[Linux-kernel-mentees] [PATCH v2 1/2] cec-follower: add tuner step increment/decrement
Hans Verkuil
hverkuil at xs4all.nl
Wed Sep 25 07:12:26 UTC 2019
On 9/25/19 8:54 AM, Hans Verkuil wrote:
> Hi Jiunn,
>
> On 9/24/19 9:24 PM, Jiunn Chang wrote:
>> Tuner step increment/decrement will select the next highest or next
>> lowest service frequency. There are a total of three possible
>> frequencies from analog_freqs_khz given a broadcast type and system.
>>
>> Opcodes implemented:
>> - <Tuner Step Increment>
>> - <Tuner Step Decrement>
>>
>> Signed-off-by: Jiunn Chang <c0d1n61at3 at gmail.com>
>> ---
>> utils/cec-follower/cec-tuner.cpp | 47 ++++++++++++++++++++++++++++++--
>> 1 file changed, 44 insertions(+), 3 deletions(-)
>>
>> diff --git a/utils/cec-follower/cec-tuner.cpp b/utils/cec-follower/cec-tuner.cpp
>> index acc3fd00..1a9b9d90 100644
>> --- a/utils/cec-follower/cec-tuner.cpp
>> +++ b/utils/cec-follower/cec-tuner.cpp
>> @@ -135,6 +135,22 @@ static bool analog_set_tuner_dev_info(struct node *node, struct cec_msg *msg)
>> return false;
>> }
>>
>> +static int analog_find_freq_index(struct cec_op_tuner_device_info *info)
>> +{
>> + if (info->analog.ana_freq == 0)
>> + return -1;
>> +
>> + int ana_freq_khz = (info->analog.ana_freq * 625) / 10;
>> +
>> + for (int i = 0; i < NUM_ANALOG_FREQS; i++) {
>> + int freq = analog_freqs_khz[info->analog.ana_bcast_type][info->analog.bcast_system][i];
>> +
>> + if (ana_freq_khz == freq)
>> + return i;
>> + }
>> + return -1;
>> +}
>
> Hmm, I don't like this code. I think that it would be cleaner to just add:
>
> static unsigned int analog_freq_idx[3][9];
>
> Which contains the index of the current frequency for each bcast_type/system
> combination.
>
> This ensures that 1) there always is a current frequency and 2) tuner stepping
> is now trivial since all you need to do is to update the corresponding index.
I've been reading up on this a bit more, and section CEC 13.8.2 states that the
Tuner Step commands cycle through a set of services defined by the tuner device.
But normally it will cycle through all services.
That means that rather than cycling through the frequencies of just the current
bcast_type/system, the follower should cycle through ALL channels, both analog
and digital.
So for analog we really have 3 * 9 * 3 channels, and this will be more once the
digital channels are added.
In any case, this means that there is just a single 'static unsigned int freq_idx;'
and not an array.
Regards,
Hans
>
> Now, that said, I was thinking that it would be nice to have one bcast_type/system
> combo with no channels at all, since that's a nice test as well.
>
> I think that setting secam-lq for satellite to { 0, 0, 0 } to indicate no
> defined channels would make a nice test case.
>
> Something for a follow-up patch, though.
>
>> +
>> void process_tuner_record_timer_msgs(struct node *node, struct cec_msg &msg, unsigned me)
>> {
>> bool is_bcast = cec_msg_is_broadcast(&msg);
>> @@ -178,12 +194,37 @@ void process_tuner_record_timer_msgs(struct node *node, struct cec_msg &msg, uns
>> return;
>>
>> case CEC_MSG_SELECT_DIGITAL_SERVICE:
>> - case CEC_MSG_TUNER_STEP_DECREMENT:
>> - case CEC_MSG_TUNER_STEP_INCREMENT:
>> - if (!cec_has_tuner(1 << me))
>> + case CEC_MSG_TUNER_STEP_DECREMENT: {
>> + if (!cec_has_tuner(1 << me) && !cec_has_tv(1 << me))
>> break;
>> +
>> + struct cec_op_tuner_device_info *info = &node->state.tuner_dev_info;
>> + int freq_idx = analog_find_freq_index(info);
>> + int idx = (freq_idx == 0) ? NUM_ANALOG_FREQS : freq_idx;
>> +
>> + if (info->is_analog) {
>> + int freq = analog_freqs_khz[info->analog.ana_bcast_type][info->analog.bcast_system][--idx];
>> +
>> + info->analog.ana_freq = (freq * 10) / 625;
>> + }
>> return;
>> + }
>> +
>> + case CEC_MSG_TUNER_STEP_INCREMENT: {
>> + if (!cec_has_tuner(1 << me) && !cec_has_tv(1 << me))
>> + break;
>>
>> + struct cec_op_tuner_device_info *info = &node->state.tuner_dev_info;
>> + int freq_idx = analog_find_freq_index(info);
>> + int idx = (freq_idx == NUM_ANALOG_FREQS - 1) ? -1 : freq_idx;
>> +
>> + if (info->is_analog) {
>> + int freq = analog_freqs_khz[info->analog.ana_bcast_type][info->analog.bcast_system][++idx];
>> +
>> + info->analog.ana_freq = (freq * 10) / 625;
>> + }
>> + return;
>> + }
>>
>> /*
>> One Touch Record
>>
>
> Regards,
>
> Hans
>
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