diff mbox

[RFC,5/5] drm/i2c: add tda998x/tda9950 CEC driver

Message ID E1bYDEx-0004ry-Jg@rmk-PC.armlinux.org.uk (mailing list archive)
State New, archived
Headers show

Commit Message

Russell King (Oracle) Aug. 12, 2016, 2:15 p.m. UTC
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@armlinux.org.uk>
---
 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

Comments

Hans Verkuil (hansverk) Aug. 12, 2016, 2:38 p.m. UTC | #1
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@armlinux.org.uk>
> ---
>  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.

> +	else
> +		addresses = priv->addresses |= BIT(addr);
> +
> +	/* TDA9950 doesn't want address 15 set */
> +	addr &= 0x7fff;
> +	buf[0] = addresses >> 8;
> +	buf[1] = addresses;
> +
> +	return tda9950_write_range(priv->client, REG_ACKH, buf, 2);
> +}
> +

<snip>

> +static int tda9950_cec_adap_enable(struct cec_adapter *adap, bool enable)
> +{
> +	struct tda9950_priv *priv = adap->priv;
> +
> +	if (!enable) {
> +		tda9950_release(priv);
> +		return 0;
> +	} else {

Nitpick: no need for 'else' here since the 'if' always returns.

> +		return tda9950_open(priv);
> +	}
> +}

Regards,

	Hans
Russell King (Oracle) Aug. 12, 2016, 2:52 p.m. UTC | #2
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@armlinux.org.uk>
> >---
> > 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 |=.
Hans Verkuil (hansverk) Aug. 12, 2016, 3:16 p.m. UTC | #3
On 08/12/2016 04:38 PM, 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@armlinux.org.uk>
>> ---
>>  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.

Yeah, you are right, priv->addresses is used. I've been reviewing too many
patches today.

The whole BIT(15) part remains weird. If log_addr is called with LOG_ADDR_INVALID
as argument, then the intention is that no more messages are to be received (unless
the hardware is in snooping mode). So there is no need to receive broadcast messages
either.

That said, I now realize that if userspace wants to configure the CEC device as
'Unregistered', then adap_log_addr is never called, which would be required if the
hardware has to enable support to receive broadcast messages.

In addition cec_received_msg should ignore received messages if log_addr_mask of
struct cec_log_addrs is 0. I think it will just pass on messages right now, and
that's not right.

I will look at this tomorrow when my brain isn't fried and do some more testing
with 'Unregistered' scenarios.

>
>> +    else
>> +        addresses = priv->addresses |= BIT(addr);
>> +
>> +    /* TDA9950 doesn't want address 15 set */
>> +    addr &= 0x7fff;

Shouldn't this be 'addresses' instead of 'addr'? 'addr' makes no sense here.

And if so, then I still don't understand setting BIT(15), since that bit is
removed by the &=.

>> +    buf[0] = addresses >> 8;
>> +    buf[1] = addresses;
>> +
>> +    return tda9950_write_range(priv->client, REG_ACKH, buf, 2);
>> +}
>> +

Regards,

	Hans
Russell King (Oracle) Aug. 12, 2016, 3:29 p.m. UTC | #4
On Fri, Aug 12, 2016 at 05:16:41PM +0200, Hans Verkuil wrote:
> On 08/12/2016 04:38 PM, 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@armlinux.org.uk>
> >>---
> >> 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.
> 
> Yeah, you are right, priv->addresses is used. I've been reviewing too many
> patches today.
> 
> The whole BIT(15) part remains weird. If log_addr is called with
> LOG_ADDR_INVALID as argument, then the intention is that no more
> messages are to be received (unless the hardware is in snooping mode).
> So there is no need to receive broadcast messages either.

What about hardware where you can't stop it receiving broadcast
addresses?  Should drivers manually check for this in their
interrupt handler?

> That said, I now realize that if userspace wants to configure the CEC
> device as 'Unregistered', then adap_log_addr is never called, which
> would be required if the hardware has to enable support to receive
> broadcast messages.

I don't see how that could possibly work.  The CEC specification
requires that we receive broadcast addressed messages so that (eg)
the current source can be tracked.  Being present on the bus, and
participating as an active source requires the reception of
broadcast messages so that you know when you stop being an active
source.

Nothing (afaics) enables broadcast address reception in the kernel
side, nor using cec-ctl in userspace.

> >>+    else
> >>+        addresses = priv->addresses |= BIT(addr);
> >>+
> >>+    /* TDA9950 doesn't want address 15 set */
> >>+    addr &= 0x7fff;
> 
> Shouldn't this be 'addresses' instead of 'addr'? 'addr' makes no sense here.
> 
> And if so, then I still don't understand setting BIT(15), since that bit is
> removed by the &=.

You're right in this case, but for dw-hdmi, bit 15 must be set for
broadcast messages to be received.
Hans Verkuil (hansverk) Aug. 12, 2016, 3:53 p.m. UTC | #5
On 08/12/2016 05:29 PM, Russell King - ARM Linux wrote:
> On Fri, Aug 12, 2016 at 05:16:41PM +0200, Hans Verkuil wrote:
>> On 08/12/2016 04:38 PM, 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@armlinux.org.uk>
>>>> ---
>>>> 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.
>>
>> Yeah, you are right, priv->addresses is used. I've been reviewing too many
>> patches today.
>>
>> The whole BIT(15) part remains weird. If log_addr is called with
>> LOG_ADDR_INVALID as argument, then the intention is that no more
>> messages are to be received (unless the hardware is in snooping mode).
>> So there is no need to receive broadcast messages either.
>
> What about hardware where you can't stop it receiving broadcast
> addresses?  Should drivers manually check for this in their
> interrupt handler?
>
>> That said, I now realize that if userspace wants to configure the CEC
>> device as 'Unregistered', then adap_log_addr is never called, which
>> would be required if the hardware has to enable support to receive
>> broadcast messages.
>
> I don't see how that could possibly work.  The CEC specification
> requires that we receive broadcast addressed messages so that (eg)
> the current source can be tracked.  Being present on the bus, and
> participating as an active source requires the reception of
> broadcast messages so that you know when you stop being an active
> source.
>
> Nothing (afaics) enables broadcast address reception in the kernel
> side, nor using cec-ctl in userspace.

There are three possible 'states' of a CEC adapter w.r.t. logical addresses:

1) There is no physical address or no logical addresses have been set
by the application (CEC_ADAP_S_LOG_ADDRS): in that case the device
will not participate on the bus, it doesn't care about receiving messages
let alone replying to them. The only exception is if the device can
snoop messages, that is allowed even if CEC_ADAP_S_LOG_ADDRS is never
called. That is ideal to have a 'neutral' observer of the bus that just
listens but never participates. Not all hardware supports snooping, though.

2) CEC_ADAP_S_LOG_ADDRS is called and the device becomes an 'Unregistered'
device (i.e. it gets logical address 15). In that case it should receive
broadcast messages and be able to transmit messages.

3) CEC_ADAP_S_LOG_ADDRS is called and the device claims one or more logical
addresses in the range 0-14. Then it can receive broadcast and directed
messages, and of course transmit messages.

 From the point of view of the hardware state 1 is selected if adap_log_addr
is called with LOG_ADDR_INVALID. Some hardware might still receive broadcast
messages (because they can't turn that off) and those should be filtered out
by the CEC framework. But I think that doesn't happen, which would be a bug.
I'll verify that tomorrow.

State 2 is a problem for hardware that has to enable support to receive
broadcast messages since adap_log_addr is never called with
LOG_ADDR_UNREGISTERED as argument. I missed that, since the hardware I tested
with always accepts broadcast messages. I'll look into this tomorrow as well.
It should be easy to fix.

State 3 works OK.

So for the dw-hdmi cec driver that means that for state 1 you set 'addresses'
to 0, for state 2 you set it to BIT(15) and for state 3 you always
OR with BIT(15). At least, as I understand your hardware.

BTW, if either the tda or dw-hdmi supports snooping mode, then I strongly
recommend supporting that. It's great for debugging.

Regards,

	Hans

>
>>>> +    else
>>>> +        addresses = priv->addresses |= BIT(addr);
>>>> +
>>>> +    /* TDA9950 doesn't want address 15 set */
>>>> +    addr &= 0x7fff;
>>
>> Shouldn't this be 'addresses' instead of 'addr'? 'addr' makes no sense here.
>>
>> And if so, then I still don't understand setting BIT(15), since that bit is
>> removed by the &=.
>
> You're right in this case, but for dw-hdmi, bit 15 must be set for
> broadcast messages to be received.
>
Russell King (Oracle) Aug. 12, 2016, 3:59 p.m. UTC | #6
On Fri, Aug 12, 2016 at 05:53:17PM +0200, Hans Verkuil wrote:
> There are three possible 'states' of a CEC adapter w.r.t. logical addresses:
> 
> 1) There is no physical address or no logical addresses have been set
> by the application (CEC_ADAP_S_LOG_ADDRS): in that case the device
> will not participate on the bus, it doesn't care about receiving messages
> let alone replying to them. The only exception is if the device can
> snoop messages, that is allowed even if CEC_ADAP_S_LOG_ADDRS is never
> called. That is ideal to have a 'neutral' observer of the bus that just
> listens but never participates. Not all hardware supports snooping, though.
> 
> 2) CEC_ADAP_S_LOG_ADDRS is called and the device becomes an 'Unregistered'
> device (i.e. it gets logical address 15). In that case it should receive
> broadcast messages and be able to transmit messages.
> 
> 3) CEC_ADAP_S_LOG_ADDRS is called and the device claims one or more logical
> addresses in the range 0-14. Then it can receive broadcast and directed
> messages, and of course transmit messages.
> 
> From the point of view of the hardware state 1 is selected if adap_log_addr
> is called with LOG_ADDR_INVALID. Some hardware might still receive broadcast
> messages (because they can't turn that off) and those should be filtered out
> by the CEC framework. But I think that doesn't happen, which would be a bug.
> I'll verify that tomorrow.
> 
> State 2 is a problem for hardware that has to enable support to receive
> broadcast messages since adap_log_addr is never called with
> LOG_ADDR_UNREGISTERED as argument. I missed that, since the hardware I tested
> with always accepts broadcast messages. I'll look into this tomorrow as well.
> It should be easy to fix.
> 
> State 3 works OK.
> 
> So for the dw-hdmi cec driver that means that for state 1 you set 'addresses'
> to 0, for state 2 you set it to BIT(15) and for state 3 you always
> OR with BIT(15). At least, as I understand your hardware.

Thanks, I think that needs documenting in Documentation/cec.txt.

> BTW, if either the tda or dw-hdmi supports snooping mode, then I strongly
> recommend supporting that. It's great for debugging.

Neither do.
diff mbox

Patch

diff --git a/drivers/gpu/drm/i2c/Kconfig b/drivers/gpu/drm/i2c/Kconfig
index 22c7ed63a001..f4af13203993 100644
--- a/drivers/gpu/drm/i2c/Kconfig
+++ b/drivers/gpu/drm/i2c/Kconfig
@@ -31,4 +31,9 @@  config DRM_I2C_NXP_TDA998X
 	help
 	  Support for NXP Semiconductors TDA998X HDMI encoders.
 
+config DRM_I2C_NXP_TDA9950
+	tristate "NXP Semiconductors TDA9950/TDA998X HDMI CEC"
+	depends on MEDIA_CEC
+	select HDMI_NOTIFIERS
+
 endmenu
diff --git a/drivers/gpu/drm/i2c/Makefile b/drivers/gpu/drm/i2c/Makefile
index 2c72eb584ab7..07bed58410e9 100644
--- a/drivers/gpu/drm/i2c/Makefile
+++ b/drivers/gpu/drm/i2c/Makefile
@@ -10,3 +10,4 @@  obj-$(CONFIG_DRM_I2C_SIL164) += sil164.o
 
 tda998x-y := tda998x_drv.o
 obj-$(CONFIG_DRM_I2C_NXP_TDA998X) += tda998x.o
+obj-$(CONFIG_DRM_I2C_NXP_TDA9950) += tda9950.o
diff --git a/drivers/gpu/drm/i2c/tda9950.c b/drivers/gpu/drm/i2c/tda9950.c
new file mode 100644
index 000000000000..2a792067f3b2
--- /dev/null
+++ b/drivers/gpu/drm/i2c/tda9950.c
@@ -0,0 +1,514 @@ 
+/*
+ *  TDA9950 Consumer Electronics Control driver
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * The NXP TDA9950 implements the HDMI Consumer Electronics Control
+ * interface.  The host interface is similar to a mailbox: the data
+ * registers starting at REG_CDR0 are written to send a command to the
+ * internal CPU, and replies are read from these registers.
+ *
+ * As the data registers represent a mailbox, they must be accessed
+ * as a single I2C transaction.  See the TDA9950 data sheet for details.
+ */
+#include <linux/delay.h>
+#include <linux/hdmi-notifier.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/platform_data/tda9950.h>
+#include <linux/slab.h>
+#include <drm/drm_edid.h>
+#include <media/cec.h>
+
+enum {
+	REG_CSR = 0x00,
+	CSR_BUSY = BIT(7),
+	CSR_INT  = BIT(6),
+	CSR_ERR  = BIT(5),
+
+	REG_CER = 0x01,
+
+	REG_CVR = 0x02,
+
+	REG_CCR = 0x03,
+	CCR_RESET = BIT(7),
+	CCR_ON    = BIT(6),
+
+	REG_ACKH = 0x04,
+	REG_ACKL = 0x05,
+
+	REG_CCONR = 0x06,
+	CCONR_ENABLE_ERROR = BIT(4),
+
+	REG_CDR0 = 0x07,
+
+	CDR1_REQ = 0x00,
+	CDR1_CNF = 0x01,
+	CDR1_IND = 0x81,
+	CDR1_ERR = 0x82,
+	CDR1_IER = 0x83,
+
+	CDR2_CNF_SUCCESS    = 0x00,
+	CDR2_CNF_OFF_STATE  = 0x80,
+	CDR2_CNF_BAD_REQ    = 0x81,
+	CDR2_CNF_CEC_ACCESS = 0x82,
+	CDR2_CNF_ARB_ERROR  = 0x83,
+	CDR2_CNF_BAD_TIMING = 0x84,
+	CDR2_CNF_NACK_ADDR  = 0x85,
+	CDR2_CNF_NACK_DATA  = 0x86,
+};
+
+struct tda9950_priv {
+	struct i2c_client *client;
+	struct device *hdmi;
+	struct cec_adapter *adap;
+	struct tda9950_glue *glue;
+	u16 addresses;
+	struct cec_msg rx_msg;
+	struct notifier_block nb;
+	bool open;
+};
+
+static int tda9950_write_range(struct i2c_client *client, u8 addr, u8 *p, int cnt)
+{
+	struct i2c_msg msg;
+	u8 buf[cnt + 1];
+	int ret;
+
+	buf[0] = addr;
+	memcpy(buf + 1, p, cnt);
+
+	msg.addr = client->addr;
+	msg.flags = 0;
+	msg.len = cnt + 1;
+	msg.buf = buf;
+
+	dev_dbg(&client->dev, "wr 0x%02x: %*ph\n", addr, cnt, p);
+
+	ret = i2c_transfer(client->adapter, &msg, 1);
+	if (ret < 0)
+		dev_err(&client->dev, "Error %d writing to cec:0x%x\n", ret, addr);
+	return ret < 0 ? ret : 0;
+}
+
+static void tda9950_write(struct i2c_client *client, u8 addr, u8 val)
+{
+	tda9950_write_range(client, addr, &val, 1);
+}
+
+static int tda9950_read_range(struct i2c_client *client, u8 addr, u8 *p, int cnt)
+{
+	struct i2c_msg msg[2];
+	int ret;
+
+	msg[0].addr = client->addr;
+	msg[0].flags = 0;
+	msg[0].len = 1;
+	msg[0].buf = &addr;
+	msg[1].addr = client->addr;
+	msg[1].flags = I2C_M_RD;
+	msg[1].len = cnt;
+	msg[1].buf = p;
+
+	ret = i2c_transfer(client->adapter, msg, 2);
+	if (ret < 0)
+		dev_err(&client->dev, "Error %d reading from cec:0x%x\n", ret, addr);
+
+	dev_dbg(&client->dev, "rd 0x%02x: %*ph\n", addr, cnt, p);
+
+	return ret;
+}
+
+static u8 tda9950_read(struct i2c_client *client, u8 addr)
+{
+	int ret;
+	u8 val;
+
+	ret = tda9950_read_range(client, addr, &val, 1);
+	if (ret < 0)
+		val = 0;
+
+	return val;
+}
+
+static irqreturn_t tda9950_irq(int irq, void *data)
+{
+	struct tda9950_priv *priv = data;
+	unsigned int tx_status;
+	u8 csr, buf[19];
+
+	if (!priv->open)
+		return IRQ_NONE;
+
+	csr = tda9950_read(priv->client, REG_CSR);
+	if (!(csr & CSR_INT))
+		return IRQ_NONE;
+
+	tda9950_read_range(priv->client, REG_CDR0, buf, sizeof(buf));
+
+	/*
+	 * This should never happen: the data sheet says that there will
+	 * always be a valid message if the interrupt line is asserted.
+	 */
+	if (buf[0] == 0) {
+		dev_warn(&priv->client->dev, "interrupt pending, but no message?\n");
+		return IRQ_NONE;
+	}
+
+	switch (buf[1]) {
+	case CDR1_CNF: /* transmit result */
+		switch (buf[2]) {
+		case CDR2_CNF_SUCCESS:
+			tx_status = CEC_TX_STATUS_OK;
+			break;
+
+		case CDR2_CNF_NACK_ADDR:
+			tx_status = CEC_TX_STATUS_NACK;
+			break;
+
+		default: /* some other error, refer to TDA9950 docs */
+			dev_err(&priv->client->dev, "CNF reply error 0x%02x\n",
+				buf[2]);
+			tx_status = CEC_TX_STATUS_ERROR;
+			break;
+		}
+		cec_transmit_done(priv->adap, tx_status, 0, 0, 0, 0);
+		break;
+
+	case CDR1_IND:
+		priv->rx_msg.len = buf[0] - 2;
+		memcpy(priv->rx_msg.msg, buf + 2, priv->rx_msg.len);
+		cec_received_msg(priv->adap, &priv->rx_msg);
+		break;
+
+	default: /* unknown */
+		dev_err(&priv->client->dev, "unknown service id 0x%02x\n",
+			buf[1]);
+		break;
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int tda9950_cec_transmit(struct cec_adapter *adap, u8 attempts,
+				u32 signal_free_time, struct cec_msg *msg)
+{
+	struct tda9950_priv *priv = adap->priv;
+	u8 buf[16 + 2];
+
+	buf[0] = 2 + msg->len;
+	buf[1] = CDR1_REQ;
+	memcpy(buf + 2, msg->msg, msg->len);
+
+	return tda9950_write_range(priv->client, REG_CDR0, buf, 2 + msg->len);
+}
+
+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);
+	else
+		addresses = priv->addresses |= BIT(addr);
+
+	/* TDA9950 doesn't want address 15 set */
+	addr &= 0x7fff;
+	buf[0] = addresses >> 8;
+	buf[1] = addresses;
+
+	return tda9950_write_range(priv->client, REG_ACKH, buf, 2);
+}
+
+/*
+ * When operating as part of the TDA998x, we need additional handling
+ * to initialise and shut down the TDA9950 part of the device.  These
+ * two hooks are provided to allow the TDA998x code to perform those
+ * activities.
+ */
+static int tda9950_glue_open(struct tda9950_priv *priv)
+{
+	int ret = 0;
+
+	if (priv->glue && priv->glue->open)
+		ret = priv->glue->open(priv->glue->data);
+
+	priv->open = true;
+
+	return ret;
+}
+
+static void tda9950_glue_release(struct tda9950_priv *priv)
+{
+	priv->open = false;
+
+	if (priv->glue && priv->glue->release)
+		priv->glue->release(priv->glue->data);
+}
+
+static int tda9950_open(struct tda9950_priv *priv)
+{
+	struct i2c_client *client = priv->client;
+	int ret;
+
+	ret = tda9950_glue_open(priv);
+	if (ret)
+		return ret;
+
+	/* Reset the TDA9950, and wait 250ms for it to recover */
+	tda9950_write(client, REG_CCR, CCR_RESET);
+	msleep(250);
+
+	/* Configure for the standard 5 retries */
+	tda9950_write(client, REG_CCONR, 5);
+	tda9950_cec_adap_log_addr(priv->adap, CEC_LOG_ADDR_INVALID);
+
+	/* Start the command processor */
+	tda9950_write(client, REG_CCR, CCR_ON);
+
+	return 0;
+}
+
+static void tda9950_release(struct tda9950_priv *priv)
+{
+	struct i2c_client *client = priv->client;
+	int timeout = 50;
+	u8 csr;
+
+	/* Stop the command processor */
+	tda9950_write(client, REG_CCR, 0);
+
+	/* Wait up to .5s for it to signal non-busy */
+	do {
+		csr = tda9950_read(client, REG_CSR);
+		if (!(csr & CSR_BUSY) || --timeout)
+			break;
+		msleep(10);
+	} while (1);
+
+	/* Warn the user that their IRQ may die if it's shared. */
+	if (csr & CSR_BUSY)
+		dev_warn(&client->dev, "command processor failed to stop, irq%d may die (csr=0x%02x)\n",
+			 client->irq, csr);
+
+	tda9950_glue_release(priv);
+}
+
+static int tda9950_cec_adap_enable(struct cec_adapter *adap, bool enable)
+{
+	struct tda9950_priv *priv = adap->priv;
+
+	if (!enable) {
+		tda9950_release(priv);
+		return 0;
+	} else {
+		return tda9950_open(priv);
+	}
+}
+
+static const struct cec_adap_ops tda9950_cec_ops = {
+	.adap_enable = tda9950_cec_adap_enable,
+	.adap_log_addr = tda9950_cec_adap_log_addr,
+	.adap_transmit = tda9950_cec_transmit,
+};
+
+static unsigned int parse_hdmi_addr(const struct edid *edid)
+{
+	if (!edid || edid->extensions == 0)
+		return (u16)~0;
+
+	return cec_get_edid_phys_addr((u8 *)edid,
+				EDID_LENGTH * (edid->extensions + 1), NULL);
+}
+
+static int tda9950_cec_notify(struct notifier_block *nb, unsigned long event,
+			      void *data)
+{
+	struct tda9950_priv *priv = container_of(nb, struct tda9950_priv, nb);
+	union hdmi_event *event_block = data;
+	unsigned int phys;
+
+	if (event_block->base.source != priv->hdmi)
+		return NOTIFY_OK;
+
+	switch (event) {
+	case HDMI_DISCONNECTED:
+		cec_s_phys_addr(priv->adap, CEC_PHYS_ADDR_INVALID, false);
+		break;
+
+	case HDMI_NEW_EDID:
+		phys = parse_hdmi_addr(event_block->edid.edid);
+		cec_s_phys_addr(priv->adap, phys, false);
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+/*
+ * When operating as part of the TDA998x, we need to claim additional
+ * resources.  These two hooks permit the management of those resources.
+ */
+static void tda9950_devm_glue_exit(void *data)
+{
+	struct tda9950_glue *glue = data;
+
+	if (glue && glue->exit)
+		glue->exit(glue->data);
+}
+
+static int tda9950_devm_glue_init(struct device *dev, struct tda9950_glue *glue)
+{
+	int ret;
+
+	if (glue && glue->init) {
+		ret = glue->init(glue->data);
+		if (ret)
+			return ret;
+	}
+
+	ret = devm_add_action(dev, tda9950_devm_glue_exit, glue);
+	if (ret)
+		tda9950_devm_glue_exit(glue);
+
+	return ret;
+}
+
+static void tda9950_cec_del(void *data)
+{
+	struct tda9950_priv *priv = data;
+
+	cec_delete_adapter(priv->adap);
+}
+
+static int tda9950_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct tda9950_glue *glue = client->dev.platform_data;
+	struct device *dev = &client->dev;
+	struct tda9950_priv *priv;
+	int ret;
+	u8 cvr;
+
+	/*
+	 * We must have I2C functionality: our multi-byte accesses
+	 * must be performed as a single contiguous transaction.
+	 */
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+		dev_err(&client->dev,
+			"adapter does not support I2C functionality\n");
+		return -ENXIO;
+	}
+
+	/* We must have an interrupt to be functional. */
+	if (client->irq <= 0) {
+		dev_err(&client->dev, "driver requires an interrupt\n");
+		return -ENXIO;
+	}
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->client = client;
+	priv->glue = glue;
+	priv->nb.notifier_call = tda9950_cec_notify;
+
+	i2c_set_clientdata(client, priv);
+
+	/*
+	 * If we're part of a TDA998x, we want the class devices to be
+	 * associated with the HDMI Tx so we have a tight relationship
+	 * between the HDMI interface and the CEC interface.
+	 */
+	priv->hdmi = dev;
+	if (glue && glue->parent)
+		priv->hdmi = glue->parent;
+
+	priv->adap = cec_allocate_adapter(&tda9950_cec_ops, priv, "tda9950",
+					  CEC_CAP_LOG_ADDRS |
+					  CEC_CAP_TRANSMIT | CEC_CAP_RC,
+					  CEC_MAX_LOG_ADDRS, priv->hdmi);
+	if (IS_ERR(priv->adap))
+		return PTR_ERR(priv->adap);
+
+	ret = devm_add_action(dev, tda9950_cec_del, priv);
+	if (ret) {
+		cec_delete_adapter(priv->adap);
+		return ret;
+	}
+
+	ret = tda9950_devm_glue_init(dev, glue);
+	if (ret)
+		return ret;
+
+	ret = tda9950_glue_open(priv);
+	if (ret)
+		return ret;
+
+	cvr = tda9950_read(client, REG_CVR);
+
+	dev_info(&client->dev,
+		 "TDA9950 CEC interface, hardware version %u.%u\n",
+		 cvr >> 4, cvr & 15);
+
+	tda9950_glue_release(priv);
+
+	ret = devm_request_threaded_irq(dev, client->irq, NULL, tda9950_irq,
+					IRQF_TRIGGER_FALLING | IRQF_SHARED |
+					IRQF_ONESHOT,
+					dev_name(&client->dev), priv);
+	if (ret < 0)
+		return ret;
+
+	ret = cec_register_adapter(priv->adap);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * CEC documentation says we must not call cec_delete_adapter
+	 * after a successful call to cec_register_adapter().
+	 */
+	devm_remove_action(dev, tda9950_cec_del, priv);
+
+	hdmi_register_notifier(&priv->nb);
+
+	return ret;
+}
+
+static int tda9950_remove(struct i2c_client *client)
+{
+	struct tda9950_priv *priv = i2c_get_clientdata(client);
+
+	hdmi_unregister_notifier(&priv->nb);
+	cec_unregister_adapter(priv->adap);
+
+	return 0;
+}
+
+static struct i2c_device_id tda9950_ids[] = {
+	{ "tda9950", 0 },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, tda9950_ids);
+
+static struct i2c_driver tda9950_driver = {
+	.probe = tda9950_probe,
+	.remove = tda9950_remove,
+	.driver = {
+		.name = "tda9950",
+	},
+	.id_table = tda9950_ids,
+};
+
+module_i2c_driver(tda9950_driver);
+
+MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>");
+MODULE_DESCRIPTION("TDA9950/TDA998x Consumer Electronics Control Driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/platform_data/tda9950.h b/include/linux/platform_data/tda9950.h
new file mode 100644
index 000000000000..08da9c989dad
--- /dev/null
+++ b/include/linux/platform_data/tda9950.h
@@ -0,0 +1,15 @@ 
+#ifndef LINUX_PLATFORM_DATA_TDA9950_H
+#define LINUX_PLATFORM_DATA_TDA9950_H
+
+struct device;
+
+struct tda9950_glue {
+	struct device *parent;
+	void *data;
+	int (*init)(void *);
+	void (*exit)(void *);
+	int (*open)(void *);
+	void (*release)(void *);
+};
+
+#endif