[U-Boot] [PATCH 4/4] i2c: mux: Add support for not listed sub-buses

Michal Simek michal.simek at xilinx.com
Fri Jan 18 15:13:16 UTC 2019 

Before this patch is applied all i2c sub-buses are using number -1 and
they can't be addresses(switch to). If all busses are listed in DT alias
they will get proper numbers and U-Boot can work with them.
In Linux buses which are not listed in DT alias get uniq number which
starts from the first highest free ID.

This is the behavior on ZynqMP zcu100-revA before this patch is applied.

Bus 0:	i2c at ff020000
   20: gpio at 20, offset len 1, flags 0
   21: gpio at 21, offset len 1, flags 0
   75: i2c-mux at 75, offset len 1, flags 0
Bus -1:	i2c at 0
Bus -1:	i2c at 1
Bus -1:	i2c at 2
Bus 1:	i2c at ff030000
   74: i2c-mux at 74, offset len 1, flags 0
   75: i2c-mux at 75, offset len 1, flags 0
Bus -1:	i2c at 0
Bus -1:	i2c at 1
Bus -1:	i2c at 2
Bus -1:	i2c at 3
Bus -1:	i2c at 4
Bus -1:	i2c at 0
Bus -1:	i2c at 1
Bus -1:	i2c at 2
Bus -1:	i2c at 3
Bus -1:	i2c at 4
Bus -1:	i2c at 5
Bus -1:	i2c at 6
Bus -1:	i2c at 7

When the patch is applied also i2c-mux busses are listed properly.

ZynqMP> i2c bus
Bus 0:	i2c at ff020000
   20: gpio at 20, offset len 1, flags 0
   21: gpio at 21, offset len 1, flags 0
   75: i2c-mux at 75, offset len 1, flags 0
Bus 2:	i2c at ff020000->i2c-mux at 75->i2c at 0
Bus 3:	i2c at ff020000->i2c-mux at 75->i2c at 1
Bus 4:	i2c at ff020000->i2c-mux at 75->i2c at 2
Bus 1:	i2c at ff030000  (active 1)
   74: i2c-mux at 74, offset len 1, flags 0
   75: i2c-mux at 75, offset len 1, flags 0
Bus 5:	i2c at ff030000->i2c-mux at 74->i2c at 0 (active 5)
   54: generic_54, offset len 1, flags 0
Bus 6:	i2c at ff030000->i2c-mux at 74->i2c at 1
Bus 7:	i2c at ff030000->i2c-mux at 74->i2c at 2
Bus 8:	i2c at ff030000->i2c-mux at 74->i2c at 3
Bus 9:	i2c at ff030000->i2c-mux at 74->i2c at 4
Bus 10:	i2c at ff030000->i2c-mux at 75->i2c at 0
Bus 11:	i2c at ff030000->i2c-mux at 75->i2c at 1
Bus 12:	i2c at ff030000->i2c-mux at 75->i2c at 2
Bus 13:	i2c at ff030000->i2c-mux at 75->i2c at 3
Bus 14:	i2c at ff030000->i2c-mux at 75->i2c at 4
Bus 15:	i2c at ff030000->i2c-mux at 75->i2c at 5
Bus 16:	i2c at ff030000->i2c-mux at 75->i2c at 6
Bus 17:	i2c at ff030000->i2c-mux at 75->i2c at 7

Signed-off-by: Michal Simek <michal.simek at xilinx.com>
---

zcu102-revA

Before this patch applied for !DM case with static description
ZynqMP> i2c bus
Bus 0:	zynq_0
Bus 1:	zynq_0->PCA9544A at 0x75:0
Bus 2:	zynq_0->PCA9544A at 0x75:1
Bus 3:	zynq_0->PCA9544A at 0x75:2
Bus 4:	zynq_1
Bus 5:	zynq_1->PCA9548 at 0x74:0
Bus 6:	zynq_1->PCA9548 at 0x74:1
Bus 7:	zynq_1->PCA9548 at 0x74:2
Bus 8:	zynq_1->PCA9548 at 0x74:3
Bus 9:	zynq_1->PCA9548 at 0x74:4
Bus 10:	zynq_1->PCA9548 at 0x75:0
Bus 11:	zynq_1->PCA9548 at 0x75:1
Bus 12:	zynq_1->PCA9548 at 0x75:2
Bus 13:	zynq_1->PCA9548 at 0x75:3
Bus 14:	zynq_1->PCA9548 at 0x75:4
Bus 15:	zynq_1->PCA9548 at 0x75:5
Bus 16:	zynq_1->PCA9548 at 0x75:6
Bus 17:	zynq_1->PCA9548 at 0x75:7

When Patch is applied with OF_LIVE - of_alias_get_highest_id() is used
ZynqMP> i2c bus
Bus 0:	i2c at ff020000
   75: i2c-mux at 75, offset len 1, flags 0
Bus 2:	i2c at ff020000->i2c-mux at 75->i2c at 0
Bus 3:	i2c at ff020000->i2c-mux at 75->i2c at 1
Bus 4:	i2c at ff020000->i2c-mux at 75->i2c at 2
Bus 1:	i2c at ff030000
   74: i2c-mux at 74, offset len 1, flags 0
   75: i2c-mux at 75, offset len 1, flags 0
Bus 5:	i2c at ff030000->i2c-mux at 74->i2c at 0
Bus 6:	i2c at ff030000->i2c-mux at 74->i2c at 1
Bus 7:	i2c at ff030000->i2c-mux at 74->i2c at 2
Bus 8:	i2c at ff030000->i2c-mux at 74->i2c at 3
Bus 9:	i2c at ff030000->i2c-mux at 74->i2c at 4
Bus 10:	i2c at ff030000->i2c-mux at 75->i2c at 0
Bus 11:	i2c at ff030000->i2c-mux at 75->i2c at 1
Bus 12:	i2c at ff030000->i2c-mux at 75->i2c at 2
Bus 13:	i2c at ff030000->i2c-mux at 75->i2c at 3
Bus 14:	i2c at ff030000->i2c-mux at 75->i2c at 4
Bus 15:	i2c at ff030000->i2c-mux at 75->i2c at 5
Bus 16:	i2c at ff030000->i2c-mux at 75->i2c at 6
Bus 17:	i2c at ff030000->i2c-mux at 75->i2c at 7

For !OF_LIVE - hardcoded number is used
ZynqMP> i2c bus
Bus 0:	i2c at ff020000
   75: i2c-mux at 75, offset len 1, flags 0
Bus 21:	i2c at ff020000->i2c-mux at 75->i2c at 0
Bus 22:	i2c at ff020000->i2c-mux at 75->i2c at 1
Bus 23:	i2c at ff020000->i2c-mux at 75->i2c at 2
Bus 1:	i2c at ff030000
   74: i2c-mux at 74, offset len 1, flags 0
   75: i2c-mux at 75, offset len 1, flags 0
Bus 24:	i2c at ff030000->i2c-mux at 74->i2c at 0
Bus 25:	i2c at ff030000->i2c-mux at 74->i2c at 1
Bus 26:	i2c at ff030000->i2c-mux at 74->i2c at 2
Bus 27:	i2c at ff030000->i2c-mux at 74->i2c at 3
Bus 28:	i2c at ff030000->i2c-mux at 74->i2c at 4
Bus 29:	i2c at ff030000->i2c-mux at 75->i2c at 0
Bus 30:	i2c at ff030000->i2c-mux at 75->i2c at 1
Bus 31:	i2c at ff030000->i2c-mux at 75->i2c at 2
Bus 32:	i2c at ff030000->i2c-mux at 75->i2c at 3
Bus 33:	i2c at ff030000->i2c-mux at 75->i2c at 4
Bus 34:	i2c at ff030000->i2c-mux at 75->i2c at 5
Bus 35:	i2c at ff030000->i2c-mux at 75->i2c at 6
Bus 36:	i2c at ff030000->i2c-mux at 75->i2c at 7

---
 drivers/i2c/muxes/i2c-mux-uclass.c | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/muxes/i2c-mux-uclass.c b/drivers/i2c/muxes/i2c-mux-uclass.c
index a680ee176253..cb69d053fd59 100644
--- a/drivers/i2c/muxes/i2c-mux-uclass.c
+++ b/drivers/i2c/muxes/i2c-mux-uclass.c
@@ -9,6 +9,7 @@
 #include <errno.h>
 #include <i2c.h>
 #include <dm/lists.h>
+#include <dm/of_access.h>
 #include <dm/root.h>
 
 /**
@@ -59,13 +60,42 @@ static int i2c_mux_post_bind(struct udevice *mux)
 	dev_for_each_subnode(node, mux) {
 		struct udevice *dev;
 		const char *name;
+		const char *arrow = "->";
+		char *full_name;
+		int parent_name_len, arrow_len, mux_name_len, name_len;
 
 		name = ofnode_get_name(node);
-		ret = device_bind_driver_to_node(mux, "i2c_mux_bus_drv", name,
-						 node, &dev);
+
+		/* Calculate lenghts of strings */
+		parent_name_len = strlen(mux->parent->name);
+		arrow_len = strlen(arrow);
+		mux_name_len = strlen(mux->name);
+		name_len = strlen(name);
+
+		full_name = calloc(1, parent_name_len + arrow_len +
+				   mux_name_len + arrow_len + name_len + 1);
+		if (!full_name)
+			return -ENOMEM;
+
+		/* Compose bus name */
+		strcat(full_name, mux->parent->name);
+		strcat(full_name, arrow);
+		strcat(full_name, mux->name);
+		strcat(full_name, arrow);
+		strcat(full_name, name);
+
+		ret = device_bind_driver_to_node(mux, "i2c_mux_bus_drv",
+						 full_name, node, &dev);
 		debug("   - bind ret=%d, %s\n", ret, dev ? dev->name : NULL);
 		if (ret)
 			return ret;
+
+		/* If dt alias is not found start to allocate new IDs */
+		if (dev->req_seq == -1)
+			dev->req_seq = ++i2c_highest_id;
+
+		debug("%s: MUX bus %d: %s\n", __func__, dev->req_seq,
+		      full_name);
 	}
 
 	return 0;
@@ -192,6 +222,7 @@ U_BOOT_DRIVER(i2c_mux_bus) = {
 
 UCLASS_DRIVER(i2c_mux) = {
 	.id		= UCLASS_I2C_MUX,
+	.flags		= DM_UC_FLAG_SEQ_ALIAS,
 	.name		= "i2c_mux",
 	.post_bind	= i2c_mux_post_bind,
 	.post_probe	= i2c_mux_post_probe,
-- 
1.9.1

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