mtd: spi-nor: Decouple SPI NOR's device_node from controller device

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=11bff0b70cc003b995cf4c2acec4adab90957b02
Commit:     11bff0b70cc003b995cf4c2acec4adab90957b02
Parent:     f9b97fe61402f7f18da71e034b1e72f68df82c1a
Author:     Marek Vasut <marex at denx.de>
AuthorDate: Thu Sep 3 18:35:36 2015 +0200
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Fri Sep 11 15:48:21 2015 -0700

    mtd: spi-nor: Decouple SPI NOR's device_node from controller device
    
    The problem this patch is trying to address is such, that SPI NOR flash
    devices attached to a dedicated SPI NOR controller cannot read their
    properties from the associated struct device_node.
    
    A couple of facts first:
    1) Each SPI NOR flash has a struct spi_nor associated with it.
    2) Each SPI NOR flash has certain device properties associated
       with it, for example the OF property 'm25p,fast-read' is a
       good pick. These properties are used by the SPI NOR core to
       select which opcodes are sent to such SPI NOR flash. These
       properties are coming from spi_nor .dev->of_node .
    
    The problem is, that for SPI NOR controllers, the struct spi_nor .dev
    element points to the struct device of the SPI NOR controller, not the
    SPI NOR flash. Therefore, the associated dev->of_node also is the
    one of the controller and therefore the SPI NOR core code is trying to
    parse the SPI NOR controller's properties, not the properties of the
    SPI NOR flash.
    
    Note: The m25p80 driver is not affected, because the controller and
          the flash are the same device, so the associated device_node
          of the controller and the flash are the same.
    
    This patch adjusts the SPI NOR core such that the device_node is not
    picked from spi_nor .dev directly, but from a new separate spi_nor
    .flash_node element. This let's the SPI NOR controller drivers set up
    a different spi_nor .flash_node element for each SPI NOR flash.
    
    This patch also fixes the controller drivers to be compatible with
    this modification and correctly set the spi_nor .flash_node element.
    
    This patch is inspired by 5844feeaa4154d1c46d3462c7a4653d22356d8b4
    mtd: nand: add common DT init code
    
    Signed-off-by: Marek Vasut <marex at denx.de>
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
---
 drivers/mtd/devices/m25p80.c      | 1 +
 drivers/mtd/spi-nor/fsl-quadspi.c | 1 +
 drivers/mtd/spi-nor/nxp-spifi.c   | 1 +
 drivers/mtd/spi-nor/spi-nor.c     | 2 +-
 include/linux/mtd/spi-nor.h       | 2 ++
 5 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index b6bc9a2..05bf0d7 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -200,6 +200,7 @@ static int m25p_probe(struct spi_device *spi)
 	nor->read_reg = m25p80_read_reg;
 
 	nor->dev = &spi->dev;
+	nor->flash_node = spi->dev.of_node;
 	nor->priv = flash;
 
 	spi_set_drvdata(spi, flash);
diff --git a/drivers/mtd/spi-nor/fsl-quadspi.c b/drivers/mtd/spi-nor/fsl-quadspi.c
index f28dcc1..f724832 100644
--- a/drivers/mtd/spi-nor/fsl-quadspi.c
+++ b/drivers/mtd/spi-nor/fsl-quadspi.c
@@ -1013,6 +1013,7 @@ static int fsl_qspi_probe(struct platform_device *pdev)
 		mtd = &nor->mtd;
 
 		nor->dev = dev;
+		nor->flash_node = np;
 		nor->priv = q;
 
 		/* fill the hooks */
diff --git a/drivers/mtd/spi-nor/nxp-spifi.c b/drivers/mtd/spi-nor/nxp-spifi.c
index 0f6b452..ce7bf6b 100644
--- a/drivers/mtd/spi-nor/nxp-spifi.c
+++ b/drivers/mtd/spi-nor/nxp-spifi.c
@@ -331,6 +331,7 @@ static int nxp_spifi_setup_flash(struct nxp_spifi *spifi,
 	writel(ctrl, spifi->io_base + SPIFI_CTRL);
 
 	spifi->nor.dev   = spifi->dev;
+	spifi->nor.flash_node = np;
 	spifi->nor.priv  = spifi;
 	spifi->nor.read  = nxp_spifi_read;
 	spifi->nor.write = nxp_spifi_write;
diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 55c67a4..22cca87 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -1005,7 +1005,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
 	const struct flash_info *info = NULL;
 	struct device *dev = nor->dev;
 	struct mtd_info *mtd = &nor->mtd;
-	struct device_node *np = dev->of_node;
+	struct device_node *np = nor->flash_node;
 	int ret;
 	int i;
 
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 495433d..6379e10 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -134,6 +134,7 @@ struct mtd_info;
  * @mtd:		point to a mtd_info structure
  * @lock:		the lock for the read/write/erase/lock/unlock operations
  * @dev:		point to a spi device, or a spi nor controller device.
+ * @flash_node:		point to a device node describing this flash instance.
  * @page_size:		the page size of the SPI NOR
  * @addr_width:		number of address bytes
  * @erase_opcode:	the opcode for erasing a sector
@@ -165,6 +166,7 @@ struct spi_nor {
 	struct mtd_info		mtd;
 	struct mutex		lock;
 	struct device		*dev;
+	struct device_node	*flash_node;
 	u32			page_size;
 	u8			addr_width;
 	u8			erase_opcode;