[PATCH v3 2/2] soc: ti: wkup_m3_ipc: Add support for IO Isolation

[Drew Fustini <dfustini@baylibre.com>]

From: Dave Gerlach <d-gerlach@ti.com>

AM43xx support isolation of the IOs so that control is taken
from the peripheral they are connected to and overridden by values
present in the CTRL_CONF_* registers for the pad in the control module.

The actual toggling happens from the wkup_m3, so use a DT property from
the wkup_m3_ipc node to allow the PM code to communicate the necessity
for placing the IOs into isolation to the firmware.

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Drew Fustini <dfustini@baylibre.com>
---
No changes from v1

 drivers/soc/ti/wkup_m3_ipc.c | 14 ++++++++++++--
 include/linux/wkup_m3_ipc.h  |  1 +
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/ti/wkup_m3_ipc.c b/drivers/soc/ti/wkup_m3_ipc.c
index 247a4b57a372..988162dd153a 100644
--- a/drivers/soc/ti/wkup_m3_ipc.c
+++ b/drivers/soc/ti/wkup_m3_ipc.c
@@ -46,6 +46,8 @@
 #define IPC_VTT_STAT_MASK		(0x1 << 3)
 #define IPC_VTT_GPIO_PIN_SHIFT		(0x4)
 #define IPC_VTT_GPIO_PIN_MASK		(0x3f << 4)
+#define IPC_IO_ISOLATION_STAT_SHIFT	(10)
+#define IPC_IO_ISOLATION_STAT_MASK	(0x1 << 10)
 
 #define M3_STATE_UNKNOWN		0
 #define M3_STATE_RESET			1
@@ -228,6 +230,11 @@ static void wkup_m3_set_vtt_gpio(struct wkup_m3_ipc *m3_ipc, int gpio)
 			    (gpio << IPC_VTT_GPIO_PIN_SHIFT);
 }
 
+static void wkup_m3_set_io_isolation(struct wkup_m3_ipc *m3_ipc)
+{
+	m3_ipc->isolation_conf = (1 << IPC_IO_ISOLATION_STAT_SHIFT);
+}
+
 /* Public functions */
 /**
  * wkup_m3_set_mem_type - Pass wkup_m3 which type of memory is in use
@@ -308,8 +315,8 @@ static int wkup_m3_prepare_low_power(struct wkup_m3_ipc *m3_ipc, int state)
 	wkup_m3_ctrl_ipc_write(m3_ipc, m3_ipc->resume_addr, 0);
 	wkup_m3_ctrl_ipc_write(m3_ipc, m3_power_state, 1);
 	wkup_m3_ctrl_ipc_write(m3_ipc, m3_ipc->mem_type |
-			       m3_ipc->vtt_conf, 4);
-
+			       m3_ipc->vtt_conf |
+			       m3_ipc->isolation_conf, 4);
 	wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 2);
 	wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 3);
 	wkup_m3_ctrl_ipc_write(m3_ipc, DS_IPC_DEFAULT, 5);
@@ -518,6 +525,9 @@ static int wkup_m3_ipc_probe(struct platform_device *pdev)
 			dev_warn(dev, "Invalid VTT GPIO(%d) pin\n", temp);
 	}
 
+	if (of_find_property(np, "ti,set-io-isolation", NULL))
+		wkup_m3_set_io_isolation(m3_ipc);
+
 	/*
 	 * Wait for firmware loading completion in a thread so we
 	 * can boot the wkup_m3 as soon as it's ready without holding
diff --git a/include/linux/wkup_m3_ipc.h b/include/linux/wkup_m3_ipc.h
index 2bc52c6381d5..b706eac58f92 100644
--- a/include/linux/wkup_m3_ipc.h
+++ b/include/linux/wkup_m3_ipc.h
@@ -34,6 +34,7 @@ struct wkup_m3_ipc {
 	int mem_type;
 	unsigned long resume_addr;
 	int vtt_conf;
+	int isolation_conf;
 	int state;
 
 	struct completion sync_complete;
-- 
2.32.0


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