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[PATCH V1 3/9] clk: sprd: add gate clock support

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  [PATCH V1 3/9] clk: sprd: add gate clock support Chunyan Zhang <chunyan.zhang@spreadtrum.com> - 2017-06-18 04:10 +0200
    Re: [PATCH V1 3/9] clk: sprd: add gate clock support Stephen Boyd <sboyd@codeaurora.org> - 2017-06-20 03:40 +0200
      Re: [PATCH V1 3/9] clk: sprd: add gate clock support Chunyan Zhang <zhang.lyra@gmail.com> - 2017-06-22 12:20 +0200
        Re: [PATCH V1 3/9] clk: sprd: add gate clock support Stephen Boyd <sboyd@codeaurora.org> - 2017-06-30 03:50 +0200

#1668504 — [PATCH V1 3/9] clk: sprd: add gate clock support

Some clocks on the Spreadtrum's SoCs are just simple gates. Add
support for those clocks.

Also, some gate clocks are orphan, so this patch also added
registration code for those.

Signed-off-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com>
---
 drivers/clk/sprd/Makefile   |   2 +-
 drivers/clk/sprd/ccu_gate.c | 102 ++++++++++++++++++++++++++++++++++++++++++++
 drivers/clk/sprd/ccu_gate.h |  73 +++++++++++++++++++++++++++++++
 3 files changed, 176 insertions(+), 1 deletion(-)
 create mode 100644 drivers/clk/sprd/ccu_gate.c
 create mode 100644 drivers/clk/sprd/ccu_gate.h

diff --git a/drivers/clk/sprd/Makefile b/drivers/clk/sprd/Makefile
index 8f802b2..333e2b2 100644
--- a/drivers/clk/sprd/Makefile
+++ b/drivers/clk/sprd/Makefile
@@ -1,3 +1,3 @@
 ifneq ($(CONFIG_OF),)
-obj-y	+= ccu_common.o
+obj-y	+= ccu_common.o ccu_gate.o
 endif
diff --git a/drivers/clk/sprd/ccu_gate.c b/drivers/clk/sprd/ccu_gate.c
new file mode 100644
index 0000000..3d27615
--- /dev/null
+++ b/drivers/clk/sprd/ccu_gate.c
@@ -0,0 +1,102 @@
+/*
+ * Spreadtrum gate clock driver
+ *
+ * Copyright (C) 2017 Spreadtrum, Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <linux/clk-provider.h>
+
+#include "ccu_gate.h"
+
+DEFINE_SPINLOCK(gate_lock);
+
+static void ccu_gate_endisable(struct ccu_gate *cg, u32 en)
+{
+	struct ccu_common *common = &cg->common;
+	unsigned long flags = 0;
+	u32 reg;
+	int set = cg->flags & CLK_GATE_SET_TO_DISABLE ? 1 : 0;
+
+	set ^= en;
+
+	spin_lock_irqsave(common->lock, flags);
+
+	reg = ccu_readl(common);
+
+	if (set)
+		reg |= cg->op_bit;
+	else
+		reg &= ~cg->op_bit;
+
+	ccu_writel(reg, common);
+
+	spin_unlock_irqrestore(common->lock, flags);
+}
+
+static void ccu_sc_gate_endisable(struct ccu_gate *cg, u32 en)
+{
+	struct ccu_common *common = &cg->common;
+	unsigned long flags = 0;
+	int set = cg->flags & CLK_GATE_SET_TO_DISABLE ? 1 : 0;
+	u32 offset;
+
+	set ^= en;
+
+	/*
+	 * Each set/clear gate clock has three registers:
+	 * common->reg			- base register
+	 * common->reg + offset		- set register
+	 * common->reg + 2 * offset	- clear register
+	 */
+	offset = set ? cg->sc_offset : cg->sc_offset * 2;
+
+	spin_lock_irqsave(common->lock, flags);
+	ccu_writel_offset(cg->op_bit, common, offset);
+	spin_unlock_irqrestore(common->lock, flags);
+}
+
+static void ccu_gate_disable(struct clk_hw *hw)
+{
+	struct ccu_gate *cg = hw_to_ccu_gate(hw);
+
+	if (cg->sc_offset)
+		ccu_sc_gate_endisable(cg, 0);
+	else
+		ccu_gate_endisable(cg, 0);
+}
+
+static int ccu_gate_enable(struct clk_hw *hw)
+{
+	struct ccu_gate *cg = hw_to_ccu_gate(hw);
+
+	if (cg->sc_offset)
+		ccu_sc_gate_endisable(cg, 1);
+	else
+		ccu_gate_endisable(cg, 1);
+
+	return 0;
+}
+
+static int ccu_gate_is_enabled(struct clk_hw *hw)
+{
+	struct ccu_gate *cg = hw_to_ccu_gate(hw);
+	struct ccu_common *common = &cg->common;
+	u32 reg;
+
+	reg = ccu_readl(common);
+
+	if (cg->flags & CLK_GATE_SET_TO_DISABLE)
+		reg ^= cg->op_bit;
+
+	reg &= cg->op_bit;
+
+	return reg ? 1 : 0;
+}
+
+const struct clk_ops ccu_gate_ops = {
+	.disable	= ccu_gate_disable,
+	.enable		= ccu_gate_enable,
+	.is_enabled	= ccu_gate_is_enabled,
+};
diff --git a/drivers/clk/sprd/ccu_gate.h b/drivers/clk/sprd/ccu_gate.h
new file mode 100644
index 0000000..bc40169
--- /dev/null
+++ b/drivers/clk/sprd/ccu_gate.h
@@ -0,0 +1,73 @@
+/*
+ * Spreadtrum gate clock driver
+ *
+ * Copyright (C) 2017 Spreadtrum, Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#ifndef _CCU_GATE_H_
+#define _CCU_GATE_H_
+
+#include "ccu_common.h"
+
+struct ccu_gate {
+	u32			op_bit;
+	u16			flags;
+	u16			sc_offset;
+
+	struct ccu_common	common;
+};
+
+#define SPRD_CCU_GATE(_struct, _name, _parent, _reg, _sc_offset,	\
+		      _op_bit, _flags, _gate_flags)			\
+	struct ccu_gate _struct = {					\
+		.op_bit		= _op_bit,				\
+		.sc_offset	= _sc_offset,				\
+		.flags		= _gate_flags,				\
+		.common	= {						\
+			.reg		= _reg,				\
+			.lock		= &gate_lock,			\
+			.hw.init	= CLK_HW_INIT(_name,		\
+						      _parent,		\
+						      &ccu_gate_ops,	\
+						      _flags),		\
+		}							\
+	}
+
+#define SPRD_CCU_GATE_NO_PARENT(_struct, _name, _reg, _sc_offset,	\
+				_op_bit, _flags, _gate_flags)		\
+	struct ccu_gate _struct = {					\
+		.op_bit		= _op_bit,				\
+		.sc_offset	= _sc_offset,				\
+		.flags		= _gate_flags,				\
+		.common	= {						\
+			.reg	= _reg,					\
+			.lock	= &gate_lock,				\
+			.hw.init = CLK_HW_INIT_NO_PARENT(_name,		\
+							 &ccu_gate_ops,	\
+							 _flags),	\
+		}							\
+	}
+
+static inline struct ccu_gate *hw_to_ccu_gate(struct clk_hw *hw)
+{
+	struct ccu_common *common = hw_to_ccu_common(hw);
+
+	return container_of(common, struct ccu_gate, common);
+}
+
+static inline void ccu_writel_offset(u32 val,
+	struct ccu_common *common, u32 offset)
+{
+	writel(val, common->base + common->reg + offset);
+}
+
+void ccu_gate_helper_disable(struct ccu_common *common, u32 gate);
+int ccu_gate_helper_enable(struct ccu_common *common, u32 gate);
+int ccu_gate_helper_is_enabled(struct ccu_common *common, u32 gate);
+
+extern const struct clk_ops ccu_gate_ops;
+extern spinlock_t gate_lock;
+
+#endif /* _CCU_GATE_H_ */
-- 
2.7.4

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#1670159

On 06/18, Chunyan Zhang wrote:
> diff --git a/drivers/clk/sprd/Makefile b/drivers/clk/sprd/Makefile
> index 8f802b2..333e2b2 100644
> --- a/drivers/clk/sprd/Makefile
> +++ b/drivers/clk/sprd/Makefile
> @@ -1,3 +1,3 @@
>  ifneq ($(CONFIG_OF),)
> -obj-y	+= ccu_common.o
> +obj-y	+= ccu_common.o ccu_gate.o

Can this be built as a module?

>  endif
> diff --git a/drivers/clk/sprd/ccu_gate.c b/drivers/clk/sprd/ccu_gate.c
> new file mode 100644
> index 0000000..3d27615
> --- /dev/null
> +++ b/drivers/clk/sprd/ccu_gate.c
> @@ -0,0 +1,102 @@
> +/*
> + * Spreadtrum gate clock driver
> + *
> + * Copyright (C) 2017 Spreadtrum, Inc.
> + *
> + * SPDX-License-Identifier: GPL-2.0
> + */
> +
> +#include <linux/clk-provider.h>
> +
> +#include "ccu_gate.h"
> +
> +DEFINE_SPINLOCK(gate_lock);

This variable name is not very unique for debugging lockdep
reports. Probably needs 'sprd' in the name.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

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#1672501

On 20 June 2017 at 09:31, Stephen Boyd <sboyd@codeaurora.org> wrote:
> On 06/18, Chunyan Zhang wrote:
>> diff --git a/drivers/clk/sprd/Makefile b/drivers/clk/sprd/Makefile
>> index 8f802b2..333e2b2 100644
>> --- a/drivers/clk/sprd/Makefile
>> +++ b/drivers/clk/sprd/Makefile
>> @@ -1,3 +1,3 @@
>>  ifneq ($(CONFIG_OF),)
>> -obj-y        += ccu_common.o
>> +obj-y        += ccu_common.o ccu_gate.o
>
> Can this be built as a module?

Since most of all Spreadtrum device drivers would depend on if clocks
have been initialized, so we'd prefer to build this into the kernel
image.

>
>>  endif
>> diff --git a/drivers/clk/sprd/ccu_gate.c b/drivers/clk/sprd/ccu_gate.c
>> new file mode 100644
>> index 0000000..3d27615
>> --- /dev/null
>> +++ b/drivers/clk/sprd/ccu_gate.c
>> @@ -0,0 +1,102 @@
>> +/*
>> + * Spreadtrum gate clock driver
>> + *
>> + * Copyright (C) 2017 Spreadtrum, Inc.
>> + *
>> + * SPDX-License-Identifier: GPL-2.0
>> + */
>> +
>> +#include <linux/clk-provider.h>
>> +
>> +#include "ccu_gate.h"
>> +
>> +DEFINE_SPINLOCK(gate_lock);
>
> This variable name is not very unique for debugging lockdep
> reports. Probably needs 'sprd' in the name.

Ok.

Thank you for your comments,
Chunyan

>
> --
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
> a Linux Foundation Collaborative Project

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#1678382

On 06/22, Chunyan Zhang wrote:
> On 20 June 2017 at 09:31, Stephen Boyd <sboyd@codeaurora.org> wrote:
> > On 06/18, Chunyan Zhang wrote:
> >> diff --git a/drivers/clk/sprd/Makefile b/drivers/clk/sprd/Makefile
> >> index 8f802b2..333e2b2 100644
> >> --- a/drivers/clk/sprd/Makefile
> >> +++ b/drivers/clk/sprd/Makefile
> >> @@ -1,3 +1,3 @@
> >>  ifneq ($(CONFIG_OF),)
> >> -obj-y        += ccu_common.o
> >> +obj-y        += ccu_common.o ccu_gate.o
> >
> > Can this be built as a module?
> 
> Since most of all Spreadtrum device drivers would depend on if clocks
> have been initialized, so we'd prefer to build this into the kernel
> image.

This isn't really a good reason, but OK. Hopefully nobody wants
to make a module for every driver on the system and jam the ones
needed to access the rootfs into a ramdisk. Don't worry, you
don't need to support modules here.

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

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