On Wednesday, February 22, 2012 09:35:28 Ondrej Zary wrote:
On Tuesday 21 February 2012, Hans Verkuil wrote:
On Saturday, February 18, 2012 17:45:45 Ondrej Zary wrote:
Fix HW seek in TEA575x to work properly:
- a delay must be present after search start and before first register
read or the seek does weird things
- when the search stops, the new frequency is not available immediately,
we must wait until it appears in the register (fortunately, we can clear the frequency bits when starting the search as it starts at the frequency currently set, not from the value written)
- sometimes, seek remains on the current frequency (or moves only a
little), so repeat it until it moves by at least 50 kHz
Signed-off-by: Ondrej Zary linux@rainbow-software.org
--- a/sound/i2c/other/tea575x-tuner.c +++ b/sound/i2c/other/tea575x-tuner.c @@ -89,7 +89,7 @@ static void snd_tea575x_write(struct snd_tea575x *tea, unsigned int val) tea->ops->set_pins(tea, 0); }
-static unsigned int snd_tea575x_read(struct snd_tea575x *tea) +static u32 snd_tea575x_read(struct snd_tea575x *tea) { u16 l, rdata; u32 data = 0; @@ -120,6 +120,27 @@ static unsigned int snd_tea575x_read(struct snd_tea575x *tea) return data; }
+static void snd_tea575x_get_freq(struct snd_tea575x *tea) +{
- u32 freq = snd_tea575x_read(tea) & TEA575X_BIT_FREQ_MASK;
- if (freq == 0) {
tea->freq = 0;Wouldn't it be better to return -EBUSY in this case? VIDIOC_G_FREQUENCY should not return frequencies outside the valid frequency range. In this case returning -EBUSY seems to make more sense to me.
The device returns zero frequency when the scan fails to find a frequency. This is not an error, just an indication that "nothing" is tuned. So maybe we can return some bogus frequency in vidioc_g_frequency (like FREQ_LO) in this case (don't know if -EBUSY will break anything). But HW seek should get the real one (i.e. zero when it's there).
How about the following patch? vidioc_g_frequency just returns the last set frequency and the hw_seek restores the original frequency if it can't find another channel.
Also note that the check for < 50 kHz in hw_seek actually checked for < 500 kHz. I've fixed that, but I can't test it.
Do you also know what happens at the boundaries of the frequency range? Does it wrap around, or do you get a timeout?
Regards,
Hans
diff --git a/sound/i2c/other/tea575x-tuner.c b/sound/i2c/other/tea575x-tuner.c index 474bb81..1bdf1f3 100644 --- a/sound/i2c/other/tea575x-tuner.c +++ b/sound/i2c/other/tea575x-tuner.c @@ -120,14 +120,12 @@ static u32 snd_tea575x_read(struct snd_tea575x *tea) return data; }
-static void snd_tea575x_get_freq(struct snd_tea575x *tea) +static u32 snd_tea575x_get_freq(struct snd_tea575x *tea) { u32 freq = snd_tea575x_read(tea) & TEA575X_BIT_FREQ_MASK;
- if (freq == 0) { - tea->freq = 0; - return; - } + if (freq == 0) + return freq;
/* freq *= 12.5 */ freq *= 125; @@ -138,7 +136,7 @@ static void snd_tea575x_get_freq(struct snd_tea575x *tea) else freq -= TEA575X_FMIF;
- tea->freq = clamp(freq * 16, FREQ_LO, FREQ_HI); /* from kHz */ + return clamp(freq * 16, FREQ_LO, FREQ_HI); /* from kHz */ }
static void snd_tea575x_set_freq(struct snd_tea575x *tea) @@ -224,8 +222,6 @@ static int vidioc_g_frequency(struct file *file, void *priv, if (f->tuner != 0) return -EINVAL; f->type = V4L2_TUNER_RADIO; - if (!tea->cannot_read_data) - snd_tea575x_get_freq(tea); f->frequency = tea->freq; return 0; } @@ -248,14 +244,12 @@ static int vidioc_s_hw_freq_seek(struct file *file, void *fh, struct v4l2_hw_freq_seek *a) { struct snd_tea575x *tea = video_drvdata(file); - int i, old_freq; unsigned long timeout; + int i;
if (tea->cannot_read_data) return -ENOTTY;
- snd_tea575x_get_freq(tea); - old_freq = tea->freq; /* clear the frequency, HW will fill it in */ tea->val &= ~TEA575X_BIT_FREQ_MASK; tea->val |= TEA575X_BIT_SEARCH; @@ -271,26 +265,33 @@ static int vidioc_s_hw_freq_seek(struct file *file, void *fh, if (schedule_timeout_interruptible(msecs_to_jiffies(10))) { /* some signal arrived, stop search */ tea->val &= ~TEA575X_BIT_SEARCH; - snd_tea575x_write(tea, tea->val); + snd_tea575x_set_freq(tea); return -ERESTARTSYS; } if (!(snd_tea575x_read(tea) & TEA575X_BIT_SEARCH)) { + u32 freq; + /* Found a frequency, wait until it can be read */ for (i = 0; i < 100; i++) { msleep(10); - snd_tea575x_get_freq(tea); - if (tea->freq != 0) /* available */ + freq = snd_tea575x_get_freq(tea); + if (freq) /* available */ break; } + if (freq == 0) /* shouldn't happen */ + break; /* if we moved by less than 50 kHz, continue seeking */ - if (abs(old_freq - tea->freq) < 16 * 500) { + if (abs(tea->freq - freq) < 16 * 50) { snd_tea575x_write(tea, tea->val); continue; } + tea->freq = freq; tea->val &= ~TEA575X_BIT_SEARCH; return 0; } } + tea->val &= ~TEA575X_BIT_SEARCH; + snd_tea575x_set_freq(tea); return -ETIMEDOUT; }