Messages in this thread | | | Subject | Re: [PATCH 2/2] hwmon: (ucd9000) Add debugfs attributes to provide mfr_status | From | Eddie James <> | Date | Tue, 13 Mar 2018 15:00:13 -0500 |
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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 */ >>>>
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