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authorArnd Bergmann <arnd@arndb.de>2012-11-26 11:57:58 (GMT)
committerArnd Bergmann <arnd@arndb.de>2012-11-26 11:57:58 (GMT)
commiteabc5fa51c1fae4b66cf883e3a3c2b3ca794494c (patch)
tree7e17333920f4ab9986f3f40e881b4bc890a91724 /Documentation
parent9489e9dcae718d5fde988e4a684a0f55b5f94d17 (diff)
parentdf1590d9ae5e37e07e7cf91107e4c2c946ce8bf4 (diff)
downloadlinux-fsl-qoriq-eabc5fa51c1fae4b66cf883e3a3c2b3ca794494c.tar.xz
Merge branch 'spear-for-3.8' of git://git.linaro.org/people/vireshk/linux into next/dt2
From Viresh Kumar <viresh.kumar@linaro.org>: These are DT updates for SPEAr SoCs. There aren't any fixes that we want to get into 3.7-rc* and we are happy with 3.8. Some of the dtbs which use gpiopinctrl have dependency on Linus's pinctrl tree, where an earlier update for adding gpiopinctrl node is present. * 'spear-for-3.8' of git://git.linaro.org/people/vireshk/linux: ARM: SPEAr3xx: Shirq: Move shirq controller out of plat/ ARM: SPEAr320: DT: Add SPEAr 320 HMI board support ARM: SPEAr3xx: DT: add shirq node for interrupt multiplexor ARM: SPEAr3xx: shirq: simplify and move the shared irq multiplexor to DT ARM: SPEAr1310: Fix AUXDATA for compact flash controller ARM: SPEAr13xx: Remove fields not required for ssp controller ARM: SPEAr1310: Move 1310 specific misc register into machine specific files ARM: SPEAr: DT: Update device nodes ARM: SPEAr: DT: add uart state to fix warning ARM: SPEAr: DT: Modify DT bindings for STMMAC ARM: SPEAr: DT: Fix existing DT support ARM: SPEAr: DT: Update partition info for MTD devices ARM: SPEAr: DT: Update pinctrl list ARM: SPEAr13xx: DT: Add spics gpio controller nodes Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/arm/spear/shirq.txt48
-rw-r--r--Documentation/devicetree/bindings/gpio/gpio.txt36
-rw-r--r--Documentation/devicetree/bindings/gpio/spear_spics.txt50
-rw-r--r--Documentation/gpio.txt42
-rw-r--r--Documentation/pinctrl.txt7
5 files changed, 182 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/arm/spear/shirq.txt b/Documentation/devicetree/bindings/arm/spear/shirq.txt
new file mode 100644
index 0000000..13fbb88
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/spear/shirq.txt
@@ -0,0 +1,48 @@
+* SPEAr Shared IRQ layer (shirq)
+
+SPEAr3xx architecture includes shared/multiplexed irqs for certain set
+of devices. The multiplexor provides a single interrupt to parent
+interrupt controller (VIC) on behalf of a group of devices.
+
+There can be multiple groups available on SPEAr3xx variants but not
+exceeding 4. The number of devices in a group can differ, further they
+may share same set of status/mask registers spanning across different
+bit masks. Also in some cases the group may not have enable or other
+registers. This makes software little complex.
+
+A single node in the device tree is used to describe the shared
+interrupt multiplexor (one node for all groups). A group in the
+interrupt controller shares config/control registers with other groups.
+For example, a 32-bit interrupt enable/disable config register can
+accommodate upto 4 interrupt groups.
+
+Required properties:
+ - compatible: should be, either of
+ - "st,spear300-shirq"
+ - "st,spear310-shirq"
+ - "st,spear320-shirq"
+ - interrupt-controller: Identifies the node as an interrupt controller.
+ - #interrupt-cells: should be <1> which basically contains the offset
+ (starting from 0) of interrupts for all the groups.
+ - reg: Base address and size of shirq registers.
+ - interrupts: The list of interrupts generated by the groups which are
+ then connected to a parent interrupt controller. Each group is
+ associated with one of the interrupts, hence number of interrupts (to
+ parent) is equal to number of groups. The format of the interrupt
+ specifier depends in the interrupt parent controller.
+
+ Optional properties:
+ - interrupt-parent: pHandle of the parent interrupt controller, if not
+ inherited from the parent node.
+
+Example:
+
+The following is an example from the SPEAr320 SoC dtsi file.
+
+shirq: interrupt-controller@0xb3000000 {
+ compatible = "st,spear320-shirq";
+ reg = <0xb3000000 0x1000>;
+ interrupts = <28 29 30 1>;
+ #interrupt-cells = <1>;
+ interrupt-controller;
+};
diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentation/devicetree/bindings/gpio/gpio.txt
index 4e16ba4..a336287 100644
--- a/Documentation/devicetree/bindings/gpio/gpio.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio.txt
@@ -75,4 +75,40 @@ Example of two SOC GPIO banks defined as gpio-controller nodes:
gpio-controller;
};
+2.1) gpio-controller and pinctrl subsystem
+------------------------------------------
+gpio-controller on a SOC might be tightly coupled with the pinctrl
+subsystem, in the sense that the pins can be used by other functions
+together with optional gpio feature.
+
+While the pin allocation is totally managed by the pin ctrl subsystem,
+gpio (under gpiolib) is still maintained by gpio drivers. It may happen
+that different pin ranges in a SoC is managed by different gpio drivers.
+
+This makes it logical to let gpio drivers announce their pin ranges to
+the pin ctrl subsystem and call 'pinctrl_request_gpio' in order to
+request the corresponding pin before any gpio usage.
+
+For this, the gpio controller can use a pinctrl phandle and pins to
+announce the pinrange to the pin ctrl subsystem. For example,
+
+ qe_pio_e: gpio-controller@1460 {
+ #gpio-cells = <2>;
+ compatible = "fsl,qe-pario-bank-e", "fsl,qe-pario-bank";
+ reg = <0x1460 0x18>;
+ gpio-controller;
+ gpio-ranges = <&pinctrl1 20 10>, <&pinctrl2 50 20>;
+
+ }
+
+where,
+ &pinctrl1 and &pinctrl2 is the phandle to the pinctrl DT node.
+
+ Next values specify the base pin and number of pins for the range
+ handled by 'qe_pio_e' gpio. In the given example from base pin 20 to
+ pin 29 under pinctrl1 and pin 50 to pin 69 under pinctrl2 is handled
+ by this gpio controller.
+
+The pinctrl node must have "#gpio-range-cells" property to show number of
+arguments to pass with phandle from gpio controllers node.
diff --git a/Documentation/devicetree/bindings/gpio/spear_spics.txt b/Documentation/devicetree/bindings/gpio/spear_spics.txt
new file mode 100644
index 0000000..96c37eb
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/spear_spics.txt
@@ -0,0 +1,50 @@
+=== ST Microelectronics SPEAr SPI CS Driver ===
+
+SPEAr platform provides a provision to control chipselects of ARM PL022 Prime
+Cell spi controller through its system registers, which otherwise remains under
+PL022 control. If chipselect remain under PL022 control then they would be
+released as soon as transfer is over and TxFIFO becomes empty. This is not
+desired by some of the device protocols above spi which expect (multiple)
+transfers without releasing their chipselects.
+
+Chipselects can be controlled by software by turning them as GPIOs. SPEAr
+provides another interface through system registers through which software can
+directly control each PL022 chipselect. Hence, it is natural for SPEAr to export
+the control of this interface as gpio.
+
+Required properties:
+
+ * compatible: should be defined as "st,spear-spics-gpio"
+ * reg: mentioning address range of spics controller
+ * st-spics,peripcfg-reg: peripheral configuration register offset
+ * st-spics,sw-enable-bit: bit offset to enable sw control
+ * st-spics,cs-value-bit: bit offset to drive chipselect low or high
+ * st-spics,cs-enable-mask: chip select number bit mask
+ * st-spics,cs-enable-shift: chip select number program offset
+ * gpio-controller: Marks the device node as gpio controller
+ * #gpio-cells: should be 1 and will mention chip select number
+
+All the above bit offsets are within peripcfg register.
+
+Example:
+-------
+spics: spics@e0700000{
+ compatible = "st,spear-spics-gpio";
+ reg = <0xe0700000 0x1000>;
+ st-spics,peripcfg-reg = <0x3b0>;
+ st-spics,sw-enable-bit = <12>;
+ st-spics,cs-value-bit = <11>;
+ st-spics,cs-enable-mask = <3>;
+ st-spics,cs-enable-shift = <8>;
+ gpio-controller;
+ #gpio-cells = <2>;
+};
+
+
+spi0: spi@e0100000 {
+ status = "okay";
+ num-cs = <3>;
+ cs-gpios = <&gpio1 7 0>, <&spics 0>,
+ <&spics 1>;
+ ...
+}
diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt
index e08a883..77a1d11 100644
--- a/Documentation/gpio.txt
+++ b/Documentation/gpio.txt
@@ -439,6 +439,48 @@ slower clock delays the rising edge of SCK, and the I2C master adjusts its
signaling rate accordingly.
+GPIO controllers and the pinctrl subsystem
+------------------------------------------
+
+A GPIO controller on a SOC might be tightly coupled with the pinctrl
+subsystem, in the sense that the pins can be used by other functions
+together with an optional gpio feature. We have already covered the
+case where e.g. a GPIO controller need to reserve a pin or set the
+direction of a pin by calling any of:
+
+pinctrl_request_gpio()
+pinctrl_free_gpio()
+pinctrl_gpio_direction_input()
+pinctrl_gpio_direction_output()
+
+But how does the pin control subsystem cross-correlate the GPIO
+numbers (which are a global business) to a certain pin on a certain
+pin controller?
+
+This is done by registering "ranges" of pins, which are essentially
+cross-reference tables. These are described in
+Documentation/pinctrl.txt
+
+While the pin allocation is totally managed by the pinctrl subsystem,
+gpio (under gpiolib) is still maintained by gpio drivers. It may happen
+that different pin ranges in a SoC is managed by different gpio drivers.
+
+This makes it logical to let gpio drivers announce their pin ranges to
+the pin ctrl subsystem before it will call 'pinctrl_request_gpio' in order
+to request the corresponding pin to be prepared by the pinctrl subsystem
+before any gpio usage.
+
+For this, the gpio controller can register its pin range with pinctrl
+subsystem. There are two ways of doing it currently: with or without DT.
+
+For with DT support refer to Documentation/devicetree/bindings/gpio/gpio.txt.
+
+For non-DT support, user can call gpiochip_add_pin_range() with appropriate
+parameters to register a range of gpio pins with a pinctrl driver. For this
+exact name string of pinctrl device has to be passed as one of the
+argument to this routine.
+
+
What do these conventions omit?
===============================
One of the biggest things these conventions omit is pin multiplexing, since
diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt
index 3b4ee53..da40efb 100644
--- a/Documentation/pinctrl.txt
+++ b/Documentation/pinctrl.txt
@@ -364,6 +364,9 @@ will get an pin number into its handled number range. Further it is also passed
the range ID value, so that the pin controller knows which range it should
deal with.
+Calling pinctrl_add_gpio_range from pinctrl driver is DEPRECATED. Please see
+section 2.1 of Documentation/devicetree/bindings/gpio/gpio.txt on how to bind
+pinctrl and gpio drivers.
PINMUX interfaces
=================
@@ -1193,4 +1196,6 @@ foo_switch()
...
}
-The above has to be done from process context.
+The above has to be done from process context. The reservation of the pins
+will be done when the state is activated, so in effect one specific pin
+can be used by different functions at different times on a running system.