On SAMA7G5 the prescaler part of master clock has been implemented as a
changeable one. Everytime the prescaler is changed the PMC_SR.MCKRDY bit
must be polled. Value 1 for PMC_SR.MCKRDY means the prescaler update is
done. Driver polls for this bit until it becomes 1. On SAMA7G5 it has
been discovered that in some conditions the PMC_SR.MCKRDY is not rising
but the rate it provides it's stable. The workaround is to add a timeout
when polling for PMC_SR.MCKRDY. At the moment, for SAMA7G5, the prescaler
will be removed from Linux clock tree as all the frequencies for CPU could
be obtained from PLL and also there will be less overhead when changing
frequency via DVFS.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20211011112719.3951784-14-claudiu.beznea@microchip.com
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
SAMA7G5 supports DVFS by changing cpuck. On SAMA7G5 mck0 shares the same
parent with cpuck as seen in the following clock tree:
+----------> cpuck
|
FRAC PLL ---> DIV PLL -+-> DIV ---> mck0
mck0 could go b/w 32KHz and 200MHz on SAMA7G5. To avoid mck0 overclocking
while changing FRAC PLL or DIV PLL the commit implements a notifier for
mck0 which applies a safe divider to register (maximum value of the divider
which is 5) on PRE_RATE_CHANGE events (such that changes on PLL to not
overclock mck0) and sets the maximum allowed rate on POST_RATE_CHANGE
events.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20211011112719.3951784-13-claudiu.beznea@microchip.com
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
SAM9X60's PLL which is also part of SAMA7G5 is composed of 2 parts:
one fractional part and one divider. On SAMA7G5 the CPU PLL could be
changed at run-time to implement DVFS. The hardware clock tree on
SAMA7G5 for CPU PLL is as follows:
+---- div1 ----------------> cpuck
|
FRAC PLL ---> DIV PLL -+-> prescaler ---> div0 ---> mck0
The div1 block is not implemented in Linux; on prescaler block it has
been discovered a bug on some scenarios and will be removed from Linux
in next commits. Thus, the final clock tree that will be used in Linux
will be as follows:
+-----------> cpuck
|
FRAC PLL ---> DIV PLL -+-> div0 ---> mck0
It has been proposed in [1] to not introduce a new CPUFreq driver but
to overload the proper clock drivers with proper operation such that
cpufreq-dt to be used. To accomplish this DIV PLL and div0 implement
clock notifiers which applies safe dividers before FRAC PLL is changed.
The current commit treats only the DIV PLL by adding a notifier that
sets a safe divider on PRE_RATE_CHANGE events. The safe divider is
provided by initialization clock code (sama7g5.c). The div0 is treated
in next commits (to keep the changes as clean as possible).
[1] https://lore.kernel.org/lkml/20210105104426.4tmgc2l3vyicwedd@vireshk-i7/
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20211011112719.3951784-12-claudiu.beznea@microchip.com
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
SAMA7G5 has 4 master clocks (MCK1..4) which are controlled though the
register at offset 0x30 (relative to PMC). In the last/first phase of
suspend/resume procedure (which is architecture specific) the parent
of master clocks are changed (via assembly code) for more power saving
(see file arch/arm/mach-at91/pm_suspend.S, macros at91_mckx_ps_enable
and at91_mckx_ps_restore). Thus the macros corresponding to register
at offset 0x30 need to be shared b/w clk-master.c and pm_suspend.S.
commit ec03f18cc2 ("clk: at91: add register definition for sama7g5's
master clock") introduced the proper macros but didn't adapted the
clk-master.c as well. Thus, this commit adapt the clk-master.c to use
the macros introduced in commit ec03f18cc2 ("clk: at91: add register
definition for sama7g5's master clock").
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20211011112719.3951784-5-claudiu.beznea@microchip.com
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
SAMA5D2 and SAMA7G5 have a special power saving mode (backup mode) where
most of the SoC's components are powered off (including PMC). Resuming
from this mode is done with the help of bootloader. Peripherals are not
aware of the power saving mode thus most of them are disabling clocks in
proper suspend API and re-enable them in resume API without taking into
account the previously setup rate. Moreover some of the peripherals are
acting as wakeup sources and are not disabling the clocks in this
scenario, when suspending. Since backup mode cuts the power for
peripherals, in resume part these clocks needs to be re-configured.
The initial PMC suspend/resume code was designed only for SAMA5D2's PMC
(as it was the only one supporting backup mode). SAMA7G supports also
backup mode and its PMC is different (few new functionalities, different
registers offsets, different offsets in registers for each
functionalities). To address both SAMA5D2 and SAMA7G5 PMC add
.save_context()/.resume_context() support to each clocks driver and call
this from PMC driver.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20211011112719.3951784-2-claudiu.beznea@microchip.com
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
The Ux500 PRCC (peripheral reset and clock controller) can also
control reset of the IP blocks, not just clocks. As the PRCC is probed
as a clock controller and we have other platforms implementing combined
clock and reset controllers, follow this pattern and implement the PRCC
rest controller as part of the clock driver.
The reset controller needs to be selected from the machine as Ux500 has
traditionally selected its mandatory subsystem prerequisites from there.
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210921184803.1757916-2-linus.walleij@linaro.org
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
[sboyd@kernel.org: Dropped allocation error message]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
The driver, once it found a divider, tries to round it up by increasing
the least significant bit of the fractional part by one when the
round_up argument is set and there's a remainder.
However, since it increases the divider it will actually reduce the
clock rate below what we were asking for, leading to issues with
clk_set_min_rate() that will complain that our rounded clock rate is
below the minimum of the rate.
Since the dividers are fairly precise already, let's remove that part so
that we can have clk_set_min_rate() working.
This is effectively a revert of 9c95b32ca0 ("clk: bcm2835: add a round
up ability to the clock divisor").
Fixes: 9c95b32ca0 ("clk: bcm2835: add a round up ability to the clock divisor")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Reviewed-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Tested-by: Nicolas Saenz Julienne <nsaenz@kernel.org> # boot and basic functionality
Tested-by: Michael Stapelberg <michael@stapelberg.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922125419.4125779-3-maxime@cerno.tech
The driver currently tries to pick the closest rate that is lower than
the rate being requested.
This causes an issue with clk_set_min_rate() since it actively checks
for the rounded rate to be above the minimum that was just set.
Let's change the logic a bit to pick the closest rate to the requested
rate, no matter if it's actually higher or lower.
Fixes: 6d18b8adbe ("clk: bcm2835: Support for clock parent selection")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Reviewed-by: Nicolas Saenz Julienne <nsaenz@kernel.org>
Tested-by: Nicolas Saenz Julienne <nsaenz@kernel.org> # boot and basic functionality
Tested-by: Michael Stapelberg <michael@stapelberg.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210922125419.4125779-2-maxime@cerno.tech
Update clk_composite_determine_rate() to use rate_ops.determine_rate
when available in combination with a mux. So far clk_divider_ops provide
both, .round_rate and .determine_rate. Removing the former would make
clk-composite fail silently for example on Rockchip platforms (which
heavily use composite clocks).
Add support for using rate_ops.determine_rate when either
rate_ops.round_rate is not available or both (.round_rate and
.determine_rate) are provided.
Suggested-by: Alex Bee <knaerzche@gmail.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20211016105022.303413-3-martin.blumenstingl@googlemail.com
Tested-by: Alex Bee <knaerzche@gmail.com>
Tested-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Commit 69a00fb3d6 ("clk: divider: Implement and wire up
.determine_rate by default") switches clk_divider_ops to implement
.determine_rate by default. This breaks composite clocks with multiple
parents because clk-composite.c does not use the special handling for
mux + divider combinations anymore (that was restricted to rate clocks
which only implement .round_rate, but not .determine_rate).
Alex reports:
This breaks lot of clocks for Rockchip which intensively uses
composites, i.e. those clocks will always stay at the initial parent,
which in some cases is the XTAL clock and I strongly guess it is the
same for other platforms, which use composite clocks having more than
one parent (e.g. mediatek, ti ...)
Example (RK3399)
clk_sdio is set (initialized) with XTAL (24 MHz) as parent in u-boot.
It will always stay at this parent, even if the mmc driver sets a rate
of 200 MHz (fails, as the nature of things), which should switch it
to any of its possible parent PLLs defined in
mux_pll_src_cpll_gpll_npll_ppll_upll_24m_p (see clk-rk3399.c) - which
never happens.
Restore the original behavior by changing the priority of the conditions
inside clk-composite.c. Now the special rate + mux case (with rate_ops
having a .round_rate - which is still the case for the default
clk_divider_ops) is preferred over rate_ops which have .determine_rate
defined (and not further considering the mux).
Fixes: 69a00fb3d6 ("clk: divider: Implement and wire up .determine_rate by default")
Reported-by: Alex Bee <knaerzche@gmail.com>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20211016105022.303413-2-martin.blumenstingl@googlemail.com
Tested-by: Alex Bee <knaerzche@gmail.com>
Tested-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Adds 'struct samsung_cpu_clock' and corresponding CPU clock registration
function to the samsung common clk driver. This allows samsung clock
drivers to register their CPU clocks with the samsung_cmu_register_one()
API.
Currently the exynos5433 apollo and atlas clks have their own custom
init functions to handle registering their CPU clocks. With this patch
we can drop their custom CLK_OF_DECLARE functions and directly call
samsung_cmu_register_one().
Signed-off-by: Will McVicker <willmcvicker@google.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20211014195347.3635601-2-willmcvicker@google.com
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
This is the initial implementation adding only basic clocks like UART,
MMC, I2C and corresponding parent clocks. Design is influenced by
Exynos5433 clock driver.
Bus clock is enabled by default (in probe function) for all CMUs except
CMU_TOP, the reasoning is as follows. By default if bus clock has no
users its "enable count" value is 0. It might be actually running if
it's already enabled in bootloader, but then in some cases it can be
disabled by mistake. For example, such case was observed when
dw_mci_probe() enabled the bus clock, then failed to do something and
disabled that bus clock on error path. After that, even the attempt to
read the 'clk_summary' file in DebugFS freezed forever, as CMU bus clock
ended up being disabled and it wasn't possible to access CMU registers
anymore.
To avoid such cases, CMU driver must increment the ref count for that
bus clock by running clk_prepare_enable(). There is already existing
'.clk_name' field in struct samsung_cmu_info, exactly for that reason.
It was added in commit 523d3de41f ("clk: samsung: exynos5433: Add
support for runtime PM"), with next mentioning in commit message:
> Also for each CMU there is one special parent clock, which has to be
> enabled all the time when any access to CMU registers is being done.
But that clock is actually only enabled in Exynos5433 clock driver right
now. So the same code is added to exynos850_cmu_probe() function,
As was described above, it might be helpful not only for PM reasons, but
also to prevent possible erroneous clock gating on error paths.
Another way to workaround that issue would be to use CLOCK_IS_CRITICAL
flag for corresponding gate clocks. But that might be not very good
design decision, as we might still want to disable that bus clock, e.g.
on PM suspend.
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Link: https://lore.kernel.org/r/20211008154352.19519-6-semen.protsenko@linaro.org
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
On sm8250 dispcc and videocc registers are powered up by the MMCX power
domain. Currently we use a regulator to enable this domain on demand,
however this has some consequences, as genpd code is not reentrant.
Make gdsc code also use pm_runtime calls to ensure that registers are
accessible during the gdsc_enable/gdsc_disable operations.
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20210829154757.784699-6-dmitry.baryshkov@linaro.org
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
As there is a `rate` field in clk_smd_rpm, clk_smd_rpm_recalc_rate() can
be used by branch clocks to report rate as well, rather than assuming
the rate is always same as parent clock. This assumption doesn't hold
on platforms like QCM2290, where xo_board is 38.4MHz while bi_tcxo is
19.2MHz.
To get this work, XO buffered clocks need the following updates.
- Assign a correct rate rather than the fake one which is being used to
generate binary value for clk_smd_rpm_req interface.
- Explicitly handle the clk_smd_rpm_req interface value for XO buffered
clocks (.rpm_res_type being QCOM_SMD_RPM_CLK_BUF_A).
Suggested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Link: https://lore.kernel.org/r/20210917030434.19859-2-shawn.guo@linaro.org
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
[sboyd@kernel.org: Do cpu_to_le32() again to keep sparse happy]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Add Global Clock Controller (GCC) driver for QCM2290. This is a porting
of gcc-scuba driver from CAF msm-4.19, with GDSC support added on top.
Because the alpha_pll on the platform has a different register
layout (offsets), its own clk_alpha_pll_regs_offset[] is used in the
driver.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Link: https://lore.kernel.org/r/20210919023308.24498-3-shawn.guo@linaro.org
Acked-by: Rob Herring <robh@kernel.org>
[sboyd@kernel.org: Drop duplicate includes, clk.h include, module alias]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
