On 2019-06-11 19:49, Thomas Preston wrote:
Add speaker_test device attribute. When the speaker-test node is read
the hardware speaker test is started.

        $ cat /sys/devices/.../device:00/speaker_test
        04 04 04 04

Signed-off-by: Thomas Preston <thomas.pres...@codethink.co.uk>
Cc: Patrick Glaser <pgla...@tesla.com>
Cc: Rob Duncan <rdun...@tesla.com>
Cc: Nate Case <nc...@tesla.com>
---
  sound/soc/codecs/tda7802.c | 172 +++++++++++++++++++++++++++++++++++++++++++++
  1 file changed, 172 insertions(+)

diff --git a/sound/soc/codecs/tda7802.c b/sound/soc/codecs/tda7802.c
index 62aae011d9f1..edfa752c0c9f 100644
--- a/sound/soc/codecs/tda7802.c
+++ b/sound/soc/codecs/tda7802.c
@@ -157,6 +157,7 @@ static const u8 IB3_FORMAT[4][4] = {
  #define DUMP_NUM_REGS                    (DUMP_NUM_BLOCK * 2)
struct tda7802_priv {
+       struct mutex mutex;
        struct i2c_client *i2c;
        struct regmap *regmap;
        struct regulator *enable_reg;
@@ -458,6 +459,159 @@ static struct snd_soc_dai_driver tda7802_dai_driver = {
        .ops = &tda7802_dai_ops,
  };
+/* The speaker test is triggered by reading a sysfs attribute file attached to
+ * the I2C device. The user space thread that's doing the reading is blocked
+ * until the test completes (or times out). We only permit one test to be in
+ * progress at a time.
+ */
+
+static int speaker_test_start(struct regmap *regmap)
+{
+       int err;
+
+       err = regmap_update_bits(regmap, TDA7802_IB5, IB5_AMPLIFIER_ON, 0);
+       if (err < 0) {
+               dev_err(regmap_get_device(regmap),
+                       "Cannot disable amp for speaker test (%d)\n", err);
+               return err;
+       }
+
+       err = regmap_update_bits(regmap, TDA7802_IB4, IB4_DIAG_MODE_ENABLE, 0);
+       if (err < 0) {
+               dev_err(regmap_get_device(regmap),
+                       "Cannot disable diag mode before speaker test (%d)\n",
+                       err);
+               return err;
+       }
+
+       /* Seem to need at least a 15 ms delay here before the rising
+        * edge. Otherwise the diagnostics never complete (perhaps
+        * they never start).
+        */
+       msleep(20);
+
+       err = regmap_update_bits(regmap, TDA7802_IB4,
+                                IB4_DIAG_MODE_ENABLE, IB4_DIAG_MODE_ENABLE);
+       if (err < 0) {
+               dev_err(regmap_get_device(regmap),
+                       "Cannot enable diag mode for speaker test (%d)\n", err);
+               return err;
+       }
+
+       return 0;

You may want to follow path set by speaker_test_stop: replace "return 0" with "return err" and have only error msg found within preceding if-statement.

+}
+
+static int speaker_test_stop(struct regmap *regmap)
+{
+       int err;
+
+       err = regmap_update_bits(regmap, TDA7802_IB4, IB4_DIAG_MODE_ENABLE, 0);
+       if (err < 0)
+               dev_err(regmap_get_device(regmap),
+                       "Cannot disable diag mode after speaker test (%d)\n",
+                       err);
+       return err;
+}
+
+/* We poll the test completion bit, letting the current thread sleep
+ * until we're done. These values are not critical.
+ */
+#define SPEAKER_TEST_DONE_POLL_PERIOD_US 5000
+#define SPEAKER_TEST_DONE_TIMEOUT_US    5000000
+
+static int speaker_test_check(struct tda7802_priv *tda7802,
+               unsigned int *status)
+{
+       struct regmap *regmap = tda7802->regmap;
+       struct device *dev = &tda7802->i2c->dev;
+       int reg_err = 0, err = 0, i, amp_on;

Both reg_err and err are initialized unnecessarily.

+       unsigned int val;
+
+       reg_err = regulator_enable(tda7802->enable_reg);
+       if (reg_err < 0) {
+               dev_err(dev, "Could not enable (speaker-test).\n");
+               return reg_err;
+       }
+       msleep(ENABLE_DELAY_MS);
+
+       /* we should return amp on state when speaker-test is done */
+       err = regmap_read(regmap, TDA7802_IB5, &amp_on);
+       if (err < 0) {
+               dev_err(dev, "Could not read amp on state (speaker-test)\n");
+               goto speaker_test_disable;
+       }
+
+       for (i = 0; i < CHANNELS_PER_AMP; ++i)
+               status[i] = 0xff;
+
+       err = speaker_test_start(regmap);
+       if (err < 0)
+               goto speaker_test_restore;
+
+       /* Wait until DB0_STARTUP_DIAG_STATUS is set */
+       err = regmap_read_poll_timeout(regmap, TDA7802_DB0, val,
+                       val & DB0_STARTUP_DIAG_STATUS,
+                       SPEAKER_TEST_DONE_POLL_PERIOD_US,
+                       SPEAKER_TEST_DONE_TIMEOUT_US);
+       if (err < 0) {
+               if (err == -ENODATA)
+                       dev_err(dev,
+                               "Speaker diagnostic test did not complete\n");
+               speaker_test_stop(regmap);
+               goto speaker_test_restore;
+       }
+
+       err = speaker_test_stop(regmap);
+       if (err < 0)
+               goto speaker_test_restore;

This sequence looks weird and as if it could be simplified but I might be just plain wrong. speaker_test_stop gets invoked whether or not regmap_read_poll_timeout fails, though only in "happy" path its return is account for. If it's not too much to ask, could you clarify?

+
+       for (i = 0; i < CHANNELS_PER_AMP; ++i) {
+               err = regmap_read(regmap, TDA7802_DB1 + i, status + i);
+               if (err < 0) {
+                       dev_err(dev,
+                               "Cannot get speaker %d status (%d)\n", i, err);
+                       goto speaker_test_restore;
+               }
+       }
+
+speaker_test_restore:
+       err = regmap_update_bits(regmap, TDA7802_IB5, IB5_AMPLIFIER_ON,
+                       amp_on);
+       if (err < 0)
+               dev_err(dev, "Could not restore amp on state (speaker-test)\n");
+
+speaker_test_disable:
+       reg_err = regulator_disable(tda7802->enable_reg);
+       if (reg_err < 0) {
+               dev_err(dev, "Could not disable (speaker-test).\n");
+               return reg_err;
+       }
+       return err;
+}
+
+static ssize_t speaker_test_show(struct device *dev,
+               struct device_attribute *attr, char *buf)
+{
+       struct tda7802_priv *tda7802 = dev_get_drvdata(dev);
+       unsigned int channel_status[CHANNELS_PER_AMP];
+       char *str = buf;
+       int ret, i;
+
+       mutex_lock(&tda7802->mutex);
+       ret = speaker_test_check(tda7802, channel_status);
+       mutex_unlock(&tda7802->mutex);
+       if (ret < 0)
+               return ret;
+
+       for (i = 0; i < CHANNELS_PER_AMP; i++)
+               str += sprintf(str, "%02x ", channel_status[i]);
+       str += sprintf(str, "\n");
+
+       return str - buf;
+}
+
+static DEVICE_ATTR_RO(speaker_test);
+
  static ssize_t enable_show(struct device *dev, struct device_attribute *attr,
                char *buf)
  {
@@ -537,12 +691,28 @@ static int tda7802_probe(struct snd_soc_component 
*component)
dev_dbg(dev, "%s\n", __func__); + /* Device is ready, now we should create sysfs attributes.
+        * Rememer to cleanup
+        */
        err = device_create_file(dev, &dev_attr_enable);
        if (err < 0) {
                dev_err(dev, "Could not create enable attr\n");
                return err;
        }
+ mutex_init(&tda7802->mutex);
+       err = device_create_file(dev, &dev_attr_speaker_test);
+       if (err < 0) {
+               dev_err(dev, "Could not create speaker_test attr\n");
+               goto cleanup_speaker_test;
+       }
+
+       return 0;
+
+cleanup_speaker_test:
+       mutex_destroy(&tda7802->mutex);
+       device_remove_file(&tda7802->i2c->dev, &dev_attr_enable);
+
        return err;
  }
@@ -550,6 +720,8 @@ static void tda7802_remove(struct snd_soc_component *component)
  {
        struct tda7802_priv *tda7802 = snd_soc_component_get_drvdata(component);
+ device_remove_file(&tda7802->i2c->dev, &dev_attr_speaker_test);
+       mutex_destroy(&tda7802->mutex);
        device_remove_file(&tda7802->i2c->dev, &dev_attr_enable);
  }

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