linux-toradex.git/drivers/clk/mvebu, branch v4.0.3

clk: mvebu: add suspend/resume for gatable clocks

2014-11-30T16:40:12+00:00

This commit adds suspend/resume support for the gatable clock driver
used on Marvell EBU platforms. When getting out of suspend, the
Marvell EBU platforms go through the bootloader, which re-enables all
gatable clocks. However, upon resume, the clock framework will not
disable again all gatable clocks that are not used.

Therefore, if the clock driver does not save/restore the state of the
gatable clocks, all gatable clocks that are not claimed by any device
driver will remain enabled after a resume. This is why this driver
saves and restores the state of those clocks.

Since clocks aren't real devices, we don't have the normal ->suspend()
and ->resume() of the device model, and have to use the ->suspend()
and ->resume() hooks of the syscore_ops mechanism. This mechanism has
the unfortunate idea of not providing a way of passing private data,
which requires us to change the driver to make the assumption that
there is only once instance of the gatable clock control structure.

Signed-off-by: Thomas Petazzoni 
Cc: Mike Turquette 
Cc: linux-kernel@vger.kernel.org
Acked-by: Gregory CLEMENT 
Link: https://lkml.kernel.org/r/1416585613-2113-9-git-send-email-thomas.petazzoni@free-electrons.com
Signed-off-by: Jason Cooper

Merge tag 'clk-mvebu-3.18-2' of git://git.infradead.org/linux-mvebu into clk-next

2014-10-03T23:43:02+00:00

clock mvebu changes for v3.18 (round 2)

 - armada 370/375
    - Fix SSCG node lookup

Merge tag 'clk-mvebu-3.18' of git://git.infradead.org/linux-mvebu into clk-next

2014-09-27T00:04:08+00:00

clock changes for mvebu for v3.18

 - correct timer drift caused by SSCG deviation
 - fix typo in comment

clk: mvebu: fix sscg node lookup

2014-09-16T15:39:33+00:00

Commit 15917b16022427c53755abff4dc7051f3076dd7a ("clk: mvebu: Fix clk
frequency value if SSCG is enabled") introduced some logic in the
common mvebu clock code to adjust the clock frequency according to the
configuration of the SSCG.

In order to do this, it looks up for a DT node called "sscg" and maps
it before accessing the SSCG configuration register.

However, the lookup is currently done using:

sscg_np = of_find_node_by_name(np, "sscg");

where "np" is a pointer to the DT node of the clock for which we are
calculating the adjusted frequency. This means that if the "sscg" node
is *after* the clock node in the Device Tree, it works fine (and
that's the case for Armada 370).

However, if it turns out that the "sscg" node is *before* the clock
node in the Device Tree, it won't work because the sscg node will not
be found.

What we really want here is a search of the entire Device Tree, not
only starting from the clock node, so instead of passing "np" as first
argument of of_find_node_by_name(), we simply need to pass
NULL. Passing a non-NULL argument is typically used in a loop, so that
the search for the next matching node starts right after the node that
was matched.

This makes the "np" argument to the kirkwood_fix_sscg_deviation()
function unnecessary, which leads to further cleanups.

Signed-off-by: Thomas Petazzoni
Fixes: 15917b1602242 ("clk: mvebu: Fix clk frequency value if SSCG is enabled")
Acked-by: Gregory CLEMENT
Link: https://lkml.kernel.org/r/1410880503-2322-1-git-send-email-thomas.petazzoni@free-electrons.com
Signed-off-by: Jason Cooper

clk: mvebu: armada-375: Fix the description of the SAR in the comment

2014-09-09T15:15:22+00:00

For dealing with the code we use the SAR1 and not the SAR0. The code
was correct, and now the comments too.

Signed-off-by: Gregory CLEMENT 
Tested-by: Leigh Brown 
Link: https://lkml.kernel.org/r/1409645719-20003-5-git-send-email-gregory.clement@free-electrons.com
Signed-off-by: Jason Cooper

clk: mvebu: armada-370: Fix timer drift caused by the SSCG deviation

2014-09-09T15:15:03+00:00

This commit activates the SSCG deviation correction for the Armada
370. It uses the optional function introduced by the commit "clk:
mvebu: Fix clk frequency value if SSCG is enabled".

Without this fix the deviation measured on a Mirabox was of a few
second each hour, whereas with this fix it was reduced at around
50ppm (around 4s per day).

Signed-off-by: Gregory CLEMENT 
Tested-by: Leigh Brown 
Link: https://lkml.kernel.org/r/1409645719-20003-3-git-send-email-gregory.clement@free-electrons.com
Signed-off-by: Jason Cooper

clk: mvebu: Fix clk frequency value if SSCG is enabled

2014-09-09T15:14:47+00:00

When the SSCG (Spread Spectrum Clock Generator) is enabled, it shifts
the frequency of the clock. The percentage is no more than 1% but when
the clock is used for a timer it leads to a clock drift.

This patch allows to correct the affected clock when the SSCG is
enabled. The check is done in an new optional function related to each
SoC: is_sscg_enabled(). The fix is done with the other new optional
function related to each SoC: fix_sscg_deviation. If one these
functions are not present then no correction is done on the clock
frequency.

Signed-off-by: Gregory CLEMENT 
Tested-by: Leigh Brown 
Link: https://lkml.kernel.org/r/1409645719-20003-2-git-send-email-gregory.clement@free-electrons.com
Signed-off-by: Jason Cooper

cpufreq: kirkwood: use the powersave multiplexer

2014-09-02T22:02:54+00:00

The powersave clock acts like a multiplexer for the cpu, selecting
either the clock signal derived from the cpu pll or from the ddr clock.
This patch changes powersave from a gate clock to a mux clock to better
reflect this behavior.

This is a cleaner approach whereby the frequency of the cpu always
matches the rate of powersave_clk. The cpufreq driver for the kirkwood
platform no longer must parse this behavior out of various calls to
clk_enable and clk_disable, but can instead simply select the parent cpu
it wants when changing rate. Likewise when requesting the cpu rate we
need only query powersave_clk's rate through the usual call to
clk_get_rate.

The new clock data and corresponding changes to the cpufreq driver are
combined into this single commit to avoid a git bisect issue where this
cpufreq driver fails to work properly between the commit that updates
the kirkwood clock driver and the commit that changes how the cpufreq
driver uses that clock.

Cc: Tomeu Vizoso 
Cc: Rafael J. Wysocki 
Tested-by: Andrew Lunn 
Acked-by: Viresh Kumar 
Signed-off-by: Mike Turquette

clk: mvebu: powersave clock is a multiplexer

2014-09-02T00:43:52+00:00

Kirkwood is unique among the mvebu SoCs for having a clock multiplexer
that feeds into the cpu. This multiplexer can select either the cpu pll
or the ddr clock as its input signal, allowing for a choice between
performance and power savings.

This patch introduces the code needed to register the clock multiplexer
on Kirkwood SoCs but does not include the clock data to actually
register the clock. That will be done in a follow-up patch which is
necessary to prevent breaking git bisect.

Cc: Tomeu Vizoso 
Tested-by: Andrew Lunn 
Signed-off-by: Mike Turquette

clk: mvebu: share locks between gate clocks

2014-09-02T00:43:52+00:00

Refactor mvebu_clk_gating_setup() to use a common spinlock instead of a
unique lock for every instance of a struct clk_gating_ctrl object. This
will be used later for a separate mux clock type that shares a register
with gate clock types and needs to use the same lock to protect access
to the register.

Cc: Andrew Lunn 
Tested-by: Andrew Lunn 
Signed-off-by: Mike Turquette