Re: [PATCH v2 2/2] media: rc: add driver for IR remote receiver on MT7623 SoC

[Sean Wang]

okay, I will continue to work based on your changes unless someone else
has concerns

On Wed, 2017-01-11 at 07:45 +0900, Andi Shyti wrote:
> Hi Sean,
> 
> >include/linux/compiler.h:253:8: sparse: attribute 'no_sanitize_address': 
> > unknown attribute
> > >> drivers/media/rc/mtk-cir.c:215:41: sparse: too many arguments for 
> > >> function devm_rc_allocate_device
> >drivers/media/rc/mtk-cir.c: In function 'mtk_ir_probe':
> >drivers/media/rc/mtk-cir.c:215:11: error: too many arguments to function 
> > 'devm_rc_allocate_device'
> >  ir->rc = devm_rc_allocate_device(dev, RC_DRIVER_IR_RAW);
> >   ^~~
> >In file included from drivers/media/rc/mtk-cir.c:22:0:
> >include/media/rc-core.h:213:16: note: declared here
> > struct rc_dev *devm_rc_allocate_device(struct device *dev);
> >^~~
> > 
> > vim +/devm_rc_allocate_device +215 drivers/media/rc/mtk-cir.c
> > 
> >209  ir->base = devm_ioremap_resource(dev, res);
> >210  if (IS_ERR(ir->base)) {
> >211  dev_err(dev, "failed to map registers\n");
> >212  return PTR_ERR(ir->base);
> >213  }
> >214  
> >  > 215  ir->rc = devm_rc_allocate_device(dev, RC_DRIVER_IR_RAW);
> 
> this error comes because the patches I pointed out have not been
> applied yet. I guess you can ignore them as long as you tested
> yours on top those patches.
> 
> Andi


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Re: [PATCH v2 2/2] media: rc: add driver for IR remote receiver on MT7623 SoC

[Sean Wang]

On Tue, 2017-01-10 at 17:23 +, Sean Young wrote:
> Hi Sean,
> 

> > > 
> > > The kernel guarantees that calls to the interrupt handler are serialised,
> > > no need to disable the interrupt in the handler.
> > 
> > agreed. I will save the mtk irq disable/enable and retest again.
> > 
> > 
> > > > +
> > > > +   /* Reset decoder state machine */
> > > > +   ir_raw_event_reset(ir->rc);
> > > 
> > > Not needed.
> > 
> > 
> > two reasons I added the line here
> > 
> > 1) 
> > I thought it is possible the decoder goes to the
> > middle state when getting the data not belonged
> > to the protocol. If so, that would cause the decoding
> > fails in the next time receiving the valid protocol data.
> 
> The last IR event submitted will always be a long space, that's enough
> to reset the decoders. Adding a ir_raw_event_reset() will do this
> more explicitly, rather than their state machines resetting themselves
> through the trailing space.

thanks for the detailed explanation :) i got it

but some hardware limitation let me can't do it in implicit way :(

reset decoder state machine explicitly is needed because 
1) the longest duration for space MTK IR hardware can record is not
safely long. e.g  12ms if rx resolution is 46us by default. There is
still the risk to satisfying every decoder to reset themselves through
long enough trailing spaces
 
2) the IRQ handler called guarantees that start of IR message is always
contained in and starting from register MTK_CHKDATA_REG(0). 

I will add these words for hardware limitation into comments in the
driver

> > 2) 
> > the mtk hardware register always contains the start of 
> > IR message. So force to sync the state between 
> > HW and ir-core.
> > 
> > 
> > 
> > > > +
> > > > +   /* First message must be pulse */
> > > > +   rawir.pulse = false;
> > > 
> > > pulse = true?
> > 
> > becasue of rawir.pulse = !rawir.pulse does as below
> > so the initial value is set as false.
> 
> Ah, sorry, of course. :)
> 
> > > > +
> > > > +   /* Handle all pulse and space IR controller captures */
> > > > +   for (i = 0 ; i < MTK_CHKDATA_SZ ; i++) {
> > > > +   val = mtk_r32(ir, MTK_CHKDATA_REG(i));
> > > > +   dev_dbg(ir->dev, "@reg%d=0x%08x\n", i, val);
> > > > +
> > > > +   for (j = 0 ; j < 4 ; j++) {
> > > > +   wid = (val & (MTK_WIDTH_MASK << j * 8)) >> j * 
> > > > 8;
> > > > +   rawir.pulse = !rawir.pulse;
> > > > +   rawir.duration = wid * (MTK_IR_SAMPLE + 1);
> > > > +   ir_raw_event_store_with_filter(ir->rc, );
> > > > +   }
> > > 
> > > In v1 you would break out of the loop if the ir message was shorter, but
> > > now you are always passing on 68 pulses and spaces. Is that right?
> > 
> > as I asked in the previous mail list as below i copied from it, so i
> > made some changes ...
> > 
> > "
> > > I had another question. I found multiple and same IR messages being
> > > received when using SONY remote controller. Should driver needs to
> > > report each message or only one of these to the upper layer ?
> > 
> > In general the driver shouldn't try to change any IR message, this
> > should be done in rc-core if necessary.
> > 
> > rc-core should handle this correctly. If the same key is received twice
> > within IR_KEYPRESS_TIMEOUT (250ms) then it not reported to the input
> > layer.
> > 
> > 
> > for example:
> > the 68 pulse/spaces might contains 2.x IR messages when I
> > pressed one key on SONY remote control. 
> > 
> > the v1 proposed is passing only one IR message into ir-core ; 
> > the v2 done is passing all IR messages even including the last
> > incomplete message into ir-core. 
> 
> Yes, agreed. Sorry if I wasn't clear. I just wanted to make sure you've
> thought about what happens when the IR message is short (e.g. rc-5 with
> 23 pulse-spaces). Are the remaining registers 0 or do we get stale data
> from a previous transmit?

Before exit from this IRQ handler , mtk_w32_mask(ir, 0x1, MTK_IRCLR,
MTK_IRCLR_REG) would be done that causes all registers used to store 
pulses and spaces to be cleared, so no stale data appears in the next 
transmit.


> > But I was still afraid the state machine can't  go back to initial state
> > after receiving these incomplete data. 
> > 
> > So the ir_raw_event_reset() call in the beginning of ISR seems becoming
> > more important.
> > 
> > > > +   }
> > > > +
> > > > +   /* The maximum number of edges the IR controller can
> > > > +* hold is MTK_CHKDATA_SZ * 4. So if received IR messages
> > > > +* is over the limit, the last incomplete IR message would
> > > > +* be appended trailing space and still would be sent into
> > > > +* ir-rc-raw to decode. That helps it is possible that it
> > > > +* has 

Re: [PATCH v2 2/2] media: rc: add driver for IR remote receiver on MT7623 SoC

[Andi Shyti]

Hi Sean,

>include/linux/compiler.h:253:8: sparse: attribute 'no_sanitize_address': 
> unknown attribute
> >> drivers/media/rc/mtk-cir.c:215:41: sparse: too many arguments for function 
> >> devm_rc_allocate_device
>drivers/media/rc/mtk-cir.c: In function 'mtk_ir_probe':
>drivers/media/rc/mtk-cir.c:215:11: error: too many arguments to function 
> 'devm_rc_allocate_device'
>  ir->rc = devm_rc_allocate_device(dev, RC_DRIVER_IR_RAW);
>   ^~~
>In file included from drivers/media/rc/mtk-cir.c:22:0:
>include/media/rc-core.h:213:16: note: declared here
> struct rc_dev *devm_rc_allocate_device(struct device *dev);
>^~~
> 
> vim +/devm_rc_allocate_device +215 drivers/media/rc/mtk-cir.c
> 
>209ir->base = devm_ioremap_resource(dev, res);
>210if (IS_ERR(ir->base)) {
>211dev_err(dev, "failed to map registers\n");
>212return PTR_ERR(ir->base);
>213}
>214
>  > 215ir->rc = devm_rc_allocate_device(dev, RC_DRIVER_IR_RAW);

this error comes because the patches I pointed out have not been
applied yet. I guess you can ignore them as long as you tested
yours on top those patches.

Andi
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Re: [PATCH v2 2/2] media: rc: add driver for IR remote receiver on MT7623 SoC

[Sean Young]

Hi Sean,

The driver is looking very good, we are looking at minor details now.

On Tue, Jan 10, 2017 at 09:59:49PM +0800, Sean Wang wrote:
> On Tue, 2017-01-10 at 11:09 +, Sean Young wrote:
> 
> > > +#include 
> > > +#include 
> > > +#include 
> > > +#include 
> > > +#include 
> > > +#include 
> > > +
> > > +#define MTK_IR_DEV KBUILD_MODNAME
> > 
> > You could remove this #define and just use KBUILD_MODNAME
> 
> I preferred to use MTK_IR_DEV internally that helps
> renaming in the future if necessary.

ok.

> >  
> > > +
> > > +/* Register to enable PWM and IR */
> > > +#define MTK_CONFIG_HIGH_REG   0x0c
> > > +/* Enable IR pulse width detection */
> > > +#define MTK_PWM_EN BIT(13)
> > > +/* Enable IR hardware function */
> > > +#define MTK_IR_EN  BIT(0)
> > > +
> > > +/* Register to setting sample period */
> > > +#define MTK_CONFIG_LOW_REG0x10
> > > +/* Field to set sample period */
> > > +#define CHK_PERIOD DIV_ROUND_CLOSEST(MTK_IR_SAMPLE,  \
> > > + MTK_IR_CLK_PERIOD)
> > > +#define MTK_CHK_PERIOD(((CHK_PERIOD) << 8) & (GENMASK(20, 
> > > 8)))
> > > +#define MTK_CHK_PERIOD_MASK(GENMASK(20, 8))
> > > +
> > > +/* Register to clear state of state machine */
> > > +#define MTK_IRCLR_REG 0x20
> > > +/* Bit to restart IR receiving */
> > > +#define MTK_IRCLR  BIT(0)
> > > +
> > > +/* Register containing pulse width data */
> > > +#define MTK_CHKDATA_REG(i)(0x88 + 4 * (i))
> > > +#define MTK_WIDTH_MASK (GENMASK(7, 0))
> > > +
> > > +/* Register to enable IR interrupt */
> > > +#define MTK_IRINT_EN_REG  0xcc
> > > +/* Bit to enable interrupt */
> > > +#define MTK_IRINT_EN   BIT(0)
> > > +
> > > +/* Register to ack IR interrupt */
> > > +#define MTK_IRINT_CLR_REG 0xd0
> > > +/* Bit to clear interrupt status */
> > > +#define MTK_IRINT_CLR  BIT(0)
> > > +
> > > +/* Maximum count of samples */
> > > +#define MTK_MAX_SAMPLES0xff
> > > +/* Indicate the end of IR message */
> > > +#define MTK_IR_END(v, p)   ((v) == MTK_MAX_SAMPLES && (p) == 0)
> > > +/* Number of registers to record the pulse width */
> > > +#define MTK_CHKDATA_SZ 17
> > > +/* Source clock frequency */
> > > +#define MTK_IR_BASE_CLK27300
> > > +/* Frequency after IR internal divider */
> > > +#define MTK_IR_CLK_FREQ(MTK_IR_BASE_CLK / 4)
> 
> > > +static irqreturn_t mtk_ir_irq(int irqno, void *dev_id)
> > > +{
> > > + struct mtk_ir *ir = dev_id;
> > > + u8  wid = 0;
> > > + u32 i, j, val;
> > > + DEFINE_IR_RAW_EVENT(rawir);
> > > +
> > > + mtk_irq_disable(ir, MTK_IRINT_EN);
> > 
> > The kernel guarantees that calls to the interrupt handler are serialised,
> > no need to disable the interrupt in the handler.
> 
> agreed. I will save the mtk irq disable/enable and retest again.
> 
> 
> > > +
> > > + /* Reset decoder state machine */
> > > + ir_raw_event_reset(ir->rc);
> > 
> > Not needed.
> 
> 
> two reasons I added the line here
> 
> 1) 
> I thought it is possible the decoder goes to the
> middle state when getting the data not belonged
> to the protocol. If so, that would cause the decoding
> fails in the next time receiving the valid protocol data.

The last IR event submitted will always be a long space, that's enough
to reset the decoders. Adding a ir_raw_event_reset() will do this
more explicitly, rather than their state machines resetting themselves
through the trailing space.

> 2) 
> the mtk hardware register always contains the start of 
> IR message. So force to sync the state between 
> HW and ir-core.
> 
> 
> 
> > > +
> > > + /* First message must be pulse */
> > > + rawir.pulse = false;
> > 
> > pulse = true?
> 
> becasue of rawir.pulse = !rawir.pulse does as below
> so the initial value is set as false.

Ah, sorry, of course. :)

> > > +
> > > + /* Handle all pulse and space IR controller captures */
> > > + for (i = 0 ; i < MTK_CHKDATA_SZ ; i++) {
> > > + val = mtk_r32(ir, MTK_CHKDATA_REG(i));
> > > + dev_dbg(ir->dev, "@reg%d=0x%08x\n", i, val);
> > > +
> > > + for (j = 0 ; j < 4 ; j++) {
> > > + wid = (val & (MTK_WIDTH_MASK << j * 8)) >> j * 8;
> > > + rawir.pulse = !rawir.pulse;
> > > + rawir.duration = wid * (MTK_IR_SAMPLE + 1);
> > > + ir_raw_event_store_with_filter(ir->rc, );
> > > + }
> > 
> > In v1 you would break out of the loop if the ir message was shorter, but
> > now you are always passing on 68 pulses and spaces. Is that right?
> 
> as I asked in the previous mail list as below i copied from it, so i
> made some changes ...
> 
> "
> > I had another question. I found multiple and same IR messages being
> > received when using SONY remote controller. Should driver needs to
> > report each message or only 

Re: [PATCH v2 2/2] media: rc: add driver for IR remote receiver on MT7623 SoC

[Sean Wang]

On Tue, 2017-01-10 at 11:09 +, Sean Young wrote:

> > +#include 
> > +#include 
> > +#include 
> > +#include 
> > +#include 
> > +#include 
> > +
> > +#define MTK_IR_DEV KBUILD_MODNAME
> 
> You could remove this #define and just use KBUILD_MODNAME

I preferred to use MTK_IR_DEV internally that helps
renaming in the future if necessary.
>  
> > +
> > +/* Register to enable PWM and IR */
> > +#define MTK_CONFIG_HIGH_REG   0x0c
> > +/* Enable IR pulse width detection */
> > +#define MTK_PWM_EN   BIT(13)
> > +/* Enable IR hardware function */
> > +#define MTK_IR_ENBIT(0)
> > +
> > +/* Register to setting sample period */
> > +#define MTK_CONFIG_LOW_REG0x10
> > +/* Field to set sample period */
> > +#define CHK_PERIOD   DIV_ROUND_CLOSEST(MTK_IR_SAMPLE,  \
> > +   MTK_IR_CLK_PERIOD)
> > +#define MTK_CHK_PERIOD(((CHK_PERIOD) << 8) & (GENMASK(20, 8)))
> > +#define MTK_CHK_PERIOD_MASK  (GENMASK(20, 8))
> > +
> > +/* Register to clear state of state machine */
> > +#define MTK_IRCLR_REG 0x20
> > +/* Bit to restart IR receiving */
> > +#define MTK_IRCLRBIT(0)
> > +
> > +/* Register containing pulse width data */
> > +#define MTK_CHKDATA_REG(i)(0x88 + 4 * (i))
> > +#define MTK_WIDTH_MASK   (GENMASK(7, 0))
> > +
> > +/* Register to enable IR interrupt */
> > +#define MTK_IRINT_EN_REG  0xcc
> > +/* Bit to enable interrupt */
> > +#define MTK_IRINT_EN BIT(0)
> > +
> > +/* Register to ack IR interrupt */
> > +#define MTK_IRINT_CLR_REG 0xd0
> > +/* Bit to clear interrupt status */
> > +#define MTK_IRINT_CLRBIT(0)
> > +
> > +/* Maximum count of samples */
> > +#define MTK_MAX_SAMPLES  0xff
> > +/* Indicate the end of IR message */
> > +#define MTK_IR_END(v, p) ((v) == MTK_MAX_SAMPLES && (p) == 0)
> > +/* Number of registers to record the pulse width */
> > +#define MTK_CHKDATA_SZ   17
> > +/* Source clock frequency */
> > +#define MTK_IR_BASE_CLK  27300
> > +/* Frequency after IR internal divider */
> > +#define MTK_IR_CLK_FREQ  (MTK_IR_BASE_CLK / 4)

> > +static irqreturn_t mtk_ir_irq(int irqno, void *dev_id)
> > +{
> > +   struct mtk_ir *ir = dev_id;
> > +   u8  wid = 0;
> > +   u32 i, j, val;
> > +   DEFINE_IR_RAW_EVENT(rawir);
> > +
> > +   mtk_irq_disable(ir, MTK_IRINT_EN);
> 
> The kernel guarantees that calls to the interrupt handler are serialised,
> no need to disable the interrupt in the handler.

agreed. I will save the mtk irq disable/enable and retest again.


> > +
> > +   /* Reset decoder state machine */
> > +   ir_raw_event_reset(ir->rc);
> 
> Not needed.


two reasons I added the line here

1) 
I thought it is possible the decoder goes to the
middle state when getting the data not belonged
to the protocol. If so, that would cause the decoding
fails in the next time receiving the valid protocol data.

2) 
the mtk hardware register always contains the start of 
IR message. So force to sync the state between 
HW and ir-core.



> > +
> > +   /* First message must be pulse */
> > +   rawir.pulse = false;
> 
> pulse = true?

becasue of rawir.pulse = !rawir.pulse does as below
so the initial value is set as false.

> > +
> > +   /* Handle all pulse and space IR controller captures */
> > +   for (i = 0 ; i < MTK_CHKDATA_SZ ; i++) {
> > +   val = mtk_r32(ir, MTK_CHKDATA_REG(i));
> > +   dev_dbg(ir->dev, "@reg%d=0x%08x\n", i, val);
> > +
> > +   for (j = 0 ; j < 4 ; j++) {
> > +   wid = (val & (MTK_WIDTH_MASK << j * 8)) >> j * 8;
> > +   rawir.pulse = !rawir.pulse;
> > +   rawir.duration = wid * (MTK_IR_SAMPLE + 1);
> > +   ir_raw_event_store_with_filter(ir->rc, );
> > +   }
> 
> In v1 you would break out of the loop if the ir message was shorter, but
> now you are always passing on 68 pulses and spaces. Is that right?

as I asked in the previous mail list as below i copied from it, so i
made some changes ...

"
> I had another question. I found multiple and same IR messages being
> received when using SONY remote controller. Should driver needs to
> report each message or only one of these to the upper layer ?

In general the driver shouldn't try to change any IR message, this
should be done in rc-core if necessary.

rc-core should handle this correctly. If the same key is received twice
within IR_KEYPRESS_TIMEOUT (250ms) then it not reported to the input
layer.


for example:
the 68 pulse/spaces might contains 2.x IR messages when I
pressed one key on SONY remote control. 

the v1 proposed is passing only one IR message into ir-core ; 
the v2 done is passing all IR messages even including the last
incomplete message into ir-core. 

But 

Re: [PATCH v2 2/2] media: rc: add driver for IR remote receiver on MT7623 SoC

[kbuild test robot]

Hi Sean,

[auto build test ERROR on linuxtv-media/master]
[also build test ERROR on v4.10-rc3 next-20170110]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:
https://github.com/0day-ci/linux/commits/sean-wang-mediatek-com/Documentation-devicetree-Add-document-bindings-for-mtk-cir/20170110-193357
base:   git://linuxtv.org/media_tree.git master
config: x86_64-allmodconfig (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64 

All errors (new ones prefixed by >>):

   include/linux/compiler.h:253:8: sparse: attribute 'no_sanitize_address': 
unknown attribute
   drivers/media/rc/mtk-cir.c:215:41: sparse: too many arguments for function 
devm_rc_allocate_device
   drivers/media/rc/mtk-cir.c: In function 'mtk_ir_probe':
>> drivers/media/rc/mtk-cir.c:215:11: error: too many arguments to function 
>> 'devm_rc_allocate_device'
 ir->rc = devm_rc_allocate_device(dev, RC_DRIVER_IR_RAW);
  ^~~
   In file included from drivers/media/rc/mtk-cir.c:22:0:
   include/media/rc-core.h:213:16: note: declared here
struct rc_dev *devm_rc_allocate_device(struct device *dev);
   ^~~

sparse warnings: (new ones prefixed by >>)

   include/linux/compiler.h:253:8: sparse: attribute 'no_sanitize_address': 
unknown attribute
>> drivers/media/rc/mtk-cir.c:215:41: sparse: too many arguments for function 
>> devm_rc_allocate_device
   drivers/media/rc/mtk-cir.c: In function 'mtk_ir_probe':
   drivers/media/rc/mtk-cir.c:215:11: error: too many arguments to function 
'devm_rc_allocate_device'
 ir->rc = devm_rc_allocate_device(dev, RC_DRIVER_IR_RAW);
  ^~~
   In file included from drivers/media/rc/mtk-cir.c:22:0:
   include/media/rc-core.h:213:16: note: declared here
struct rc_dev *devm_rc_allocate_device(struct device *dev);
   ^~~

vim +/devm_rc_allocate_device +215 drivers/media/rc/mtk-cir.c

   209  ir->base = devm_ioremap_resource(dev, res);
   210  if (IS_ERR(ir->base)) {
   211  dev_err(dev, "failed to map registers\n");
   212  return PTR_ERR(ir->base);
   213  }
   214  
 > 215  ir->rc = devm_rc_allocate_device(dev, RC_DRIVER_IR_RAW);
   216  if (!ir->rc) {
   217  dev_err(dev, "failed to allocate device\n");
   218  return -ENOMEM;

---
0-DAY kernel test infrastructureOpen Source Technology Center
https://lists.01.org/pipermail/kbuild-all   Intel Corporation


.config.gz
Description: application/gzip

Re: [PATCH v2 2/2] media: rc: add driver for IR remote receiver on MT7623 SoC

[Sean Young]

Hi Sean

Some more review comments. 

On Tue, Jan 10, 2017 at 05:13:51PM +0800, sean.w...@mediatek.com wrote:
> From: Sean Wang 
> 
> This patch adds driver for IR controller on MT7623 SoC.
> and should also work on similar Mediatek SoC. Currently
> testing successfully on NEC and SONY remote controller
> only but it should work on others (lirc, rc-5 and rc-6).
> 
> Signed-off-by: Sean Wang 
> Reviewed-by: Sean Young 
> ---
>  drivers/media/rc/Kconfig   |  11 ++
>  drivers/media/rc/Makefile  |   1 +
>  drivers/media/rc/mtk-cir.c | 326 
> +
>  3 files changed, 338 insertions(+)
>  create mode 100644 drivers/media/rc/mtk-cir.c
> 
> diff --git a/drivers/media/rc/Kconfig b/drivers/media/rc/Kconfig
> index 629e8ca..9228479 100644
> --- a/drivers/media/rc/Kconfig
> +++ b/drivers/media/rc/Kconfig
> @@ -235,6 +235,17 @@ config IR_MESON
>  To compile this driver as a module, choose M here: the
>  module will be called meson-ir.
>  
> +config IR_MTK
> + tristate "Mediatek IR remote receiver"
> + depends on RC_CORE
> + depends on ARCH_MEDIATEK || COMPILE_TEST
> + ---help---
> +Say Y if you want to use the IR remote receiver available
> +on Mediatek SoCs.
> +
> +To compile this driver as a module, choose M here: the
> +module will be called mtk-cir.
> +
>  config IR_NUVOTON
>   tristate "Nuvoton w836x7hg Consumer Infrared Transceiver"
>   depends on PNP
> diff --git a/drivers/media/rc/Makefile b/drivers/media/rc/Makefile
> index 3a984ee..a78570b 100644
> --- a/drivers/media/rc/Makefile
> +++ b/drivers/media/rc/Makefile
> @@ -38,3 +38,4 @@ obj-$(CONFIG_RC_ST) += st_rc.o
>  obj-$(CONFIG_IR_SUNXI) += sunxi-cir.o
>  obj-$(CONFIG_IR_IMG) += img-ir/
>  obj-$(CONFIG_IR_SERIAL) += serial_ir.o
> +obj-$(CONFIG_IR_MTK) += mtk-cir.o
> diff --git a/drivers/media/rc/mtk-cir.c b/drivers/media/rc/mtk-cir.c
> new file mode 100644
> index 000..f752f63
> --- /dev/null
> +++ b/drivers/media/rc/mtk-cir.c
> @@ -0,0 +1,326 @@
> +/*
> + * Driver for Mediatek IR Receiver Controller
> + *
> + * Copyright (C) 2017 Sean Wang 
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +
> +#define MTK_IR_DEV KBUILD_MODNAME

You could remove this #define and just use KBUILD_MODNAME 
> +
> +/* Register to enable PWM and IR */
> +#define MTK_CONFIG_HIGH_REG   0x0c
> +/* Enable IR pulse width detection */
> +#define MTK_PWM_EN BIT(13)
> +/* Enable IR hardware function */
> +#define MTK_IR_EN  BIT(0)
> +
> +/* Register to setting sample period */
> +#define MTK_CONFIG_LOW_REG0x10
> +/* Field to set sample period */
> +#define CHK_PERIOD DIV_ROUND_CLOSEST(MTK_IR_SAMPLE,  \
> + MTK_IR_CLK_PERIOD)
> +#define MTK_CHK_PERIOD(((CHK_PERIOD) << 8) & (GENMASK(20, 8)))
> +#define MTK_CHK_PERIOD_MASK(GENMASK(20, 8))
> +
> +/* Register to clear state of state machine */
> +#define MTK_IRCLR_REG 0x20
> +/* Bit to restart IR receiving */
> +#define MTK_IRCLR  BIT(0)
> +
> +/* Register containing pulse width data */
> +#define MTK_CHKDATA_REG(i)(0x88 + 4 * (i))
> +#define MTK_WIDTH_MASK (GENMASK(7, 0))
> +
> +/* Register to enable IR interrupt */
> +#define MTK_IRINT_EN_REG  0xcc
> +/* Bit to enable interrupt */
> +#define MTK_IRINT_EN   BIT(0)
> +
> +/* Register to ack IR interrupt */
> +#define MTK_IRINT_CLR_REG 0xd0
> +/* Bit to clear interrupt status */
> +#define MTK_IRINT_CLR  BIT(0)
> +
> +/* Maximum count of samples */
> +#define MTK_MAX_SAMPLES0xff
> +/* Indicate the end of IR message */
> +#define MTK_IR_END(v, p)   ((v) == MTK_MAX_SAMPLES && (p) == 0)
> +/* Number of registers to record the pulse width */
> +#define MTK_CHKDATA_SZ 17
> +/* Source clock frequency */
> +#define MTK_IR_BASE_CLK27300
> +/* Frequency after IR internal divider */
> +#define MTK_IR_CLK_FREQ(MTK_IR_BASE_CLK / 4)
> +/* Period for MTK_IR_CLK in ns*/
> +#define MTK_IR_CLK_PERIOD  DIV_ROUND_CLOSEST(10ul,  \
> + MTK_IR_CLK_FREQ)
> +/* Sample period in ns */
> +#define MTK_IR_SAMPLE  

[PATCH v2 2/2] media: rc: add driver for IR remote receiver on MT7623 SoC

[sean.wang]

From: Sean Wang 

This patch adds driver for IR controller on MT7623 SoC.
and should also work on similar Mediatek SoC. Currently
testing successfully on NEC and SONY remote controller
only but it should work on others (lirc, rc-5 and rc-6).

Signed-off-by: Sean Wang 
Reviewed-by: Sean Young 
---
 drivers/media/rc/Kconfig   |  11 ++
 drivers/media/rc/Makefile  |   1 +
 drivers/media/rc/mtk-cir.c | 326 +
 3 files changed, 338 insertions(+)
 create mode 100644 drivers/media/rc/mtk-cir.c

diff --git a/drivers/media/rc/Kconfig b/drivers/media/rc/Kconfig
index 629e8ca..9228479 100644
--- a/drivers/media/rc/Kconfig
+++ b/drivers/media/rc/Kconfig
@@ -235,6 +235,17 @@ config IR_MESON
   To compile this driver as a module, choose M here: the
   module will be called meson-ir.
 
+config IR_MTK
+   tristate "Mediatek IR remote receiver"
+   depends on RC_CORE
+   depends on ARCH_MEDIATEK || COMPILE_TEST
+   ---help---
+  Say Y if you want to use the IR remote receiver available
+  on Mediatek SoCs.
+
+  To compile this driver as a module, choose M here: the
+  module will be called mtk-cir.
+
 config IR_NUVOTON
tristate "Nuvoton w836x7hg Consumer Infrared Transceiver"
depends on PNP
diff --git a/drivers/media/rc/Makefile b/drivers/media/rc/Makefile
index 3a984ee..a78570b 100644
--- a/drivers/media/rc/Makefile
+++ b/drivers/media/rc/Makefile
@@ -38,3 +38,4 @@ obj-$(CONFIG_RC_ST) += st_rc.o
 obj-$(CONFIG_IR_SUNXI) += sunxi-cir.o
 obj-$(CONFIG_IR_IMG) += img-ir/
 obj-$(CONFIG_IR_SERIAL) += serial_ir.o
+obj-$(CONFIG_IR_MTK) += mtk-cir.o
diff --git a/drivers/media/rc/mtk-cir.c b/drivers/media/rc/mtk-cir.c
new file mode 100644
index 000..f752f63
--- /dev/null
+++ b/drivers/media/rc/mtk-cir.c
@@ -0,0 +1,326 @@
+/*
+ * Driver for Mediatek IR Receiver Controller
+ *
+ * Copyright (C) 2017 Sean Wang 
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+
+#define MTK_IR_DEV KBUILD_MODNAME
+
+/* Register to enable PWM and IR */
+#define MTK_CONFIG_HIGH_REG   0x0c
+/* Enable IR pulse width detection */
+#define MTK_PWM_EN   BIT(13)
+/* Enable IR hardware function */
+#define MTK_IR_ENBIT(0)
+
+/* Register to setting sample period */
+#define MTK_CONFIG_LOW_REG0x10
+/* Field to set sample period */
+#define CHK_PERIOD   DIV_ROUND_CLOSEST(MTK_IR_SAMPLE,  \
+   MTK_IR_CLK_PERIOD)
+#define MTK_CHK_PERIOD(((CHK_PERIOD) << 8) & (GENMASK(20, 8)))
+#define MTK_CHK_PERIOD_MASK  (GENMASK(20, 8))
+
+/* Register to clear state of state machine */
+#define MTK_IRCLR_REG 0x20
+/* Bit to restart IR receiving */
+#define MTK_IRCLRBIT(0)
+
+/* Register containing pulse width data */
+#define MTK_CHKDATA_REG(i)(0x88 + 4 * (i))
+#define MTK_WIDTH_MASK   (GENMASK(7, 0))
+
+/* Register to enable IR interrupt */
+#define MTK_IRINT_EN_REG  0xcc
+/* Bit to enable interrupt */
+#define MTK_IRINT_EN BIT(0)
+
+/* Register to ack IR interrupt */
+#define MTK_IRINT_CLR_REG 0xd0
+/* Bit to clear interrupt status */
+#define MTK_IRINT_CLRBIT(0)
+
+/* Maximum count of samples */
+#define MTK_MAX_SAMPLES  0xff
+/* Indicate the end of IR message */
+#define MTK_IR_END(v, p) ((v) == MTK_MAX_SAMPLES && (p) == 0)
+/* Number of registers to record the pulse width */
+#define MTK_CHKDATA_SZ   17
+/* Source clock frequency */
+#define MTK_IR_BASE_CLK  27300
+/* Frequency after IR internal divider */
+#define MTK_IR_CLK_FREQ  (MTK_IR_BASE_CLK / 4)
+/* Period for MTK_IR_CLK in ns*/
+#define MTK_IR_CLK_PERIODDIV_ROUND_CLOSEST(10ul,  \
+   MTK_IR_CLK_FREQ)
+/* Sample period in ns */
+#define MTK_IR_SAMPLE(MTK_IR_CLK_PERIOD * 0xc00)
+
+/* struct mtk_ir - This is the main datasructure for holding the state
+ * of the driver
+ * @dev:   The device pointer
+ * @rc:The rc instrance
+ * @irq:   The IRQ that we are using
+ * @base:  The mapped register i/o base
+ * @clk:   The clock that we are using
+ */
+struct