Re: [PATCH v2 2/2] cec: add STM32 cec driver

2017-05-16 15:09 GMT+02:00 Hans Verkuil [off-list ref]:

Looks good, except for the logical address handling that I think is wrong:

On 16/05/17 14:56, Benjamin Gaignard wrote:

quoted

This patch add cec driver for STM32 platforms.
cec hardware block isn't not always used with hdmi so
cec notifier is not implemented. That will be done later
when STM32 DSI driver will be available.

Driver compliance has been tested with cec-ctl and cec-compliance
tools.

Signed-off-by: Benjamin Gaignard <redacted>
Signed-off-by: Yannick Fertre <redacted>
---
 drivers/media/platform/Kconfig           |  11 +
 drivers/media/platform/Makefile          |   2 +
 drivers/media/platform/stm32/Makefile    |   1 +
 drivers/media/platform/stm32/stm32-cec.c | 384 +++++++++++++++++++++++++++++++
 4 files changed, 398 insertions(+)
 create mode 100644 drivers/media/platform/stm32/Makefile
 create mode 100644 drivers/media/platform/stm32/stm32-cec.c

<snip>

quoted

+static int stm32_cec_adap_log_addr(struct cec_adapter *adap, u8 logical_addr)
+{
+     struct stm32_cec *cec = adap->priv;
+
+     regmap_update_bits(cec->regmap, CEC_CR, CECEN, 0);
+
+     if (logical_addr == CEC_LOG_ADDR_INVALID)
+             regmap_update_bits(cec->regmap, CEC_CFGR, OAR, 0);
+     else
+             regmap_update_bits(cec->regmap, CEC_CFGR, OAR,
+                                (1 << logical_addr) << 16);
+
+     regmap_update_bits(cec->regmap, CEC_CR, CECEN, CECEN);
+
+     return 0;
+}
+

If you allocate more than one logical address, then stm32_cec_adap_log_addr()
is called once for each LA. But right now the second call would overwrite
the first LA. Right?

Try 'cec-ctl --audio --playback' to allocate two logical addresses.

I will fix that in v3

<snip>

quoted

+static int stm32_cec_monitor_all(struct cec_adapter *adap, bool enable)
+{
+     struct stm32_cec *cec = adap->priv;
+
+     regmap_update_bits(cec->regmap, CEC_CR, CECEN, 0);
+
+     if (enable) {
+             regmap_update_bits(cec->regmap, CEC_CFGR, OAR, OAR)

You shouldn't have to change the OAR mask. This would have the adapter
Ack all logical addresses.

quoted

+             regmap_update_bits(cec->regmap, CEC_CFGR, LSTN, 0);
+     } else {
+             regmap_update_bits(cec->regmap, CEC_CFGR, OAR, 0);

And this would disable all logical addresses.

I would expect that only the LSTN bit was changed.

In monitoring mode it should still Ack any messages directed to us.

This is an impossible mix in my hardware: messages are received if
corresponding OAR
bit is set and acked if LSTN is set to 1.
It can't receive all messages and only ack some of them....

quoted

+             regmap_update_bits(cec->regmap, CEC_CFGR, LSTN, LSTN);
+     }
+
+     regmap_update_bits(cec->regmap, CEC_CR, CECEN, CECEN);
+
+     return 0;
+}

<snip>

Regards,

        Hans

-- 
Benjamin Gaignard

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