[PATCH v7 5/7] clk: clock-wizard: Add support for fractional support

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Currently the set rate granularity is to integral divisors.
Add support for the fractional divisors.
Only the first output0 is fractional in the hardware.


Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xxxxxxxxxx>
---
v7:
Remove unnecessary comments
use mult_frac
use a common divisor function.

 drivers/clk/clk-xlnx-clock-wizard.c | 219 ++++++++++++++++++++++++++++++++----
 1 file changed, 199 insertions(+), 20 deletions(-)

diff --git a/drivers/clk/clk-xlnx-clock-wizard.c b/drivers/clk/clk-xlnx-clock-wizard.c
index 5581b24..ed3b0ef 100644
--- a/drivers/clk/clk-xlnx-clock-wizard.c
+++ b/drivers/clk/clk-xlnx-clock-wizard.c
@@ -29,20 +29,25 @@
 
 #define WZRD_CLKFBOUT_MULT_SHIFT	8
 #define WZRD_CLKFBOUT_MULT_MASK		(0xff << WZRD_CLKFBOUT_MULT_SHIFT)
+#define WZRD_CLKFBOUT_FRAC_SHIFT	16
+#define WZRD_CLKFBOUT_FRAC_MASK		(0x3ff << WZRD_CLKFBOUT_FRAC_SHIFT)
 #define WZRD_DIVCLK_DIVIDE_SHIFT	0
 #define WZRD_DIVCLK_DIVIDE_MASK		(0xff << WZRD_DIVCLK_DIVIDE_SHIFT)
 #define WZRD_CLKOUT_DIVIDE_SHIFT	0
 #define WZRD_CLKOUT_DIVIDE_WIDTH	8
 #define WZRD_CLKOUT_DIVIDE_MASK		(0xff << WZRD_DIVCLK_DIVIDE_SHIFT)
+#define WZRD_CLKOUT_FRAC_SHIFT		8
+#define WZRD_CLKOUT_FRAC_MASK		0x3ff
 
 #define WZRD_DR_MAX_INT_DIV_VALUE	255
-#define WZRD_DR_NUM_RETRIES		10000
 #define WZRD_DR_STATUS_REG_OFFSET	0x04
 #define WZRD_DR_LOCK_BIT_MASK		0x00000001
 #define WZRD_DR_INIT_REG_OFFSET		0x25C
 #define WZRD_DR_DIV_TO_PHASE_OFFSET	4
 #define WZRD_DR_BEGIN_DYNA_RECONF	0x03
 
+#define WZRD_USEC_POLL		10
+#define WZRD_TIMEOUT_POLL		1000
 /* Get the mask from width */
 #define div_mask(width)			((1 << (width)) - 1)
 
@@ -52,6 +57,7 @@
 enum clk_wzrd_int_clks {
 	wzrd_clk_mul,
 	wzrd_clk_mul_div,
+	wzrd_clk_mul_frac,
 	wzrd_clk_int_max
 };
 
@@ -186,7 +192,7 @@ static long clk_wzrd_round_rate(struct clk_hw *hw, unsigned long rate,
 	 */
 	div = DIV_ROUND_CLOSEST(*prate, rate);
 
-	return (*prate / div);
+	return *prate / div;
 }
 
 static const struct clk_ops clk_wzrd_clk_divider_ops = {
@@ -195,6 +201,117 @@ static const struct clk_ops clk_wzrd_clk_divider_ops = {
 	.recalc_rate = clk_wzrd_recalc_rate,
 };
 
+static unsigned long clk_wzrd_recalc_ratef(struct clk_hw *hw,
+					   unsigned long parent_rate)
+{
+	unsigned int val;
+	u32 div, frac;
+	struct clk_wzrd_divider *divider = to_clk_wzrd_divider(hw);
+	void __iomem *div_addr = divider->base + divider->offset;
+
+	val = readl(div_addr);
+	div = val & div_mask(divider->width);
+	frac = (val >> WZRD_CLKOUT_FRAC_SHIFT) & WZRD_CLKOUT_FRAC_MASK;
+
+	return mult_frac(parent_rate, 1000, (div * 1000) + frac);
+}
+
+static int clk_wzrd_dynamic_reconfig_f(struct clk_hw *hw, unsigned long rate,
+				       unsigned long parent_rate)
+{
+	int err;
+	u32 value, pre;
+	unsigned long rate_div, f, clockout0_div;
+	struct clk_wzrd_divider *divider = to_clk_wzrd_divider(hw);
+	void __iomem *div_addr = divider->base + divider->offset;
+
+	rate_div = ((parent_rate * 1000) / rate);
+	clockout0_div = rate_div / 1000;
+
+	pre = DIV_ROUND_CLOSEST((parent_rate * 1000), rate);
+	f = (u32)(pre - (clockout0_div * 1000));
+	f = f & WZRD_CLKOUT_FRAC_MASK;
+	f = f << WZRD_CLKOUT_DIVIDE_WIDTH;
+
+	value = (f  | (clockout0_div & WZRD_CLKOUT_DIVIDE_MASK));
+
+	/* Set divisor and clear phase offset */
+	writel(value, div_addr);
+	writel(0x0, div_addr + WZRD_DR_DIV_TO_PHASE_OFFSET);
+
+	/* Check status register */
+	err = readl_poll_timeout(divider->base + WZRD_DR_STATUS_REG_OFFSET, value,
+				 value & WZRD_DR_LOCK_BIT_MASK,
+				 WZRD_USEC_POLL, WZRD_TIMEOUT_POLL);
+	if (err)
+		return err;
+
+	/* Initiate reconfiguration */
+	writel(WZRD_DR_BEGIN_DYNA_RECONF,
+	       divider->base + WZRD_DR_INIT_REG_OFFSET);
+
+	/* Check status register */
+	return readl_poll_timeout(divider->base + WZRD_DR_STATUS_REG_OFFSET, value,
+				value & WZRD_DR_LOCK_BIT_MASK,
+				WZRD_USEC_POLL, WZRD_TIMEOUT_POLL);
+}
+
+static long clk_wzrd_round_rate_f(struct clk_hw *hw, unsigned long rate,
+				  unsigned long *prate)
+{
+	return rate;
+}
+
+static const struct clk_ops clk_wzrd_clk_divider_ops_f = {
+	.round_rate = clk_wzrd_round_rate_f,
+	.set_rate = clk_wzrd_dynamic_reconfig_f,
+	.recalc_rate = clk_wzrd_recalc_ratef,
+};
+
+static struct clk *clk_wzrd_register_divf(struct device *dev,
+					  const char *name,
+					  const char *parent_name,
+					  unsigned long flags,
+					  void __iomem *base, u16 offset,
+					  u8 shift, u8 width,
+					  u8 clk_divider_flags,
+					  const struct clk_div_table *table,
+					  spinlock_t *lock)
+{
+	struct clk_wzrd_divider *div;
+	struct clk_hw *hw;
+	struct clk_init_data init;
+	int ret;
+
+	div = devm_kzalloc(dev, sizeof(*div), GFP_KERNEL);
+	if (!div)
+		return ERR_PTR(-ENOMEM);
+
+	init.name = name;
+
+	init.ops = &clk_wzrd_clk_divider_ops_f;
+
+	init.flags = flags;
+	init.parent_names = &parent_name;
+	init.num_parents = 1;
+
+	div->base = base;
+	div->offset = offset;
+	div->shift = shift;
+	div->width = width;
+	div->flags = clk_divider_flags;
+	div->lock = lock;
+	div->hw.init = &init;
+	div->table = table;
+
+	hw = &div->hw;
+	ret =  devm_clk_hw_register(dev, hw);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return hw->clk;
+}
+
 static struct clk *clk_wzrd_register_divider(struct device *dev,
 					     const char *name,
 					     const char *parent_name,
@@ -229,7 +346,6 @@ static struct clk *clk_wzrd_register_divider(struct device *dev,
 	div->hw.init = &init;
 	div->table = table;
 
-	/* register the clock */
 	hw = &div->hw;
 	ret = devm_clk_hw_register(dev, hw);
 	if (ret)
@@ -237,7 +353,6 @@ static struct clk *clk_wzrd_register_divider(struct device *dev,
 
 	return hw->clk;
 }
-
 static int clk_wzrd_clk_notifier(struct notifier_block *nb, unsigned long event,
 				 void *data)
 {
@@ -267,6 +382,61 @@ static int clk_wzrd_clk_notifier(struct notifier_block *nb, unsigned long event,
 	}
 }
 
+static int clk_wzrd_register_dividers(struct platform_device *pdev,
+				      const char *clk_name)
+{
+	int i, ret;
+	struct device_node *np = pdev->dev.of_node;
+	int outputs;
+	unsigned long flags = 0;
+	struct clk_wzrd *clk_wzrd = platform_get_drvdata(pdev);
+	const char *clkout_name;
+
+	outputs = of_property_count_strings(np, "clock-output-names");
+	if (outputs == 1)
+		flags = CLK_SET_RATE_PARENT;
+
+	for (i = outputs - 1; i >= 0 ; i--) {
+		if (of_property_read_string_index(np, "clock-output-names", i,
+						  &clkout_name)) {
+			dev_err(&pdev->dev,
+				"clock output name not specified\n");
+			ret = -EINVAL;
+			return ret;
+		}
+
+		if (!i)
+			clk_wzrd->clkout[i] = clk_wzrd_register_divf
+				(&pdev->dev, clkout_name,
+				clk_name, flags,
+				clk_wzrd->base, (WZRD_CLK_CFG_REG(2) + i * 12),
+				WZRD_CLKOUT_DIVIDE_SHIFT,
+				WZRD_CLKOUT_DIVIDE_WIDTH,
+				CLK_DIVIDER_ONE_BASED | CLK_DIVIDER_ALLOW_ZERO,
+				NULL, &clkwzrd_lock);
+		else
+			clk_wzrd->clkout[i] = clk_wzrd_register_divider
+				(&pdev->dev, clkout_name,
+				clk_name, 0,
+				clk_wzrd->base, (WZRD_CLK_CFG_REG(2) + i * 12),
+				WZRD_CLKOUT_DIVIDE_SHIFT,
+				WZRD_CLKOUT_DIVIDE_WIDTH,
+				CLK_DIVIDER_ONE_BASED | CLK_DIVIDER_ALLOW_ZERO,
+				NULL, &clkwzrd_lock);
+
+		if (IS_ERR(clk_wzrd->clkout[i])) {
+			int j;
+
+			for (j = i + 1; j < outputs; j++)
+				clk_unregister(clk_wzrd->clkout[j]);
+			dev_err(&pdev->dev,
+				"unable to register divider clock\n");
+			ret = PTR_ERR(clk_wzrd->clkout[i]);
+			return ret;
+		}
+	}
+	return 0;
+}
 static int __maybe_unused clk_wzrd_suspend(struct device *dev)
 {
 	struct clk_wzrd *clk_wzrd = dev_get_drvdata(dev);
@@ -298,8 +468,8 @@ static SIMPLE_DEV_PM_OPS(clk_wzrd_dev_pm_ops, clk_wzrd_suspend,
 
 static int clk_wzrd_probe(struct platform_device *pdev)
 {
-	int i, ret;
-	u32 reg;
+	int ret;
+	u32 reg, reg_f, mult;
 	unsigned long rate;
 	const char *clk_name;
 	struct clk_wzrd *clk_wzrd;
@@ -349,17 +519,13 @@ static int clk_wzrd_probe(struct platform_device *pdev)
 		goto err_disable_clk;
 	}
 
-	/* we don't support fractional div/mul yet */
-	reg = readl(clk_wzrd->base + WZRD_CLK_CFG_REG(0)) &
-		    WZRD_CLKFBOUT_FRAC_EN;
-	reg |= readl(clk_wzrd->base + WZRD_CLK_CFG_REG(2)) &
-		     WZRD_CLKOUT0_FRAC_EN;
-	if (reg)
-		dev_warn(&pdev->dev, "fractional div/mul not supported\n");
+	reg = readl(clk_wzrd->base + WZRD_CLK_CFG_REG(0));
+	reg_f = reg & WZRD_CLKFBOUT_FRAC_MASK;
+	reg_f =  reg_f >> WZRD_CLKFBOUT_FRAC_SHIFT;
 
-	/* register multiplier */
-	reg = (readl(clk_wzrd->base + WZRD_CLK_CFG_REG(0)) &
-		     WZRD_CLKFBOUT_MULT_MASK) >> WZRD_CLKFBOUT_MULT_SHIFT;
+	reg = reg & WZRD_CLKFBOUT_MULT_MASK;
+	reg =  reg >> WZRD_CLKFBOUT_MULT_SHIFT;
+	mult = (reg * 1000) + reg_f;
 	clk_name = kasprintf(GFP_KERNEL, "%s_mul", dev_name(&pdev->dev));
 	if (!clk_name) {
 		ret = -ENOMEM;
@@ -368,8 +534,7 @@ static int clk_wzrd_probe(struct platform_device *pdev)
 	clk_wzrd->clks_internal[wzrd_clk_mul] = clk_register_fixed_factor
 			(&pdev->dev, clk_name,
 			 __clk_get_name(clk_wzrd->clk_in1),
-			 0, reg, 1);
-	kfree(clk_name);
+			0, mult, 1000);
 	if (IS_ERR(clk_wzrd->clks_internal[wzrd_clk_mul])) {
 		dev_err(&pdev->dev, "unable to register fixed-factor clock\n");
 		ret = PTR_ERR(clk_wzrd->clks_internal[wzrd_clk_mul]);
@@ -407,8 +572,18 @@ static int clk_wzrd_probe(struct platform_device *pdev)
 			ret = -EINVAL;
 			goto err_rm_int_clks;
 		}
-		clk_wzrd->clkout[i] = clk_wzrd_register_divider(&pdev->dev,
-								clkout_name,
+		if (!i)
+			clk_wzrd->clkout[i] = clk_wzrd_register_divf
+				(&pdev->dev, clkout_name,
+				clk_name, 0,
+				clk_wzrd->base, (WZRD_CLK_CFG_REG(2) + i * 12),
+				WZRD_CLKOUT_DIVIDE_SHIFT,
+				WZRD_CLKOUT_DIVIDE_WIDTH,
+				CLK_DIVIDER_ONE_BASED | CLK_DIVIDER_ALLOW_ZERO,
+				NULL, &clkwzrd_lock);
+		else
+			clk_wzrd->clkout[i] = clk_wzrd_register_divider
+				(&pdev->dev, clkout_name,
 				clk_name, 0,
 				clk_wzrd->base, (WZRD_CLK_CFG_REG(2) + i * 12),
 				WZRD_CLKOUT_DIVIDE_SHIFT,
@@ -427,6 +602,10 @@ static int clk_wzrd_probe(struct platform_device *pdev)
 		}
 	}
 
+	ret = clk_wzrd_register_dividers(pdev, clk_name);
+	if (ret)
+		goto err_rm_int_clks;
+
 	kfree(clk_name);
 
 	clk_wzrd->clk_data.clks = clk_wzrd->clkout;
-- 
2.1.1




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