[PATCH v9 2/4] clk: meson: add emmc sub clock phase delay driver

[Liang Yang]

Export the emmc sub clock phase delay ops which will be used
by the emmc sub clock driver itself.

Signed-off-by: Liang Yang <liang.yang@xxxxxxxxxxx>
---
 drivers/clk/meson/Kconfig           |  4 ++
 drivers/clk/meson/Makefile          |  1 +
 drivers/clk/meson/clk-phase-delay.c | 69 +++++++++++++++++++++++++++++
 drivers/clk/meson/clk-phase-delay.h | 20 +++++++++
 4 files changed, 94 insertions(+)
 create mode 100644 drivers/clk/meson/clk-phase-delay.c
 create mode 100644 drivers/clk/meson/clk-phase-delay.h

diff --git a/drivers/clk/meson/Kconfig b/drivers/clk/meson/Kconfig
index 3014e2f1fbb4..bb0f59eea366 100644
--- a/drivers/clk/meson/Kconfig
+++ b/drivers/clk/meson/Kconfig
@@ -18,6 +18,10 @@ config COMMON_CLK_MESON_PHASE
 	tristate
 	select COMMON_CLK_MESON_REGMAP
 
+config COMMON_CLK_MESON_PHASE_DELAY
+	tristate
+	select COMMON_CLK_MESON_REGMAP
+
 config COMMON_CLK_MESON_PLL
 	tristate
 	select COMMON_CLK_MESON_REGMAP
diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
index b3ef5f67820f..c450f38d3801 100644
--- a/drivers/clk/meson/Makefile
+++ b/drivers/clk/meson/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_COMMON_CLK_MESON_PLL) += clk-pll.o
 obj-$(CONFIG_COMMON_CLK_MESON_REGMAP) += clk-regmap.o
 obj-$(CONFIG_COMMON_CLK_MESON_SCLK_DIV) += sclk-div.o
 obj-$(CONFIG_COMMON_CLK_MESON_VID_PLL_DIV) += vid-pll-div.o
+obj-$(CONFIG_COMMON_CLK_MESON_PHASE_DELAY) += clk-phase-delay.o
 
 # Amlogic Clock controllers
 
diff --git a/drivers/clk/meson/clk-phase-delay.c b/drivers/clk/meson/clk-phase-delay.c
new file mode 100644
index 000000000000..3c1ae0ee2a24
--- /dev/null
+++ b/drivers/clk/meson/clk-phase-delay.c
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright (c) 2019 Amlogic, Inc. All rights reserved.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+
+#include "clk-regmap.h"
+#include "clk-phase-delay.h"
+
+static inline struct meson_clk_phase_delay_data *
+meson_clk_get_phase_delay_data(struct clk_regmap *clk)
+{
+	return clk->data;
+}
+
+static int meson_clk_phase_delay_get_phase(struct clk_hw *hw)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct meson_clk_phase_delay_data *ph;
+	unsigned long period_ps, p, d;
+	int degrees;
+
+	ph = meson_clk_get_phase_delay_data(clk);
+	p = meson_parm_read(clk->map, &ph->phase);
+	degrees = p * 360 / (1 << (ph->phase.width));
+
+	period_ps = DIV_ROUND_UP_ULL(NSEC_PER_SEC * 1000ull,
+				     clk_hw_get_rate(hw));
+
+	d = meson_parm_read(clk->map, &ph->delay);
+	degrees += d * ph->delay_step_ps * 360 / period_ps;
+	degrees %= 360;
+
+	return degrees;
+}
+
+static int meson_clk_phase_delay_set_phase(struct clk_hw *hw, int degrees)
+{
+	struct clk_regmap *clk = to_clk_regmap(hw);
+	struct meson_clk_phase_delay_data *ph;
+	unsigned long period_ps, d = 0;
+	unsigned int p;
+
+	ph = meson_clk_get_phase_delay_data(clk);
+	period_ps = DIV_ROUND_UP_ULL(NSEC_PER_SEC * 1000ull,
+				     clk_hw_get_rate(hw));
+
+	/*
+	 * First compute the phase index (p), the remainder (r) is the
+	 * part we'll try to acheive using the delays (d).
+	 */
+	p = 360 / 1 << (ph->phase.width);
+	degrees = degrees / p;
+	d = DIV_ROUND_CLOSEST((degrees % p) * period_ps,
+			      360 * ph->delay_step_ps);
+	d = min(d, PMASK(ph->delay.width));
+
+	meson_parm_write(clk->map, &ph->phase, degrees);
+	meson_parm_write(clk->map, &ph->delay, d);
+	return 0;
+}
+
+const struct clk_ops meson_clk_phase_delay_ops = {
+	.get_phase = meson_clk_phase_delay_get_phase,
+	.set_phase = meson_clk_phase_delay_set_phase,
+};
+EXPORT_SYMBOL_GPL(meson_clk_phase_delay_ops);
diff --git a/drivers/clk/meson/clk-phase-delay.h b/drivers/clk/meson/clk-phase-delay.h
new file mode 100644
index 000000000000..b4f211d02c84
--- /dev/null
+++ b/drivers/clk/meson/clk-phase-delay.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: (GPL-2.0+ OR MIT) */
+/*
+ * Copyright (c) 2019 Amlogic, Inc. All rights reserved.
+ */
+
+#ifndef __MESON_CLK_PHASE_DELAY_H
+#define __MESON_CLK_PHASE_DELAY_H
+
+#include <linux/clk-provider.h>
+#include "parm.h"
+
+struct meson_clk_phase_delay_data {
+	struct parm     phase;
+	struct parm     delay;
+	unsigned int    delay_step_ps;
+};
+
+extern const struct clk_ops meson_clk_phase_delay_ops;
+
+#endif /* __MESON_CLK_PHASE_DELAY_H */
-- 
2.34.1