> 5) & 0x07)
>   #define UCD9000_MON_PAGE(x)	((x) & 0x0f)
>   
> @@ -47,9 +58,15 @@
>   
>   #define UCD9000_NUM_FAN		4
>   
> +#define UCD9000_GPIO_NAME_LEN	16
> +#define UCD9090_NUM_GPIOS	23
> +#define UCD901XX_NUM_GPIOS	26
> +#define UCD90910_NUM_GPIOS	26
> +
>   struct ucd9000_data {
>   	u8 fan_data[UCD9000_NUM_FAN][I2C_SMBUS_BLOCK_MAX];
>   	struct pmbus_driver_info info;
> +	struct gpio_chip gpio;
>   };
>   #define to_ucd9000_data(_info) container_of(_info, struct ucd9000_data, info)
>   
> @@ -149,6 +166,168 @@ static int ucd9000_read_byte_data(struct i2c_client *client, int page, int reg)
>   };
>   MODULE_DEVICE_TABLE(of, ucd9000_of_match);
>   
> +static int ucd9000_gpio_read_config(struct i2c_client *client,
> +				    unsigned int offset)
> +{
> +	int ret;
> +
> +	/* No page set required */
> +	ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_SELECT, offset);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Failed to select GPIO %d: %d\n", offset,
> +			ret);
> +

I am not a fan of kernel log error messages outside the probe function.
Please consider dropping those or making it dev_dbg.

Would it make sense to cache those values ?

> +		return ret;
> +	}
> +
> +	return i2c_smbus_read_byte_data(client, UCD9000_GPIO_CONFIG);
> +}
> +
> +static int ucd9000_gpio_get(struct gpio_chip *gc, unsigned int offset)
> +{
> +	struct i2c_client *client  = gpiochip_get_data(gc);
> +	int ret;
> +
> +	ret = ucd9000_gpio_read_config(client, offset);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "failed to read GPIO %d config: %d\n",
> +			offset, ret);
> +
... even more so if a single error can result in multiple error messages.

> +		return ret;
> +	}
> +
> +	return !!(ret & UCD9000_GPIO_CONFIG_STATUS);
> +}
> +
> +static void ucd9000_gpio_set(struct gpio_chip *gc, unsigned int offset,
> +			     int value)
> +{
> +	struct i2c_client *client = gpiochip_get_data(gc);
> +	int ret;
> +
> +	ret = ucd9000_gpio_read_config(client, offset);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "failed to read GPIO %d config: %d\n",
> +			offset, ret);
> +
> +		return;
> +	}
> +
> +	if (value) {
> +		if (ret & UCD9000_GPIO_CONFIG_STATUS)
> +			return;
> +
> +		ret |= UCD9000_GPIO_CONFIG_STATUS;
> +	} else {
> +		if (!(ret & UCD9000_GPIO_CONFIG_STATUS))
> +			return;
> +
> +		ret &= ~UCD9000_GPIO_CONFIG_STATUS;
> +	}
> +
> +	ret |= UCD9000_GPIO_CONFIG_ENABLE;
> +
> +	/* Page set not required */
> +	ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, ret);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Failed to write GPIO %d config: %d\n",
> +			offset, ret);
> +
> +		return;
> +	}
> +
> +	ret &= ~UCD9000_GPIO_CONFIG_ENABLE;
> +
> +	ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, ret);
> +	if (ret < 0)
> +		dev_err(&client->dev, "Failed to write GPIO %d config: %d\n",
> +			offset, ret);
> +}
> +
> +static int ucd9000_gpio_get_direction(struct gpio_chip *gc,
> +				      unsigned int offset)
> +{
> +	struct i2c_client *client = gpiochip_get_data(gc);
> +	int ret;
> +
> +	ret = ucd9000_gpio_read_config(client, offset);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "failed to read GPIO %d config: %d\n",
> +			offset, ret);
> +
> +		return ret;
> +	}
> +
> +	return !(ret & UCD9000_GPIO_CONFIG_OUT_ENABLE);
> +}
> +
> +static int ucd9000_gpio_set_direction(struct gpio_chip *gc,
> +				      unsigned int offset, bool direction_out,
> +				      int requested_out)
> +{
> +	struct i2c_client *client = gpiochip_get_data(gc);
> +	int ret, config, out_val;
> +
> +	ret = ucd9000_gpio_read_config(client, offset);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "failed to read GPIO %d config: %d\n",
> +			offset, ret);
> +
> +		return ret;
> +	}
> +
> +	if (direction_out) {
> +		out_val = requested_out ? UCD9000_GPIO_CONFIG_OUT_VALUE : 0;
> +
> +		if (ret & UCD9000_GPIO_CONFIG_OUT_ENABLE) {
> +			if ((ret & UCD9000_GPIO_CONFIG_OUT_VALUE) == out_val)
> +				return 0;
> +		} else {
> +			ret |= UCD9000_GPIO_CONFIG_OUT_ENABLE;
> +		}
> +
> +		if (out_val)
> +			ret |= UCD9000_GPIO_CONFIG_OUT_VALUE;
> +		else
> +			ret &= ~UCD9000_GPIO_CONFIG_OUT_VALUE;
> +
> +	} else {
> +		if (!(ret & UCD9000_GPIO_CONFIG_OUT_ENABLE))
> +			return 0;
> +
> +		ret &= ~UCD9000_GPIO_CONFIG_OUT_ENABLE;
> +	}
> +
> +	ret |= UCD9000_GPIO_CONFIG_ENABLE;
> +	config = ret;
> +
> +	/* Page set not required */
> +	ret = i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, config);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Failed to write GPIO %d config: %d\n",
> +			offset, ret);
> +
> +		return ret;
> +	}
> +
> +	config &= ~UCD9000_GPIO_CONFIG_ENABLE;
> +
> +	return i2c_smbus_write_byte_data(client, UCD9000_GPIO_CONFIG, config);
> +}
> +
> +static int ucd9000_gpio_direction_input(struct gpio_chip *gc,
> +					unsigned int offset)
> +{
> +	return ucd9000_gpio_set_direction(gc, offset, UCD9000_GPIO_INPUT, 0);
> +}
> +
> +static int ucd9000_gpio_direction_output(struct gpio_chip *gc,
> +					 unsigned int offset, int val)
> +{
> +	return ucd9000_gpio_set_direction(gc, offset, UCD9000_GPIO_OUTPUT,
> +					  val);
> +}
> +
>   static int ucd9000_probe(struct i2c_client *client,
>   			 const struct i2c_device_id *id)
>   {
> @@ -263,6 +442,47 @@ static int ucd9000_probe(struct i2c_client *client,
>   		  | PMBUS_HAVE_FAN34 | PMBUS_HAVE_STATUS_FAN34;
>   	}
>   
> +	/*
> +	 * Note:
> +	 *
> +	 * Pinmux support has not been added to the new gpio_chip.
> +	 * This support should be added when possible given the mux
> +	 * behavior of these IO devices.
> +	 */
> +	data->gpio.label = (const char *)&client->name;
> +	data->gpio.get_direction = ucd9000_gpio_get_direction;
> +	data->gpio.direction_input = ucd9000_gpio_direction_input;
> +	data->gpio.direction_output = ucd9000_gpio_direction_output;
> +	data->gpio.get = ucd9000_gpio_get;
> +	data->gpio.set = ucd9000_gpio_set;
> +	data->gpio.can_sleep = 1;
> +	data->gpio.base = -1;
> +

Also set of_node ?

> +	/* No default case. No data available for ucd9000. */
> +	switch (mid->driver_data) {
> +	case ucd9090:
> +		data->gpio.ngpio = UCD9090_NUM_GPIOS;
> +		break;
> +	case ucd90120:
> +	case ucd90124:
> +	case ucd90160:
> +		data->gpio.ngpio = UCD901XX_NUM_GPIOS;
> +		break;
> +	case ucd90910:
> +		data->gpio.ngpio = UCD90910_NUM_GPIOS;
> +		break;

Why not:

	default:
		break;

instead of the comment above ?

> +	}
> +
> +	data->gpio.parent = &client->dev;
> +	data->gpio.owner = THIS_MODULE;
> +

Since there are chips with no gpio support (ngpio=0), it would be better
to make the gpio registration conditional.

> +	ret = devm_gpiochip_add_data(&client->dev, &data->gpio, client);
> +	if (ret) {
> +		data->gpio.parent = NULL;
> +		dev_warn(&client->dev, "Could not add gpiochip: %d\n", ret);

Either dev_warn and ignore the error, or dev_err. Either case setting data->gpio.parent
to NULL should be unnecessary.

> +		return ret;
> +	}
> +
>   	return pmbus_do_probe(client, mid, info);
>   }
>   
> 

Re: [PATCH 2/2] hwmon: (ucd9000) Add debugfs attributes to provide mfr_status

[Guenter Roeck]

On 03/09/2018 11:19 AM, Eddie James wrote:
> From: Christopher Bostic <cbostic@linux.vnet.ibm.com>
> 
> Expose the gpiN_fault fields of mfr_status as individual debugfs
> attributes. This provides a way for users to be easily notified of gpi
> faults. Also provide the whole mfr_status register in debugfs.
> 
> Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> Signed-off-by: Eddie James <eajames@linux.vnet.ibm.com>
> ---
>   drivers/hwmon/pmbus/ucd9000.c | 172 +++++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 171 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
> index e3a507f..297da0e 100644
> --- a/drivers/hwmon/pmbus/ucd9000.c
> +++ b/drivers/hwmon/pmbus/ucd9000.c
> @@ -19,6 +19,7 @@
>    * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
>    */
>   
> +#include <linux/debugfs.h>
>   #include <linux/kernel.h>
>   #include <linux/module.h>
>   #include <linux/of_device.h>
> @@ -36,6 +37,7 @@
>   #define UCD9000_NUM_PAGES		0xd6
>   #define UCD9000_FAN_CONFIG_INDEX	0xe7
>   #define UCD9000_FAN_CONFIG		0xe8
> +#define UCD9000_MFR_STATUS		0xf3
>   #define UCD9000_GPIO_SELECT		0xfa
>   #define UCD9000_GPIO_CONFIG		0xfb
>   #define UCD9000_DEVICE_ID		0xfd
> @@ -63,13 +65,22 @@
>   #define UCD901XX_NUM_GPIOS	26
>   #define UCD90910_NUM_GPIOS	26
>   
> +#define UCD9000_DEBUGFS_NAME_LEN	24
> +#define UCD9000_GPI_COUNT		8
> +
>   struct ucd9000_data {
>   	u8 fan_data[UCD9000_NUM_FAN][I2C_SMBUS_BLOCK_MAX];
>   	struct pmbus_driver_info info;
>   	struct gpio_chip gpio;
> +	struct dentry *debugfs;
>   };
>   #define to_ucd9000_data(_info) container_of(_info, struct ucd9000_data, info)
>   
> +struct ucd9000_debugfs_entry {
> +	struct i2c_client *client;
> +	u8 index;
> +};
> +
>   static int ucd9000_get_fan_config(struct i2c_client *client, int fan)
>   {
>   	int fan_config = 0;
> @@ -328,6 +339,156 @@ static int ucd9000_gpio_direction_output(struct gpio_chip *gc,
>   					  val);
>   }
>   
> +#if IS_ENABLED(CONFIG_DEBUG_FS)
> +static int ucd9000_get_mfr_status(struct i2c_client *client, u8 *buffer)
> +{
> +	int ret = pmbus_set_page(client, 0);
> +
> +	if (ret < 0)
> +		return ret;
> +
> +	/*
> +	 * With the ucd90120 and ucd90124 devices, this command [MFR_STATUS]
> +	 * is 2 bytes long (bits 0-15).  With the ucd90240 this command is 5
> +	 * bytes long.  With all other devices, it is 4 bytes long.
> +	 */
> +	return i2c_smbus_read_block_data(client, UCD9000_MFR_STATUS, buffer);
> +}
> +
> +static int ucd9000_debugfs_show_mfr_status_bit(void *data, u64 *val)
> +{
> +	struct ucd9000_debugfs_entry *entry = data;
> +	struct i2c_client *client = entry->client;
> +	u8 buffer[4];
> +	int ret;
> +
> +	/*
> +	 * This attribute is only created for devices that return 4 bytes for
> +	 * status_mfr, so it's safe to call with 4-byte buffer.
> +	 */
> +	ret = ucd9000_get_mfr_status(client, buffer);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
> +			ret);
> +
> +		return ret;
> +	}
> +
> +	/*
> +	 * Attribute only created for devices with gpi fault bits at bits
> +	 * 16-23, which is the second byte of the response.
> +	 */
> +	*val = !!(buffer[1] & BIT(entry->index));
> +
> +	return 0;
> +}
> +DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_bit,
> +			 ucd9000_debugfs_show_mfr_status_bit, NULL, "%1lld\n");
> +
> +static int ucd9000_debugfs_show_mfr_status_word2(void *data, u64 *val)
> +{
> +	struct i2c_client *client = data;
> +	__be16 buffer;
> +	int ret;
> +
> +	ret = ucd9000_get_mfr_status(client, (u8 *)&buffer);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
> +			ret);
> +
> +		return ret;
> +	}
> +
> +	*val = be16_to_cpu(buffer);
> +
> +	return 0;
> +}
> +DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_word2,
> +			 ucd9000_debugfs_show_mfr_status_word2, NULL,
> +			 "%04llx\n");
> +
> +static int ucd9000_debugfs_show_mfr_status_word4(void *data, u64 *val)
> +{
> +	struct i2c_client *client = data;
> +	__be32 buffer;
> +	int ret;
> +
> +	ret = ucd9000_get_mfr_status(client, (u8 *)&buffer);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
> +			ret);
> +
> +		return ret;
> +	}
> +
> +	*val = be32_to_cpu(buffer);
> +
> +	return 0;
> +}
> +DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_word4,
> +			 ucd9000_debugfs_show_mfr_status_word4, NULL,
> +			 "%08llx\n");
> +
> +static int ucd9000_init_debugfs(struct i2c_client *client,
> +				const struct i2c_device_id *mid,
> +				struct ucd9000_data *data)
> +{
> +	struct dentry *debugfs;
> +	struct ucd9000_debugfs_entry *entries;
> +	int i;
> +	char name[UCD9000_DEBUGFS_NAME_LEN];
> +
> +	debugfs = pmbus_get_debugfs_dir(client);
> +	if (!debugfs)
> +		return -ENOENT;
> +
> +	data->debugfs = debugfs_create_dir(client->name, debugfs);
> +	if (!data->debugfs)
> +		return -ENOENT;
> +
> +	/*
> +	 * Of the chips this driver supports, only the UCD9090, UCD90160,
> +	 * and UCD90910 report GPI faults in their MFR_STATUS register, so only
> +	 * create the GPI fault debugfs attributes for those chips.
> +	 */
> +	if (mid->driver_data == ucd9090 || mid->driver_data == ucd90160 ||
> +	    mid->driver_data == ucd90910) {
> +		entries = devm_kzalloc(&client->dev,
> +				       sizeof(*entries) * UCD9000_GPI_COUNT,
> +				       GFP_KERNEL);
> +		if (!entries)
> +			return -ENOMEM;
> +
> +		for (i = 0; i < UCD9000_GPI_COUNT; i++) {
> +			entries[i].client = client;
> +			entries[i].index = i;
> +			scnprintf(name, UCD9000_DEBUGFS_NAME_LEN,
> +				  "gpi%d_alarm", i + 1);
> +			debugfs_create_file(name, 0444, data->debugfs,
> +					    &entries[i],
> +					    &ucd9000_debugfs_mfr_status_bit);
> +		}
> +
> +		scnprintf(name, UCD9000_DEBUGFS_NAME_LEN, "mfr_status");
> +		debugfs_create_file(name, 0444, data->debugfs, client,
> +				    &ucd9000_debugfs_mfr_status_word4);
> +	} else if (mid->driver_data == ucd90120 ||
> +		   mid->driver_data == ucd90124) {
> +		scnprintf(name, UCD9000_DEBUGFS_NAME_LEN, "mfr_status");
> +		debugfs_create_file(name, 0444, data->debugfs, client,
> +				    &ucd9000_debugfs_mfr_status_word2);
> +	}
> +
> +	return 0;
> +}

Is all that complexity really worth it ? Why not just read the manufacturing
status as byte string into a buffer and use hexdump to pront it, no matter how
many bytes are actually returned ? This would also be less error prone, and
automatically support future chips.

Thanks,
Guenter

> +#else
> +static int ucd9000_init_debugfs(struct i2c_client *client,
> +				struct ucd9000_data *data)
> +{
> +	return 0;
> +}
> +#endif /* IS_ENABLED(CONFIG_DEBUG_FS) */
> +
>   static int ucd9000_probe(struct i2c_client *client,
>   			 const struct i2c_device_id *id)
>   {
> @@ -483,7 +644,16 @@ static int ucd9000_probe(struct i2c_client *client,
>   		return ret;
>   	}
>   
> -	return pmbus_do_probe(client, mid, info);
> +	ret = pmbus_do_probe(client, mid, info);
> +	if (ret)
> +		return ret;
> +
> +	ret = ucd9000_init_debugfs(client, mid, data);
> +	if (ret)
> +		dev_warn(&client->dev, "Failed to register debugfs: %d\n",
> +			 ret);
> +
> +	return 0;
>   }
>   
>   /* This is the driver that will be inserted */
> 

Re: [PATCH 2/2] hwmon: (ucd9000) Add debugfs attributes to provide mfr_status

[Eddie James]

On 03/10/2018 10:50 AM, Guenter Roeck wrote:
> On 03/09/2018 11:19 AM, Eddie James wrote:
>> From: Christopher Bostic <cbostic@linux.vnet.ibm.com>
>>
>> Expose the gpiN_fault fields of mfr_status as individual debugfs
>> attributes. This provides a way for users to be easily notified of gpi
>> faults. Also provide the whole mfr_status register in debugfs.
>>
>> Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
>> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
>> Signed-off-by: Eddie James <eajames@linux.vnet.ibm.com>
>> ---
>>   drivers/hwmon/pmbus/ucd9000.c | 172 
>> +++++++++++++++++++++++++++++++++++++++++-
>>   1 file changed, 171 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/hwmon/pmbus/ucd9000.c 
>> b/drivers/hwmon/pmbus/ucd9000.c
>> index e3a507f..297da0e 100644
>> --- a/drivers/hwmon/pmbus/ucd9000.c
>> +++ b/drivers/hwmon/pmbus/ucd9000.c
>> @@ -19,6 +19,7 @@
>>    * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
>>    */
>>   +#include <linux/debugfs.h>
>>   #include <linux/kernel.h>
>>   #include <linux/module.h>
>>   #include <linux/of_device.h>
>> @@ -36,6 +37,7 @@
>>   #define UCD9000_NUM_PAGES        0xd6
>>   #define UCD9000_FAN_CONFIG_INDEX    0xe7
>>   #define UCD9000_FAN_CONFIG        0xe8
>> +#define UCD9000_MFR_STATUS        0xf3
>>   #define UCD9000_GPIO_SELECT        0xfa
>>   #define UCD9000_GPIO_CONFIG        0xfb
>>   #define UCD9000_DEVICE_ID        0xfd
>> @@ -63,13 +65,22 @@
>>   #define UCD901XX_NUM_GPIOS    26
>>   #define UCD90910_NUM_GPIOS    26
>>   +#define UCD9000_DEBUGFS_NAME_LEN    24
>> +#define UCD9000_GPI_COUNT        8
>> +
>>   struct ucd9000_data {
>>       u8 fan_data[UCD9000_NUM_FAN][I2C_SMBUS_BLOCK_MAX];
>>       struct pmbus_driver_info info;
>>       struct gpio_chip gpio;
>> +    struct dentry *debugfs;
>>   };
>>   #define to_ucd9000_data(_info) container_of(_info, struct 
>> ucd9000_data, info)
>>   +struct ucd9000_debugfs_entry {
>> +    struct i2c_client *client;
>> +    u8 index;
>> +};
>> +
>>   static int ucd9000_get_fan_config(struct i2c_client *client, int fan)
>>   {
>>       int fan_config = 0;
>> @@ -328,6 +339,156 @@ static int ucd9000_gpio_direction_output(struct 
>> gpio_chip *gc,
>>                         val);
>>   }
>>   +#if IS_ENABLED(CONFIG_DEBUG_FS)
>> +static int ucd9000_get_mfr_status(struct i2c_client *client, u8 
>> *buffer)
>> +{
>> +    int ret = pmbus_set_page(client, 0);
>> +
>> +    if (ret < 0)
>> +        return ret;
>> +
>> +    /*
>> +     * With the ucd90120 and ucd90124 devices, this command 
>> [MFR_STATUS]
>> +     * is 2 bytes long (bits 0-15).  With the ucd90240 this command 
>> is 5
>> +     * bytes long.  With all other devices, it is 4 bytes long.
>> +     */
>> +    return i2c_smbus_read_block_data(client, UCD9000_MFR_STATUS, 
>> buffer);
>> +}
>> +
>> +static int ucd9000_debugfs_show_mfr_status_bit(void *data, u64 *val)
>> +{
>> +    struct ucd9000_debugfs_entry *entry = data;
>> +    struct i2c_client *client = entry->client;
>> +    u8 buffer[4];
>> +    int ret;
>> +
>> +    /*
>> +     * This attribute is only created for devices that return 4 
>> bytes for
>> +     * status_mfr, so it's safe to call with 4-byte buffer.
>> +     */
>> +    ret = ucd9000_get_mfr_status(client, buffer);
>> +    if (ret < 0) {
>> +        dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
>> +            ret);
>> +
>> +        return ret;
>> +    }
>> +
>> +    /*
>> +     * Attribute only created for devices with gpi fault bits at bits
>> +     * 16-23, which is the second byte of the response.
>> +     */
>> +    *val = !!(buffer[1] & BIT(entry->index));
>> +
>> +    return 0;
>> +}
>> +DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_bit,
>> +             ucd9000_debugfs_show_mfr_status_bit, NULL, "%1lld\n");
>> +
>> +static int ucd9000_debugfs_show_mfr_status_word2(void *data, u64 *val)
>> +{
>> +    struct i2c_client *client = data;
>> +    __be16 buffer;
>> +    int ret;
>> +
>> +    ret = ucd9000_get_mfr_status(client, (u8 *)&buffer);
>> +    if (ret < 0) {
>> +        dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
>> +            ret);
>> +
>> +        return ret;
>> +    }
>> +
>> +    *val = be16_to_cpu(buffer);
>> +
>> +    return 0;
>> +}
>> +DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_word2,
>> +             ucd9000_debugfs_show_mfr_status_word2, NULL,
>> +             "%04llx\n");
>> +
>> +static int ucd9000_debugfs_show_mfr_status_word4(void *data, u64 *val)
>> +{
>> +    struct i2c_client *client = data;
>> +    __be32 buffer;
>> +    int ret;
>> +
>> +    ret = ucd9000_get_mfr_status(client, (u8 *)&buffer);
>> +    if (ret < 0) {
>> +        dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
>> +            ret);
>> +
>> +        return ret;
>> +    }
>> +
>> +    *val = be32_to_cpu(buffer);
>> +
>> +    return 0;
>> +}
>> +DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_word4,
>> +             ucd9000_debugfs_show_mfr_status_word4, NULL,
>> +             "%08llx\n");
>> +
>> +static int ucd9000_init_debugfs(struct i2c_client *client,
>> +                const struct i2c_device_id *mid,
>> +                struct ucd9000_data *data)
>> +{
>> +    struct dentry *debugfs;
>> +    struct ucd9000_debugfs_entry *entries;
>> +    int i;
>> +    char name[UCD9000_DEBUGFS_NAME_LEN];
>> +
>> +    debugfs = pmbus_get_debugfs_dir(client);
>> +    if (!debugfs)
>> +        return -ENOENT;
>> +
>> +    data->debugfs = debugfs_create_dir(client->name, debugfs);
>> +    if (!data->debugfs)
>> +        return -ENOENT;
>> +
>> +    /*
>> +     * Of the chips this driver supports, only the UCD9090, UCD90160,
>> +     * and UCD90910 report GPI faults in their MFR_STATUS register, 
>> so only
>> +     * create the GPI fault debugfs attributes for those chips.
>> +     */
>> +    if (mid->driver_data == ucd9090 || mid->driver_data == ucd90160 ||
>> +        mid->driver_data == ucd90910) {
>> +        entries = devm_kzalloc(&client->dev,
>> +                       sizeof(*entries) * UCD9000_GPI_COUNT,
>> +                       GFP_KERNEL);
>> +        if (!entries)
>> +            return -ENOMEM;
>> +
>> +        for (i = 0; i < UCD9000_GPI_COUNT; i++) {
>> +            entries[i].client = client;
>> +            entries[i].index = i;
>> +            scnprintf(name, UCD9000_DEBUGFS_NAME_LEN,
>> +                  "gpi%d_alarm", i + 1);
>> +            debugfs_create_file(name, 0444, data->debugfs,
>> +                        &entries[i],
>> +                        &ucd9000_debugfs_mfr_status_bit);
>> +        }
>> +
>> +        scnprintf(name, UCD9000_DEBUGFS_NAME_LEN, "mfr_status");
>> +        debugfs_create_file(name, 0444, data->debugfs, client,
>> +                    &ucd9000_debugfs_mfr_status_word4);
>> +    } else if (mid->driver_data == ucd90120 ||
>> +           mid->driver_data == ucd90124) {
>> +        scnprintf(name, UCD9000_DEBUGFS_NAME_LEN, "mfr_status");
>> +        debugfs_create_file(name, 0444, data->debugfs, client,
>> +                    &ucd9000_debugfs_mfr_status_word2);
>> +    }
>> +
>> +    return 0;
>> +}
>
> Is all that complexity really worth it ? Why not just read the 
> manufacturing
> status as byte string into a buffer and use hexdump to pront it, no 
> matter how
> many bytes are actually returned ? This would also be less error 
> prone, and
> automatically support future chips.

Hm, well then we have the additional complexity of setting up custom 
debugfs file operations to show the binary data instead of just using 
DEFINE_DEBUGFS_ATTRIBUTE. Plus, at some point someone has to interpret 
it as either a word, half-word, or 5 bytes chunk. Where better to do it 
than the driver, as this is hw-dependent?

I could just use one function and do a byte-swap based on data length in 
a loop within #ifdef LITTLE_ENDIAN, but that's a little messy. It will 
handle all the cases though. What do you think?

Thanks,
Eddie

>
> Thanks,
> Guenter
>
>> +#else
>> +static int ucd9000_init_debugfs(struct i2c_client *client,
>> +                struct ucd9000_data *data)
>> +{
>> +    return 0;
>> +}
>> +#endif /* IS_ENABLED(CONFIG_DEBUG_FS) */
>> +
>>   static int ucd9000_probe(struct i2c_client *client,
>>                const struct i2c_device_id *id)
>>   {
>> @@ -483,7 +644,16 @@ static int ucd9000_probe(struct i2c_client *client,
>>           return ret;
>>       }
>>   -    return pmbus_do_probe(client, mid, info);
>> +    ret = pmbus_do_probe(client, mid, info);
>> +    if (ret)
>> +        return ret;
>> +
>> +    ret = ucd9000_init_debugfs(client, mid, data);
>> +    if (ret)
>> +        dev_warn(&client->dev, "Failed to register debugfs: %d\n",
>> +             ret);
>> +
>> +    return 0;
>>   }
>>     /* This is the driver that will be inserted */
>>
>

Re: [PATCH 2/2] hwmon: (ucd9000) Add debugfs attributes to provide mfr_status

[Guenter Roeck]

On Tue, Mar 13, 2018 at 02:01:51PM -0500, Eddie James wrote:
> 
> 
> On 03/10/2018 10:50 AM, Guenter Roeck wrote:
> >On 03/09/2018 11:19 AM, Eddie James wrote:
> >>From: Christopher Bostic <cbostic@linux.vnet.ibm.com>
> >>
> >>Expose the gpiN_fault fields of mfr_status as individual debugfs
> >>attributes. This provides a way for users to be easily notified of gpi
> >>faults. Also provide the whole mfr_status register in debugfs.
> >>
> >>Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
> >>Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> >>Signed-off-by: Eddie James <eajames@linux.vnet.ibm.com>
> >>---
> >>  drivers/hwmon/pmbus/ucd9000.c | 172
> >>+++++++++++++++++++++++++++++++++++++++++-
> >>  1 file changed, 171 insertions(+), 1 deletion(-)
> >>
> >>diff --git a/drivers/hwmon/pmbus/ucd9000.c
> >>b/drivers/hwmon/pmbus/ucd9000.c
> >>index e3a507f..297da0e 100644
> >>--- a/drivers/hwmon/pmbus/ucd9000.c
> >>+++ b/drivers/hwmon/pmbus/ucd9000.c
> >>@@ -19,6 +19,7 @@
> >>   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
> >>   */
> >>  +#include <linux/debugfs.h>
> >>  #include <linux/kernel.h>
> >>  #include <linux/module.h>
> >>  #include <linux/of_device.h>
> >>@@ -36,6 +37,7 @@
> >>  #define UCD9000_NUM_PAGES        0xd6
> >>  #define UCD9000_FAN_CONFIG_INDEX    0xe7
> >>  #define UCD9000_FAN_CONFIG        0xe8
> >>+#define UCD9000_MFR_STATUS        0xf3
> >>  #define UCD9000_GPIO_SELECT        0xfa
> >>  #define UCD9000_GPIO_CONFIG        0xfb
> >>  #define UCD9000_DEVICE_ID        0xfd
> >>@@ -63,13 +65,22 @@
> >>  #define UCD901XX_NUM_GPIOS    26
> >>  #define UCD90910_NUM_GPIOS    26
> >>  +#define UCD9000_DEBUGFS_NAME_LEN    24
> >>+#define UCD9000_GPI_COUNT        8
> >>+
> >>  struct ucd9000_data {
> >>      u8 fan_data[UCD9000_NUM_FAN][I2C_SMBUS_BLOCK_MAX];
> >>      struct pmbus_driver_info info;
> >>      struct gpio_chip gpio;
> >>+    struct dentry *debugfs;
> >>  };
> >>  #define to_ucd9000_data(_info) container_of(_info, struct
> >>ucd9000_data, info)
> >>  +struct ucd9000_debugfs_entry {
> >>+    struct i2c_client *client;
> >>+    u8 index;
> >>+};
> >>+
> >>  static int ucd9000_get_fan_config(struct i2c_client *client, int fan)
> >>  {
> >>      int fan_config = 0;
> >>@@ -328,6 +339,156 @@ static int ucd9000_gpio_direction_output(struct
> >>gpio_chip *gc,
> >>                        val);
> >>  }
> >>  +#if IS_ENABLED(CONFIG_DEBUG_FS)
> >>+static int ucd9000_get_mfr_status(struct i2c_client *client, u8
> >>*buffer)
> >>+{
> >>+    int ret = pmbus_set_page(client, 0);
> >>+
> >>+    if (ret < 0)
> >>+        return ret;
> >>+
> >>+    /*
> >>+     * With the ucd90120 and ucd90124 devices, this command
> >>[MFR_STATUS]
> >>+     * is 2 bytes long (bits 0-15).  With the ucd90240 this command is
> >>5
> >>+     * bytes long.  With all other devices, it is 4 bytes long.
> >>+     */
> >>+    return i2c_smbus_read_block_data(client, UCD9000_MFR_STATUS,
> >>buffer);
> >>+}
> >>+
> >>+static int ucd9000_debugfs_show_mfr_status_bit(void *data, u64 *val)
> >>+{
> >>+    struct ucd9000_debugfs_entry *entry = data;
> >>+    struct i2c_client *client = entry->client;
> >>+    u8 buffer[4];
> >>+    int ret;
> >>+
> >>+    /*
> >>+     * This attribute is only created for devices that return 4 bytes
> >>for
> >>+     * status_mfr, so it's safe to call with 4-byte buffer.
> >>+     */
> >>+    ret = ucd9000_get_mfr_status(client, buffer);
> >>+    if (ret < 0) {
> >>+        dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
> >>+            ret);
> >>+
> >>+        return ret;
> >>+    }
> >>+
> >>+    /*
> >>+     * Attribute only created for devices with gpi fault bits at bits
> >>+     * 16-23, which is the second byte of the response.
> >>+     */
> >>+    *val = !!(buffer[1] & BIT(entry->index));
> >>+
> >>+    return 0;
> >>+}
> >>+DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_bit,
> >>+             ucd9000_debugfs_show_mfr_status_bit, NULL, "%1lld\n");
> >>+
> >>+static int ucd9000_debugfs_show_mfr_status_word2(void *data, u64 *val)
> >>+{
> >>+    struct i2c_client *client = data;
> >>+    __be16 buffer;
> >>+    int ret;
> >>+
> >>+    ret = ucd9000_get_mfr_status(client, (u8 *)&buffer);
> >>+    if (ret < 0) {
> >>+        dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
> >>+            ret);
> >>+
> >>+        return ret;
> >>+    }
> >>+
> >>+    *val = be16_to_cpu(buffer);
> >>+
> >>+    return 0;
> >>+}
> >>+DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_word2,
> >>+             ucd9000_debugfs_show_mfr_status_word2, NULL,
> >>+             "%04llx\n");
> >>+
> >>+static int ucd9000_debugfs_show_mfr_status_word4(void *data, u64 *val)
> >>+{
> >>+    struct i2c_client *client = data;
> >>+    __be32 buffer;
> >>+    int ret;
> >>+
> >>+    ret = ucd9000_get_mfr_status(client, (u8 *)&buffer);
> >>+    if (ret < 0) {
> >>+        dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
> >>+            ret);
> >>+
> >>+        return ret;
> >>+    }
> >>+
> >>+    *val = be32_to_cpu(buffer);
> >>+
> >>+    return 0;
> >>+}
> >>+DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_word4,
> >>+             ucd9000_debugfs_show_mfr_status_word4, NULL,
> >>+             "%08llx\n");
> >>+
> >>+static int ucd9000_init_debugfs(struct i2c_client *client,
> >>+                const struct i2c_device_id *mid,
> >>+                struct ucd9000_data *data)
> >>+{
> >>+    struct dentry *debugfs;
> >>+    struct ucd9000_debugfs_entry *entries;
> >>+    int i;
> >>+    char name[UCD9000_DEBUGFS_NAME_LEN];
> >>+
> >>+    debugfs = pmbus_get_debugfs_dir(client);
> >>+    if (!debugfs)
> >>+        return -ENOENT;
> >>+
> >>+    data->debugfs = debugfs_create_dir(client->name, debugfs);
> >>+    if (!data->debugfs)
> >>+        return -ENOENT;
> >>+
> >>+    /*
> >>+     * Of the chips this driver supports, only the UCD9090, UCD90160,
> >>+     * and UCD90910 report GPI faults in their MFR_STATUS register, so
> >>only
> >>+     * create the GPI fault debugfs attributes for those chips.
> >>+     */
> >>+    if (mid->driver_data == ucd9090 || mid->driver_data == ucd90160 ||
> >>+        mid->driver_data == ucd90910) {
> >>+        entries = devm_kzalloc(&client->dev,
> >>+                       sizeof(*entries) * UCD9000_GPI_COUNT,
> >>+                       GFP_KERNEL);
> >>+        if (!entries)
> >>+            return -ENOMEM;
> >>+
> >>+        for (i = 0; i < UCD9000_GPI_COUNT; i++) {
> >>+            entries[i].client = client;
> >>+            entries[i].index = i;
> >>+            scnprintf(name, UCD9000_DEBUGFS_NAME_LEN,
> >>+                  "gpi%d_alarm", i + 1);
> >>+            debugfs_create_file(name, 0444, data->debugfs,
> >>+                        &entries[i],
> >>+                        &ucd9000_debugfs_mfr_status_bit);
> >>+        }
> >>+
> >>+        scnprintf(name, UCD9000_DEBUGFS_NAME_LEN, "mfr_status");
> >>+        debugfs_create_file(name, 0444, data->debugfs, client,
> >>+                    &ucd9000_debugfs_mfr_status_word4);
> >>+    } else if (mid->driver_data == ucd90120 ||
> >>+           mid->driver_data == ucd90124) {
> >>+        scnprintf(name, UCD9000_DEBUGFS_NAME_LEN, "mfr_status");
> >>+        debugfs_create_file(name, 0444, data->debugfs, client,
> >>+                    &ucd9000_debugfs_mfr_status_word2);
> >>+    }
> >>+
> >>+    return 0;
> >>+}
> >
> >Is all that complexity really worth it ? Why not just read the
> >manufacturing
> >status as byte string into a buffer and use hexdump to pront it, no matter
> >how
> >many bytes are actually returned ? This would also be less error prone,
> >and
> >automatically support future chips.
> 
> Hm, well then we have the additional complexity of setting up custom debugfs
> file operations to show the binary data instead of just using
> DEFINE_DEBUGFS_ATTRIBUTE. Plus, at some point someone has to interpret it as
> either a word, half-word, or 5 bytes chunk. Where better to do it than the
> driver, as this is hw-dependent?
> 
I can't exactly follow your logic. You mean it is acceptable for the user to
have to look into the datasheet to find out what the 1/2/4 byte hex value means,
but it is unacceptable to expect the user to have to use the datasheet to
identify what a 1..5 byte hex string, displayed in the order received from the
chip, means ? I am having difficulties understanding the difference. How is
12345678 different from, say, 12 34 56 78 (which you could display as 12345678
as well) ?

The macro generates the file operations as part of the define, so I don't see
having to define as valid argument. One could instead add a generic debugfs
macro to display a string if that is of interest.

> I could just use one function and do a byte-swap based on data length in a
> loop within #ifdef LITTLE_ENDIAN, but that's a little messy. It will handle
> all the cases though. What do you think?
> 
Personally I don't see a problem displaying data as received. Either case, there
are functions/macros to convert from big/little endian to host byte order, so
related ifdefs in the code should never be necessary.

Guenter

> Thanks,
> Eddie
> 
> >
> >Thanks,
> >Guenter
> >
> >>+#else
> >>+static int ucd9000_init_debugfs(struct i2c_client *client,
> >>+                struct ucd9000_data *data)
> >>+{
> >>+    return 0;
> >>+}
> >>+#endif /* IS_ENABLED(CONFIG_DEBUG_FS) */
> >>+
> >>  static int ucd9000_probe(struct i2c_client *client,
> >>               const struct i2c_device_id *id)
> >>  {
> >>@@ -483,7 +644,16 @@ static int ucd9000_probe(struct i2c_client *client,
> >>          return ret;
> >>      }
> >>  -    return pmbus_do_probe(client, mid, info);
> >>+    ret = pmbus_do_probe(client, mid, info);
> >>+    if (ret)
> >>+        return ret;
> >>+
> >>+    ret = ucd9000_init_debugfs(client, mid, data);
> >>+    if (ret)
> >>+        dev_warn(&client->dev, "Failed to register debugfs: %d\n",
> >>+             ret);
> >>+
> >>+    return 0;
> >>  }
> >>    /* This is the driver that will be inserted */
> >>
> >
> 

Re: [PATCH 2/2] hwmon: (ucd9000) Add debugfs attributes to provide mfr_status

[Eddie James]

On 03/13/2018 02:29 PM, Guenter Roeck wrote:
> On Tue, Mar 13, 2018 at 02:01:51PM -0500, Eddie James wrote:
>>
>> On 03/10/2018 10:50 AM, Guenter Roeck wrote:
>>> On 03/09/2018 11:19 AM, Eddie James wrote:
>>>> From: Christopher Bostic <cbostic@linux.vnet.ibm.com>
>>>>
>>>> Expose the gpiN_fault fields of mfr_status as individual debugfs
>>>> attributes. This provides a way for users to be easily notified of gpi
>>>> faults. Also provide the whole mfr_status register in debugfs.
>>>>
>>>> Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
>>>> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
>>>> Signed-off-by: Eddie James <eajames@linux.vnet.ibm.com>
>>>> ---
>>>>    drivers/hwmon/pmbus/ucd9000.c | 172
>>>> +++++++++++++++++++++++++++++++++++++++++-
>>>>    1 file changed, 171 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/hwmon/pmbus/ucd9000.c
>>>> b/drivers/hwmon/pmbus/ucd9000.c
>>>> index e3a507f..297da0e 100644
>>>> --- a/drivers/hwmon/pmbus/ucd9000.c
>>>> +++ b/drivers/hwmon/pmbus/ucd9000.c
>>>> @@ -19,6 +19,7 @@
>>>>     * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
>>>>     */
>>>>    +#include <linux/debugfs.h>
>>>>    #include <linux/kernel.h>
>>>>    #include <linux/module.h>
>>>>    #include <linux/of_device.h>
>>>> @@ -36,6 +37,7 @@
>>>>    #define UCD9000_NUM_PAGES        0xd6
>>>>    #define UCD9000_FAN_CONFIG_INDEX    0xe7
>>>>    #define UCD9000_FAN_CONFIG        0xe8
>>>> +#define UCD9000_MFR_STATUS        0xf3
>>>>    #define UCD9000_GPIO_SELECT        0xfa
>>>>    #define UCD9000_GPIO_CONFIG        0xfb
>>>>    #define UCD9000_DEVICE_ID        0xfd
>>>> @@ -63,13 +65,22 @@
>>>>    #define UCD901XX_NUM_GPIOS    26
>>>>    #define UCD90910_NUM_GPIOS    26
>>>>    +#define UCD9000_DEBUGFS_NAME_LEN    24
>>>> +#define UCD9000_GPI_COUNT        8
>>>> +
>>>>    struct ucd9000_data {
>>>>        u8 fan_data[UCD9000_NUM_FAN][I2C_SMBUS_BLOCK_MAX];
>>>>        struct pmbus_driver_info info;
>>>>        struct gpio_chip gpio;
>>>> +    struct dentry *debugfs;
>>>>    };
>>>>    #define to_ucd9000_data(_info) container_of(_info, struct
>>>> ucd9000_data, info)
>>>>    +struct ucd9000_debugfs_entry {
>>>> +    struct i2c_client *client;
>>>> +    u8 index;
>>>> +};
>>>> +
>>>>    static int ucd9000_get_fan_config(struct i2c_client *client, int fan)
>>>>    {
>>>>        int fan_config = 0;
>>>> @@ -328,6 +339,156 @@ static int ucd9000_gpio_direction_output(struct
>>>> gpio_chip *gc,
>>>>                          val);
>>>>    }
>>>>    +#if IS_ENABLED(CONFIG_DEBUG_FS)
>>>> +static int ucd9000_get_mfr_status(struct i2c_client *client, u8
>>>> *buffer)
>>>> +{
>>>> +    int ret = pmbus_set_page(client, 0);
>>>> +
>>>> +    if (ret < 0)
>>>> +        return ret;
>>>> +
>>>> +    /*
>>>> +     * With the ucd90120 and ucd90124 devices, this command
>>>> [MFR_STATUS]
>>>> +     * is 2 bytes long (bits 0-15).  With the ucd90240 this command is
>>>> 5
>>>> +     * bytes long.  With all other devices, it is 4 bytes long.
>>>> +     */
>>>> +    return i2c_smbus_read_block_data(client, UCD9000_MFR_STATUS,
>>>> buffer);
>>>> +}
>>>> +
>>>> +static int ucd9000_debugfs_show_mfr_status_bit(void *data, u64 *val)
>>>> +{
>>>> +    struct ucd9000_debugfs_entry *entry = data;
>>>> +    struct i2c_client *client = entry->client;
>>>> +    u8 buffer[4];
>>>> +    int ret;
>>>> +
>>>> +    /*
>>>> +     * This attribute is only created for devices that return 4 bytes
>>>> for
>>>> +     * status_mfr, so it's safe to call with 4-byte buffer.
>>>> +     */
>>>> +    ret = ucd9000_get_mfr_status(client, buffer);
>>>> +    if (ret < 0) {
>>>> +        dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
>>>> +            ret);
>>>> +
>>>> +        return ret;
>>>> +    }
>>>> +
>>>> +    /*
>>>> +     * Attribute only created for devices with gpi fault bits at bits
>>>> +     * 16-23, which is the second byte of the response.
>>>> +     */
>>>> +    *val = !!(buffer[1] & BIT(entry->index));
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_bit,
>>>> +             ucd9000_debugfs_show_mfr_status_bit, NULL, "%1lld\n");
>>>> +
>>>> +static int ucd9000_debugfs_show_mfr_status_word2(void *data, u64 *val)
>>>> +{
>>>> +    struct i2c_client *client = data;
>>>> +    __be16 buffer;
>>>> +    int ret;
>>>> +
>>>> +    ret = ucd9000_get_mfr_status(client, (u8 *)&buffer);
>>>> +    if (ret < 0) {
>>>> +        dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
>>>> +            ret);
>>>> +
>>>> +        return ret;
>>>> +    }
>>>> +
>>>> +    *val = be16_to_cpu(buffer);
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_word2,
>>>> +             ucd9000_debugfs_show_mfr_status_word2, NULL,
>>>> +             "%04llx\n");
>>>> +
>>>> +static int ucd9000_debugfs_show_mfr_status_word4(void *data, u64 *val)
>>>> +{
>>>> +    struct i2c_client *client = data;
>>>> +    __be32 buffer;
>>>> +    int ret;
>>>> +
>>>> +    ret = ucd9000_get_mfr_status(client, (u8 *)&buffer);
>>>> +    if (ret < 0) {
>>>> +        dev_err(&client->dev, "Failed to read mfr status. rc:%d\n",
>>>> +            ret);
>>>> +
>>>> +        return ret;
>>>> +    }
>>>> +
>>>> +    *val = be32_to_cpu(buffer);
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +DEFINE_DEBUGFS_ATTRIBUTE(ucd9000_debugfs_mfr_status_word4,
>>>> +             ucd9000_debugfs_show_mfr_status_word4, NULL,
>>>> +             "%08llx\n");
>>>> +
>>>> +static int ucd9000_init_debugfs(struct i2c_client *client,
>>>> +                const struct i2c_device_id *mid,
>>>> +                struct ucd9000_data *data)
>>>> +{
>>>> +    struct dentry *debugfs;
>>>> +    struct ucd9000_debugfs_entry *entries;
>>>> +    int i;
>>>> +    char name[UCD9000_DEBUGFS_NAME_LEN];
>>>> +
>>>> +    debugfs = pmbus_get_debugfs_dir(client);
>>>> +    if (!debugfs)
>>>> +        return -ENOENT;
>>>> +
>>>> +    data->debugfs = debugfs_create_dir(client->name, debugfs);
>>>> +    if (!data->debugfs)
>>>> +        return -ENOENT;
>>>> +
>>>> +    /*
>>>> +     * Of the chips this driver supports, only the UCD9090, UCD90160,
>>>> +     * and UCD90910 report GPI faults in their MFR_STATUS register, so
>>>> only
>>>> +     * create the GPI fault debugfs attributes for those chips.
>>>> +     */
>>>> +    if (mid->driver_data == ucd9090 || mid->driver_data == ucd90160 ||
>>>> +        mid->driver_data == ucd90910) {
>>>> +        entries = devm_kzalloc(&client->dev,
>>>> +                       sizeof(*entries) * UCD9000_GPI_COUNT,
>>>> +                       GFP_KERNEL);
>>>> +        if (!entries)
>>>> +            return -ENOMEM;
>>>> +
>>>> +        for (i = 0; i < UCD9000_GPI_COUNT; i++) {
>>>> +            entries[i].client = client;
>>>> +            entries[i].index = i;
>>>> +            scnprintf(name, UCD9000_DEBUGFS_NAME_LEN,
>>>> +                  "gpi%d_alarm", i + 1);
>>>> +            debugfs_create_file(name, 0444, data->debugfs,
>>>> +                        &entries[i],
>>>> +                        &ucd9000_debugfs_mfr_status_bit);
>>>> +        }
>>>> +
>>>> +        scnprintf(name, UCD9000_DEBUGFS_NAME_LEN, "mfr_status");
>>>> +        debugfs_create_file(name, 0444, data->debugfs, client,
>>>> +                    &ucd9000_debugfs_mfr_status_word4);
>>>> +    } else if (mid->driver_data == ucd90120 ||
>>>> +           mid->driver_data == ucd90124) {
>>>> +        scnprintf(name, UCD9000_DEBUGFS_NAME_LEN, "mfr_status");
>>>> +        debugfs_create_file(name, 0444, data->debugfs, client,
>>>> +                    &ucd9000_debugfs_mfr_status_word2);
>>>> +    }
>>>> +
>>>> +    return 0;
>>>> +}
>>> Is all that complexity really worth it ? Why not just read the
>>> manufacturing
>>> status as byte string into a buffer and use hexdump to pront it, no matter
>>> how
>>> many bytes are actually returned ? This would also be less error prone,
>>> and
>>> automatically support future chips.
>> Hm, well then we have the additional complexity of setting up custom debugfs
>> file operations to show the binary data instead of just using
>> DEFINE_DEBUGFS_ATTRIBUTE. Plus, at some point someone has to interpret it as
>> either a word, half-word, or 5 bytes chunk. Where better to do it than the
>> driver, as this is hw-dependent?
>>
> I can't exactly follow your logic. You mean it is acceptable for the user to
> have to look into the datasheet to find out what the 1/2/4 byte hex value means,
> but it is unacceptable to expect the user to have to use the datasheet to
> identify what a 1..5 byte hex string, displayed in the order received from the
> chip, means ? I am having difficulties understanding the difference. How is
> 12345678 different from, say, 12 34 56 78 (which you could display as 12345678
> as well) ?

Yea, it's not different at all. Sorry, I wasn't very clear, when I said 
"interpret," I meant "figure out the endian swapping," so my proposal 
would display 78563412, so the user can directly use the value. I 
typically expect the kernel to provide data through interfaces in host 
endian, but displaying it as-received is fine as well. User can figure 
it out.

V2 incoming.

Thanks,
Eddie

>
> The macro generates the file operations as part of the define, so I don't see
> having to define as valid argument. One could instead add a generic debugfs
> macro to display a string if that is of interest.
>
>> I could just use one function and do a byte-swap based on data length in a
>> loop within #ifdef LITTLE_ENDIAN, but that's a little messy. It will handle
>> all the cases though. What do you think?
>>
> Personally I don't see a problem displaying data as received. Either case, there
> are functions/macros to convert from big/little endian to host byte order, so
> related ifdefs in the code should never be necessary.
>
> Guenter
>
>> Thanks,
>> Eddie
>>
>>> Thanks,
>>> Guenter
>>>
>>>> +#else
>>>> +static int ucd9000_init_debugfs(struct i2c_client *client,
>>>> +                struct ucd9000_data *data)
>>>> +{
>>>> +    return 0;
>>>> +}
>>>> +#endif /* IS_ENABLED(CONFIG_DEBUG_FS) */
>>>> +
>>>>    static int ucd9000_probe(struct i2c_client *client,
>>>>                 const struct i2c_device_id *id)
>>>>    {
>>>> @@ -483,7 +644,16 @@ static int ucd9000_probe(struct i2c_client *client,
>>>>            return ret;
>>>>        }
>>>>    -    return pmbus_do_probe(client, mid, info);
>>>> +    ret = pmbus_do_probe(client, mid, info);
>>>> +    if (ret)
>>>> +        return ret;
>>>> +
>>>> +    ret = ucd9000_init_debugfs(client, mid, data);
>>>> +    if (ret)
>>>> +        dev_warn(&client->dev, "Failed to register debugfs: %d\n",
>>>> +             ret);
>>>> +
>>>> +    return 0;
>>>>    }
>>>>      /* This is the driver that will be inserted */
>>>>