[PATCH] clk: imx: introduce imx_clk_hw_critical

[peng.fan@nxp.com]

From: Peng Fan <peng.fan@nxp.com>

To i.MX8M SoC, there is an case is when running dual OSes
with hypervisor, the clk of the hardware that passthrough
to the 2nd OS needs to be setup by 1st Linux OS.
So detect clock-critical from ccm node and enable the clocks to let
the 2nd OS could use the hardware without touch CCM module.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
 drivers/clk/imx/clk.c | 19 +++++++++++++++++++
 drivers/clk/imx/clk.h |  1 +
 2 files changed, 20 insertions(+)

diff --git a/drivers/clk/imx/clk.c b/drivers/clk/imx/clk.c
index 87ab8db3d282..ec7d422540c1 100644
--- a/drivers/clk/imx/clk.c
+++ b/drivers/clk/imx/clk.c
@@ -177,3 +177,22 @@ static int __init imx_clk_disable_uart(void)
 	return 0;
 }
 late_initcall_sync(imx_clk_disable_uart);
+
+int imx_clk_hw_critical(struct device_node *np, struct clk_hw * const hws[])
+{
+	struct property *prop;
+	const __be32 *cur;
+	u32 idx;
+	int ret;
+
+	if (!np || !hws)
+		return -EINVAL;
+
+	of_property_for_each_u32(np, "clock-critical", prop, cur, idx) {
+		ret = clk_prepare_enable(hws[idx]->clk);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
index d4ea1609bcb7..701d7440f98c 100644
--- a/drivers/clk/imx/clk.h
+++ b/drivers/clk/imx/clk.h
@@ -9,6 +9,7 @@ extern spinlock_t imx_ccm_lock;
 
 void imx_check_clocks(struct clk *clks[], unsigned int count);
 void imx_check_clk_hws(struct clk_hw *clks[], unsigned int count);
+int imx_clk_hw_critical(struct device_node *np, struct clk_hw * const hws[]);
 void imx_register_uart_clocks(struct clk ** const clks[]);
 void imx_mmdc_mask_handshake(void __iomem *ccm_base, unsigned int chn);
 void imx_unregister_clocks(struct clk *clks[], unsigned int count);
-- 
2.16.4