From 43d3d092c7cbd1685e1c8ff25ae0b89b5b729388 Mon Sep 17 00:00:00 2001
From: Ulf Hansson <ulf.hansson@linaro.org>
Date: Wed, 7 Jun 2017 11:08:21 +0200
Subject: [PATCH] Bluetooth: hci_ll: Add support for the external clock
Git-commit: 43d3d092c7cbd1685e1c8ff25ae0b89b5b729388
Patch-mainline: v4.13-rc1
References: bsc#1051510

Add support to manage the external clock provided to the WiLink combo chip
as it's needed for any of the transport interfaces.

To avoid breaking platforms not yet specifying the external clock, we make
it optional. In case the clock is successfully fetched during ->probe(),
let's manage it via the ->open|close() callbacks, to make sure the device
get properly powered on/off.

Fixes: ea452678734e ("arm64: dts: hikey: Fix WiFi support")
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/bluetooth/hci_ll.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/bluetooth/hci_ll.c b/drivers/bluetooth/hci_ll.c
index 1b0487310117..2b16d48d82ee 100644
--- a/drivers/bluetooth/hci_ll.c
+++ b/drivers/bluetooth/hci_ll.c
@@ -48,6 +48,7 @@
 #include <linux/serdev.h>
 #include <linux/skbuff.h>
 #include <linux/ti_wilink_st.h>
+#include <linux/clk.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
@@ -84,6 +85,7 @@ struct ll_device {
 	struct hci_uart hu;
 	struct serdev_device *serdev;
 	struct gpio_desc *enable_gpio;
+	struct clk *ext_clk;
 };
 
 struct ll_struct {
@@ -146,8 +148,12 @@ static int ll_open(struct hci_uart *hu)
 
 	hu->priv = ll;
 
-	if (hu->serdev)
+	if (hu->serdev) {
+		struct ll_device *lldev = serdev_device_get_drvdata(hu->serdev);
 		serdev_device_open(hu->serdev);
+		if (!IS_ERR(lldev->ext_clk))
+			clk_prepare_enable(lldev->ext_clk);
+	}
 
 	return 0;
 }
@@ -181,6 +187,8 @@ static int ll_close(struct hci_uart *hu)
 		struct ll_device *lldev = serdev_device_get_drvdata(hu->serdev);
 		gpiod_set_value_cansleep(lldev->enable_gpio, 0);
 
+		clk_disable_unprepare(lldev->ext_clk);
+
 		serdev_device_close(hu->serdev);
 	}
 
@@ -721,6 +729,10 @@ static int hci_ti_probe(struct serdev_device *serdev)
 	if (IS_ERR(lldev->enable_gpio))
 		return PTR_ERR(lldev->enable_gpio);
 
+	lldev->ext_clk = devm_clk_get(&serdev->dev, "ext_clock");
+	if (IS_ERR(lldev->ext_clk) && PTR_ERR(lldev->ext_clk) != -ENOENT)
+		return PTR_ERR(lldev->ext_clk);
+
 	of_property_read_u32(serdev->dev.of_node, "max-speed", &max_speed);
 	hci_uart_set_speeds(hu, 115200, max_speed);
 
-- 
2.18.0