From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752614AbeCMT3I (ORCPT ); Tue, 13 Mar 2018 15:29:08 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:36389 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752468AbeCMT3H (ORCPT ); Tue, 13 Mar 2018 15:29:07 -0400 X-Google-Smtp-Source: AG47ELsoHlLZ38DeLDtjiv6c2gBeegEga9jb33Y978gGb4lmOZlmnxiL5N6Uc1YTU+suw5Sh6HmOhg== Date: Tue, 13 Mar 2018 12:29:03 -0700 From: Guenter Roeck To: Eddie James Cc: linux-hwmon@vger.kernel.org, linux-kernel@vger.kernel.org, jdelvare@suse.com, joel@jms.id.au, Christopher Bostic , Andrew Jeffery Subject: Re: [PATCH 2/2] hwmon: (ucd9000) Add debugfs attributes to provide mfr_status Message-ID: <20180313192903.GA14572@roeck-us.net> References: <1520623196-9534-1-git-send-email-eajames@linux.vnet.ibm.com> <1520623196-9534-3-git-send-email-eajames@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > >> > >>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 > >>Signed-off-by: Andrew Jeffery > >>Signed-off-by: Eddie James > >>--- > >>  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 > >>  #include > >>  #include > >>  #include > >>@@ -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 */ > >> > > >