linux-toradex.git/drivers/rtc/rtc-armada38x.c, branch v4.12-rc1

rtc: armada38x: Add support for Armada 7K/8K

2017-02-21T22:21:30+00:00

The Armada 7K/8K use the same RTC IP than the Armada 38x. However the SOC
integration differs in 2 points:
 - MBUS bridge timing initialization
 - IRQ configuration at SoC level

Moreover the Armada 7K/8K have an issue preventing to get the interrupt
from alarm 1. This commit allows to use alarm 2 for these A7K/8K but to
still use alarm 1 for the Armada 38x.

Signed-off-by: Gregory CLEMENT 
Signed-off-by: Alexandre Belloni

rtc: armada38x: Prepare driver to manage different versions

2017-02-21T22:21:28+00:00

In order to prepare the introduction of the A7K/A8K version of the RTC,
this commit introduces a new data structure. This structure allows to
handle the differences between the integration of the RTC IP in the
SoCs. It will be:
 - MBUS bridge timing initialization
 - IRQ configuration at SoC level

Signed-off-by: Gregory CLEMENT 
Signed-off-by: Alexandre Belloni

rtc: armada38x: make struct rtc_class_ops const

2017-01-12T11:33:58+00:00

Armada38x wants to modify its rtc_class_ops to remove the interrupt
handling when there is no usable interrupt, but this means we leave
function pointers in writable memory.

Since rtc_class_ops is small, arrange to have two instances, one for
when we have interrupts, and one for when we have none, both marked
const.  This allows the compiler to place them in read-only memory,
which is better than placing them in __ro_after_init.

Thanks to Bhumika Goyal  for pointing out that
the structure was writable and submitting a patch to add
__ro_after_init.

Signed-off-by: Russell King 
Signed-off-by: Alexandre Belloni

rtc: armada38x: Follow the new recommendation for errata implementation

2017-01-11T16:23:03+00:00

According to RES-3124064:

The device supports CPU write and read access to the RTC time register.
However, due to this restriction, read and write from/to internal RTC
register may fail.

Workaround:
General setup:
1. Configure the RTC Mbus Bridge Timing Control register (offset 0x184A0)
   to value 0xFD4D4FFF
   Write RTC WRCLK Period to its maximum value (0x3FF)
   Write RTC WRCLK setup to 0x29
   Write RTC WRCLK High Time to 0x53 (default value)
   Write RTC Read Output Delay to its maximum value (0x1F)
   Mbus - Read All Byte Enable to 0x1 (default value)
2. Configure the RTC Test Configuration Register (offset 0xA381C) bit3
   to '1' (Reserved, Marvell internal)

For any RTC register read operation:
1. Read the requested register 100 times.
2. Find the result that appears most frequently and use this result
   as the correct value.

For any RTC register write operation:
1. Issue two dummy writes of 0x0 to the RTC Status register (offset
   0xA3800).
2. Write the time to the RTC Time register (offset 0xA380C).

This patch is based on the work of Shaker Daibes

Signed-off-by: Gregory CLEMENT 
Signed-off-by: Alexandre Belloni

rtc: Fix module autoload for OF platform drivers

2015-09-05T17:37:22+00:00

These platform drivers have a OF device ID table but the OF module
alias information is not created so module autoloading won't work.

Signed-off-by: Javier Martinez Canillas 
Acked-by: Andrew Lunn 
Signed-off-by: Alexandre Belloni

rtc: armada38x: Align RTC set time procedure with the official errata

2015-09-05T11:19:12+00:00

According to the Armada38x functional errata FE-3124064, writing to
the RTC TIME register may fail. As a workaround, after writing to RTC
TIME register, issue a dummy write of 0x0 twice to the RTC Status
register.  This is the updated implementation of the Errata that
eliminates the need of the long 100ms delay during the RTC set time
procedure.

[gregory.clement@free-electrons.com]: removed the mutex and use the
spinlock again

Signed-off-by: Nadav Haklai 
Reviewed-by: Neta Zur Hershkovits 
Signed-off-by: Gregory CLEMENT 
Signed-off-by: Alexandre Belloni

rtc: armada38x: Remove unused variable from armada38x_rtc_set_time()

2015-07-17T22:42:31+00:00

Remove the 'flags' variable in order to fix the following warning:

drivers/rtc/rtc-armada38x.c:91:22: warning: unused variable 'flags' [-Wunused-variable]

Signed-off-by: Fabio Estevam 
Signed-off-by: Alexandre Belloni

drivers/rtc/rtc-armada38x.c: remove unused local `flags'

2015-05-15T00:55:51+00:00

Reported-by: Fengguang Wu 
Cc: Gregory CLEMENT 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rtc: armada38x: fix concurrency access in armada38x_rtc_set_time

2015-05-06T00:10:11+00:00

While setting the time, the RTC TIME register should not be accessed.
However due to hardware constraints, setting the RTC time involves
sleeping during 100ms.  This sleep was done outside the critical section
protected by the spinlock, so it was possible to read the RTC TIME
register and get an incorrect value.  This patch introduces a mutex for
protecting the RTC TIME access, unlike the spinlock it is allowed to
sleep in a critical section protected by a mutex.

The RTC STATUS register can still be used from the interrupt handler but
it has no effect on setting the time.

Signed-off-by: Gregory CLEMENT 
Acked-by: Alexandre Belloni 
Acked-by: Andrew Lunn 
Cc: Alessandro Zummo 
Cc: 	[4.0]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

drivers/rtc/rtc-armada38x: add a new RTC driver for recent mvebu SoCs

2015-02-14T05:21:43+00:00

The new mvebu SoCs come with a new RTC driver. This patch adds the
support for this new IP which is currently found in the Armada 38x
SoCs.

This RTC provides two alarms, but only the first one is used in the
driver. The RTC also allows using periodic interrupts.

Signed-off-by: Gregory CLEMENT 
Reviewed-by: Arnaud Ebalard 
Cc: Alessandro Zummo 
Cc: Jason Cooper 
Cc: Andrew Lunn 
Cc: Sebastian Hesselbarth 
Cc: Thomas Petazzoni 
Cc: Ezequiel Garcia 
Cc: Maxime Ripard 
Cc: Boris BREZILLON 
Cc: Lior Amsalem 
Cc: Tawfik Bayouk 
Cc: Nadav Haklai 
Cc: Mark Rutland 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds