[v6,1/3] clk: meson: add emmc sub clock phase delay driver

Commit Message

Jianxin Pan Nov. 1, 2018, 4:30 p.m. UTC

From: Yixun Lan <[e-mail]>

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

Signed-off-by: Yixun Lan <[e-mail]>
Signed-off-by: Jianxin Pan <[e-mail]>
---
 drivers/clk/meson/Makefile          |  2 +-
 drivers/clk/meson/clk-phase-delay.c | 66 +++++++++++++++++++++++++++++++++++++
 drivers/clk/meson/clkc.h            | 13 ++++++++
 3 files changed, 80 insertions(+), 1 deletion(-)
 create mode 100644 drivers/clk/meson/clk-phase-delay.c

Comments

Stephen Boyd Nov. 4, 2018, 3:02 a.m. UTC | #1

Quoting Jianxin Pan (2018-11-01 09:30:53)
> diff --git a/drivers/clk/meson/clk-phase-delay.c b/drivers/clk/meson/clk-phase-delay.c
> new file mode 100644
> index 0000000..83e74ed
> --- /dev/null
> +++ b/drivers/clk/meson/clk-phase-delay.c
> @@ -0,0 +1,66 @@
> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> +/*
> + * Amlogic Meson MMC Sub Clock Controller Driver
> + *
> + * Copyright (c) 2017 Baylibre SAS.
> + * Author: Jerome Brunet <[e-mail]>
> + *
> + * Copyright (c) 2018 Amlogic, inc.
> + * Author: Yixun Lan <[e-mail]>
> + * Author: Jianxin Pan <[e-mail]>
> + */
> +
> +#include <linux/clk-provider.h>
> +#include "clkc.h"
> +
> +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 =
> +               meson_clk_get_phase_delay_data(clk);

Nitpick: Do this after declaring variables because it splits a line.

> +       unsigned long period_ps, p, d;
> +       int degrees;
> +
> +       p = meson_parm_read(clk->map, &ph->phase);
> +       degrees = p * 360 / (1 << (ph->phase.width));

Nitpick: Remove useless parenthesis.

> +
> +       period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,

Is the cast necessary?

> +                                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 =
> +               meson_clk_get_phase_delay_data(clk);
> +       unsigned long period_ps, d = 0, r;
> +       u64 p;
> +
> +       p = degrees % 360;

We don't allow phase to be larger than 360 so this isn't needed.

> +       period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,

Drop the cast?

> +                                clk_hw_get_rate(hw));
> +
> +       /* First compute the phase index (p), the remainder (r) is the

Nitpick: Please leave /* on it's own line.

> +        * part we'll try to acheive using the delays (d).
> +        */
> +       r = do_div(p, 360 / (1 << (ph->phase.width)));

Drop useless parenthesis please.

> +       d = DIV_ROUND_CLOSEST(r * period_ps,
> +                             360 * ph->delay_step_ps);
> +       d = min(d, PMASK(ph->delay.width));
> +
> +       meson_parm_write(clk->map, &ph->phase, p);
> +       meson_parm_write(clk->map, &ph->delay, d);
> +       return 0;
> +}

Jianxin Pan Nov. 4, 2018, 3:12 p.m. UTC | #2

Hi Stephen,

Thanks for your review. 
Please see me comments below.

On 2018/11/4 11:02, Stephen Boyd wrote:
> Quoting Jianxin Pan (2018-11-01 09:30:53)
>> diff --git a/drivers/clk/meson/clk-phase-delay.c b/drivers/clk/meson/clk-phase-delay.c
>> new file mode 100644
>> index 0000000..83e74ed
>> --- /dev/null
>> +++ b/drivers/clk/meson/clk-phase-delay.c
>> @@ -0,0 +1,66 @@
>> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
>> +/*
>> + * Amlogic Meson MMC Sub Clock Controller Driver
>> + *
>> + * Copyright (c) 2017 Baylibre SAS.
>> + * Author: Jerome Brunet <[e-mail]>
>> + *
>> + * Copyright (c) 2018 Amlogic, inc.
>> + * Author: Yixun Lan <[e-mail]>
>> + * Author: Jianxin Pan <[e-mail]>
>> + */
>> +
>> +#include <linux/clk-provider.h>
>> +#include "clkc.h"
>> +
>> +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 =
>> +               meson_clk_get_phase_delay_data(clk);
> 
> Nitpick: Do this after declaring variables because it splits a line.
OK. I will split the assignment into another line. Thank you.
> 
>> +       unsigned long period_ps, p, d;
>> +       int degrees;
>> +
>> +       p = meson_parm_read(clk->map, &ph->phase);
>> +       degrees = p * 360 / (1 << (ph->phase.width));
> 
> Nitpick: Remove useless parenthesis.
OK. I will remove them.
> 
>> +
>> +       period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,
> 
> Is the cast necessary?
Yes, the cast can be droped. NSEC_PER_SEC is already defined wit type long.
> 
>> +                                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 =
>> +               meson_clk_get_phase_delay_data(clk);
>> +       unsigned long period_ps, d = 0, r;
>> +       u64 p;
>> +
>> +       p = degrees % 360;
> 
> We don't allow phase to be larger than 360 so this isn't needed.
OK, Thank you.
> 
>> +       period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,
> 
> Drop the cast?
OK.
> 
>> +                                clk_hw_get_rate(hw));
>> +
>> +       /* First compute the phase index (p), the remainder (r) is the
> 
> Nitpick: Please leave /* on it's own line.
OK.
> 
>> +        * part we'll try to acheive using the delays (d).
>> +        */
>> +       r = do_div(p, 360 / (1 << (ph->phase.width)));
> 
> Drop useless parenthesis please.
OK, I will fix it. Thank you.
> 
>> +       d = DIV_ROUND_CLOSEST(r * period_ps,
>> +                             360 * ph->delay_step_ps);
>> +       d = min(d, PMASK(ph->delay.width));
>> +
>> +       meson_parm_write(clk->map, &ph->phase, p);
>> +       meson_parm_write(clk->map, &ph->delay, d);
>> +       return 0;
>> +}
> 
> .
>

Patch

diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
index 72ec8c4..39ce566 100644
--- a/drivers/clk/meson/Makefile
+++ b/drivers/clk/meson/Makefile
@@ -2,7 +2,7 @@ 
 # Makefile for Meson specific clk
 #
 
-obj-$(CONFIG_COMMON_CLK_AMLOGIC) += clk-pll.o clk-mpll.o clk-phase.o
+obj-$(CONFIG_COMMON_CLK_AMLOGIC) += clk-pll.o clk-mpll.o clk-phase.o clk-phase-delay.o
 obj-$(CONFIG_COMMON_CLK_AMLOGIC_AUDIO)	+= clk-triphase.o sclk-div.o
 obj-$(CONFIG_COMMON_CLK_MESON_AO) += meson-aoclk.o
 obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o
diff --git a/drivers/clk/meson/clk-phase-delay.c b/drivers/clk/meson/clk-phase-delay.c
new file mode 100644
index 0000000..83e74ed
--- /dev/null
+++ b/drivers/clk/meson/clk-phase-delay.c
@@ -0,0 +1,66 @@ 
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Amlogic Meson MMC Sub Clock Controller Driver
+ *
+ * Copyright (c) 2017 Baylibre SAS.
+ * Author: Jerome Brunet <[e-mail]>
+ *
+ * Copyright (c) 2018 Amlogic, inc.
+ * Author: Yixun Lan <[e-mail]>
+ * Author: Jianxin Pan <[e-mail]>
+ */
+
+#include <linux/clk-provider.h>
+#include "clkc.h"
+
+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 =
+		meson_clk_get_phase_delay_data(clk);
+	unsigned long period_ps, p, d;
+	int degrees;
+
+	p = meson_parm_read(clk->map, &ph->phase);
+	degrees = p * 360 / (1 << (ph->phase.width));
+
+	period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,
+				 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 =
+		meson_clk_get_phase_delay_data(clk);
+	unsigned long period_ps, d = 0, r;
+	u64 p;
+
+	p = degrees % 360;
+	period_ps = DIV_ROUND_UP((unsigned long)NSEC_PER_SEC * 1000,
+				 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).
+	 */
+	r = do_div(p, 360 / (1 << (ph->phase.width)));
+	d = DIV_ROUND_CLOSEST(r * period_ps,
+			      360 * ph->delay_step_ps);
+	d = min(d, PMASK(ph->delay.width));
+
+	meson_parm_write(clk->map, &ph->phase, p);
+	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/clkc.h b/drivers/clk/meson/clkc.h
index 6b96d55..30470c6 100644
--- a/drivers/clk/meson/clkc.h
+++ b/drivers/clk/meson/clkc.h
@@ -105,6 +105,18 @@  struct clk_regmap _name = {						\
 	},								\
 };
 
+struct meson_clk_phase_delay_data {
+	struct parm			phase;
+	struct parm			delay;
+	unsigned int			delay_step_ps;
+};
+
+static inline struct meson_clk_phase_delay_data *
+meson_clk_get_phase_delay_data(struct clk_regmap *clk)
+{
+	return clk->data;
+}
+
 /* clk_ops */
 extern const struct clk_ops meson_clk_pll_ro_ops;
 extern const struct clk_ops meson_clk_pll_ops;
@@ -112,5 +124,6 @@  struct clk_regmap _name = {						\
 extern const struct clk_ops meson_clk_mpll_ro_ops;
 extern const struct clk_ops meson_clk_mpll_ops;
 extern const struct clk_ops meson_clk_phase_ops;
+extern const struct clk_ops meson_clk_phase_delay_ops;
 
 #endif /* __CLKC_H */