pinctrl: at91-pio4: Add support for pinctrl config subnodes

Previously, in order for the `pinctrl-*` DT node properties
to be properly processed, the pinctrl's subnodes were limited
to only having the `pinmux` property as well as other additional
properties (slew-rate, bias-disable, etc.). Now, with this patch
the pinctrl driver is made to work similarly to the one from Linux.
It can now distinguish between one subnode and a subnode with multiple
subnodes.

Signed-off-by: Sergiu Moga <sergiu.moga@microchip.com>

diff --git a/drivers/pinctrl/pinctrl-at91-pio4.c b/drivers/pinctrl/pinctrl-at91-pio4.c
index e434a38..50e3dd4 100644 (file)
--- a/drivers/pinctrl/pinctrl-at91-pio4.c
+++ b/drivers/pinctrl/pinctrl-at91-pio4.c
@@ -15,6 +15,7 @@
 #include <linux/bitops.h>
 #include <linux/io.h>
 #include <linux/err.h>
+#include <dm/uclass-internal.h>
 #include <mach/atmel_pio4.h>
 
 DECLARE_GLOBAL_DATA_PTR;
@@ -151,12 +152,11 @@ static inline struct atmel_pio4_port *atmel_pio4_bank_base(struct udevice *dev,
 
 #define MAX_PINMUX_ENTRIES     40
 
-static int atmel_pinctrl_set_state(struct udevice *dev, struct udevice *config)
+static int atmel_process_config_dev(struct udevice *dev, struct udevice *config)
 {
        struct atmel_pio4_plat *plat = dev_get_plat(dev);
-       struct atmel_pio4_port *bank_base;
-       const void *blob = gd->fdt_blob;
        int node = dev_of_offset(config);
+       struct atmel_pio4_port *bank_base;
        u32 offset, func, bank, line;
        u32 cells[MAX_PINMUX_ENTRIES];
        u32 i, conf;
@@ -164,18 +164,17 @@ static int atmel_pinctrl_set_state(struct udevice *dev, struct udevice *config)
 
        conf = atmel_pinctrl_get_pinconf(config, plat);
 
-       count = fdtdec_get_int_array_count(blob, node, "pinmux",
+       /*
+        * The only case where this function returns a negative error value
+        * is when there is no "pinmux" property attached to this node
+        */
+       count = fdtdec_get_int_array_count(gd->fdt_blob, node, "pinmux",
                                           cells, ARRAY_SIZE(cells));
-       if (count < 0) {
-               printf("%s: bad pinmux array %d\n", __func__, count);
-               return -EINVAL;
-       }
+       if (count < 0)
+               return count;
 
-       if (count > MAX_PINMUX_ENTRIES) {
-               printf("%s: unsupported pinmux array count %d\n",
-                      __func__, count);
+       if (count > MAX_PINMUX_ENTRIES)
                return -EINVAL;
-       }
 
        for (i = 0 ; i < count; i++) {
                offset = ATMEL_GET_PIN_NO(cells[i]);
@@ -195,6 +194,56 @@ static int atmel_pinctrl_set_state(struct udevice *dev, struct udevice *config)
        return 0;
 }
 
+static int atmel_pinctrl_set_state(struct udevice *dev, struct udevice *config)
+{
+       int node = dev_of_offset(config);
+       struct udevice *subconfig;
+       int subnode, subnode_count = 0, ret;
+
+       /*
+        * If this function returns a negative error code then that means
+        * that either the "pinmux" property of the node is missing, which is
+        * the case for pinctrl nodes that do not have all the pins with the
+        * same configuration and are split in multiple subnodes, or something
+        * else went wrong and we have to stop. For the latter case, it would
+        * mean that the node failed even though it has no subnodes.
+        */
+       ret = atmel_process_config_dev(dev, config);
+       if (!ret)
+               return ret;
+
+       /*
+        * If we reach here, it means that the subnode pinctrl's DT has multiple
+        * subnodes. If it does not, then something else went wrong in the
+        * previous call to atmel_process_config_dev.
+        */
+       fdt_for_each_subnode(subnode, gd->fdt_blob, node) {
+               /* Get subnode as an udevice */
+               ret = uclass_find_device_by_of_offset(UCLASS_PINCONFIG, subnode,
+                                                     &subconfig);
+               if (ret)
+                       return ret;
+
+               /*
+                * If this time the function returns an error code on a subnode
+                * then something is totally wrong so abort.
+                */
+               ret = atmel_process_config_dev(dev, subconfig);
+               if (ret)
+                       return ret;
+
+               subnode_count++;
+       }
+
+       /*
+        * If we somehow got here and we do not have any subnodes, abort.
+        */
+       if (!subnode_count)
+               return -EINVAL;
+
+       return 0;
+}
+
 const struct pinctrl_ops atmel_pinctrl_ops  = {
        .set_state = atmel_pinctrl_set_state,
 };