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 14:01:51 -0500 |
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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 */ >> >
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