RE: [PATCH] mfd: max77686: Fix parent of rtc device

2014-12-03 Thread Yadwinder Singh Brar


On Tuesday, December 02, 2014 7:04 PM, Krzysztof Kozłowski wrote: 
 On 02.12.2014 13:45, Yadwinder Singh Brar wrote:
  rtc have different i2c client than power(pmic) block. So rtc device
  should sit under its own i2c client in device hierarchy, which
 reflects in sysfs also.
  This patch modifies code to register rtc cell with rtc-dev as
 parent.
 
  Without this patch :
  # ls /sys/class/i2c-adapter/i2c-0/0-0009/
  driver max77686-pmic  modalias   power  uevent
  max77686-clk   max77686-rtc   name   subsystem
 
  After applying patch :
  # ls /sys/class/i2c-adapter/i2c-0/0-0006/
  driver/modalias   power/ uevent
  max77686-rtc/  name   subsystem/
 
  Signed-off-by: Yadwinder Singh Brar yadi.b...@samsung.com
  ---
 
  Or Can we follow another (exhaustive but more cleaner) approach,
 which
  will be more like code refactoring and cleanup rather than only fix:
  Since rtc uses i2c client, which gets created using i2c_new_dummy()
  and is not shared by any other cell of max77686. So we can covert rtc
  platform driver itself to i2c client driver. It will also allow to
  expilicitly describe max77686-rtc in DT which we can't do now.
  It can be applicable to some other existing and new mfd pmic drivers.
  Any suggestion/comments ?
 
 Hi,
 
 What kind of problem is solved by this patch?


Let me try to explain once again :)
After seeing a message i2c i2c-0:  , addr=0x06, .. in dmesg log,
I was not able to find any such device in sysfs as well as device tree.
There was no device under /sys/class/i2c-dev/i2c-0/device/0-0006/
Isn't something wrong or missing ?

This patch fixes that missing parent child relation, which IMO
should be correct always, though it causes any major problem or not.

Still I am thinking, 0-0006 slave device(rtc) shouldn't also appear in DT?
As DT should describe the hardware that we are using.

Warm regards,
Yadwinder

 Best regards,
 Krzysztof
 
 
 
  ---
   drivers/mfd/max77686.c |   22 --
   1 files changed, 20 insertions(+), 2 deletions(-)
 
  diff --git a/drivers/mfd/max77686.c b/drivers/mfd/max77686.c index
  929795e..22c0948 100644
  --- a/drivers/mfd/max77686.c
  +++ b/drivers/mfd/max77686.c
  @@ -39,10 +39,13 @@
 
   static const struct mfd_cell max77686_devs[] = {
  { .name = max77686-pmic, },
  -   { .name = max77686-rtc, },
  { .name = max77686-clk, },
   };
 
  +static const struct mfd_cell max77686_rtc_dev[] = {
  +   { .name = max77686-rtc, },
  +};
  +
   static const struct mfd_cell max77802_devs[] = {
  { .name = max77802-pmic, },
  { .name = max77802-clk, },
  @@ -332,14 +335,27 @@ static int max77686_i2c_probe(struct i2c_client
 *i2c,
  goto err_del_irqc;
  }
 
  +   if (max77686-type == TYPE_MAX77686) {
  +   ret = mfd_add_devices(max77686-rtc-dev, -1,
 max77686_rtc_dev,
  +   1, NULL, 0, NULL);
  +   if (ret  0) {
  +   dev_err(max77686-rtc-dev,
  +   failed to add RTC device %d\n, ret);
  +   goto err_del_rtc_irqc;
  +   }
  +   }
  +
  ret = mfd_add_devices(max77686-dev, -1, cells, n_devs, NULL, 0,
 NULL);
  if (ret  0) {
  dev_err(i2c-dev, failed to add MFD devices: %d\n, ret);
  -   goto err_del_rtc_irqc;
  +   goto err_del_rtc_dev;
  }
 
  return 0;
 
  +err_del_rtc_dev:
  +   if (max77686-type == TYPE_MAX77686)
  +   mfd_remove_devices(max77686-rtc-dev);
   err_del_rtc_irqc:
  regmap_del_irq_chip(max77686-irq, max77686-rtc_irq_data);
   err_del_irqc:
  @@ -356,6 +372,8 @@ static int max77686_i2c_remove(struct i2c_client
 *i2c)
  struct max77686_dev *max77686 = i2c_get_clientdata(i2c);
 
  mfd_remove_devices(max77686-dev);
  +   if (max77686-type == TYPE_MAX77686)
  +   mfd_remove_devices(max77686-rtc-dev);
 
  regmap_del_irq_chip(max77686-irq, max77686-rtc_irq_data);
  regmap_del_irq_chip(max77686-irq, max77686-irq_data);
 

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Re: [PATCH] mfd: max77686: Fix parent of rtc device

2014-12-03 Thread Krzysztof Kozlowski
On śro, 2014-12-03 at 14:32 +0530, Yadwinder Singh Brar wrote:
 
 On Tuesday, December 02, 2014 7:04 PM, Krzysztof Kozłowski wrote: 
  On 02.12.2014 13:45, Yadwinder Singh Brar wrote:
   rtc have different i2c client than power(pmic) block. So rtc device
   should sit under its own i2c client in device hierarchy, which
  reflects in sysfs also.
   This patch modifies code to register rtc cell with rtc-dev as
  parent.
  
   Without this patch :
   # ls /sys/class/i2c-adapter/i2c-0/0-0009/
   driver max77686-pmic  modalias   power  uevent
   max77686-clk   max77686-rtc   name   subsystem
  
   After applying patch :
   # ls /sys/class/i2c-adapter/i2c-0/0-0006/
   driver/modalias   power/ uevent
   max77686-rtc/  name   subsystem/
  
   Signed-off-by: Yadwinder Singh Brar yadi.b...@samsung.com
   ---
  
   Or Can we follow another (exhaustive but more cleaner) approach,
  which
   will be more like code refactoring and cleanup rather than only fix:
   Since rtc uses i2c client, which gets created using i2c_new_dummy()
   and is not shared by any other cell of max77686. So we can covert rtc
   platform driver itself to i2c client driver. It will also allow to
   expilicitly describe max77686-rtc in DT which we can't do now.
   It can be applicable to some other existing and new mfd pmic drivers.
   Any suggestion/comments ?
  
  Hi,
  
  What kind of problem is solved by this patch?
 
 
 Let me try to explain once again :)
 After seeing a message i2c i2c-0:  , addr=0x06, .. in dmesg log,
 I was not able to find any such device in sysfs as well as device tree.
 There was no device under /sys/class/i2c-dev/i2c-0/device/0-0006/
 Isn't something wrong or missing ?
 
 This patch fixes that missing parent child relation, which IMO
 should be correct always, though it causes any major problem or not.

OK, I got your point. I'm fine with both solutions and the patch looks
good, so:
Reviewed-by: Krzysztof Kozlowski k.kozlow...@samsung.com

 Still I am thinking, 0-0006 slave device(rtc) shouldn't also appear in DT?
 As DT should describe the hardware that we are using.

Your patch properly describes the hardware. However from driver
perspective, the RTC here is not an standalone driver and depends on
parent (MFD) driver.

Although max77686 RTC could have its own DeviceTree node, I think it
should still be put under main MFD driver's node, because the parent
manages stuff like interrupts.

Best regards,
Krzysztof





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RE: [PATCH] mfd: max77686: Fix parent of rtc device

2014-12-03 Thread Yadwinder Singh Brar
On Wednesday, December 03, 2014 2:56 PM, Krzysztof Kozlowski wrote:
 
 On śro, 2014-12-03 at 14:32 +0530, Yadwinder Singh Brar wrote:
 
  On Tuesday, December 02, 2014 7:04 PM, Krzysztof Kozłowski wrote:
   On 02.12.2014 13:45, Yadwinder Singh Brar wrote:
rtc have different i2c client than power(pmic) block. So rtc
device should sit under its own i2c client in device hierarchy,
which
   reflects in sysfs also.
This patch modifies code to register rtc cell with rtc-dev as
   parent.
   
Without this patch :
# ls /sys/class/i2c-adapter/i2c-0/0-0009/
driver max77686-pmic  modalias   power
 uevent
max77686-clk   max77686-rtc   name   subsystem
   
After applying patch :
# ls /sys/class/i2c-adapter/i2c-0/0-0006/
driver/modalias   power/ uevent
max77686-rtc/  name   subsystem/
   
Signed-off-by: Yadwinder Singh Brar yadi.b...@samsung.com
---
   
Or Can we follow another (exhaustive but more cleaner) approach,
   which
will be more like code refactoring and cleanup rather than only
 fix:
Since rtc uses i2c client, which gets created using
i2c_new_dummy() and is not shared by any other cell of max77686.
So we can covert rtc platform driver itself to i2c client driver.
It will also allow to expilicitly describe max77686-rtc in DT
 which we can't do now.
It can be applicable to some other existing and new mfd pmic
 drivers.
Any suggestion/comments ?
  
   Hi,
  
   What kind of problem is solved by this patch?
  
 
  Let me try to explain once again :)
  After seeing a message i2c i2c-0:  , addr=0x06, .. in dmesg
 log,
  I was not able to find any such device in sysfs as well as device
 tree.
  There was no device under /sys/class/i2c-dev/i2c-0/device/0-0006/
  Isn't something wrong or missing ?
 
  This patch fixes that missing parent child relation, which IMO should
  be correct always, though it causes any major problem or not.
 
 OK, I got your point. I'm fine with both solutions and the patch looks
 good, so:
 Reviewed-by: Krzysztof Kozlowski k.kozlow...@samsung.com
 

Thanks for reviewing :).

  Still I am thinking, 0-0006 slave device(rtc) shouldn't also appear
 in DT?
  As DT should describe the hardware that we are using.
 
 Your patch properly describes the hardware. However from driver
 perspective, the RTC here is not an standalone driver and depends on
 parent (MFD) driver.
 

Hmm ... I can't see any hard dependency. I think rtc can survive as independent 
i2c device.
And rtc(@06) is more like a sibling of existing MFD driver(max77686@09)

 Although max77686 RTC could have its own DeviceTree node, I think it
 should still be put under main MFD driver's node, because the parent
 manages stuff like interrupts.
 

I think it will not sound good to have something like max77686-rtc@06
node under max77686@09 node, since both are kind of siblings.
And interrupts should not be a restricting factor, In case of
max77686 interrupt source and mask registers for rtc also lie in rtc
i2c register bank so we can add an irq_chip from rtc driver itself.

Only thing I can see which can be little bit tricky, is providing
alarm-pending info(pending interrupt) in alarm_read() callback
in rtc as currently its based on MAX77686_REG_STATUS2 which is
only common register in power(pmic) register bank of max77686.
Though in practical scenarios it may not be non zero, since
reading once source register clears this status also, but we may
have to keep it for sake of functionality completeness.

I can’t see any way(something similar to syscon) for sharing
i2c regmap between independent drivers, other than getting
reference to regmap from i2c device found by of_find_i2c_device_by_node().
Anyone can suggest better idea?


Best Regards,
Yadwinder

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Re: [PATCH] mfd: max77686: Fix parent of rtc device

2014-12-02 Thread Krzysztof Kozłowski
On 02.12.2014 13:45, Yadwinder Singh Brar wrote:
 rtc have different i2c client than power(pmic) block. So rtc device should
 sit under its own i2c client in device hierarchy, which reflects in sysfs 
 also.
 This patch modifies code to register rtc cell with rtc-dev as parent.
 
 Without this patch :
 # ls /sys/class/i2c-adapter/i2c-0/0-0009/
 driver max77686-pmic  modalias   power  uevent
 max77686-clk   max77686-rtc   name   subsystem
 
 After applying patch :
 # ls /sys/class/i2c-adapter/i2c-0/0-0006/
 driver/modalias   power/ uevent
 max77686-rtc/  name   subsystem/
 
 Signed-off-by: Yadwinder Singh Brar yadi.b...@samsung.com
 ---
 
 Or Can we follow another (exhaustive but more cleaner) approach, which will
 be more like code refactoring and cleanup rather than only fix:
 Since rtc uses i2c client, which gets created using i2c_new_dummy() and is not
 shared by any other cell of max77686. So we can covert rtc platform driver
 itself to i2c client driver. It will also allow to expilicitly describe
 max77686-rtc in DT which we can't do now.
 It can be applicable to some other existing and new mfd pmic drivers.
 Any suggestion/comments ?

Hi,

What kind of problem is solved by this patch?

Best regards,
Krzysztof


 
 ---
  drivers/mfd/max77686.c |   22 --
  1 files changed, 20 insertions(+), 2 deletions(-)
 
 diff --git a/drivers/mfd/max77686.c b/drivers/mfd/max77686.c
 index 929795e..22c0948 100644
 --- a/drivers/mfd/max77686.c
 +++ b/drivers/mfd/max77686.c
 @@ -39,10 +39,13 @@
  
  static const struct mfd_cell max77686_devs[] = {
   { .name = max77686-pmic, },
 - { .name = max77686-rtc, },
   { .name = max77686-clk, },
  };
  
 +static const struct mfd_cell max77686_rtc_dev[] = {
 + { .name = max77686-rtc, },
 +};
 +
  static const struct mfd_cell max77802_devs[] = {
   { .name = max77802-pmic, },
   { .name = max77802-clk, },
 @@ -332,14 +335,27 @@ static int max77686_i2c_probe(struct i2c_client *i2c,
   goto err_del_irqc;
   }
  
 + if (max77686-type == TYPE_MAX77686) {
 + ret = mfd_add_devices(max77686-rtc-dev, -1, max77686_rtc_dev,
 + 1, NULL, 0, NULL);
 + if (ret  0) {
 + dev_err(max77686-rtc-dev,
 + failed to add RTC device %d\n, ret);
 + goto err_del_rtc_irqc;
 + }
 + }
 +
   ret = mfd_add_devices(max77686-dev, -1, cells, n_devs, NULL, 0, NULL);
   if (ret  0) {
   dev_err(i2c-dev, failed to add MFD devices: %d\n, ret);
 - goto err_del_rtc_irqc;
 + goto err_del_rtc_dev;
   }
  
   return 0;
  
 +err_del_rtc_dev:
 + if (max77686-type == TYPE_MAX77686)
 + mfd_remove_devices(max77686-rtc-dev);
  err_del_rtc_irqc:
   regmap_del_irq_chip(max77686-irq, max77686-rtc_irq_data);
  err_del_irqc:
 @@ -356,6 +372,8 @@ static int max77686_i2c_remove(struct i2c_client *i2c)
   struct max77686_dev *max77686 = i2c_get_clientdata(i2c);
  
   mfd_remove_devices(max77686-dev);
 + if (max77686-type == TYPE_MAX77686)
 + mfd_remove_devices(max77686-rtc-dev);
  
   regmap_del_irq_chip(max77686-irq, max77686-rtc_irq_data);
   regmap_del_irq_chip(max77686-irq, max77686-irq_data);
 

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