On Fri, Aug 12, 2016 at 04:38:04PM +0200, Hans Verkuil wrote:
> On 08/12/2016 04:15 PM, Russell King wrote:
> >Add a CEC driver for the TDA9950, which is a stand-alone I2C CEC device.
> >The TDA9950 contains a command processor which handles retransmissions
> >and the low level bus protocol. The driver just has to read and write
> >the messages, and handle error conditions.
> >
> >Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
> >---
> > drivers/gpu/drm/i2c/Kconfig | 5 +
> > drivers/gpu/drm/i2c/Makefile | 1 +
> > drivers/gpu/drm/i2c/tda9950.c | 514 ++++++++++++++++++++++++++++++++++
> > include/linux/platform_data/tda9950.h | 15 +
> > 4 files changed, 535 insertions(+)
> > create mode 100644 drivers/gpu/drm/i2c/tda9950.c
> > create mode 100644 include/linux/platform_data/tda9950.h
> >
>
> <snip>
>
> >+static int tda9950_cec_adap_log_addr(struct cec_adapter *adap, u8 addr)
> >+{
> >+ struct tda9950_priv *priv = adap->priv;
> >+ u16 addresses;
> >+ u8 buf[2];
> >+
> >+ if (addr == CEC_LOG_ADDR_INVALID)
> >+ addresses = priv->addresses = BIT(15);
>
> I saw this in patch 4/5 as well: why set bit 15? I would expect that this
> is just set to 0. And priv->addresses doesn't seem to be used anywhere.
It's needed to be set so that the hardware receives messages sent
to the broadcast (15) address.
> >+ else
> >+ addresses = priv->addresses |= BIT(addr);
For the second point, read this line, paying close attention to the |=.
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