[PATCH v2 0/5] Fix the gate2 and make it more flexible

[PATCH v2 0/5] Fix the gate2 and make it more flexible

[Abel Vesa]

First version here: https://lkml.org/lkml/2020/10/26/988

Changes since v1:
 * split the work in multiple iterative patches

Abel Vesa (5):
  clk: imx: gate2: Remove the IMX_CLK_GATE2_SINGLE_BIT special case
  clk: imx: gate2: Keep the register writing in on place
  clk: imx: gate2: Check if clock is enabled against cgr_val
  clk: imx: gate2: Add cgr_mask for more flexible number of control bits
  clk: imx: gate2: Add locking in is_enabled op

 drivers/clk/imx/clk-gate2.c | 65 +++++++++++++++++++++------------------------
 drivers/clk/imx/clk.h       | 27 +++++++++----------
 2 files changed, 43 insertions(+), 49 deletions(-)

-- 
2.7.4


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[PATCH v2 1/5] clk: imx: gate2: Remove the IMX_CLK_GATE2_SINGLE_BIT special case

[Abel Vesa]

This was a hack which would allow multiple HW gates to be controlled
by a single bit. The only user of this is the imx_dev_clk_hw_gate_shared
which is not used anywhere as of now. Basically, complicates the logic
of the driver for no reason.

Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
---
 drivers/clk/imx/clk-gate2.c | 28 +++++++---------------------
 drivers/clk/imx/clk.h       |  5 +----
 2 files changed, 8 insertions(+), 25 deletions(-)

diff --git a/drivers/clk/imx/clk-gate2.c b/drivers/clk/imx/clk-gate2.c
index 7eed708..49952ee 100644
--- a/drivers/clk/imx/clk-gate2.c
+++ b/drivers/clk/imx/clk-gate2.c
@@ -49,14 +49,10 @@ static int clk_gate2_enable(struct clk_hw *hw)
 	if (gate->share_count && (*gate->share_count)++ > 0)
 		goto out;
 
-	if (gate->flags & IMX_CLK_GATE2_SINGLE_BIT) {
-		ret = clk_gate_ops.enable(hw);
-	} else {
-		reg = readl(gate->reg);
-		reg &= ~(3 << gate->bit_idx);
-		reg |= gate->cgr_val << gate->bit_idx;
-		writel(reg, gate->reg);
-	}
+	reg = readl(gate->reg);
+	reg &= ~(3 << gate->bit_idx);
+	reg |= gate->cgr_val << gate->bit_idx;
+	writel(reg, gate->reg);
 
 out:
 	spin_unlock_irqrestore(gate->lock, flags);
@@ -79,13 +75,9 @@ static void clk_gate2_disable(struct clk_hw *hw)
 			goto out;
 	}
 
-	if (gate->flags & IMX_CLK_GATE2_SINGLE_BIT) {
-		clk_gate_ops.disable(hw);
-	} else {
-		reg = readl(gate->reg);
-		reg &= ~(3 << gate->bit_idx);
-		writel(reg, gate->reg);
-	}
+	reg = readl(gate->reg);
+	reg &= ~(3 << gate->bit_idx);
+	writel(reg, gate->reg);
 
 out:
 	spin_unlock_irqrestore(gate->lock, flags);
@@ -105,9 +97,6 @@ static int clk_gate2_is_enabled(struct clk_hw *hw)
 {
 	struct clk_gate2 *gate = to_clk_gate2(hw);
 
-	if (gate->flags & IMX_CLK_GATE2_SINGLE_BIT)
-		return clk_gate_ops.is_enabled(hw);
-
 	return clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx);
 }
 
@@ -117,9 +106,6 @@ static void clk_gate2_disable_unused(struct clk_hw *hw)
 	unsigned long flags;
 	u32 reg;
 
-	if (gate->flags & IMX_CLK_GATE2_SINGLE_BIT)
-		return;
-
 	spin_lock_irqsave(gate->lock, flags);
 
 	if (!gate->share_count || *gate->share_count == 0) {
diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
index 3b796b3..87b2744f 100644
--- a/drivers/clk/imx/clk.h
+++ b/drivers/clk/imx/clk.h
@@ -6,8 +6,6 @@
 #include <linux/spinlock.h>
 #include <linux/clk-provider.h>
 
-#define IMX_CLK_GATE2_SINGLE_BIT	1
-
 extern spinlock_t imx_ccm_lock;
 
 void imx_check_clocks(struct clk *clks[], unsigned int count);
@@ -384,8 +382,7 @@ static inline struct clk_hw *imx_dev_clk_hw_gate_shared(struct device *dev,
 				unsigned int *share_count)
 {
 	return clk_hw_register_gate2(NULL, name, parent, CLK_SET_RATE_PARENT |
-					CLK_OPS_PARENT_ENABLE, reg, shift, 0x3,
-					IMX_CLK_GATE2_SINGLE_BIT,
+					CLK_OPS_PARENT_ENABLE, reg, shift, 0x1, 0,
 					&imx_ccm_lock, share_count);
 }
 
-- 
2.7.4


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[PATCH v2 2/5] clk: imx: gate2: Keep the register writing in on place

[Abel Vesa]

Move all the register writing to the newly added clk_gate2_do_shared_clks
and call that everywhere need needed. Cleans up the code a little bit.

Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
---
 drivers/clk/imx/clk-gate2.c | 33 ++++++++++++++++-----------------
 1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/drivers/clk/imx/clk-gate2.c b/drivers/clk/imx/clk-gate2.c
index 49952ee..e1f6cd9 100644
--- a/drivers/clk/imx/clk-gate2.c
+++ b/drivers/clk/imx/clk-gate2.c
@@ -37,10 +37,21 @@ struct clk_gate2 {
 
 #define to_clk_gate2(_hw) container_of(_hw, struct clk_gate2, hw)
 
+static void clk_gate2_do_shared_clks(struct clk_hw *hw, bool enable)
+{
+	struct clk_gate2 *gate = to_clk_gate2(hw);
+	u32 reg;
+
+	reg = readl(gate->reg);
+	reg &= ~(3 << gate->bit_idx);
+	if (enable)
+		reg |= gate->cgr_val << gate->bit_idx;
+	writel(reg, gate->reg);
+}
+
 static int clk_gate2_enable(struct clk_hw *hw)
 {
 	struct clk_gate2 *gate = to_clk_gate2(hw);
-	u32 reg;
 	unsigned long flags;
 	int ret = 0;
 
@@ -49,11 +60,7 @@ static int clk_gate2_enable(struct clk_hw *hw)
 	if (gate->share_count && (*gate->share_count)++ > 0)
 		goto out;
 
-	reg = readl(gate->reg);
-	reg &= ~(3 << gate->bit_idx);
-	reg |= gate->cgr_val << gate->bit_idx;
-	writel(reg, gate->reg);
-
+	clk_gate2_do_shared_clks(hw, true);
 out:
 	spin_unlock_irqrestore(gate->lock, flags);
 
@@ -63,7 +70,6 @@ static int clk_gate2_enable(struct clk_hw *hw)
 static void clk_gate2_disable(struct clk_hw *hw)
 {
 	struct clk_gate2 *gate = to_clk_gate2(hw);
-	u32 reg;
 	unsigned long flags;
 
 	spin_lock_irqsave(gate->lock, flags);
@@ -75,10 +81,7 @@ static void clk_gate2_disable(struct clk_hw *hw)
 			goto out;
 	}
 
-	reg = readl(gate->reg);
-	reg &= ~(3 << gate->bit_idx);
-	writel(reg, gate->reg);
-
+	clk_gate2_do_shared_clks(hw, false);
 out:
 	spin_unlock_irqrestore(gate->lock, flags);
 }
@@ -104,15 +107,11 @@ static void clk_gate2_disable_unused(struct clk_hw *hw)
 {
 	struct clk_gate2 *gate = to_clk_gate2(hw);
 	unsigned long flags;
-	u32 reg;
 
 	spin_lock_irqsave(gate->lock, flags);
 
-	if (!gate->share_count || *gate->share_count == 0) {
-		reg = readl(gate->reg);
-		reg &= ~(3 << gate->bit_idx);
-		writel(reg, gate->reg);
-	}
+	if (!gate->share_count || *gate->share_count == 0)
+		clk_gate2_do_shared_clks(hw, false);
 
 	spin_unlock_irqrestore(gate->lock, flags);
 }
-- 
2.7.4


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[PATCH v2 3/5] clk: imx: gate2: Check if clock is enabled against cgr_val

[Abel Vesa]

Seems the logic here was wrong all along. For example, if
the cgr_val is 2 (0b10), the clk_gate2_reg_is_enabled would
report the clock as disabled. So check against cgr_val instead.

Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
---
 drivers/clk/imx/clk-gate2.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/imx/clk-gate2.c b/drivers/clk/imx/clk-gate2.c
index e1f6cd9..40bcc2d 100644
--- a/drivers/clk/imx/clk-gate2.c
+++ b/drivers/clk/imx/clk-gate2.c
@@ -86,11 +86,11 @@ static void clk_gate2_disable(struct clk_hw *hw)
 	spin_unlock_irqrestore(gate->lock, flags);
 }
 
-static int clk_gate2_reg_is_enabled(void __iomem *reg, u8 bit_idx)
+static int clk_gate2_reg_is_enabled(void __iomem *reg, u8 bit_idx, u8 cgr_val)
 {
 	u32 val = readl(reg);
 
-	if (((val >> bit_idx) & 1) == 1)
+	if (((val >> bit_idx) & 3) == cgr_val)
 		return 1;
 
 	return 0;
@@ -100,7 +100,7 @@ static int clk_gate2_is_enabled(struct clk_hw *hw)
 {
 	struct clk_gate2 *gate = to_clk_gate2(hw);
 
-	return clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx);
+	return clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx, gate->cgr_val);
 }
 
 static void clk_gate2_disable_unused(struct clk_hw *hw)
-- 
2.7.4


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[PATCH v2 4/5] clk: imx: gate2: Add cgr_mask for more flexible number of control bits

[Abel Vesa]

On some i.MX8 platforms, there are HW gates that share the same bit.
So in order to make this clock type more usable, use a mask to specify
how many bits belong to those HW gates.

Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
---
 drivers/clk/imx/clk-gate2.c | 16 ++++++++++------
 drivers/clk/imx/clk.h       | 24 ++++++++++++------------
 2 files changed, 22 insertions(+), 18 deletions(-)

diff --git a/drivers/clk/imx/clk-gate2.c b/drivers/clk/imx/clk-gate2.c
index 40bcc2d..7e4b5e8 100644
--- a/drivers/clk/imx/clk-gate2.c
+++ b/drivers/clk/imx/clk-gate2.c
@@ -30,6 +30,7 @@ struct clk_gate2 {
 	void __iomem	*reg;
 	u8		bit_idx;
 	u8		cgr_val;
+	u8		cgr_mask;
 	u8		flags;
 	spinlock_t	*lock;
 	unsigned int	*share_count;
@@ -43,9 +44,9 @@ static void clk_gate2_do_shared_clks(struct clk_hw *hw, bool enable)
 	u32 reg;
 
 	reg = readl(gate->reg);
-	reg &= ~(3 << gate->bit_idx);
+	reg &= ~(gate->cgr_mask << gate->bit_idx);
 	if (enable)
-		reg |= gate->cgr_val << gate->bit_idx;
+		reg |= (gate->cgr_val & gate->cgr_mask) << gate->bit_idx;
 	writel(reg, gate->reg);
 }
 
@@ -86,11 +87,12 @@ static void clk_gate2_disable(struct clk_hw *hw)
 	spin_unlock_irqrestore(gate->lock, flags);
 }
 
-static int clk_gate2_reg_is_enabled(void __iomem *reg, u8 bit_idx, u8 cgr_val)
+static int clk_gate2_reg_is_enabled(void __iomem *reg, u8 bit_idx,
+					u8 cgr_val, u8 cgr_mask)
 {
 	u32 val = readl(reg);
 
-	if (((val >> bit_idx) & 3) == cgr_val)
+	if (((val >> bit_idx) & cgr_mask) == cgr_val)
 		return 1;
 
 	return 0;
@@ -100,7 +102,8 @@ static int clk_gate2_is_enabled(struct clk_hw *hw)
 {
 	struct clk_gate2 *gate = to_clk_gate2(hw);
 
-	return clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx, gate->cgr_val);
+	return clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx,
+					gate->cgr_val, gate->cgr_mask);
 }
 
 static void clk_gate2_disable_unused(struct clk_hw *hw)
@@ -125,7 +128,7 @@ static const struct clk_ops clk_gate2_ops = {
 
 struct clk_hw *clk_hw_register_gate2(struct device *dev, const char *name,
 		const char *parent_name, unsigned long flags,
-		void __iomem *reg, u8 bit_idx, u8 cgr_val,
+		void __iomem *reg, u8 bit_idx, u8 cgr_val, u8 cgr_mask,
 		u8 clk_gate2_flags, spinlock_t *lock,
 		unsigned int *share_count)
 {
@@ -142,6 +145,7 @@ struct clk_hw *clk_hw_register_gate2(struct device *dev, const char *name,
 	gate->reg = reg;
 	gate->bit_idx = bit_idx;
 	gate->cgr_val = cgr_val;
+	gate->cgr_mask = cgr_mask;
 	gate->flags = clk_gate2_flags;
 	gate->lock = lock;
 	gate->share_count = share_count;
diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
index 87b2744f..3d8e40b 100644
--- a/drivers/clk/imx/clk.h
+++ b/drivers/clk/imx/clk.h
@@ -66,9 +66,9 @@ extern struct imx_pll14xx_clk imx_1443x_dram_pll;
 	to_clk(imx_clk_hw_cpu(name, parent_name, div, mux, pll, step))
 
 #define clk_register_gate2(dev, name, parent_name, flags, reg, bit_idx, \
-				cgr_val, clk_gate_flags, lock, share_count) \
+				cgr_val, cgr_mask, clk_gate_flags, lock, share_count) \
 	to_clk(clk_hw_register_gate2(dev, name, parent_name, flags, reg, bit_idx, \
-				cgr_val, clk_gate_flags, lock, share_count))
+				cgr_val, cgr_mask, clk_gate_flags, lock, share_count))
 
 #define imx_clk_pllv3(type, name, parent_name, base, div_mask) \
 	to_clk(imx_clk_hw_pllv3(type, name, parent_name, base, div_mask))
@@ -196,7 +196,7 @@ struct clk_hw *imx_clk_hw_pllv4(const char *name, const char *parent_name,
 
 struct clk_hw *clk_hw_register_gate2(struct device *dev, const char *name,
 		const char *parent_name, unsigned long flags,
-		void __iomem *reg, u8 bit_idx, u8 cgr_val,
+		void __iomem *reg, u8 bit_idx, u8 cgr_val, u8 cgr_mask,
 		u8 clk_gate_flags, spinlock_t *lock,
 		unsigned int *share_count);
 
@@ -349,14 +349,14 @@ static inline struct clk_hw *imx_clk_hw_gate2(const char *name, const char *pare
 		void __iomem *reg, u8 shift)
 {
 	return clk_hw_register_gate2(NULL, name, parent, CLK_SET_RATE_PARENT, reg,
-			shift, 0x3, 0, &imx_ccm_lock, NULL);
+			shift, 0x3, 0x3, 0, &imx_ccm_lock, NULL);
 }
 
 static inline struct clk_hw *imx_clk_hw_gate2_flags(const char *name, const char *parent,
 		void __iomem *reg, u8 shift, unsigned long flags)
 {
 	return clk_hw_register_gate2(NULL, name, parent, flags | CLK_SET_RATE_PARENT, reg,
-			shift, 0x3, 0, &imx_ccm_lock, NULL);
+			shift, 0x3, 0x3, 0, &imx_ccm_lock, NULL);
 }
 
 static inline struct clk_hw *imx_clk_hw_gate2_shared(const char *name,
@@ -364,7 +364,7 @@ static inline struct clk_hw *imx_clk_hw_gate2_shared(const char *name,
 		unsigned int *share_count)
 {
 	return clk_hw_register_gate2(NULL, name, parent, CLK_SET_RATE_PARENT, reg,
-			shift, 0x3, 0, &imx_ccm_lock, share_count);
+			shift, 0x3, 0x3, 0, &imx_ccm_lock, share_count);
 }
 
 static inline struct clk_hw *imx_clk_hw_gate2_shared2(const char *name,
@@ -372,7 +372,7 @@ static inline struct clk_hw *imx_clk_hw_gate2_shared2(const char *name,
 		unsigned int *share_count)
 {
 	return clk_hw_register_gate2(NULL, name, parent, CLK_SET_RATE_PARENT |
-				  CLK_OPS_PARENT_ENABLE, reg, shift, 0x3, 0,
+				  CLK_OPS_PARENT_ENABLE, reg, shift, 0x3, 0x3, 0,
 				  &imx_ccm_lock, share_count);
 }
 
@@ -382,15 +382,15 @@ static inline struct clk_hw *imx_dev_clk_hw_gate_shared(struct device *dev,
 				unsigned int *share_count)
 {
 	return clk_hw_register_gate2(NULL, name, parent, CLK_SET_RATE_PARENT |
-					CLK_OPS_PARENT_ENABLE, reg, shift, 0x1, 0,
-					&imx_ccm_lock, share_count);
+					CLK_OPS_PARENT_ENABLE, reg, shift, 0x1,
+					0x1, 0, &imx_ccm_lock, share_count);
 }
 
 static inline struct clk *imx_clk_gate2_cgr(const char *name,
 		const char *parent, void __iomem *reg, u8 shift, u8 cgr_val)
 {
 	return clk_register_gate2(NULL, name, parent, CLK_SET_RATE_PARENT, reg,
-			shift, cgr_val, 0, &imx_ccm_lock, NULL);
+			shift, cgr_val, 0x3, 0, &imx_ccm_lock, NULL);
 }
 
 static inline struct clk_hw *imx_clk_hw_gate3(const char *name, const char *parent,
@@ -418,7 +418,7 @@ static inline struct clk_hw *imx_clk_hw_gate4(const char *name, const char *pare
 {
 	return clk_hw_register_gate2(NULL, name, parent,
 			CLK_SET_RATE_PARENT | CLK_OPS_PARENT_ENABLE,
-			reg, shift, 0x3, 0, &imx_ccm_lock, NULL);
+			reg, shift, 0x3, 0x3, 0, &imx_ccm_lock, NULL);
 }
 
 static inline struct clk_hw *imx_clk_hw_gate4_flags(const char *name,
@@ -427,7 +427,7 @@ static inline struct clk_hw *imx_clk_hw_gate4_flags(const char *name,
 {
 	return clk_hw_register_gate2(NULL, name, parent,
 			flags | CLK_SET_RATE_PARENT | CLK_OPS_PARENT_ENABLE,
-			reg, shift, 0x3, 0, &imx_ccm_lock, NULL);
+			reg, shift, 0x3, 0x3, 0, &imx_ccm_lock, NULL);
 }
 
 #define imx_clk_gate4_flags(name, parent, reg, shift, flags) \
-- 
2.7.4


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[PATCH v2 5/5] clk: imx: gate2: Add locking in is_enabled op

[Abel Vesa]

Protect against enabling/disabling the gate while we're
checking if it is enabled.

Signed-off-by: Abel Vesa <abel.vesa@nxp.com>
---
 drivers/clk/imx/clk-gate2.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/clk/imx/clk-gate2.c b/drivers/clk/imx/clk-gate2.c
index 7e4b5e8..480a184 100644
--- a/drivers/clk/imx/clk-gate2.c
+++ b/drivers/clk/imx/clk-gate2.c
@@ -101,9 +101,17 @@ static int clk_gate2_reg_is_enabled(void __iomem *reg, u8 bit_idx,
 static int clk_gate2_is_enabled(struct clk_hw *hw)
 {
 	struct clk_gate2 *gate = to_clk_gate2(hw);
+	unsigned long flags;
+	int ret = 0;
 
-	return clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx,
+	spin_lock_irqsave(gate->lock, flags);
+
+	ret = clk_gate2_reg_is_enabled(gate->reg, gate->bit_idx,
 					gate->cgr_val, gate->cgr_mask);
+
+	spin_unlock_irqrestore(gate->lock, flags);
+
+	return ret;
 }
 
 static void clk_gate2_disable_unused(struct clk_hw *hw)
-- 
2.7.4


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Re: [PATCH v2 0/5] Fix the gate2 and make it more flexible

[Sascha Hauer]

On Wed, Oct 28, 2020 at 02:58:57PM +0200, Abel Vesa wrote:
> First version here: https://lkml.org/lkml/2020/10/26/988
> 
> Changes since v1:
>  * split the work in multiple iterative patches
> 
> Abel Vesa (5):
>   clk: imx: gate2: Remove the IMX_CLK_GATE2_SINGLE_BIT special case
>   clk: imx: gate2: Keep the register writing in on place
>   clk: imx: gate2: Check if clock is enabled against cgr_val
>   clk: imx: gate2: Add cgr_mask for more flexible number of control bits
>   clk: imx: gate2: Add locking in is_enabled op

For the series:

Reviewed-by: Sascha Hauer <s.hauer@pengutronix.de>

Sascha

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Re: [PATCH v2 0/5] Fix the gate2 and make it more flexible

[Shawn Guo]

On Wed, Oct 28, 2020 at 02:58:57PM +0200, Abel Vesa wrote:
> First version here: https://lkml.org/lkml/2020/10/26/988
> 
> Changes since v1:
>  * split the work in multiple iterative patches
> 
> Abel Vesa (5):
>   clk: imx: gate2: Remove the IMX_CLK_GATE2_SINGLE_BIT special case
>   clk: imx: gate2: Keep the register writing in on place
>   clk: imx: gate2: Check if clock is enabled against cgr_val
>   clk: imx: gate2: Add cgr_mask for more flexible number of control bits
>   clk: imx: gate2: Add locking in is_enabled op

Applied all, thanks.

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