Inline Crypto Engine (ICE) supports wrapped key generation. While
registering crypto profile the supported key types are queried from ICE
driver. So the explicit check for RAW key is not needed.
Fixes: fd78e2b582 ("mmc: sdhci-msm: Add support for wrapped keys")
Signed-off-by: Neeraj Soni <neeraj.soni@oss.qualcomm.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
According to the ASIC design recommendations, the clock must be
disabled before operating the DLL to prevent glitches that could
affect the internal digital logic. In extreme cases, failing to
do so may cause the controller to malfunction completely.
Adds a step to disable the clock before DLL configuration and
re-enables it at the end.
Fixes: 08f3dff799 ("mmc: sdhci-of-dwcmshc: add rockchip platform support")
Cc: stable@vger.kernel.org
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Use scoped for-each loop when iterating over device nodes to simplify the
code, but also to ensure the device node reference is automatically
released when the loop scope ends.
Signed-off-by: Hans Zhang <18255117159@163.com>
Reviewed-by: Shawn Lin <shawn.lin@linux.dev>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
ioc_count won't be more than MMC_IOC_MAX_CMDS (255), retries won't be more
than MMC_NO_RETRIES (6), flags is newly introduced and uses only 1 bit.
Therefore let's change them all to become u8.
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Clean up module init by dropping redundant error messages (e.g.
allocation and USB driver registration failure will already have been
logged) and naming error labels after what they do.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Error labels should be named after what they do.
Rename the probe error labels.
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Merge the mmc fixes for v7.0-rc[n] into the next branch, to allow them to
get tested together with the mmc changes that are targeted for the next
release.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The vub300 driver maintains an explicit reference count for the
controller and its driver data and the last reference can in theory be
dropped after the driver has been unbound.
This specifically means that the controller allocation must not be
device managed as that can lead to use-after-free.
Note that the lifetime is currently also incorrectly tied the parent USB
device rather than interface, which can lead to memory leaks if the
driver is unbound without its device being physically disconnected (e.g.
on probe deferral).
Fix both issues by reverting to non-managed allocation of the controller.
Fixes: dcfdd698dc ("mmc: vub300: Use devm_mmc_alloc_host() helper")
Cc: stable@vger.kernel.org # 6.17+
Cc: Binbin Zhou <zhoubinbin@loongson.cn>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Make sure to deregister the controller before dropping the reference to
the driver data on disconnect to avoid NULL-pointer dereferences or
use-after-free.
Fixes: 88095e7b47 ("mmc: Add new VUB300 USB-to-SD/SDIO/MMC driver")
Cc: stable@vger.kernel.org # 3.0+
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The function dw_mci_start_request() was just a thin wrapper around
__dw_mci_start_request(). Since it serves almost no functional purpose,
remove the wrapper to simplify the code flow.
Consequently, rename __dw_mci_start_request() to dw_mci_start_request()
so that the core implementation uses the primary name.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
With the removal of queue support, the function dw_mci_queue_request()
is now just a wrapper with a confusing name that doesn't suggest
anything about queue. Removes the function and moves its body into
dw_mci_request().
No functional changes intended.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Currently, the code uses the MQRQ_XFER_SINGLE_BLOCK flag to handle write
failures by retrying with single-block transfers. However, read failures
bypass this mechanism and instead use a dedicated legacy path mmc_blk_read_single()
that performs sector-by-sector retries.
Extend the MQRQ_XFER_SINGLE_BLOCK logic to cover multi-block read failures
as well. By doing so, we can remove the redundant and complex mmc_blk_read_single()
function, unifying the retry logic for both read and write operations under
a single, consistent, easier-to-maintain mechanism.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Replacing hard-coded values with standardized macros to improve code clarity,
simplify future maintenance.
Meanwhile, introduce global bs and sg_len arrays for block sizes and SG lengths,
eliminating redundant local definitions in multiple test functions.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Convert to use DEFINE_SIMPLE_DEV_PM_OPS() and pm_sleep_ptr() to drop the
CONFIG_PM_SLEEP to handle the conditional compilation when PM support is
disabled. This allows the compiler to automatically optimize away the
unused code paths when CONFIG_PM_SLEEP is not selected.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
These shift-by-9 operations are for converting between bytes and sectors.
Use the SECTOR_SHIFT macro to improve code readability and maintainability.
No functional changes intended.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The driver previously used an enum (dwcmshc_rk_type) to distinguish
platforms like the RK3568 and RK3588 based on DT compatible names.
This approach is inflexible, scales poorly for future revisions or
mixed-revision platforms, and conflates SoC names with controller
revisions. One example is RK3576 which lists "rockchip,rk3588-dwcmshc"
as a secondary compatible string just in order to claim it uses the
same controller revision as RK3588. This is confusing and makes it
error-prone to add new SoC support.
Introduces a new struct rockchip_pltfm_data containing a dedicated
revision field. The old enum is removed, and all code paths are
updated to use the revision-based data.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Currently, the mmc_host_class_dev_pm_ops and its callback
functions are wrapped in #ifdef CONFIG_PM_SLEEP to handle the
conditional compilation when PM support is disabled.
Replace this #ifdef usage with the standard pm_ptr() helpers. This
allows the compiler to automatically optimize away the unused code
paths when CONFIG_PM_SLEEP is not selected, resulting in cleaner and
more maintainable code.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The 'enable-sdio-wakeup' device tree property was marked as legacy and
superseded by the standard 'wakeup-source' property in commit 71a0151c5c
("Documentation: devicetree: fix reference to legacy wakeup properties")
back in 2015.
Since it has been a decade and the migration to the standard property
has long been completed, remove this obsolete legacy support.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Simplifies allocations by using a flexible array member in these structs.
Add __counted_by to get extra runtime analysis.
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Disable new_tx/rx to avoid data transmission instability, and adjust
.data_tune, .stop_dly_sel, and .pop_en_cnt to fit the overall
configuration after disabling new_tx/rx, making it more compatible
with mt8189.
Fixes: 846a3a2fdf ("mmc: mtk-sd: add support for MT8189 SoC")
Tested-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Signed-off-by: Cathy Xu <ot_cathy.xu@mediatek.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Due to errata i2493[0], multi-block write would still fail in retries.
With i2493, the MMC interface has the potential of write failures when
issuing multi-block writes operating in HS200 mode with excessive IO
supply noise.
While the errata provides guidance in hardware design and layout to
minimize the IO supply noise, in theory the write failure cannot be
resolved in hardware. The software solution to ensure the data integrity
is to add minimum 5us delay between block writes. Single-block write is
the practical way to introduce the delay.
This patch reuses recovery_mode flag, and switches to single-block
write in retry when multi-block write fails. It covers both CQE and
non-CQE cases.
[0] https://www.ti.com/lit/pdf/sprz582
Cc: stable@vger.kernel.org
Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Convert the Arasan SDHCI driver to use the mainline standard
mmc_clk_phase_map infrastructure instead of custom clk_phase_in/out
arrays as well as arasan_dt_read_clk_phase().
The phase values for ZynqMP, Versal, and Versal-NET platforms are
still initialized from the predefined tables.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Reviewed-by: Sai Krishna Potthuri <sai.krishna.potthuri@amd.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Get the optional reset line for the ASPEED SD controller during probe by
using devm_reset_control_get_optional_exclusive_deasserted().
This allows platforms such as AST2700, which require the SD controller
to be taken out of reset before use, to work with the existing driver.
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This driver includes the legacy header <linux/gpio.h> but does
not use any symbols from it. Drop the inclusion.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Add support for the eMMC controller integrated in the HPE GSC (ARM64
Cortex-A53) BMC SoC under the new 'hpe,gsc-dwcmshc' compatible
string.
The HPE GSC eMMC controller is based on the DesignWare Cores MSHC IP
but requires several platform-specific adjustments:
Clock mux (dwcmshc_hpe_set_clock):
The GSC SoC wires SDHCI_CLOCK_CONTROL.freq_sel directly to a clock
mux rather than a divider. Forcing freq_sel = 1 when the requested
clock is 200 MHz (HS200) selects the correct high-speed clock source.
Using the generic sdhci_set_clock() would otherwise leave the mux on
the wrong source after tuning.
Auto-tuning / vendor config (dwcmshc_hpe_vendor_specific):
Disables the command-conflict check (DWCMSHC_HOST_CTRL3 BIT(0)) and
programs the ATCTRL register using existing AT_CTRL_* macros:
AT_CTRL_AT_EN auto-tuning circuit enable
AT_CTRL_SWIN_TH_EN sampling window threshold enable
AT_CTRL_TUNE_CLK_STOP_EN tune-clock-stop enable
PRE_CHANGE_DLY = 3 pre-change delay
POST_CHANGE_DLY = 3 post-change delay
SWIN_TH_VAL = 2 sampling window threshold
This combination is required for reliable HS200 signal integrity on
the GSC PCB trace topology.
eMMC mode (dwcmshc_hpe_set_emmc):
Helper that sets DWCMSHC_CARD_IS_EMMC unconditionally. Called from
both the reset and UHS-signaling paths.
Reset (dwcmshc_hpe_reset):
Calls dwcmshc_reset(), re-applies the vendor config above via
dwcmshc_hpe_vendor_specific(), and then calls dwcmshc_hpe_set_emmc().
The GSC controller clears the CARD_IS_EMMC bit on every reset;
leaving it clear causes card-detect mis-identification on an
eMMC-only slot.
UHS signaling (dwcmshc_hpe_set_uhs_signaling):
Wraps dwcmshc_set_uhs_signaling() and calls dwcmshc_hpe_set_emmc()
to ensure CARD_IS_EMMC is set for all timing modes, not just HS400.
Init (dwcmshc_hpe_gsc_init):
Obtains the SoC register block and MSHCCS offset via the
'hpe,gxp-sysreg' syscon phandle argument and sets SCGSyncDis
(BIT(18)) to allow the HS200 RX delay lines to settle while the
card clock is stopped during auto-tuning. Enables SDHCI v4 mode.
Quirks:
SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN: base clock not advertised in
capabilities; must be obtained from the DTS 'clocks' property.
SDHCI_QUIRK2_PRESET_VALUE_BROKEN: preset-value registers are not
populated in the GSC ROM.
All HPE-specific code is isolated to the new hpe_gsc_init / hpe_ops /
hpe_gsc_pdata symbols. No existing platform (Rockchip, T-Head, sg2042,
etc.) is affected.
Signed-off-by: Nick Hawkins <nick.hawkins@hpe.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This change aligns the SoCFPGA driver with the current dw_mmc core,
which now manages clock phases through host->phase_map. The phase values
are still scaled by SOCFPGA_DW_MMC_CLK_PHASE_STEP before being written
to the system manager registers.
No functional changes intended.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The "keep-power-in-suspend", "wakeup-source" and "enable-sdio-wakeup"
properties are already parsed in mmc_of_parse(). All sdhci drivers that
call sdhci_get_property() also call mmc_of_parse(). The only exception
is sdhci-of-hlwd, which does not call mmc_of_parse(), but its devicetree
does not use these properties anyway.
Signed-off-by: Luke Wang <ziniu.wang_1@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
mmc_validate_host_caps() already validates that HS400/HS400ES requires
8-bit bus width. Remove the duplicate validation.
Signed-off-by: Luke Wang <ziniu.wang_1@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Add sdhci_get_property() call to parse common SDHCI DT properties,
including "bus-width = <1>" which sets SDHCI_QUIRK_FORCE_1_BIT_DATA
quirk for 1-bit data bus width configuration.
Remove the duplicate "no-1-8-v" property parsing since
sdhci_get_property() already handles it.
Signed-off-by: Luke Wang <ziniu.wang_1@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Merge the mmc fixes for v7.0-rc[n] into the next branch, to allow them to
get tested together with the mmc changes that are targeted for the next
release.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
When 1-bit bus width is used with HS200/HS400 capabilities set,
mmc_select_hs200() returns 0 without actually switching. This
causes mmc_select_timing() to skip mmc_select_hs(), leaving eMMC
in legacy mode (26MHz) instead of High Speed SDR (52MHz).
Per JEDEC eMMC spec section 5.3.2, 1-bit mode supports High Speed
SDR. Drop incompatible HS200/HS400/UHS/DDR caps early so timing
selection falls through to mmc_select_hs() correctly.
Fixes: f2119df6b7 ("mmc: sd: add support for signal voltage switch procedure")
Signed-off-by: Luke Wang <ziniu.wang_1@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The bus width support for UHS mode is now validated in mmc_validate_host_caps().
Therefore, we can safely remove the explicit MMC_CAP_4_BIT_DATA check from
mmc_host_can_uhs(). As part of this cleanup, simplify the condition by using
the consolidated MMC_CAP_UHS flag.
Signed-off-by: Shawn Lin <shawn.lin@linux.dev>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
UHS/DDR/HS200 modes require at least 4-bit bus support. Host controllers
that lack relevant capability registers rely on paring properties provided
by firmware, which may incorrectly set these modes. Now that mmc_validate_host_caps()
has been introduced to validate such configuration violations, let's also
add checks for UHS/DDR/HS200 modes.
This fixes an issue where, if the HS200/HS400 property is set while only
a 1-bit bus width is used, mmc_select_hs200() returns 0 without actually
performing the mode switch. Consequently, mmc_select_timing() proceeds
without falling back to mmc_select_hs(), leaving the eMMC device operating
in legacy mode (26 MHz) instead of switching to High Speed mode (52 MHz).
Signed-off-by: Luke Wang <ziniu.wang_1@nxp.com>
[Shawn: reword the commit msg and rework the code]
Signed-off-by: Shawn Lin <shawn.lin@linux.dev>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Multiple boards require different phase settings, rendering the default
phase policy unscalable. Therefore, we introduce phase map to address this
limitation. To preserve backward compatibility, the default_sample_phase
and original drv phase for different modes are retained, with phase map
values taking precedence when available.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The dw_mmc library already assists in invoking mmc_of_parse() to
provide unified parsing for variant drivers. We can also call
mmc_of_parse_clk_phase() to help variant drivers achieve unified parsing.
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Add support for the uSDHC controller found in NXP S32N79 automotive SoCs,
which reuse the existing sdhci-esdhc-imx driver with slice difference.
Compared with s32g2/s32g3, needn't set ESDHC_FLAG_SKIP_CD_WAKE flag
because s32n79 does not have this limitation.
Co-developed-by: Larisa Grigore <larisa.grigore@nxp.com>
Signed-off-by: Larisa Grigore <larisa.grigore@nxp.com>
Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Convert the Renesas SDHI SD/SDIO controller driver using SYS-DMAC from
an open-coded dev_pm_ops structure to DEFINE_RUNTIME_DEV_PM_OPS() and
pm_ptr(). This simplifies the code, and reduces kernel size in case
CONFIG_PM is disabled.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This patch describes the two MMC controllers of the Loongson-2K0300 SoC,
one providing an eMMC interface and the other exporting an SD/SDIO
interface.
Its hardware design is similar to that of the Loongson-2K2000, but it
suffers from hardware defects such as missing CMD48 interrupts.
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
More Loongson SoCs will be added, gathering all SoC private data
(`loongson2_mmc_pdata`) together to make the code clearer.
No functional change intended.
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
In sdhci_bst_alloc_bounce_buffer(), if dma_alloc_coherent() fails, the
function immediately returns -ENOMEM without releasing the reserved
memory, which results in a memory leak.
Add the missing of_reserved_mem_device_release() call before returning
-ENOMEM to properly clean up the reserved memory.
Fixes: 695824f456 ("mmc: sdhci: add Black Sesame Technologies BST C1200 controller driver")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The mux branch contains updates to the mux core along with some
corresponding changes for a couple of consumer drivers, including an mmc
driver. Let's merge it into the next branch to get it tested and queued for
the next release.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Some hardware designs route data or control signals through a mux to
support multiple devices on a single sdhi controller.
In particular SolidRun RZ/G2L/G2LC/V2L System on Module use a mux for
switching between soldered eMMC and an optional microSD on a carrier
board, e.g. for development or provisioning.
SD/SDIO/eMMC are not well suited for runtime switching between different
cards, however boot-time selection is possible and useful - in
particular considering dt overlays.
Add support for an optional SD/SDIO/eMMC mux defined in dt, and select
it during probe.
Similar functionality already exists in other places, e.g. i2c-omap.
Signed-off-by: Josua Mayer <josua@solid-run.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Merge the mmc fixes for v7.0-rc[n] into the next branch, to allow them to
get tested together with the mmc changes that are targeted for the next
release.
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
The GL9750 SD host controller has intermittent data corruption during
DMA write operations. The GM_BURST register's R_OSRC_Lmt field
(bits 17:16), which limits outstanding DMA read requests from system
memory, is not being cleared during initialization. The Windows driver
sets R_OSRC_Lmt to zero, limiting requests to the smallest unit.
Clear R_OSRC_Lmt to match the Windows driver behavior. This eliminates
write corruption verified with f3write/f3read tests while maintaining
DMA performance.
Cc: stable@vger.kernel.org
Fixes: e51df6ce66 ("mmc: host: sdhci-pci: Add Genesys Logic GL975x support")
Closes: https://lore.kernel.org/linux-mmc/33d12807-5c72-41ce-8679-57aa11831fad@linux.dev/
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Matthew Schwartz <matthew.schwartz@linux.dev>
Reviewed-by: Ben Chuang <ben.chuang@genesyslogic.com.tw>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Now that the Realtek PCIe SDMMC host implements the card_busy() callback,
the MMC core performs the required DAT[3:0] validation during the signal
voltage switch sequence.
As a result, the driver-side voltage stabilization helpers
sd_wait_voltage_stable_1() and sd_wait_voltage_stable_2() become redundant.
These helpers duplicate DAT line checks that are now handled centrally by
the MMC core via card_busy().
Remove the two stabilization helpers and simplify sdmmc_switch_voltage()
accordingly, keeping only the minimal clock control needed around the
voltage switch.
No functional changes and intended.
Signed-off-by: Ricky Wu <ricky_wu@realtek.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
