Date:   Wed, 12 Jan 2022 17:27:44 -0500
From:   Gabriel Somlo <gsomlo@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     robh+dt@...nel.org, devicetree@...r.kernel.org,
        ulf.hansson@...aro.org, linux-mmc@...r.kernel.org,
        kgugala@...micro.com, mholenko@...micro.com, krakoczy@...micro.com,
        mdudek@...ernships.antmicro.com, paulus@...abs.org, joel@....id.au,
        shorne@...il.com, geert@...ux-m68k.org,
        david.abdurachmanov@...ive.com, florent@...oy-digital.fr,
        rdunlap@...radead.org, andy.shevchenko@...il.com, hdanton@...a.com
Subject: [PATCH v13 0/3] mmc: Add LiteSDCard mmc driver

Add support for the LiteX SD-Card device, LiteSDCard.

LiteSDCard is a simple SD-Card interface available as part of the LiteX
environment, used with various RISC-V and other FPGA based SoCs.

New in v13:
Documentation/devicetree/bindings/mmc/litex,mmc.yaml:
  - add `vmmc-supply` requirement
drivers/mmc/host/Kconfig:
  - add dependency on REGULATOR, REGULATOR_FIXED_VOLTAGE
drivers/mmc/host/litex_mmc.c:
  - use `mmc_regulator_get_supply()`, with fallback to hardcoded 3.3V

>New in v12:
>drivers/mmc/host/Kconfig:
>  - add dependency on HAVE_CLK for litex_mmc driver
>  - (re)add "If unsure, say N" to the litex_mmc driver help message
>drivers/mmc/host/litex_mmc.c:
>  - prints message using dev_info() before returning success from probe()
>
>>New in v11:
>>  - picked up r/b from Andy
>>drivers/mmc/host/litex_mmc.c:
>>  - defensive coding of litex_mmc_interrupt() return logic
>>  - remove `dev` member of `struct litex_mmc_host`, only used during probe
>>
>>>New in v10:
>>>drivers/mmc/host/litex_mmc.c:
>>>  - group `linux/mmc/*` includes by themselves
>>>  - clean-up of `return` style (multiple locations throughout source)
>>>  - create `mmc_free_host()` wrapper for use with
>>>    `devm_add_action_or_reset()`
>>>  - use GFP_KERNEL with `dmam_alloc_coherent()`
>>>
>>>>New in v9:
>>>>drivers/mmc/host/Kconfig:
>>>>  - fix OF dependency
>>>>drivers/mmc/host/litex_mmc.c:
>>>>  - remove `linux/of.h` include, no longer needed since dropping
>>>>    `of_match_ptr()`
>>>>  - add `linux/mod_devicetable.h` include
>>>>  - use devm_action_or_reset() to devm-ify mmc_alloc_host(), and obviate
>>>>    the need to call mmc_free_host() explicitly during either probe()
>>>>    error path or during remove()
>>>>
>>>>>New in v8:
>>>>>commit blurbs:
>>>>>  - cosmetic editing of descriptions
>>>>>  - removed `Cc:` lines
>>>>>drivers/mmc/host/litex_mmc.c:
>>>>>  - fix file header comment (for real, this time)
>>>>>  - add explicit `bits.h` include
>>>>>  - remove `of_match_ptr()` wrapper from around .of_match_table argument
>>>>>  - fix devm ordering issues: use `devm_request_irq()`, which precludes
>>>>>    the need to call `free_irq()` on `probe()` error path or from `remove()`
>>>>>
>>>>>>New in v7:
>>>>>>
>>>>>>drivers/mmc/host/Kconfig:
>>>>>>  - added module name in LiteSDCard Kconfig entry
>>>>>>
>>>>>>drivers/mmc/host/litex_mmc.c:
>>>>>>  - fixed comment formatting, ordering, and capitalization throughout
>>>>>>    the entire file
>>>>>>  - sorted header #include statements
>>>>>>  - removed redundant parantheses in readx_poll_timeout() condition
>>>>>>  - explicit handling of readx_poll_timeout() timeout scenarios
>>>>>>  - dev_err() used in litex_mmc_sdcard_wait_done()
>>>>>>  - use memcpy_fromio() to grab command response
>>>>>>  - no need to apply 0xffff mask to a 32-bit value right-shifted by 16
>>>>>>    (host->resp[3])
>>>>>>  - use clamp() instead of min(max(...)...)
>>>>>>  - reworked platform_get_irq_optional() error handling logic
>>>>>>  - no need to explicitly zero host->irq, kzalloc() does that already
>>>>>>  - added missing free_irq() in litex_mmc_probe() error path
>>>>>>  - reordered calls inside litex_mmc_remove() (calling mmc_free_host()
>>>>>>    before free_irq()
>>>>>>
>>>>>>>New in v6:
>>>>>>>
>>>>>>>drivers/mmc/host/litex_mmc.c:
>>>>>>>  - fix handling of deferred probe vs. platform_get_irq_optional()
>>>>>>>  - don't #ifdef dma_set_mask_and_coherent(), since it automatically
>>>>>>>    does the right thing on both 32- and 64-bit DMA capable arches
>>>>>>>  - remove MMC_CAP2_FULL_PWR_CYCLE, add MMC_CAP2_NO_MMC to list of
>>>>>>>    hardcoded capabilities during litex_mmc_probe()
>>>>>>>  - hardcode mmc->ocr_avail to the full 2.7-3.6V range allowed by the
>>>>>>>    SDCard spec (the LiteSDCard device doesn't accept software
>>>>>>>    configuration)
>>>>>>>
>>>>>>>>New in v5:
>>>>>>>>
>>>>>>>>MAINTAINERS:
>>>>>>>>
>>>>>>>>  - picked up a/b Mateusz
>>>>>>>>
>>>>>>>>Doc/dt/bindings/mmc/litex,mmc.yaml:
>>>>>>>>
>>>>>>>>  - picked up r/b Rob, Joel
>>>>>>>>
>>>>>>>>drivers/mmc/host/litex_mmc.c:
>>>>>>>>
>>>>>>>>  - shorten #define constant names (cosmetic, make them less unwieldy)
>>>>>>>>  - picked up r/b Joel
>>>>>>>>
>>>>>>>>>New in v4:
>>>>>>>>>
>>>>>>>>>Doc/dt/bindings/mmc/litex,mmc.yaml:
>>>>>>>>>
>>>>>>>>>  - fixed `dt_binding_check` errors uncovered by Rob's script
>>>>>>>>>
>>>>>>>>>drivers/mmc/host/litex_mmc.c:
>>>>>>>>>
>>>>>>>>>  - struct litex_mmc_host fields re-ordered so that `pahole` reports
>>>>>>>>>    no holes in either 32- or 64-bit builds
>>>>>>>>>  - litex_mmc_set_bus_width() now encapsulates check for
>>>>>>>>>    host->is_bus_width_set
>>>>>>>>>  - litex_mmc_request() - factor out dma data setup into separate
>>>>>>>>>    helper function: litex_mmc_do_dma()
>>>>>>>>>
>>>>>>>>>>New in v3:
>>>>>>>>>>
>>>>>>>>>>  MAINTAINERS:
>>>>>>>>>>
>>>>>>>>>>  - picked up acked-by Joel
>>>>>>>>>>  - added listing for liteeth driver
>>>>>>>>>>  - added Joel as additional co-maintainer (thanks!)
>>>>>>>>>>
>>>>>>>>>>  Doc/dt/bindings/mmc/litex,mmc.yaml:
>>>>>>>>>>
>>>>>>>>>>  - picked up r/b Geert Uytterhoeven <geert@...ux-m68k.org> in DT
>>>>>>>>>>    bindings document (please let me know if that was premature, and
>>>>>>>>>>    happy to take further review if needed :)
>>>>>>>>>>  - add dedicated DT property for source clock frequency
>>>>>>>>>>
>>>>>>>>>>  drivers/mmc/host/litex_mmc.c:
>>>>>>>>>>
>>>>>>>>>>  - fixed function signature (no line split), and naming (litex_mmc_*)
>>>>>>>>>>  - more informative MODULE_AUTHOR() entries
>>>>>>>>>>    - also added matching "Copyright" entries in file header
>>>>>>>>>>  - fixed description in Kconfig
>>>>>>>>>>  - fixed DT documentation
>>>>>>>>>>  - removed magic constants
>>>>>>>>>>  - removed litex_map_status(), have sdcard_wait_done() return *real*
>>>>>>>>>>    error codes directly instead.
>>>>>>>>>>  - streamlined litex_mmc_reponse_len()
>>>>>>>>>>  - call litex_mmc_set_bus_width() only once, and ensure it returns
>>>>>>>>>>    correct error code(s)
>>>>>>>>>>  - use readx_poll_timeout() -- more concise -- instead of
>>>>>>>>>>    read_poll_timeout()
>>>>>>>>>>  - use dev_err() in litex_mmc_send_cmd() (instead of pr_err())
>>>>>>>>>>  - litex_mmc_setclk() will update host->clock before returning
>>>>>>>>>>  - separate irq initialization into its own function,
>>>>>>>>>>    litex_mmc_irq_init()
>>>>>>>>>>  - document rationale for f_min, f_max
>>>>>>>>>>  - use dmam_alloc_coherent(), which simplifies cleanup significantly
>>>>>>>>>>  - large `if (data) { ... }` block in litex_mmc_request() left as-is,
>>>>>>>>>>    there are too many variables shared with the rest of the parent
>>>>>>>>>>    function body to easily separate (e.g., `len`, `transfer`, `direct`).
>>>>>>>>>>    If this is indeed a blocker, I can take another shot at refactoring
>>>>>>>>>>    it in a future revision!
>>>>>>>>>>  - bump dma_set_mask_and_coherent() to 64-bits on suitable
>>>>>>>>>>    architectures
>>>>>>>>>>  - clock source picked up from dedicated DT clock reference property
>>>>>>>>>>  - remove gpio card-detect logic (needs testing and a dt binding
>>>>>>>>>>    example before being eligible for upstream inclusion)
>>>>>>>>>>
>>>>>>>>>>> New in v2:
>>>>>>>>>>>   - reword info message in litex_set_clk()
>>>>>>>>>>>   - streamline code in litex_map_status()
>>>>>>>>>>>   - fix typos in Kconfig (thanks Randy Dunlap <rdunlap@...radead.org>)
>>>>>>>>>>>   - improvements suggested by Stafford Horne <shorne@...il.com>
>>>>>>>>>>>     - allow COMPILE_TEST in Kconfig
>>>>>>>>>>>     - use read_poll_timeout() when waiting for cmd/data/DMA
>>>>>>>>>>>       xfer completion
>>>>>>>>>>>   - include interrupt.h (thanks kernel test robot <lkp@...el.com>)

Gabriel Somlo (3):
  MAINTAINERS: co-maintain LiteX platform
  dt-bindings: mmc: Add bindings for LiteSDCard
  mmc: Add driver for LiteX's LiteSDCard interface

 .../devicetree/bindings/mmc/litex,mmc.yaml    |  77 ++
 MAINTAINERS                                   |   9 +-
 drivers/mmc/host/Kconfig                      |  13 +
 drivers/mmc/host/Makefile                     |   1 +
 drivers/mmc/host/litex_mmc.c                  | 661 ++++++++++++++++++
 5 files changed, 759 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/mmc/litex,mmc.yaml
 create mode 100644 drivers/mmc/host/litex_mmc.c

-- 
2.31.1

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