This patch adds a new rate rounding algorithm for DPLL clocks on the
OMAP2/3 architecture.
For a desired DPLL target rate, there may be several
multiplier/divider (M, N) values which will generate a sufficiently
close rate. Lower N values result in greater power economy. However,
lower N values can cause the difference between the rounded rate and
the target rate ("rate error") to be larger than it would be with a
higher N. This can cause downstream devices to run more slowly than
they otherwise would.
This DPLL rate rounding algorithm:
- attempts to find the lowest possible N (DPLL divider) to reach the
target_rate (since, according to Richard Woodruff <r-woodruff@ti.com>,
lower N values save more power than higher N values).
- allows developers to set an upper bound on the error between the
rounded rate and the desired target rate ("rate tolerance"), so an
appropriate balance between rate fidelity and power savings can be
set. This maximum rate error tolerance is set via
omap2_set_dpll_rate_tolerance().
- never returns a rounded rate higher than the target rate.
The rate rounding algorithm caches the last rounded M, N, and rate
computation to avoid rounding the rate twice for each clk_set_rate()
call. (This patch does not yet implement set_rate for DPLLs; that
follows in a future patch.)
The algorithm trades execution speed for rate accuracy. It will find
the (M, N) set that results in the least rate error, within a
specified rate tolerance. It does this by evaluating each divider
setting - on OMAP3, this involves 128 steps. Another approach to DPLL
rate rounding would be to bail out as soon as a valid rate is found
within the rate tolerance, which would trade rate accuracy for
execution speed. Alternate implementations welcome.
This code is not yet used by the OMAP24XX DPLL clock, since it
is currently defined as a composite clock, fusing the DPLL M,N and the
M2 output divider. This patch also renames the existing OMAP24xx DPLL
programming functions to highlight that they program both the DPLL and
the DPLL's output multiplier.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
ssi_l4_ick should have PARENT_CONTROLS_CLOCK flag.
ST_SSI_STDBY bit in idlest register cannot be used in omap2_clk_wait_ready
Signed-off-by: Jouni Högander <jouni.hogander@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
These changes is the result of the discussion with Paul Walmsley.
His ideas are included into this patch.
Remove DPLL output divider handling from DPLLs and CLKOUTX2 clocks,
and place it into specific DPLL output divider clocks (e.g., dpll3_m2_clk).
omap2_get_dpll_rate() now returns the correct DPLL rate, as represented
by the DPLL's CLKOUT output. Also add MPU and IVA2 subsystem clocks, along
with high-frequency bypass support.
Add support for DPLLs function in locked and bypass clock modes.
Signed-off-by: Roman Tereshonkov <roman.tereshonkov@nokia.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
This patch changes 24xx to use shared clock code and new register
access.
Note that patch adds some temporary OLD_CK defines to keep patch
more readable. These temporary defines will be removed in the next
patch. Also not all clocks are changed in this patch to limit the
size.
Also, the patch fixes few incorrect clock defines in clock24xx.h.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
This patch adds a common clock framework for 24xx and 34xx.
Note that this patch does not add it to Makefile until in
next patch. Some functions are modified from earlier 24xx
clock framework code.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
This patch moves clock.h to clock24xx.c to make room for
adding common clock code for 24xx and 34xx.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
This patch moves clock.h to clock24xx.h to make room for
adding common clock code for 24xx and 34xx.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Fix assignment instead of condition
Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The APLLs are most efficiently idled by hardware.
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Mostly clean up CONFIG_OMAP_RESET_CLOCKS. Also includes a
patch from Imre Deak to make McSPI clocks use id.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Some peripherals seem to need additional delay until they
can actually be accessed after enabling their FCLK and ICLK.
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Enabling and disabling the 54 MHz and 96 MHz APLLs can happen
unnecessarily often during bootup. Make sure they're kept
enabled during init.
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Some boards might use the oscillator clock for powering
external peripherals. Add support for making sure osc_ck
stays active even when trying to go to sleep.
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
After adjusting clock parameters, OMAP2 CPUs need a memory
barrier to make sure the changes go into effect immediately.
Otherwise bad things will happen if we try to access the
peripheral whose clock is just being enabled.
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
A forgotten parenthesis in clock.c caused the PLL stabilization loop
to not be executed correctly.
Signed-off-by: Samuel Ortiz <samuel.ortiz@solidboot.com>
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
* 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm: (44 commits)
[ARM] 3541/2: workaround for PXA27x erratum E7
[ARM] nommu: provide a way for correct control register value selection
[ARM] 3705/1: add supersection support to ioremap()
[ARM] 3707/1: iwmmxt: use the generic thread notifier infrastructure
[ARM] 3706/2: ep93xx: add cirrus logic edb9315a support
[ARM] 3704/1: format IOP Kconfig with tabs, create more consistency
[ARM] 3703/1: Add help description for ARCH_EP80219
[ARM] 3678/1: MMC: Make OMAP MMC work
[ARM] 3677/1: OMAP: Update H2 defconfig
[ARM] 3676/1: ARM: OMAP: Fix dmtimers and timer32k to compile on OMAP1
[ARM] Add section support to ioremap
[ARM] Fix sa11x0 SDRAM selection
[ARM] Set bit 4 on section mappings correctly depending on CPU
[ARM] 3666/1: TRIZEPS4 [1/5] core
ARM: OMAP: Multiplexing for 24xx GPMC wait pin monitoring
ARM: OMAP: Fix SRAM to use MT_MEMORY instead of MT_DEVICE
ARM: OMAP: Update dmtimers
ARM: OMAP: Make clock variables static
ARM: OMAP: Fix GPMC compilation when DEBUG is defined
ARM: OMAP: Mux updates for external DMA and GPIO
...
The dmtimer framework update broke 32 kHz timer as udelay() does not work
before system timer is started (and GPT1 should not be reset).
This also makes the GP timer use GPT1. This requires a fix in clock framework.
Signed-off-by: Timo Teras <timo.teras@solidboot.com>
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
omap2_clk_set_rate: dif_off must use clk->rate_offset, not clk->src_off.
omap2_get_src_field: for the case CM_SYSCLKOUT_SEL1, val must be 2 for
96MHz and 3 for 54MHz.
Signed-off-by: Jarkko Nikula <jarkko.nikula@nokia.com>
Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Patch from Tony Lindgren
Update OMAP clock framework from linux-omap tree.
The highlights of the patch are:
- Add support for omap730 clocks by Andrzej Zaborowski
- Fix compile warnings by Dirk Behme
- Add support for using dev id by Tony Lindgren and Komal Shah
- Move memory timings and PRCM into separate files by Tony Lindgren
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch fixes OMAP clock framework to use clk_enable/disable
instead of clk_use/unuse as specified in include/linux/clk.h.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Patch from Tony Lindgren
This patch adds omap24xx specific clock code by
Richard Woodruff, Nishant Menon, Tony Lindgren et al.
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
