Author: ian
Date: Sun Sep 14 16:12:43 2014
New Revision: 271591
URL: http://svnweb.freebsd.org/changeset/base/271591
Log:
Add a comment giving an overview of the driver. Remove leftover debugging.
Modified:
head/sys/arm/freescale/imx/imx_iomux.c
Modified: head/sys/arm/freescale/imx/imx_iomux.c
==============================================================================
--- head/sys/arm/freescale/imx/imx_iomux.c Sun Sep 14 15:59:15 2014
(r271590)
+++ head/sys/arm/freescale/imx/imx_iomux.c Sun Sep 14 16:12:43 2014
(r271591)
@@ -26,6 +26,29 @@
* $FreeBSD$
*/
+/*
+ * Pin mux and pad control driver for imx5 and imx6.
+ *
+ * This driver implements the fdt_pinctrl interface for configuring the gpio
and
+ * peripheral pins based on fdt configuration data.
+ *
+ * When the driver attaches, it walks the entire fdt tree and automatically
+ * configures the pins for each device which has a pinctrl-0 property and whose
+ * status is "okay". In addition it implements the fdt_pinctrl_configure()
+ * method which any other driver can call at any time to reconfigure its pins.
+ *
+ * The nature of the fsl,pins property in fdt data makes this driver's job very
+ * easy. Instead of representing each pin and pad configuration using symbolic
+ * properties such as pullup-enable="true" and so on, the data simply contains
+ * the addresses of the registers that control the pins, and the raw values to
+ * store in those registers.
+ *
+ * The imx5 and imx6 SoCs also have a small number of "general purpose
+ * registers" in the iomuxc device which are used to control an assortment
+ * of completely unrelated aspects of SoC behavior. This driver provides other
+ * drivers with direct access to those registers via simple accessor functions.
+ */
+
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
@@ -102,13 +125,6 @@ iomux_configure_pins(device_t dev, phand
cfgnode = OF_node_from_xref(cfgxref);
ntuples = OF_getencprop_alloc(cfgnode, "fsl,pins", sizeof(*cfgtuples),
(void **)&cfgtuples);
-#ifdef DEBUG
- {
- char name[32];
- OF_getprop(cfgnode, "name", &name, sizeof(name));
- printf("found %d tuples in fsl,pins for %s\n", ntuples, name);
- }
-#endif
if (ntuples < 0)
return (ENOENT);
if (ntuples == 0)
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