Commit graph

150 commits

Author SHA1 Message Date
Kever Yang
217273cd44 rockchip: clk: remove RATE_TO_DIV
Use DIV_ROUND_UP instead RATE_TO_DIV for all Rockchip SoC
clock driver.
Add or fix the div-field overflow check at the same time.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
2017-08-13 17:15:09 +02:00
Kever Yang
3a94d75d0e rockchip: clk: update dwmmc clock div
dwmmc controller has default internal divider by 2,
and we always provide double of the clock rate request by
dwmmc controller. Sync code for all Rockchip SoC with:
4055b46 rockchip: clk: rk3288: fix mmc clock setting

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Acked-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
[fixup for 'missing DIV_ROUND_UP' conflict for clk_rk3288.c:]
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
2017-08-13 17:15:09 +02:00
Philipp Tomsich
cf8aceb1c9 rockchip: clk: rk3368: add support for configuring the SPI clocks
As SPI support may be useful in the boot-flow, this adds support for
configuring the SPI controller's clocks in the RK3368 clock driver.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-13 17:12:33 +02:00
Philipp Tomsich
4e4c40df30 rockchip: clk: rk3368: mark 'priv' __maybe_unused in rk3368_clk_set_rate()
With the clock support in rk3368_clk_set_rate() conditionalized on
various feature definitions, 'priv' can remain unused (e.g. in the
SPL build when only MMC is enabled).

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-13 17:12:32 +02:00
Philipp Tomsich
df0ae00041 rockchip: clk: rk3368: add support for GMAC (SLCK_MAC) clock
To enable the GMAC on the RK3368, we need to set up the clocking
appropriately to generate a tx_clk for the MAC.

This adds an implementation that implements the use of the <&ext_gmac>
clock (i.e. an external 125MHz clock for RGMII provided by the PHY).
This is the clock setup used by the boards currently supported by
U-Boot (i.e. Geekbox, Sheep and RK3368-uQ7).

This includes the change from commit
 - rockchip: clk: rk3368: define GMAC_MUX_SEL_EXTCLK

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-13 17:12:32 +02:00
Philipp Tomsich
6292469073 rockchip: clk: rk3368: support configuring the DRAM PLL (from TPL)
As part of the DRAM initialisation process (running as part of the TPL
stage) on the RK3368, we need to set up the DRAM PLL.

This implements support for configuring the PLL to for 1200, 1332 or
1600 MHz (i.e. for DDR3-1200, DDR3-1333, DDR3-1600 operating modes).

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-13 17:12:32 +02:00
Philipp Tomsich
f5a432959a rockchip: clk: rk3368: implement MMC/SD clock reparenting
The original clock support for MMC/SD cards on the RK3368 suffered
from a tendency to select a divider less-or-equal to the the one
giving the requested clock-rate: this can lead to higher-than-expected
(or rather: higher than supported) clock rates for the MMC/SD
communiction.

This change rewrites the MMC/SD clock generation to:
 * always generate a clock less-than-or-equal to the requested clock
 * support reparenting among the CPLL, GPLL and OSC24M parents to
   generate the highest clock that does not exceed the requested rate

In addition to this, the Linux DTS uses HCLK_MMC/HCLK_SDMMC instead of
SCLK_MMC/SCLK_SDMMC: to match this (and to ensure that clock setup
always works), we adjust the driver appropriately.

This includes the changes from:
 - rockchip: clk: rk3368: convert MMC_PLL_SEL_* definitions to shifted-value form

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-13 17:12:32 +02:00
Philipp Tomsich
a00dfa042d rockchip: clk: rk3368: implement DPLL (DRAM PLL) support
To implement a TPL stage (incl. its DRAM controller setup) for the
RK3368, we'll want to configure the DPLL (DRAM PLL).

This commit implements setting the DPLL (CLK_DDR) and provides PLL
configuration details for the common DRAM operating speeds found on
RK3368 boards.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-13 17:12:32 +02:00
Philipp Tomsich
4bebf94e85 rockchip: clk: rk3368: do not change CPLL/GPLL before returning to BROM
The RK3368 has a somewhat temperamental BootROM (which I learned the
hard way) when it comes to reconfiguring the CPLL and GPLL (in fact,
experiments show that changing the GPLL broke things for me, while
changing the CPLL seems to be more benign).  These should not be
modified by the SPL stage, if we intend to return to the BootROM for
chain booting the next stage.

This commit changes the clock initialisation to not change CPLL/GPLL
before returning to the BootROM (i.e. in TPL).  As it's safe to change
these settings if we no longer intend to return to U-Boot, we'll run
the full PLL setup a little later (i.e. in SPL).

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-13 17:12:32 +02:00
Philipp Tomsich
bee6180126 rockchip: clk: rk3368: support OF_PLATDATA for the RK3368 clk driver
With the RK3368's limited TPL size, we'll want to use OF_PLATFDATA for
the SPL stage.  This implements support for OF_PLATDATA in the clock
driver for the RK3368.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-13 17:12:30 +02:00
Philipp Tomsich
ddfe77df15 rockchip: clk: rk3368: implement bandwidth adjust for PLLs
The RK3368 TRM recommends to configure the bandwith adjustment (CON2)
for PLLs to NF/2.  This implements this for all reconfigurations of
PLLs and removes the 'has_bwadj' flag (as the RK3368 always has the
bandwidth-adjustment feature according to its manual).

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-13 17:12:28 +02:00
Philipp Tomsich
7c819e7f22 spl: dm: Kconfig: split CLK support for SPL and TPL
Introduce TPL_CLK to allow finer-grained selection of TPL features
for feature-rich (i.e. DM-based) TPL stages.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
2017-08-13 17:12:20 +02:00
Philipp Tomsich
f0776a5517 spl: dm: Kconfig: SPL_CLK depends on SPL_DM
SPL_CLK should also depend on SPL_DM (and not just on CLK).
Add the additional dependency.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
2017-08-13 17:12:20 +02:00
Tom Rini
fe84c48eeb Xilinx changes for v2017.09
Zynq:
 - Add Z-Turn board support
 
 fpga:
 - Remove intermediate buffer from code
 
 Zynqmp:
 - dts cleanup
 - change psu_init handling
 - Add options to get silicon version
 - Fix time handling
 - Map OCM/TCM via MMU
 - Add new clock driver
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iEYEABECAAYFAlmBs2kACgkQykllyylKDCFUGgCgmfop8Ki5+6QI7XQRP7u8nhjw
 KakAn1sYIRDFQ34AoxmiYa6RTmjepLMv
 =1Gh3
 -----END PGP SIGNATURE-----

Merge tag 'xilinx-for-v2017.09' of git://www.denx.de/git/u-boot-microblaze

Xilinx changes for v2017.09

Zynq:
- Add Z-Turn board support

fpga:
- Remove intermediate buffer from code

Zynqmp:
- dts cleanup
- change psu_init handling
- Add options to get silicon version
- Fix time handling
- Map OCM/TCM via MMU
- Add new clock driver
2017-08-04 07:23:32 -04:00
Marek Vasut
36c2ee4ce5 clk: rmobile: Add RCar Gen3 clock driver
Add clock driver for the RCar Gen3 R8A7795 and R8A7796 SoCs .
This driver allows reading out the clock configuration set by
previous boot stages and enabling and disabling clock using
the MSTP registers. Setting clock is not supported thus far.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
2017-08-03 04:26:24 +09:00
Michal Simek
cf772e9690 clk: zynqmp: Remove unused macros/variables
These macros and one variable is not used anywhere that's why
they should be removed.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-02 09:11:52 +02:00
Siva Durga Prasad Paladugu
154799ac95 clk: zynqmp: Dont panic incase of mmio write/read failures
Dont panic incase of mmio write/read failures instead return
error and let the peripheral driver take care of clock get
and set failures.

Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-02 09:11:52 +02:00
Siva Durga Prasad Paladugu
ad76f8cedf clk: zynqmp: Add support for CCF driver
Add support for CCF, this CCF reads the ref clocks
from dt and checks all the required clock control
registers for its source , divisors and calculates
the clock from them. This supports clock and set
functions.

Panic when read/write fails.

Signed-off-by: Siva Durga Prasad Paladugu <sivadur@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-08-02 09:11:52 +02:00
Patrice Chotard
b108d8a0de clk: fix compilation errors for poplar platform
Move clk_release_all() prototype and definition inside
OF_CONTROL flag to avoid following compilation error for
poplar platform:

aarch64:  +   poplar
+drivers/usb/host/built-in.o: In function `ehci_usb_remove':
+drivers/usb/host/ehci-generic.c:159: undefined reference to `clk_release_all'
+drivers/usb/host/built-in.o: In function `ehci_usb_probe':
+drivers/usb/host/ehci-generic.c:133: undefined reference to `clk_release_all'
+make[1]: *** [u-boot] Error 139
+make: *** [sub-make] Error 2

Introduced by 4e542c4 clk: add clk_release_all()

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
2017-07-28 23:34:46 +02:00
Patrice Chotard
82a8a669b4 clk: add clk_release_all()
Add clk_release_all() method which Disable/Free an
array of clocks that has been previously requested by
clk_request/get_by_*()

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-07-28 23:34:08 +02:00
Philipp Tomsich
cdc6080a28 rockchip: clk: rk3368: use correct (i.e. 'rk3368_clk_priv') structure for auto-alloc
The clk driver for the RK3368 picked the wrong data structure's size
for its auto-alloc size: the size was calculated on the structure
representing the CRU hardware block instead of the priv structure.
As the CRU's register file is much larger than the driver's priv,
this did not cause any pain (except wasting memory).

Fix this by using the correct data structure's size.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-07-27 14:59:02 +02:00
Patrice Chotard
81d0128d2b clk: stm32f7: remove clock_get()
All drivers which was using clock_get() are now using
clk_get_rate() from clock framework, now it's safe to
remove clock_get().

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: Vikas MANOCHA <vikas.manocha@st.com>
2017-07-26 11:28:08 -04:00
Patrice Chotard
b9e86511d1 clk: stm32f7: cleanup clocks unused definitions
clean the code by removing unused enums, structs and
defines related to clocks

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: Vikas MANOCHA <vikas.manocha@st.com>
2017-07-26 11:26:54 -04:00
Patrice Chotard
288f17e648 clk: stm32f7: add clock .get_rate() callback
Add clock framework .get_rate callback.
This step will allow to convert all drivers which was using
proprietary clock_get() to use clock framework .get_rate().

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: Vikas MANOCHA <vikas.manocha@st.com>
2017-07-26 11:26:53 -04:00
Patrice Chotard
199a2178fe clk: stm32f7: get RCC base address from DT
Retrieve RCC base address from DT, this will prepare
the ground for future STM32 SoCs support.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: Vikas MANOCHA <vikas.manocha@st.com>
2017-07-26 11:26:53 -04:00
Patrice Chotard
704e954cee clk: stm32f7: add static for configure_clocks()
Also remove its declaration from stm32.h which
is no more needed.

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: Vikas MANOCHA <vikas.manocha@st.com>
2017-07-26 11:26:53 -04:00
Kever Yang
045029cbd1 rockchip: rk322x: add clock driver
Add clock driver init support for:
- cpu, bus clock init;
- emmc, sdmmc clock;
- ddr clock;

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Fixed format specified (%x -> %p) in clk_rk322x.c:
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
2017-07-11 12:13:45 +02:00
Tom Rini
524b42bc2c Merge git://git.denx.de/u-boot-uniphier
- fix sparse warnings
- sync DT with Linux
- add new board support (LD11/LD20 global)
2017-06-24 18:18:41 -04:00
Masahiro Yamada
1d21e1b97c ARM: uniphier: fix various sparse warnings
Fix warnings reported by sparse:
 - ... was not declared. Should it be static?"
 - cast to restricted __be32

While fixing those, the type conflict of cci500_init() was found.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2017-06-25 06:06:09 +09:00
Tom Rini
7df4ff2c26 Merge branch 'master' of git://git.denx.de/u-boot-rockchip 2017-06-23 11:02:21 -04:00
Kever Yang
6a464d9cab rockchip: clk: rk3036: correct setting for pll integer mode
According to rk3036 TRM, pll_con1[12] should be set to '1' for the pll
integer mode, while the '0' means the frac mode.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
2017-06-23 16:40:23 +02:00
Tom Rini
872faf5d13 clk_rv1108.c: Fix unused variable warning
The variables gpll_init_cfg and apll_init_cfg are unused in this file,
remove them.

Cc: Simon Glass <sjg@chromium.org>
Cc: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-06-23 10:38:05 -04:00
Simon Glass
d3cb46aa8c rockchip: Init clocks again when chain-loading
Detect with a previous boot loader has already set up the clocks and set
them up again so that U-Boot gets what it expects.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-06-09 13:45:33 -06:00
Simon Glass
b223c1aead rockchip: rk3288: Convert clock driver to use shifted masks
Shifted masks are the standard approach with rockchip since it allows
use of the mask without shifting it each time. Update the definitions and
the driver to match.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-06-09 13:45:33 -06:00
Andy Yan
bae2f282a9 rockchip: clk: Add rv1108 clock driver
Add clock driver support for Rockchip rv1108 soc

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-06-07 07:29:25 -06:00
Kever Yang
1960b01034 rockchip: clock: rk3036: some fix according TRM
- hclk/pclk_div range should use '<=' instead of '<'
- use GPLL for pd_bus clock source
- pd_bus HCLK/PCLK clock rate should not bigger than ACLK

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-06-07 07:29:20 -06:00
Kever Yang
37943aaeea rockchip: rk3036: clean mask definition for cru reg
Embeded the shift in mask MACRO definition in cru header file
and clock driver.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-06-07 07:29:20 -06:00
Andy Yan
d1dcf8527e rockchip: rk3368: Add clock driver
Add driver to setup the various PLLs and peripheral
clocks on the RK3368.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-06-07 07:29:19 -06:00
Simon Glass
8b92e1cd59 dm: clk: fixed: Update to support livetree
Update the fixed-rate clock driver to support a live device tree.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-06-01 07:03:14 -06:00
Simon Glass
aa9bb0944a dm: clk: Update uclass to support livetree
Update the clk uclass to support a live device tree.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-06-01 07:03:14 -06:00
Simon Glass
a4e0ef50da clk: Modify xlate() method for livetree
Update the xlate() method to use ofnode_phandle_args instead of the fdtdec
variant. This will allow drivers to support a live device tree.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-06-01 07:03:14 -06:00
Simon Glass
45a26867e8 dm: core: Update device_bind_driver_to_node() to use ofnode
Adjust this function to us an ofnode instead of an offset, so it can be
used with livetree. This involves updating all callers.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-06-01 07:03:08 -06:00
Simon Glass
da409ccc4a dm: core: Replace of_offset with accessor (part 2)
At present devices use a simple integer offset to record the device tree
node associated with the device. In preparation for supporting a live
device tree, which uses a node pointer instead, refactor existing code to
access this field through an inline function.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-06-01 07:03:04 -06:00
Simon Glass
a821c4af79 dm: Rename dev_addr..() functions
These support the flat device tree. We want to use the dev_read_..()
prefix for functions that support both flat tree and live tree. So rename
the existing functions to avoid confusion.

In the end we will have:

   1. dev_read_addr...()    - works on devices, supports flat/live tree
   2. devfdt_get_addr...()  - current functions, flat tree only
   3. of_get_address() etc. - new functions, live tree only

All drivers will be written to use 1. That function will in turn call
either 2 or 3 depending on whether the flat or live tree is in use.

Note this involves changing some dead code - the imx_lpi2c.c file.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-06-01 07:03:01 -06:00
Simon Glass
9d922450aa dm: Use dm.h header when driver mode is used
This header includes things that are needed to make driver build. Adjust
existing users to include that always, even if other dm/ includes are
present

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-06-01 06:57:52 -06:00
Tom Rini
1f5541c881 Merge git://git.denx.de/u-boot-rockchip
This adds a new firefly-rk3399 board, MIPI support for rk3399 and
rk3288, rk818 pmic support, mkimage improvements for rockchip and a few
other things.
2017-05-10 17:40:11 -04:00
Philipp Tomsich
ffc1fac549 rockchip: clk: rk3399: allow requests for HDMI clocks
This allows requests (via the DTS) for PCLK_HDMI_CTRL/PCLK_VIO_GRF,
which are clock gates in the HDMI output path for the RK3399.

As these are enabled by default (i.e. after reset), we don't implement
any logic to actively open/close these clock gates and simply assume
that their reset-default has not been changed.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-05-10 13:37:21 -06:00
Philipp Tomsich
a70feb4620 rockchip: clk: rk3399: allow requests for PCLK_EFUSE1024NS
The (non-secure) efuse node in the DTS requests PCLK_EFUSE1024NS.
To allow us to add a efuse-driver (and more importantly, to allow
probes of such a driver to succeed), we need need to accept requests
for PCLK_EFUSE1024NS and return a non-error result.

As PCLK_EFUSE1024NS is enabled by default (i.e. after reset), we don't
implement any logic to manage this clock gate and simply assume that
the reset-default has not been changed.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Tested-by: Klaus Goger <klaus.goger@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2017-05-10 13:37:21 -06:00
Philipp Tomsich
998c61ae60 rockchip: clk: rk3399: adapt MMC clk configuration to the updated RK3399 DTS
The clocking of the designware MMC controller in the upstream
(i.e. Linux) RK3399 has changed/does not match what the current DTS in
U-Boot uses: the first clock entry now is HCLK_SDMMC instead of
SCLK_SDMMC.

With the simple clock driver used for the RK3399, this needs a change
in the selector understood by the various case statements in the driver
to ensure that the driver still loads successfully.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Acked-by: Simon Glass <sjg@chromium.org>
2017-05-10 13:37:21 -06:00
Philipp Tomsich
beb90a53f3 rockchip: clk: rk3399: fix off-by one during rate calculation in i2c/spi_set_rate
For the RK3399, i2c_set_rate (and by extension: our spi_set_rate,
which had been mindlessly following the template of the i2c_set_rate
implementation) miscalculates the rate returned due to a off-by-one
error resulting from the following sequence of events:
  1. calculates 'src_div := src_freq / target_freq'
  2. stores 'src_div - 1' into the register (the actual divider applied
     in hardware is biased by adding 1)
  3. returns the result of the DIV_RATE(src_freq, src_div) macro, which
     expects the (decremented) divider from the hardware-register and
     implictly adds 1 (i.e. 'DIV_RATE(freq, div) := freq / (div + 1)')

This can be observed with the SPI driver, which sets a rate of 99MHz
based on the GPLL frequency of 594MHz: the hardware generates a clock
of 99MHz (src_div is 6, the bitfield in the register correctly reads 5),
but reports a frequency of 84MHz (594 / 7) on return.

To fix, we have two options:
 * either we bias (i.e. "DIV_RATE(GPLL, src_div - 1)"), which doesn't
   make for a particularily nice read
 * we simply call the i2c/spi_get_rate function (introducing additional
   overhead for the additional register-read), which reads the divider
   from the register and then passes it through the DIV_RATE macro

Given that this code is not time-critical, the more readable solution
(i.e. calling the appropriate get_rate function) is implemented in this
change.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Tested-by: Klaus Goger <klaus.goger@theobroma-systems.com>
Acked-by: Simon Glass <sjg@chromium.org>
2017-05-10 13:37:21 -06:00