mtd: spi-nor: introduce SPI 1-2-2 and SPI 1-4-4 protocols
Sync the driver with Linux v4.12 and apply the patch

  commit cfc5604
  Author:     Cyrille Pitchen <cyrille.pitchen@atmel.com>
  AuthorDate: Tue Apr 25 22:08:46 2017 +0200
  Commit:     Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>
  CommitDate: Mon May 15 21:56:17 2017 +0200

      mtd: spi-nor: introduce SPI 1-2-2 and SPI 1-4-4 protocols

      This patch changes the prototype of spi_nor_scan(): its 3rd parameter
      is replaced by a 'struct spi_nor_hwcaps' pointer, which tells the spi-nor
      framework about the actual hardware capabilities supported by the SPI
      controller and its driver.

      Besides, this patch also introduces a new 'struct spi_nor_flash_parameter'
      telling the spi-nor framework about the hardware capabilities supported by
      the SPI flash memory and the associated settings required to use those
      hardware caps.

      Then, to improve the readability of spi_nor_scan(), the discovery of the
      memory settings and the memory initialization are now split into two
      dedicated functions.

      1 - spi_nor_init_params()

      The spi_nor_init_params() function is responsible for initializing the
      'struct spi_nor_flash_parameter'. Currently this structure is filled with
      legacy values but further patches will allow to override some parameter
      values dynamically, for instance by reading the JESD216 Serial Flash
      Discoverable Parameter (SFDP) tables from the SPI memory.
      The spi_nor_init_params() function only deals with the hardware
      capabilities of the SPI flash memory: especially it doesn't care about
      the hardware capabilities supported by the SPI controller.

      2 - spi_nor_setup()

      The second function is called once the 'struct spi_nor_flash_parameter'
      has been initialized by spi_nor_init_params().
      With both 'struct spi_nor_flash_parameter' and 'struct spi_nor_hwcaps',
      the new argument of spi_nor_scan(), spi_nor_setup() computes the best
      match between hardware caps supported by both the (Q)SPI memory and
      controller hence selecting the relevant settings for (Fast) Read and Page
      Program operations.

      Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
      Reviewed-by: Marek Vasut <marek.vasut@gmail.com>

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
1 parent 62a84b8 commit 8e3318b5bc593c5366edda37cde717c4f4a36ad5
@Steffen Trumtrar Steffen Trumtrar authored on 3 May 2019
Sascha Hauer committed on 8 May 2019
Showing 4 changed files
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drivers/mtd/devices/m25p80.c
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drivers/mtd/spi-nor/cadence-quadspi.c
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drivers/mtd/spi-nor/spi-nor.c
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include/linux/mtd/spi-nor.h