summaryrefslogtreecommitdiff
path: root/Documentation/memory-devices/ti-emif.txt
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2012-05-22 16:02:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-22 16:02:13 -0700
commit5d4e2d08e7fdf7339f84a1c670d296a77e02f881 (patch)
tree1c419660defa56191091dfdf50fdb57a72009173 /Documentation/memory-devices/ti-emif.txt
parentfb2123fad3b499f0898835b19dbb93b18d27ee98 (diff)
parent94ca629e40eb7e997be21d8065c25e4f3797b03f (diff)
Merge tag 'driver-core-3.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core updates from Greg Kroah-Hartman: "Here's the driver core, and other driver subsystems, pull request for the 3.5-rc1 merge window. Outside of a few minor driver core changes, we ended up with the following different subsystem and core changes as well, due to interdependancies on the driver core: - hyperv driver updates - drivers/memory being created and some drivers moved into it - extcon driver subsystem created out of the old Android staging switch driver code - dynamic debug updates - printk rework, and /dev/kmsg changes All of this has been tested in the linux-next releases for a few weeks with no reported problems. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>" Fix up conflicts in drivers/extcon/extcon-max8997.c where git noticed that a patch to the deleted drivers/misc/max8997-muic.c driver needs to be applied to this one. * tag 'driver-core-3.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (90 commits) uio_pdrv_genirq: get irq through platform resource if not set otherwise memory: tegra{20,30}-mc: Remove empty *_remove() printk() - isolate KERN_CONT users from ordinary complete lines sysfs: get rid of some lockdep false positives Drivers: hv: util: Properly handle version negotiations. Drivers: hv: Get rid of an unnecessary check in vmbus_prep_negotiate_resp() memory: tegra{20,30}-mc: Use dev_err_ratelimited() driver core: Add dev_*_ratelimited() family Driver Core: don't oops with unregistered driver in driver_find_device() printk() - restore prefix/timestamp printing for multi-newline strings printk: add stub for prepend_timestamp() ARM: tegra30: Make MC optional in Kconfig ARM: tegra20: Make MC optional in Kconfig ARM: tegra30: MC: Remove unnecessary BUG*() ARM: tegra20: MC: Remove unnecessary BUG*() printk: correctly align __log_buf ARM: tegra30: Add Tegra Memory Controller(MC) driver ARM: tegra20: Add Tegra Memory Controller(MC) driver printk() - restore timestamp printing at console output printk() - do not merge continuation lines of different threads ...
Diffstat (limited to 'Documentation/memory-devices/ti-emif.txt')
-rw-r--r--Documentation/memory-devices/ti-emif.txt57
1 files changed, 57 insertions, 0 deletions
diff --git a/Documentation/memory-devices/ti-emif.txt b/Documentation/memory-devices/ti-emif.txt
new file mode 100644
index 000000000000..f4ad9a7d0f4b
--- /dev/null
+++ b/Documentation/memory-devices/ti-emif.txt
@@ -0,0 +1,57 @@
+TI EMIF SDRAM Controller Driver:
+
+Author
+========
+Aneesh V <aneesh@ti.com>
+
+Location
+============
+driver/memory/emif.c
+
+Supported SoCs:
+===================
+TI OMAP44xx
+TI OMAP54xx
+
+Menuconfig option:
+==========================
+Device Drivers
+ Memory devices
+ Texas Instruments EMIF driver
+
+Description
+===========
+This driver is for the EMIF module available in Texas Instruments
+SoCs. EMIF is an SDRAM controller that, based on its revision,
+supports one or more of DDR2, DDR3, and LPDDR2 SDRAM protocols.
+This driver takes care of only LPDDR2 memories presently. The
+functions of the driver includes re-configuring AC timing
+parameters and other settings during frequency, voltage and
+temperature changes
+
+Platform Data (see include/linux/platform_data/emif_plat.h):
+=====================================================================
+DDR device details and other board dependent and SoC dependent
+information can be passed through platform data (struct emif_platform_data)
+- DDR device details: 'struct ddr_device_info'
+- Device AC timings: 'struct lpddr2_timings' and 'struct lpddr2_min_tck'
+- Custom configurations: customizable policy options through
+ 'struct emif_custom_configs'
+- IP revision
+- PHY type
+
+Interface to the external world:
+================================
+EMIF driver registers notifiers for voltage and frequency changes
+affecting EMIF and takes appropriate actions when these are invoked.
+- freq_pre_notify_handling()
+- freq_post_notify_handling()
+- volt_notify_handling()
+
+Debugfs
+========
+The driver creates two debugfs entries per device.
+- regcache_dump : dump of register values calculated and saved for all
+ frequencies used so far.
+- mr4 : last polled value of MR4 register in the LPDDR2 device. MR4
+ indicates the current temperature level of the device.