linux-kernel - [PATCH 2/3] clk: fractional-divider: support regmap

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Message-Id: <20210528113403.5374-3-peng.fan@oss.nxp.com>
Date:   Fri, 28 May 2021 19:34:02 +0800
From:   "Peng Fan (OSS)" <peng.fan@....nxp.com>
To:     sboyd@...nel.org, mturquette@...libre.com
Cc:     linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, kernel@...gutronix.de,
        Peng Fan <peng.fan@....com>
Subject: [PATCH 2/3] clk: fractional-divider: support regmap

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

To i.MX8ULP, a PCC register provides clk(mux, gate, divider) and peripheral
reset functionality, so we need make sure the access to the PCC register
be protected to avoid concurrent access from clk and reset subsystem.

So let's use regmap here.

Signed-off-by: Peng Fan <peng.fan@....com>
---
 drivers/clk/clk-fractional-divider.c | 26 +++++++++++++++++++++++---
 include/linux/clk-provider.h         |  5 +++++
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/clk-fractional-divider.c b/drivers/clk/clk-fractional-divider.c
index b1e556f20911..f2df5d278214 100644
--- a/drivers/clk/clk-fractional-divider.c
+++ b/drivers/clk/clk-fractional-divider.c
@@ -11,23 +11,43 @@
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/device.h>
+#include <linux/regmap.h>
 #include <linux/slab.h>
 #include <linux/rational.h>
 
 static inline u32 clk_fd_readl(struct clk_fractional_divider *fd)
 {
-	if (fd->flags & CLK_FRAC_DIVIDER_BIG_ENDIAN)
+	int ret;
+	u32 val;
+
+	if (fd->flags & CLK_FRAC_DIVIDER_BIG_ENDIAN) {
 		return ioread32be(fd->reg);
+	} else if (fd->flags & CLK_FRAC_DIVIDER_REGMAP) {
+		ret = regmap_read(fd->regmap, fd->reg_off, &val);
+		if (ret < 0) {
+			pr_warn("%s: failed %x, %d\n", __func__, fd->reg_off, ret);
+			return ret;
+		} else {
+			return val;
+		}
+	}
 
 	return readl(fd->reg);
 }
 
 static inline void clk_fd_writel(struct clk_fractional_divider *fd, u32 val)
 {
-	if (fd->flags & CLK_FRAC_DIVIDER_BIG_ENDIAN)
+	int ret;
+
+	if (fd->flags & CLK_FRAC_DIVIDER_BIG_ENDIAN) {
 		iowrite32be(val, fd->reg);
-	else
+	} else if (fd->flags & CLK_FRAC_DIVIDER_REGMAP) {
+		ret = regmap_write(fd->regmap, fd->reg_off, val);
+		if (ret < 0)
+			pr_warn("%s: failed %x, %d\n", __func__, fd->reg_off, ret);
+	} else {
 		writel(val, fd->reg);
+	}
 }
 
 static unsigned long clk_fd_recalc_rate(struct clk_hw *hw,
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 6bd9288b953d..3902f883cdaf 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -990,6 +990,8 @@ struct clk_hw *devm_clk_hw_register_fixed_factor(struct device *dev,
  * @nshift:	shift to the denominator bit field
  * @nwidth:	width of the denominator bit field
  * @lock:	register lock
+ * @regmap:	register regmap
+ * @reg_off:	register offset
  *
  * Clock with adjustable fractional divider affecting its output frequency.
  *
@@ -1012,6 +1014,8 @@ struct clk_fractional_divider {
 	u8		nwidth;
 	u32		nmask;
 	u8		flags;
+	struct regmap	*regmap;
+	u32		reg_off;
 	void		(*approximation)(struct clk_hw *hw,
 				unsigned long rate, unsigned long *parent_rate,
 				unsigned long *m, unsigned long *n);
@@ -1022,6 +1026,7 @@ struct clk_fractional_divider {
 
 #define CLK_FRAC_DIVIDER_ZERO_BASED		BIT(0)
 #define CLK_FRAC_DIVIDER_BIG_ENDIAN		BIT(1)
+#define CLK_FRAC_DIVIDER_REGMAP			BIT(2)
 
 extern const struct clk_ops clk_fractional_divider_ops;
 struct clk *clk_register_fractional_divider(struct device *dev,
-- 
2.30.0