clk: sunxi: rewrite sun6i-a31-ahb1-clk using factors clk with custom recalc

The factors clk implementation has been extended to support custom
recalc callbacks to support clocks that use one factor for certain
parents only, like a pre-divider.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

1 files changed, 83 insertions, 208 deletions

diff --git a/drivers/clk/sunxi/clk-sunxi.c b/drivers/clk/sunxi/clk-sunxi.c
index a57c36c..da15f2b 100644
--- a/drivers/clk/sunxi/clk-sunxi.c
+++ b/drivers/clk/sunxi/clk-sunxi.c
@@ -28,214 +28,6 @@
 
 static DEFINE_SPINLOCK(clk_lock);
 
-/**
- * sun6i_a31_ahb1_clk_setup() - Setup function for a31 ahb1 composite clk
- */
-
-#define SUN6I_AHB1_MAX_PARENTS		4
-#define SUN6I_AHB1_MUX_PARENT_PLL6	3
-#define SUN6I_AHB1_MUX_SHIFT		12
-/* un-shifted mask is what mux_clk expects */
-#define SUN6I_AHB1_MUX_MASK		0x3
-#define SUN6I_AHB1_MUX_GET_PARENT(reg)	((reg >> SUN6I_AHB1_MUX_SHIFT) & \
-					 SUN6I_AHB1_MUX_MASK)
-
-#define SUN6I_AHB1_DIV_SHIFT		4
-#define SUN6I_AHB1_DIV_MASK		(0x3 << SUN6I_AHB1_DIV_SHIFT)
-#define SUN6I_AHB1_DIV_GET(reg)		((reg & SUN6I_AHB1_DIV_MASK) >> \
-						SUN6I_AHB1_DIV_SHIFT)
-#define SUN6I_AHB1_DIV_SET(reg, div)	((reg & ~SUN6I_AHB1_DIV_MASK) | \
-						(div << SUN6I_AHB1_DIV_SHIFT))
-#define SUN6I_AHB1_PLL6_DIV_SHIFT	6
-#define SUN6I_AHB1_PLL6_DIV_MASK	(0x3 << SUN6I_AHB1_PLL6_DIV_SHIFT)
-#define SUN6I_AHB1_PLL6_DIV_GET(reg)	((reg & SUN6I_AHB1_PLL6_DIV_MASK) >> \
-						SUN6I_AHB1_PLL6_DIV_SHIFT)
-#define SUN6I_AHB1_PLL6_DIV_SET(reg, div) ((reg & ~SUN6I_AHB1_PLL6_DIV_MASK) | \
-						(div << SUN6I_AHB1_PLL6_DIV_SHIFT))
-
-struct sun6i_ahb1_clk {
-	struct clk_hw hw;
-	void __iomem *reg;
-};
-
-#define to_sun6i_ahb1_clk(_hw) container_of(_hw, struct sun6i_ahb1_clk, hw)
-
-static unsigned long sun6i_ahb1_clk_recalc_rate(struct clk_hw *hw,
-						unsigned long parent_rate)
-{
-	struct sun6i_ahb1_clk *ahb1 = to_sun6i_ahb1_clk(hw);
-	unsigned long rate;
-	u32 reg;
-
-	/* Fetch the register value */
-	reg = readl(ahb1->reg);
-
-	/* apply pre-divider first if parent is pll6 */
-	if (SUN6I_AHB1_MUX_GET_PARENT(reg) == SUN6I_AHB1_MUX_PARENT_PLL6)
-		parent_rate /= SUN6I_AHB1_PLL6_DIV_GET(reg) + 1;
-
-	/* clk divider */
-	rate = parent_rate >> SUN6I_AHB1_DIV_GET(reg);
-
-	return rate;
-}
-
-static long sun6i_ahb1_clk_round(unsigned long rate, u8 *divp, u8 *pre_divp,
-				 u8 parent, unsigned long parent_rate)
-{
-	u8 div, calcp, calcm = 1;
-
-	/*
-	 * clock can only divide, so we will never be able to achieve
-	 * frequencies higher than the parent frequency
-	 */
-	if (parent_rate && rate > parent_rate)
-		rate = parent_rate;
-
-	div = DIV_ROUND_UP(parent_rate, rate);
-
-	/* calculate pre-divider if parent is pll6 */
-	if (parent == SUN6I_AHB1_MUX_PARENT_PLL6) {
-		if (div < 4)
-			calcp = 0;
-		else if (div / 2 < 4)
-			calcp = 1;
-		else if (div / 4 < 4)
-			calcp = 2;
-		else
-			calcp = 3;
-
-		calcm = DIV_ROUND_UP(div, 1 << calcp);
-	} else {
-		calcp = __roundup_pow_of_two(div);
-		calcp = calcp > 3 ? 3 : calcp;
-	}
-
-	/* we were asked to pass back divider values */
-	if (divp) {
-		*divp = calcp;
-		*pre_divp = calcm - 1;
-	}
-
-	return (parent_rate / calcm) >> calcp;
-}
-
-static int sun6i_ahb1_clk_determine_rate(struct clk_hw *hw,
-					 struct clk_rate_request *req)
-{
-	struct clk_hw *parent, *best_parent = NULL;
-	int i, num_parents;
-	unsigned long parent_rate, best = 0, child_rate, best_child_rate = 0;
-
-	/* find the parent that can help provide the fastest rate <= rate */
-	num_parents = clk_hw_get_num_parents(hw);
-	for (i = 0; i < num_parents; i++) {
-		parent = clk_hw_get_parent_by_index(hw, i);
-		if (!parent)
-			continue;
-		if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)
-			parent_rate = clk_hw_round_rate(parent, req->rate);
-		else
-			parent_rate = clk_hw_get_rate(parent);
-
-		child_rate = sun6i_ahb1_clk_round(req->rate, NULL, NULL, i,
-						  parent_rate);
-
-		if (child_rate <= req->rate && child_rate > best_child_rate) {
-			best_parent = parent;
-			best = parent_rate;
-			best_child_rate = child_rate;
-		}
-	}
-
-	if (!best_parent)
-		return -EINVAL;
-
-	req->best_parent_hw = best_parent;
-	req->best_parent_rate = best;
-	req->rate = best_child_rate;
-
-	return 0;
-}
-
-static int sun6i_ahb1_clk_set_rate(struct clk_hw *hw, unsigned long rate,
-				   unsigned long parent_rate)
-{
-	struct sun6i_ahb1_clk *ahb1 = to_sun6i_ahb1_clk(hw);
-	unsigned long flags;
-	u8 div, pre_div, parent;
-	u32 reg;
-
-	spin_lock_irqsave(&clk_lock, flags);
-
-	reg = readl(ahb1->reg);
-
-	/* need to know which parent is used to apply pre-divider */
-	parent = SUN6I_AHB1_MUX_GET_PARENT(reg);
-	sun6i_ahb1_clk_round(rate, &div, &pre_div, parent, parent_rate);
-
-	reg = SUN6I_AHB1_DIV_SET(reg, div);
-	reg = SUN6I_AHB1_PLL6_DIV_SET(reg, pre_div);
-	writel(reg, ahb1->reg);
-
-	spin_unlock_irqrestore(&clk_lock, flags);
-
-	return 0;
-}
-
-static const struct clk_ops sun6i_ahb1_clk_ops = {
-	.determine_rate	= sun6i_ahb1_clk_determine_rate,
-	.recalc_rate	= sun6i_ahb1_clk_recalc_rate,
-	.set_rate	= sun6i_ahb1_clk_set_rate,
-};
-
-static void __init sun6i_ahb1_clk_setup(struct device_node *node)
-{
-	struct clk *clk;
-	struct sun6i_ahb1_clk *ahb1;
-	struct clk_mux *mux;
-	const char *clk_name = node->name;
-	const char *parents[SUN6I_AHB1_MAX_PARENTS];
-	void __iomem *reg;
-	int i;
-
-	reg = of_io_request_and_map(node, 0, of_node_full_name(node));
-	if (IS_ERR(reg))
-		return;
-
-	/* we have a mux, we will have >1 parents */
-	i = of_clk_parent_fill(node, parents, SUN6I_AHB1_MAX_PARENTS);
-	of_property_read_string(node, "clock-output-names", &clk_name);
-
-	ahb1 = kzalloc(sizeof(struct sun6i_ahb1_clk), GFP_KERNEL);
-	if (!ahb1)
-		return;
-
-	mux = kzalloc(sizeof(struct clk_mux), GFP_KERNEL);
-	if (!mux) {
-		kfree(ahb1);
-		return;
-	}
-
-	/* set up clock properties */
-	mux->reg = reg;
-	mux->shift = SUN6I_AHB1_MUX_SHIFT;
-	mux->mask = SUN6I_AHB1_MUX_MASK;
-	mux->lock = &clk_lock;
-	ahb1->reg = reg;
-
-	clk = clk_register_composite(NULL, clk_name, parents, i,
-				     &mux->hw, &clk_mux_ops,
-				     &ahb1->hw, &sun6i_ahb1_clk_ops,
-				     NULL, NULL, 0);
-
-	if (!IS_ERR(clk)) {
-		of_clk_add_provider(node, of_clk_src_simple_get, clk);
-		clk_register_clkdev(clk, clk_name, NULL);
-	}
-}
-CLK_OF_DECLARE(sun6i_a31_ahb1, "allwinner,sun6i-a31-ahb1-clk", sun6i_ahb1_clk_setup);
-
 /* Maximum number of parents our clocks have */
 #define SUNXI_MAX_PARENTS	5
 
@@ -490,6 +282,68 @@ static void sun5i_a13_get_ahb_factors(struct factors_request *req)
 	req->p = div;
 }
 
+#define SUN6I_AHB1_PARENT_PLL6	3
+
+/**
+ * sun6i_a31_get_ahb_factors() - calculates m, p factors for AHB
+ * AHB rate is calculated as follows
+ * rate = parent_rate >> p
+ *
+ * if parent is pll6, then
+ * parent_rate = pll6 rate / (m + 1)
+ */
+
+static void sun6i_get_ahb1_factors(struct factors_request *req)
+{
+	u8 div, calcp, calcm = 1;
+
+	/*
+	 * clock can only divide, so we will never be able to achieve
+	 * frequencies higher than the parent frequency
+	 */
+	if (req->parent_rate && req->rate > req->parent_rate)
+		req->rate = req->parent_rate;
+
+	div = DIV_ROUND_UP(req->parent_rate, req->rate);
+
+	/* calculate pre-divider if parent is pll6 */
+	if (req->parent_index == SUN6I_AHB1_PARENT_PLL6) {
+		if (div < 4)
+			calcp = 0;
+		else if (div / 2 < 4)
+			calcp = 1;
+		else if (div / 4 < 4)
+			calcp = 2;
+		else
+			calcp = 3;
+
+		calcm = DIV_ROUND_UP(div, 1 << calcp);
+	} else {
+		calcp = __roundup_pow_of_two(div);
+		calcp = calcp > 3 ? 3 : calcp;
+	}
+
+	req->rate = (req->parent_rate / calcm) >> calcp;
+	req->p = calcp;
+	req->m = calcm - 1;
+}
+
+/**
+ * sun6i_ahb1_recalc() - calculates AHB clock rate from m, p factors and
+ *			 parent index
+ */
+static void sun6i_ahb1_recalc(struct factors_request *req)
+{
+	req->rate = req->parent_rate;
+
+	/* apply pre-divider first if parent is pll6 */
+	if (req->parent_index == SUN6I_AHB1_PARENT_PLL6)
+		req->rate /= req->m + 1;
+
+	/* clk divider */
+	req->rate >>= req->p;
+}
+
 /**
  * sun4i_get_apb1_factors() - calculates m, p factors for APB1
  * APB1 rate is calculated as follows
@@ -619,6 +473,13 @@ static const struct clk_factors_config sun5i_a13_ahb_config = {
 	.pwidth = 2,
 };
 
+static const struct clk_factors_config sun6i_ahb1_config = {
+	.mshift = 6,
+	.mwidth = 2,
+	.pshift = 4,
+	.pwidth = 2,
+};
+
 static const struct clk_factors_config sun4i_apb1_config = {
 	.mshift = 0,
 	.mwidth = 5,
@@ -686,6 +547,14 @@ static const struct factors_data sun5i_a13_ahb_data __initconst = {
 	.getter = sun5i_a13_get_ahb_factors,
 };
 
+static const struct factors_data sun6i_ahb1_data __initconst = {
+	.mux = 12,
+	.muxmask = BIT(1) | BIT(0),
+	.table = &sun6i_ahb1_config,
+	.getter = sun6i_get_ahb1_factors,
+	.recalc = sun6i_ahb1_recalc,
+};
+
 static const struct factors_data sun4i_apb1_data __initconst = {
 	.mux = 24,
 	.muxmask = BIT(1) | BIT(0),
@@ -716,6 +585,12 @@ static struct clk * __init sunxi_factors_clk_setup(struct device_node *node,
 	return sunxi_factors_register(node, data, &clk_lock, reg);
 }
 
+static void __init sun6i_ahb1_clk_setup(struct device_node *node)
+{
+	sunxi_factors_clk_setup(node, &sun6i_ahb1_data);
+}
+CLK_OF_DECLARE(sun6i_a31_ahb1, "allwinner,sun6i-a31-ahb1-clk",
+	       sun6i_ahb1_clk_setup);
 
 
 /**