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>
Use DIV_ROUND_CLOSEST_ULL() to avoid any inconsistency b/w the rate
computed in sam9x60_frac_pll_recalc_rate() and the one computed in
sam9x60_frac_pll_compute_mul_frac().
Fixes: 43b1bb4a9b ("clk: at91: clk-sam9x60-pll: re-factor to support plls with multiple outputs")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20211011112719.3951784-8-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>
Fix variable set but not used compilation warning.
Fixes: 43b1bb4a9b ("clk: at91: clk-sam9x60-pll: re-factor to support plls with multiple outputs")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1598338751-20607-4-git-send-email-claudiu.beznea@microchip.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Some of the SAMA7G5 PLLs support multiple outputs (e.g. AUDIO PLL).
For these, split the PLL clock in two: fractional clock and
divider clock. In case PLLs supports multiple outputs (since these
outputs are dividers (with different settings) sharing the same
fractional part), it will register one fractional clock and multiple
divider clocks (dividers sharing the fractional clock).
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1595403506-8209-17-git-send-email-claudiu.beznea@microchip.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
In commit a436c2a447 ("clk: at91: add sam9x60 PLL driver")
the fractional part of PLL wasn't set on registers but it was
calculated and taken into account for determining div and mul
(see sam9x60_pll_get_best_div_mul()).
Fixes: a436c2a447 ("clk: at91: add sam9x60 PLL driver")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1595403506-8209-7-git-send-email-claudiu.beznea@microchip.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
According to datasheet the range of 600-1200MHz is for the
frequency generated by the fractional part of the PLL (namely
Fcorepllck according to datasheet). With this in mind the output
range of the PLL itself (fractional + div), taking into account
that the divider is 8 bits wide, is 600/256-1200Hz=2.3-1200MHz.
Fixes: a436c2a447 ("clk: at91: add sam9x60 PLL driver")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/1595403506-8209-6-git-send-email-claudiu.beznea@microchip.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Use logical or for range check. In case bestrate is not in
characteristics->output[0].min..characteristics->output[0].max
range we should return -ERANGE.
Fixes: a436c2a447 ("clk: at91: add sam9x60 PLL driver")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/1595403506-8209-5-git-send-email-claudiu.beznea@microchip.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Move SAM9X60's PLL register offsets to PMC header so that the
definitions would also be available from arch/arm/mach-at91/pm_suspend.S.
This is necessary to disable/enable PLLA for SAM9X60 on suspend/resume.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/1579522208-19523-7-git-send-email-claudiu.beznea@microchip.com
Product datasheet recommends different values for UPLL and PLLA analog control
register.
Adapt accordingly.
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Link: https://lkml.kernel.org/r/1573478913-19737-1-git-send-email-eugen.hristev@microchip.com
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
The PLLs on the sam9x60 (PLLA and USB PLL) use a different register set and
programming model than the previous SoCs.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
