ARM: OMAP2+: cleaned-up DT support of various ECC schemes

OMAP NAND driver support multiple ECC scheme, which can used in different
flavours, depending on in-build Hardware engines present on SoC.

This patch updates following in DT bindings related to sectionion of ecc-schemes
- ti,elm-id: replaces elm_id (maintains backward compatibility)
- ti,nand-ecc-opts: selection of h/w or s/w implementation of an ecc-scheme
	depends on ti,elm-id. (supported values ham1, bch4, and bch8)
- maintain backward compatibility to deprecated DT bindings (sw, hw, hw-romcode)

Below table shows different flavours of ecc-schemes supported by OMAP devices
+---------------------------------------+---------------+---------------+
| ECC scheme                            |ECC calculation|Error detection|
+---------------------------------------+---------------+---------------+
|OMAP_ECC_HAM1_CODE_HW                  |H/W (GPMC)     |S/W            |
+---------------------------------------+---------------+---------------+
|OMAP_ECC_BCH8_CODE_HW_DETECTION_SW     |H/W (GPMC)     |S/W            |
|(requires CONFIG_MTD_NAND_ECC_BCH)     |               |               |
+---------------------------------------+---------------+---------------+
|OMAP_ECC_BCH8_CODE_HW                  |H/W (GPMC)     |H/W (ELM)      |
|(requires CONFIG_MTD_NAND_OMAP_BCH &&  |               |               |
| ti,elm-id in DT)                      |               |               |
+---------------------------------------+---------------+---------------+

To optimize footprint of omap2-nand driver, selection of some ECC schemes
also require enabling following Kconfigs, in addition to setting appropriate
DT bindings
- Kconfig:CONFIG_MTD_NAND_ECC_BCH        error detection done in software
- Kconfig:CONFIG_MTD_NAND_OMAP_BCH       error detection done by h/w engine

Signed-off-by: Pekon Gupta <pekon@ti.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

1 files changed, 11 insertions, 2 deletions

diff --git a/include/linux/platform_data/mtd-nand-omap2.h b/include/linux/platform_data/mtd-nand-omap2.h
index 6bf9ef43ddb1..e4128f1510bf 100644
--- a/include/linux/platform_data/mtd-nand-omap2.h
+++ b/include/linux/platform_data/mtd-nand-omap2.h
@@ -28,8 +28,16 @@ enum omap_ecc {
         OMAP_ECC_HAMMING_CODE_HW, /* gpmc to detect the error */
                 /* 1-bit ecc: stored at beginning of spare area as romcode */
         OMAP_ECC_HAMMING_CODE_HW_ROMCODE, /* gpmc method & romcode layout */
-        OMAP_ECC_BCH4_CODE_HW, /* 4-bit BCH ecc code */
-        OMAP_ECC_BCH8_CODE_HW, /* 8-bit BCH ecc code */
+        /* 1-bit  ECC calculation by GPMC, Error detection by Software */
+        OMAP_ECC_HAM1_CODE_HW,
+        /* 4-bit  ECC calculation by GPMC, Error detection by Software */
+        OMAP_ECC_BCH4_CODE_HW_DETECTION_SW,
+        /* 4-bit  ECC calculation by GPMC, Error detection by ELM */
+        OMAP_ECC_BCH4_CODE_HW,
+        /* 8-bit  ECC calculation by GPMC, Error detection by Software */
+        OMAP_ECC_BCH8_CODE_HW_DETECTION_SW,
+        /* 8-bit  ECC calculation by GPMC, Error detection by ELM */
+        OMAP_ECC_BCH8_CODE_HW,
 };
 
 struct gpmc_nand_regs {
@@ -63,5 +71,6 @@ struct omap_nand_platform_data {
 
         /* for passing the partitions */
         struct device_node      *of_node;
+        struct device_node      *elm_of_node;
 };
 #endif