On Wed, Dec 9, 2009 at 18:46:51 Grant Likely wrote:
> <to-fleisc...@t-online.de> wrote:
> [...]
> > The following patch adds a function to get the active state of the chip
> > select of a SPI device by looking for the 'spi-cs-high' property in the
> > associated device tree node.
> > This function is used by the spi_mpc8xxx driver to set a proper initial
> > value to the associated GPIOs.
> >
> >
> > Signed-off-by: Torsten Fleischer <to-fleisc...@t-online.de>
>
> I like this better. See comments below.
>
[...]
Hey Grant,
below there is a new version of the patch containing the modifications
according to your comments.
Thanks for the hints,
Torsten
Signed-off-by: Torsten Fleischer <to-fleisc...@t-online.de>
---
diff -ruN linux-2.6.32_orig//drivers/of/of_spi.c
linux-2.6.32/drivers/of/of_spi.c
--- linux-2.6.32_orig//drivers/of/of_spi.c 2009-12-03 04:51:21.000000000
+0100
+++ linux-2.6.32/drivers/of/of_spi.c 2009-12-11 17:57:22.016787665 +0100
@@ -12,6 +12,43 @@
#include <linux/of_spi.h>
/**
+ * of_get_spi_cs_active_state - Gets the chip select's active state of a SPI
+ * child devices.
+ * @np: parent node of the SPI device nodes
+ * @index: index/address of the SPI device (refers to the 'reg' property)
+ *
+ * Returns 0 for 'active low' or if the child's node can't be found.
+ * Otherwise it returns 1 ('active high').
+ */
+bool of_get_spi_cs_active_state(struct device_node *np, int index)
+{
+ struct device_node *child;
+ const int *prop;
+ int len;
+ bool active = 0;
+
+ /* search for the matching SPI device */
+ for_each_child_of_node(np, child) {
+ prop = of_get_property(child, "reg", &len);
+ if (!prop || len < sizeof(*prop)) {
+ /* property 'reg' not available (not an error) */
+ continue;
+ }
+
+ if ( *prop == index ) {
+ /* matching device found */
+ if (of_find_property(child, "spi-cs-high", NULL))
+ active = 1;
+ break;
+ }
+ }
+
+ return active;
+}
+EXPORT_SYMBOL(of_get_spi_cs_active_state);
+
+
+/**
* of_register_spi_devices - Register child devices onto the SPI bus
* @master: Pointer to spi_master device
* @np: parent node of SPI device nodes
diff -ruN linux-2.6.32_orig//drivers/spi/spi_mpc8xxx.c
linux-2.6.32/drivers/spi/spi_mpc8xxx.c
--- linux-2.6.32_orig//drivers/spi/spi_mpc8xxx.c 2009-12-03
04:51:21.000000000 +0100
+++ linux-2.6.32/drivers/spi/spi_mpc8xxx.c 2009-12-11 17:15:47.957379333
+0100
@@ -705,6 +705,7 @@
for (; i < ngpios; i++) {
int gpio;
enum of_gpio_flags flags;
+ bool astate;
gpio = of_get_gpio_flags(np, i, &flags);
if (!gpio_is_valid(gpio)) {
@@ -721,8 +722,18 @@
pinfo->gpios[i] = gpio;
pinfo->alow_flags[i] = flags & OF_GPIO_ACTIVE_LOW;
+ /* get the active state of the SPI device */
+ astate = of_get_spi_cs_active_state(np, i);
+
+ /*
+ * alow_flags describe the wiring of the chip select
+ * (0 = non-inverted, 1 = inverted); this must be taken into
+ * account when setting the GPIO's initial value
+ * (see also mpc8xxx_spi_cs_control()); note that astate will
+ * be 0 for active low and 1 for active high respectively
+ */
ret = gpio_direction_output(pinfo->gpios[i],
- pinfo->alow_flags[i]);
+ pinfo->alow_flags[i] ^ !astate);
if (ret) {
dev_err(dev, "can't set output direction for gpio "
"#%d: %d\n", i, ret);
diff -ruN linux-2.6.32_orig//include/linux/of_spi.h
linux-2.6.32/include/linux/of_spi.h
--- linux-2.6.32_orig//include/linux/of_spi.h 2009-12-03 04:51:21.000000000
+0100
+++ linux-2.6.32/include/linux/of_spi.h 2009-12-11 17:10:21.681380685 +0100
@@ -15,4 +15,7 @@
extern void of_register_spi_devices(struct spi_master *master,
struct device_node *np);
+extern bool of_get_spi_cs_active_state(struct device_node *np,
+ int index);
+
#endif /* __LINUX_OF_SPI */
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