On 12/01/2015 04:04 AM, Tony Lindgren wrote:

* Vignesh R [off-list ref] [151129 21:16]:

quoted

Add qspi memory mapped region entries for DRA7xx based SoCs. Also,
update the binding documents for the controller to document this change.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Vignesh R <vigneshr@ti.com>

...

quoted

--- a/Documentation/devicetree/bindings/spi/ti_qspi.txt
+++ b/Documentation/devicetree/bindings/spi/ti_qspi.txt

@@ -26,3 +26,17 @@ qspi: qspi at 4b300000 {
 	spi-max-frequency = <25000000>;
 	ti,hwmods = "qspi";
 };
+
+For dra7xx:
+qspi: qspi at 4b300000 {
+	compatible = "ti,dra7xxx-qspi";
+	reg = <0x4b300000 0x100>,
+	      <0x5c000000 0x4000000>,
+	      <0x4a002558 0x4>;
+	reg-names = "qspi_base", "qspi_mmap",
+		    "qspi_ctrlmod";
+	#address-cells = <1>;
+	#size-cells = <0>;
+	spi-max-frequency = <48000000>;
+	ti,hwmods = "qspi";
+};

Actually none of the IO areas above are within the same interconnect target:

0x4b300000  QSPI0 address space in L3 main interconnect
0x5c000000  QSPI1 address space in L3 main interconnect

First address range (configuration port: 0x4b300000) corresponds to QSPI
registers space. These registers alone are sufficient for generic SPI
communication (serial flash as well as non-flash SPI devices).

In order to speed up SPI flash reads SFI_MM_IF(SPI memory mapped
interface) is provided by QSPI IP. This _cannot_ be used with non-flash
devices.
The second address range (0x5c000000) corresponds to memory-mapped
region of SFI_MM_IF, through which SPI flash memories can be read as if
though they were RAM addresses (i.e using readl/memcpy). The SFI_MM_IF
block that takes care of communicating over SPI bus and getting the data
from flash device.
But SFI_MM_IF block needs to know some flash specific information(such
as read opcode, address bytes, dummy bytes, mode). This information must
first be populated in QSPI_SPI_SETUP*_REG(0x4B300054-60) before
accessing SFI_MM_IF address range via readl.
Both addresses space belong to same instance of the driver, one
corresponds to register space and other is memory-mapped region.
Therefore both regions are claimed by the same driver.

0x4a002558  CTRL_CORE_CONTROL_IO_2 in System Control Module (SCM) in L4_CFG

The first two address spaces should be two separate instances of this driver.

Not actually two instances.

The CTRL_CORE_CONTROL_IO_2 needs seems like a shared clock register that
needs to be accessed using the clock framework most likely.

Not shared clock.
The CTRL_CORE_CONTROL_IO_2[10:8] QSPI_MEMMAPPED_CS bit fields provides a
functionality for remapping the previously described address space which
starts at 0x5C000000 L3_MAIN address to one of the four supported chip
selects.
How about using syscon to access CTRL_CORE_CONTROL_IO_2?

-- 
Regards
Vignesh