[PATCH v6 0/2] hwmon: (ucd9000) Add gpio and debugfs interfaces

[PATCH v6 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.

Changes since v5:
 - enclose gpio code in #ifdef GPIOLIB
 - don't initialize buffers for mfr_status; set last char to 0 instead
 - cap the size argument to bin2hex

Changes since v4:
 - max-sized buffers for smbus transfers
 - used bin2hex instead of my own code

Changes since v3:
 - remove setting of gpio_chip->owner
 - format the mfr_status data
 - switch to #ifdef rather than #if IS_ENABLED for debugfs

Changes since v2:
 - split the gpio registration into it's own function

Changes since v1:
 - dropped dev_err messages
 - made gpio chip registration conditional on having gpio pins
 - made mfr_status debugfs attribute more simple

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

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

 drivers/hwmon/pmbus/ucd9000.c | 350 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 349 insertions(+), 1 deletion(-)

-- 
1.8.3.1

[PATCH v6 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 | 212 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 212 insertions(+)

diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
index b74dbec..ef2c5bf 100644
--- a/drivers/hwmon/pmbus/ucd9000.c
+++ b/drivers/hwmon/pmbus/ucd9000.c
@@ -27,6 +27,8 @@
 #include <linux/slab.h>
 #include <linux/i2c.h>
 #include <linux/pmbus.h>
+#include <linux/gpio.h>
+#include <linux/gpio/driver.h>
 #include "pmbus.h"
 
 enum chips { ucd9000, ucd90120, ucd90124, ucd90160, ucd9090, ucd90910 };
@@ -35,8 +37,18 @@
 #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 +59,17 @@
 
 #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;
+#ifdef CONFIG_GPIOLIB
+	struct gpio_chip gpio;
+#endif
 };
 #define to_ucd9000_data(_info) container_of(_info, struct ucd9000_data, info)
 
@@ -149,6 +169,196 @@ static int ucd9000_read_byte_data(struct i2c_client *client, int page, int reg)
 };
 MODULE_DEVICE_TABLE(of, ucd9000_of_match);
 
+#ifdef CONFIG_GPIOLIB
+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)
+		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)
+		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_dbg(&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_dbg(&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_dbg(&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)
+		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)
+		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)
+		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 void ucd9000_probe_gpio(struct i2c_client *client,
+			       const struct i2c_device_id *mid,
+			       struct ucd9000_data *data)
+{
+	int rc;
+
+	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;
+	default:
+		return; /* GPIO support is optional. */
+	}
+
+	/*
+	 * 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 = 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 = true;
+	data->gpio.base = -1;
+	data->gpio.parent = &client->dev;
+
+	rc = devm_gpiochip_add_data(&client->dev, &data->gpio, client);
+	if (rc)
+		dev_warn(&client->dev, "Could not add gpiochip: %d\n", rc);
+}
+#else
+static void ucd9000_probe_gpio(struct i2c_client *client,
+			       const struct i2c_device_id *mid,
+			       struct ucd9000_data *data)
+{
+}
+#endif /* CONFIG_GPIOLIB */
+
 static int ucd9000_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
@@ -263,6 +473,8 @@ static int ucd9000_probe(struct i2c_client *client,
 		  | PMBUS_HAVE_FAN34 | PMBUS_HAVE_STATUS_FAN34;
 	}
 
+	ucd9000_probe_gpio(client, mid, data);
+
 	return pmbus_do_probe(client, mid, info);
 }
 
-- 
1.8.3.1

[PATCH v6 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 | 138 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 137 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
index ef2c5bf..88c98fb 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>
@@ -37,6 +38,7 @@
 #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
@@ -64,15 +66,24 @@
 #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;
 #ifdef CONFIG_GPIOLIB
 	struct gpio_chip gpio;
 #endif
+	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;
@@ -359,6 +370,122 @@ static void ucd9000_probe_gpio(struct i2c_client *client,
 }
 #endif /* CONFIG_GPIOLIB */
 
+#ifdef 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;
+
+	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[I2C_SMBUS_BLOCK_MAX];
+	int ret;
+
+	ret = ucd9000_get_mfr_status(client, buffer);
+	if (ret < 0)
+		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 ssize_t ucd9000_debugfs_read_mfr_status(struct file *file,
+					       char __user *buf, size_t count,
+					       loff_t *ppos)
+{
+	struct i2c_client *client = file->private_data;
+	u8 buffer[I2C_SMBUS_BLOCK_MAX];
+	char str[(I2C_SMBUS_BLOCK_MAX * 2) + 2];
+	char *res;
+	int rc;
+
+	rc = ucd9000_get_mfr_status(client, buffer);
+	if (rc < 0)
+		return rc;
+
+	res = bin2hex(str, buffer, min(rc, I2C_SMBUS_BLOCK_MAX));
+	*res++ = '\n';
+	*res++ = 0;
+
+	return simple_read_from_buffer(buf, count, ppos, str, res - str);
+}
+
+static const struct file_operations ucd9000_debugfs_show_mfr_status_fops = {
+	.llseek = noop_llseek,
+	.read = ucd9000_debugfs_read_mfr_status,
+	.open = simple_open,
+};
+
+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_show_mfr_status_fops);
+
+	return 0;
+}
+#else
+static int ucd9000_init_debugfs(struct i2c_client *client,
+				const struct i2c_device_id *mid,
+				struct ucd9000_data *data)
+{
+	return 0;
+}
+#endif /* CONFIG_DEBUG_FS */
+
 static int ucd9000_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
@@ -475,7 +602,16 @@ static int ucd9000_probe(struct i2c_client *client,
 
 	ucd9000_probe_gpio(client, mid, data);
 
-	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 v6 2/2] hwmon: (ucd9000) Add debugfs attributes to provide mfr_status

[Guenter Roeck]

On Fri, Mar 16, 2018 at 02:25:59PM -0500, 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 | 138 +++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 137 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
> index ef2c5bf..88c98fb 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>
> @@ -37,6 +38,7 @@
>  #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
> @@ -64,15 +66,24 @@
>  #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;
>  #ifdef CONFIG_GPIOLIB
>  	struct gpio_chip gpio;
>  #endif
> +	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;
> @@ -359,6 +370,122 @@ static void ucd9000_probe_gpio(struct i2c_client *client,
>  }
>  #endif /* CONFIG_GPIOLIB */
>  
> +#ifdef 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;
> +
> +	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[I2C_SMBUS_BLOCK_MAX];
> +	int ret;
> +
> +	ret = ucd9000_get_mfr_status(client, buffer);
> +	if (ret < 0)
> +		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 ssize_t ucd9000_debugfs_read_mfr_status(struct file *file,
> +					       char __user *buf, size_t count,
> +					       loff_t *ppos)
> +{
> +	struct i2c_client *client = file->private_data;
> +	u8 buffer[I2C_SMBUS_BLOCK_MAX];
> +	char str[(I2C_SMBUS_BLOCK_MAX * 2) + 2];
> +	char *res;
> +	int rc;
> +
> +	rc = ucd9000_get_mfr_status(client, buffer);
> +	if (rc < 0)
> +		return rc;
> +
> +	res = bin2hex(str, buffer, min(rc, I2C_SMBUS_BLOCK_MAX));
> +	*res++ = '\n';
> +	*res++ = 0;
> +
Unless I am missing something, this now returns the terminating '\0'
to the user. Is this really what you want ?

I see other code adding the terminator, but it doesn't usually return it
to the user.

Guenter

> +	return simple_read_from_buffer(buf, count, ppos, str, res - str);
> +}
> +
> +static const struct file_operations ucd9000_debugfs_show_mfr_status_fops = {
> +	.llseek = noop_llseek,
> +	.read = ucd9000_debugfs_read_mfr_status,
> +	.open = simple_open,
> +};
> +
> +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_show_mfr_status_fops);
> +
> +	return 0;
> +}
> +#else
> +static int ucd9000_init_debugfs(struct i2c_client *client,
> +				const struct i2c_device_id *mid,
> +				struct ucd9000_data *data)
> +{
> +	return 0;
> +}
> +#endif /* CONFIG_DEBUG_FS */
> +
>  static int ucd9000_probe(struct i2c_client *client,
>  			 const struct i2c_device_id *id)
>  {
> @@ -475,7 +602,16 @@ static int ucd9000_probe(struct i2c_client *client,
>  
>  	ucd9000_probe_gpio(client, mid, data);
>  
> -	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
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH v6 2/2] hwmon: (ucd9000) Add debugfs attributes to provide mfr_status

[Eddie James]

On 03/16/2018 02:59 PM, Guenter Roeck wrote:
> On Fri, Mar 16, 2018 at 02:25:59PM -0500, 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 | 138 +++++++++++++++++++++++++++++++++++++++++-
>>   1 file changed, 137 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
>> index ef2c5bf..88c98fb 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>
>> @@ -37,6 +38,7 @@
>>   #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
>> @@ -64,15 +66,24 @@
>>   #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;
>>   #ifdef CONFIG_GPIOLIB
>>   	struct gpio_chip gpio;
>>   #endif
>> +	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;
>> @@ -359,6 +370,122 @@ static void ucd9000_probe_gpio(struct i2c_client *client,
>>   }
>>   #endif /* CONFIG_GPIOLIB */
>>   
>> +#ifdef 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;
>> +
>> +	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[I2C_SMBUS_BLOCK_MAX];
>> +	int ret;
>> +
>> +	ret = ucd9000_get_mfr_status(client, buffer);
>> +	if (ret < 0)
>> +		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 ssize_t ucd9000_debugfs_read_mfr_status(struct file *file,
>> +					       char __user *buf, size_t count,
>> +					       loff_t *ppos)
>> +{
>> +	struct i2c_client *client = file->private_data;
>> +	u8 buffer[I2C_SMBUS_BLOCK_MAX];
>> +	char str[(I2C_SMBUS_BLOCK_MAX * 2) + 2];
>> +	char *res;
>> +	int rc;
>> +
>> +	rc = ucd9000_get_mfr_status(client, buffer);
>> +	if (rc < 0)
>> +		return rc;
>> +
>> +	res = bin2hex(str, buffer, min(rc, I2C_SMBUS_BLOCK_MAX));
>> +	*res++ = '\n';
>> +	*res++ = 0;
>> +
> Unless I am missing something, this now returns the terminating '\0'
> to the user. Is this really what you want ?

Yes, that was my intention. I thought that was normal. It worked fine 
when I cat'ed the file. Up to you, I can change it if you like.

Thanks,
Eddie

>
> I see other code adding the terminator, but it doesn't usually return it
> to the user.
>
> Guenter
>
>> +	return simple_read_from_buffer(buf, count, ppos, str, res - str);
>> +}
>> +
>> +static const struct file_operations ucd9000_debugfs_show_mfr_status_fops = {
>> +	.llseek = noop_llseek,
>> +	.read = ucd9000_debugfs_read_mfr_status,
>> +	.open = simple_open,
>> +};
>> +
>> +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_show_mfr_status_fops);
>> +
>> +	return 0;
>> +}
>> +#else
>> +static int ucd9000_init_debugfs(struct i2c_client *client,
>> +				const struct i2c_device_id *mid,
>> +				struct ucd9000_data *data)
>> +{
>> +	return 0;
>> +}
>> +#endif /* CONFIG_DEBUG_FS */
>> +
>>   static int ucd9000_probe(struct i2c_client *client,
>>   			 const struct i2c_device_id *id)
>>   {
>> @@ -475,7 +602,16 @@ static int ucd9000_probe(struct i2c_client *client,
>>   
>>   	ucd9000_probe_gpio(client, mid, data);
>>   
>> -	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
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH v6 2/2] hwmon: (ucd9000) Add debugfs attributes to provide mfr_status

[Guenter Roeck]

On Fri, Mar 16, 2018 at 03:04:47PM -0500, Eddie James wrote:
> 
> 
> On 03/16/2018 02:59 PM, Guenter Roeck wrote:
> >On Fri, Mar 16, 2018 at 02:25:59PM -0500, 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 | 138 +++++++++++++++++++++++++++++++++++++++++-
> >>  1 file changed, 137 insertions(+), 1 deletion(-)
> >>
> >>diff --git a/drivers/hwmon/pmbus/ucd9000.c b/drivers/hwmon/pmbus/ucd9000.c
> >>index ef2c5bf..88c98fb 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>
> >>@@ -37,6 +38,7 @@
> >>  #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
> >>@@ -64,15 +66,24 @@
> >>  #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;
> >>  #ifdef CONFIG_GPIOLIB
> >>  	struct gpio_chip gpio;
> >>  #endif
> >>+	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;
> >>@@ -359,6 +370,122 @@ static void ucd9000_probe_gpio(struct i2c_client *client,
> >>  }
> >>  #endif /* CONFIG_GPIOLIB */
> >>+#ifdef 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;
> >>+
> >>+	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[I2C_SMBUS_BLOCK_MAX];
> >>+	int ret;
> >>+
> >>+	ret = ucd9000_get_mfr_status(client, buffer);
> >>+	if (ret < 0)
> >>+		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 ssize_t ucd9000_debugfs_read_mfr_status(struct file *file,
> >>+					       char __user *buf, size_t count,
> >>+					       loff_t *ppos)
> >>+{
> >>+	struct i2c_client *client = file->private_data;
> >>+	u8 buffer[I2C_SMBUS_BLOCK_MAX];
> >>+	char str[(I2C_SMBUS_BLOCK_MAX * 2) + 2];
> >>+	char *res;
> >>+	int rc;
> >>+
> >>+	rc = ucd9000_get_mfr_status(client, buffer);
> >>+	if (rc < 0)
> >>+		return rc;
> >>+
> >>+	res = bin2hex(str, buffer, min(rc, I2C_SMBUS_BLOCK_MAX));
> >>+	*res++ = '\n';
> >>+	*res++ = 0;
> >>+
> >Unless I am missing something, this now returns the terminating '\0'
> >to the user. Is this really what you want ?
> 
> Yes, that was my intention. I thought that was normal. It worked fine when I
> cat'ed the file. Up to you, I can change it if you like.
> 
Please do. I suspect that you'll see the '\0' if you send the output to od.
That is unexpected. I browsed through the kernel and was unable to find
any other code doing the same, so we should not be the ones starting it.

Example is DEFINE_DEBUGFS_ATTRIBUTE, which ends up calling simple_attr_read().
This in turn passes the result of scnprintf() or strlen() to
simple_read_from_buffer(). Both not include the terminating '\0'.

Thanks,
Guenter

> Thanks,
> Eddie
> 
> >
> >I see other code adding the terminator, but it doesn't usually return it
> >to the user.
> >
> >Guenter
> >
> >>+	return simple_read_from_buffer(buf, count, ppos, str, res - str);
> >>+}
> >>+
> >>+static const struct file_operations ucd9000_debugfs_show_mfr_status_fops = {
> >>+	.llseek = noop_llseek,
> >>+	.read = ucd9000_debugfs_read_mfr_status,
> >>+	.open = simple_open,
> >>+};
> >>+
> >>+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_show_mfr_status_fops);
> >>+
> >>+	return 0;
> >>+}
> >>+#else
> >>+static int ucd9000_init_debugfs(struct i2c_client *client,
> >>+				const struct i2c_device_id *mid,
> >>+				struct ucd9000_data *data)
> >>+{
> >>+	return 0;
> >>+}
> >>+#endif /* CONFIG_DEBUG_FS */
> >>+
> >>  static int ucd9000_probe(struct i2c_client *client,
> >>  			 const struct i2c_device_id *id)
> >>  {
> >>@@ -475,7 +602,16 @@ static int ucd9000_probe(struct i2c_client *client,
> >>  	ucd9000_probe_gpio(client, mid, data);
> >>-	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
> >>
> >>--
> >>To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in
> >>the body of a message to majordomo@vger.kernel.org
> >>More majordomo info at  http://vger.kernel.org/majordomo-info.html
>