FDT/OFW GPIO bus
Luiz Otavio O Souza
loos.br at gmail.com
Mon Mar 17 12:55:48 UTC 2014
On Fri, Feb 7, 2014 at 1:21 AM, Warner Losh wrote:
>
> On Feb 6, 2014, at 11:53 AM, Luiz Otavio O Souza wrote:
>
>> Hello guys,
>>
>> Last call for alcohol^Wtest and reviews.
>>
>> I've finally managed to test these changes on a some FDT and non FDT systems, so now it is all cleared to commit.
>>
>> I plan to commit these changes on the weekend unless someone objects.
>
> This is cool.
>
>> They add support to describe GPIO connections on the DTS files. It also add the support to the in tree GPIO devices (gpioiic(4), gpioled(4)).
>>
>> The last patch (005-bbb-gpioled.diff) sets the gpioled(4) for the 4 on board LEDs on BBB (beaglebone-black). The RPi led is already set and just need the first patch (001-ofw-gpiobus.diff) to work.
>>
>> The tests were done on RPi and BBB using I2C devices (two lm75 on the same bus), LEDs (for gpioled(4)) and even with some non committed ethernet over SPI. The I2C tests are conducted using the hardware I2C controller (when available) and also the software big bang controller - gpioiic(4).
>>
>> I used the RSPRO (MIPS/ar71xx) to check for regressions without any visible problem.
>>
>> gpioiic(4) devices can be described in DTS as follow:
>>
>> gpio {
>>
>> gpioiic {
>> compatible = "gpioiic";
>
> Linux uses 'i2c-gpio' here. Can we follow that standard rather than invent our own? Or at least support both?
>
>> gpios = <&gpio 17 2 0
>> &gpio 21 2 0>;
>> scl = <0>;
>> sda = <1>;
>
> Linux doesn't have these at all, it seems, since they are implicit in the gpios property. It would be ideal if the scl and sda properties were optional...
>
> In addition, you'll often see things like:
>
> i2c-gpio,sda-open-drain;
> i2c-gpio,scl-open-drain;
> i2c-gpio,delay-us = <2>;
>
> as well. These should be easy enough to add and shouldn't gate things.
>
> There's also many DTS files that don't have this as a direct child of gpio... But that's not strictly required. I'll cope with adding support for that when I get the Atmel stuff working...
The first attached adds the ability to attach nodes compatible with
'i2c-gpio' and also nodes that are not direct childs of gpio
controllers (tested with parts of an Atmel dts).
The second patch changes the string identification for gpioiic(4) and
gpioled(4) from 'gpioiic'/'gpioled' to 'freebsd,gpioiic' and
'freebsd,gpioled'.
Did they look fine ?
Thanks,
Luiz
-------------- next part --------------
Index: sys/dev/gpio/gpioiic.c
===================================================================
--- sys/dev/gpio/gpioiic.c (revision 262131)
+++ sys/dev/gpio/gpioiic.c (working copy)
@@ -41,9 +41,9 @@
#include "gpiobus_if.h"
#ifdef FDT
-#include <dev/ofw/ofw_bus.h>
+#include <dev/fdt/fdt_common.h>
+#include <dev/gpio/gpiobusvar.h>
#include <dev/ofw/ofw_bus_subr.h>
-#include <dev/fdt/fdt_common.h>
#endif
#include <dev/iicbus/iiconf.h>
@@ -54,6 +54,18 @@
#define SCL_PIN_DEFAULT 0 /* default index of SCL pin on gpiobus */
#define SDA_PIN_DEFAULT 1
+#ifdef FDT
+#define ATTACH_NONE 0
+#define ATTACH_GPIOIIC 1
+#define ATTACH_I2CGPIO 2
+
+static struct ofw_compat_data compat_data[] = {
+ { "gpioiic", ATTACH_GPIOIIC },
+ { "i2c-gpio", ATTACH_I2CGPIO },
+ { NULL, ATTACH_NONE },
+};
+#endif
+
struct gpioiic_softc
{
device_t sc_dev;
@@ -74,14 +86,42 @@
static int gpioiic_getscl(device_t);
static int gpioiic_reset(device_t, u_char, u_char, u_char *);
+#ifdef FDT
+/*
+ * The identify() method is used here to give a chance to gpioiic to traverse
+ * the whole DTB data to find the compatible nodes which are not direct
+ * decendants from the gpiobus(4). This follows the linux standard.
+ */
+static void
+gpioiic_identify(driver_t *driver, device_t bus)
+{
+ phandle_t child, root;
+ root = OF_finddevice("/");
+ if (root == 0)
+ return;
+
+ /*
+ * Traverse all children of 'root' node, find the ones compatible
+ * with 'i2c-gpio'.
+ */
+ for (child = OF_child(root); child != 0; child = OF_peer(child))
+ if (fdt_is_compatible(child, "i2c-gpio") &&
+ fdt_is_compatible_strict(child, "i2c-gpio"))
+ if (ofw_gpiobus_add_fdt_child(bus, child) == NULL)
+ continue;
+}
+#endif
+
static int
gpioiic_probe(device_t dev)
{
+#ifdef FDT
+ int match;
-#ifdef FDT
- if (!ofw_bus_is_compatible(dev, "gpioiic"))
- return (ENXIO);
+ match = ofw_bus_search_compatible(dev, compat_data)->ocd_data;
+ if (match == ATTACH_NONE)
+ return (ENXIO);
#endif
device_set_desc(dev, "GPIO I2C bit-banging driver");
@@ -261,6 +301,9 @@
DEVMETHOD(iicbb_reset, gpioiic_reset),
#ifdef FDT
+ /* Device interface */
+ DEVMETHOD(device_identify, gpioiic_identify),
+
/* OFW bus interface */
DEVMETHOD(ofw_bus_get_node, gpioiic_get_node),
#endif
Index: share/man/man4/gpioiic.4
===================================================================
--- share/man/man4/gpioiic.4 (revision 262131)
+++ share/man/man4/gpioiic.4 (working copy)
@@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd February 13, 2014
+.Dd March 11, 2014
.Dt GPIOIIC 4
.Os
.Sh NAME
@@ -114,10 +114,34 @@
};
.Ed
.Pp
+Optionally the
+.Nm
+node can be described under the root node without being a directly descendant of any
+.Xr gpio 4
+controller:
+.Bd -literal
+simplebus0 {
+
+ ...
+
+ i2c at 0 {
+ compatible = "i2c-gpio";
+ gpios = <&GPIO 3 1 0
+ &GPIO 2 1 0>;
+
+ /* This is another example of a gpioiic child. */
+ gpioiic-child0 {
+ compatible = "lm75";
+ i2c-address = <0x4f>;
+ };
+ };
+};
+.Ed
+.Pp
Where:
.Bl -tag -width ".Va compatible"
.It Va compatible
-Should always be set to "gpioiic".
+Should be set to "gpioiic" or "i2c-gpio".
.It Va gpios
The
.Va gpios
-------------- next part --------------
Index: sys/dev/gpio/gpioled.c
===================================================================
--- sys/dev/gpio/gpioled.c (revision 262131)
+++ sys/dev/gpio/gpioled.c (working copy)
@@ -128,7 +128,7 @@
* leds nodes on the dts.
*/
match = 0;
- if (ofw_bus_is_compatible(dev, "gpioled"))
+ if (ofw_bus_is_compatible(dev, "freebsd,gpioled"))
match = 1;
if (match == 0) {
--- sys/dev/gpio/gpioiic.c.orig 2014-03-11 15:22:33.291978975 -0300
+++ sys/dev/gpio/gpioiic.c 2014-03-11 15:23:10.809976063 -0300
@@ -60,7 +60,7 @@
#define ATTACH_I2CGPIO 2
static struct ofw_compat_data compat_data[] = {
- { "gpioiic", ATTACH_GPIOIIC },
+ { "freebsd,gpioiic", ATTACH_GPIOIIC },
{ "i2c-gpio", ATTACH_I2CGPIO },
{ NULL, ATTACH_NONE },
};
Index: share/man/man4/gpioled.4
===================================================================
--- share/man/man4/gpioled.4 (revision 262131)
+++ share/man/man4/gpioled.4 (working copy)
@@ -24,7 +24,7 @@
.\"
.\" $FreeBSD$
.\"
-.Dd February 13, 2014
+.Dd March 11, 2014
.Dt GPIOLED 4
.Os
.Sh NAME
@@ -82,13 +82,13 @@
...
led0 {
- compatible = "gpioled";
+ compatible = "freebsd,gpioled";
gpios = <&gpio 16 2 0>; /* GPIO pin 16. */
name = "ok";
};
led1 {
- compatible = "gpioled";
+ compatible = "freebsd,gpioled";
gpios = <&gpio 17 2 0>; /* GPIO pin 17. */
name = "user-led1";
};
--- share/man/man4/gpioiic.4.orig 2014-03-16 10:46:41.582484179 -0300
+++ share/man/man4/gpioiic.4 2014-03-16 10:46:18.557484453 -0300
@@ -95,7 +95,7 @@
...
gpioiic0 {
- compatible = "gpioiic";
+ compatible = "freebsd,gpioiic";
/*
* Attach to GPIO pins 21 and 22. Set them
* initially as inputs.
@@ -107,7 +107,7 @@
/* This is an example of a gpioiic child. */
gpioiic-child0 {
- compatible = "lm75";
+ compatible = "freebsd,lm75";
i2c-address = <0x4f>;
};
};
@@ -131,7 +131,7 @@
/* This is another example of a gpioiic child. */
gpioiic-child0 {
- compatible = "lm75";
+ compatible = "freebsd,lm75";
i2c-address = <0x4f>;
};
};
@@ -141,7 +141,7 @@
Where:
.Bl -tag -width ".Va compatible"
.It Va compatible
-Should be set to "gpioiic" or "i2c-gpio".
+Should be set to "freebsd,gpioiic" or "i2c-gpio".
.It Va gpios
The
.Va gpios
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