[PATCH V3 2/2] clk: imx: support fsl,always-on-clocks

[Peng Fan (OSS)]

From: Peng Fan <peng.fan@xxxxxxx>

For the clocks listed in fsl,always-on-clocks, enable them to avoid
Linux disable them. This will benifit root Linux and inmate cell run
on top of Jailhouse hypervisor.

Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
---
 drivers/clk/imx/clk-imx8mm.c |  2 ++
 drivers/clk/imx/clk-imx8mn.c |  2 ++
 drivers/clk/imx/clk-imx8mp.c |  2 ++
 drivers/clk/imx/clk-imx8mq.c |  2 ++
 drivers/clk/imx/clk.c        | 21 +++++++++++++++++++++
 drivers/clk/imx/clk.h        |  2 ++
 6 files changed, 31 insertions(+)

diff --git a/drivers/clk/imx/clk-imx8mm.c b/drivers/clk/imx/clk-imx8mm.c
index aa58b2995610..d1e4d0d3c41b 100644
--- a/drivers/clk/imx/clk-imx8mm.c
+++ b/drivers/clk/imx/clk-imx8mm.c
@@ -611,6 +611,8 @@ static int imx8mm_clocks_probe(struct platform_device *pdev)
 
 	imx_register_uart_clocks(4);
 
+	imx_clk_always_on(dev, hws);
+
 	return 0;
 
 unregister_hws:
diff --git a/drivers/clk/imx/clk-imx8mn.c b/drivers/clk/imx/clk-imx8mn.c
index 79fabc0606b0..422b535013de 100644
--- a/drivers/clk/imx/clk-imx8mn.c
+++ b/drivers/clk/imx/clk-imx8mn.c
@@ -605,6 +605,8 @@ static int imx8mn_clocks_probe(struct platform_device *pdev)
 
 	imx_register_uart_clocks(4);
 
+	imx_clk_always_on(dev, hws);
+
 	return 0;
 
 unregister_hws:
diff --git a/drivers/clk/imx/clk-imx8mp.c b/drivers/clk/imx/clk-imx8mp.c
index 4297af85ab09..ff043fa0299d 100644
--- a/drivers/clk/imx/clk-imx8mp.c
+++ b/drivers/clk/imx/clk-imx8mp.c
@@ -714,6 +714,8 @@ static int imx8mp_clocks_probe(struct platform_device *pdev)
 
 	imx_register_uart_clocks(4);
 
+	imx_clk_always_on(dev, hws);
+
 	return 0;
 }
 
diff --git a/drivers/clk/imx/clk-imx8mq.c b/drivers/clk/imx/clk-imx8mq.c
index 882dcad4817d..6eec3bbcde6f 100644
--- a/drivers/clk/imx/clk-imx8mq.c
+++ b/drivers/clk/imx/clk-imx8mq.c
@@ -603,6 +603,8 @@ static int imx8mq_clocks_probe(struct platform_device *pdev)
 
 	imx_register_uart_clocks(4);
 
+	imx_clk_always_on(dev, hws);
+
 	return 0;
 
 unregister_hws:
diff --git a/drivers/clk/imx/clk.c b/drivers/clk/imx/clk.c
index 5582f18dd632..75876c81882c 100644
--- a/drivers/clk/imx/clk.c
+++ b/drivers/clk/imx/clk.c
@@ -2,6 +2,7 @@
 #include <linux/bits.h>
 #include <linux/clk.h>
 #include <linux/clk-provider.h>
+#include <linux/device.h>
 #include <linux/err.h>
 #include <linux/io.h>
 #include <linux/module.h>
@@ -214,4 +215,24 @@ static int __init imx_clk_disable_uart(void)
 late_initcall_sync(imx_clk_disable_uart);
 #endif
 
+int imx_clk_always_on(struct device *dev, struct clk_hw * const clks[])
+{
+	struct device_node *np = dev->of_node;
+	struct property *prop;
+	const __be32 *p;
+	u32 i;
+	int ret;
+
+	of_property_for_each_u32(np, "fsl,always-on-clocks", prop, p, i) {
+		ret = clk_prepare_enable(clks[i]->clk);
+		if (ret) {
+			dev_err(dev, "failed to enable %s\n", clk_hw_get_name(clks[i]));
+			return ret;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(imx_clk_always_on);
+
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
index dd49f90110e8..591d72ea4d31 100644
--- a/drivers/clk/imx/clk.h
+++ b/drivers/clk/imx/clk.h
@@ -22,6 +22,8 @@ void imx_mmdc_mask_handshake(void __iomem *ccm_base, unsigned int chn);
 void imx_unregister_clocks(struct clk *clks[], unsigned int count);
 void imx_unregister_hw_clocks(struct clk_hw *hws[], unsigned int count);
 
+int imx_clk_always_on(struct device *dev, struct clk_hw * const clks[]);
+
 extern void imx_cscmr1_fixup(u32 *val);
 
 enum imx_pllv1_type {
-- 
2.37.1