[V2,1/2] clk: imx: Add common API for masking MMDC handshake

Commit Message

Anson Huang May 15, 2019, 12:28 p.m. UTC

All i.MX6 SoCs need to mask unused MMDC channel's handshake
for low power modes, this patch provides common API for masking
the MMDC channel passed from caller.

Signed-off-by: Anson Huang <[e-mail]>
Reviewed-by: Dong Aisheng <[e-mail]>
---
Changes since V1:
	- add necessary "io.h" head file to avoid build error based on latest linux-next.
---
 drivers/clk/imx/clk.c | 15 +++++++++++++++
 drivers/clk/imx/clk.h |  1 +
 2 files changed, 16 insertions(+)

Patch

diff --git a/drivers/clk/imx/clk.c b/drivers/clk/imx/clk.c
index 1efed86..9cd7097 100644
--- a/drivers/clk/imx/clk.c
+++ b/drivers/clk/imx/clk.c
@@ -1,13 +1,28 @@ 
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/clk.h>
 #include <linux/err.h>
+#include <linux/io.h>
 #include <linux/of.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include "clk.h"
 
+#define CCM_CCDR			0x4
+#define CCDR_MMDC_CH0_MASK		BIT(17)
+#define CCDR_MMDC_CH1_MASK		BIT(16)
+
 DEFINE_SPINLOCK(imx_ccm_lock);
 
+void __init imx_mmdc_mask_handshake(void __iomem *ccm_base,
+				    unsigned int chn)
+{
+	unsigned int reg;
+
+	reg = readl_relaxed(ccm_base + CCM_CCDR);
+	reg |= chn == 0 ? CCDR_MMDC_CH0_MASK : CCDR_MMDC_CH1_MASK;
+	writel_relaxed(reg, ccm_base + CCM_CCDR);
+}
+
 void __init imx_check_clocks(struct clk *clks[], unsigned int count)
 {
 	unsigned i;
diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
index 8639a8f..6dcdc91 100644
--- a/drivers/clk/imx/clk.h
+++ b/drivers/clk/imx/clk.h
@@ -10,6 +10,7 @@  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);
 void imx_register_uart_clocks(struct clk ** const clks[]);
+void imx_mmdc_mask_handshake(void __iomem *ccm_base, unsigned int chn);
 
 extern void imx_cscmr1_fixup(u32 *val);