clk: sunxi: rewrite sun6i-ar100 using factors clk

sun6i's AR100 clock is a classic factors clk case:

AR100 = ((parent mux) >> p) / (m + 1)

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

diff --git a/drivers/clk/sunxi/clk-sun6i-ar100.c b/drivers/clk/sunxi/clk-sun6i-ar100.c
index 20887686bdbee09fe7fbc90963f179ed45c651ab..a7f5777834eb046ae788b167740ac91246b93359 100644 (file)
--- a/drivers/clk/sunxi/clk-sun6i-ar100.c
+++ b/drivers/clk/sunxi/clk-sun6i-ar100.c
@@ -8,211 +8,97 @@
  *
  */
 
+#include <linux/bitops.h>
 #include <linux/clk-provider.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/spinlock.h>
 
-#define SUN6I_AR100_MAX_PARENTS                4
-#define SUN6I_AR100_SHIFT_MASK         0x3
-#define SUN6I_AR100_SHIFT_MAX          SUN6I_AR100_SHIFT_MASK
-#define SUN6I_AR100_SHIFT_SHIFT                4
-#define SUN6I_AR100_DIV_MASK           0x1f
-#define SUN6I_AR100_DIV_MAX            (SUN6I_AR100_DIV_MASK + 1)
-#define SUN6I_AR100_DIV_SHIFT          8
-#define SUN6I_AR100_MUX_MASK           0x3
-#define SUN6I_AR100_MUX_SHIFT          16
-
-struct ar100_clk {
-       struct clk_hw hw;
-       void __iomem *reg;
-};
-
-static inline struct ar100_clk *to_ar100_clk(struct clk_hw *hw)
-{
-       return container_of(hw, struct ar100_clk, hw);
-}
-
-static unsigned long ar100_recalc_rate(struct clk_hw *hw,
-                                      unsigned long parent_rate)
-{
-       struct ar100_clk *clk = to_ar100_clk(hw);
-       u32 val = readl(clk->reg);
-       int shift = (val >> SUN6I_AR100_SHIFT_SHIFT) & SUN6I_AR100_SHIFT_MASK;
-       int div = (val >> SUN6I_AR100_DIV_SHIFT) & SUN6I_AR100_DIV_MASK;
-
-       return (parent_rate >> shift) / (div + 1);
-}
-
-static int ar100_determine_rate(struct clk_hw *hw,
-                               struct clk_rate_request *req)
-{
-       int nparents = clk_hw_get_num_parents(hw);
-       long best_rate = -EINVAL;
-       int i;
-
-       req->best_parent_hw = NULL;
-
-       for (i = 0; i < nparents; i++) {
-               unsigned long parent_rate;
-               unsigned long tmp_rate;
-               struct clk_hw *parent;
-               unsigned long div;
-               int shift;
-
-               parent = clk_hw_get_parent_by_index(hw, i);
-               parent_rate = clk_hw_get_rate(parent);
-               div = DIV_ROUND_UP(parent_rate, req->rate);
-
-               /*
-                * The AR100 clk contains 2 divisors:
-                * - one power of 2 divisor
-                * - one regular divisor
-                *
-                * First check if we can safely shift (or divide by a power
-                * of 2) without losing precision on the requested rate.
-                */
-               shift = ffs(div) - 1;
-               if (shift > SUN6I_AR100_SHIFT_MAX)
-                       shift = SUN6I_AR100_SHIFT_MAX;
-
-               div >>= shift;
-
-               /*
-                * Then if the divisor is still bigger than what the HW
-                * actually supports, use a bigger shift (or power of 2
-                * divider) value and accept to lose some precision.
-                */
-               while (div > SUN6I_AR100_DIV_MAX) {
-                       shift++;
-                       div >>= 1;
-                       if (shift > SUN6I_AR100_SHIFT_MAX)
-                               break;
-               }
-
-               /*
-                * If the shift value (or power of 2 divider) is bigger
-                * than what the HW actually support, skip this parent.
-                */
-               if (shift > SUN6I_AR100_SHIFT_MAX)
-                       continue;
-
-               tmp_rate = (parent_rate >> shift) / div;
-               if (!req->best_parent_hw || tmp_rate > best_rate) {
-                       req->best_parent_hw = parent;
-                       req->best_parent_rate = parent_rate;
-                       best_rate = tmp_rate;
-               }
-       }
-
-       if (best_rate < 0)
-               return best_rate;
-
-       req->rate = best_rate;
-
-       return 0;
-}
-
-static int ar100_set_parent(struct clk_hw *hw, u8 index)
-{
-       struct ar100_clk *clk = to_ar100_clk(hw);
-       u32 val = readl(clk->reg);
-
-       if (index >= SUN6I_AR100_MAX_PARENTS)
-               return -EINVAL;
-
-       val &= ~(SUN6I_AR100_MUX_MASK << SUN6I_AR100_MUX_SHIFT);
-       val |= (index << SUN6I_AR100_MUX_SHIFT);
-       writel(val, clk->reg);
-
-       return 0;
-}
+#include "clk-factors.h"
 
-static u8 ar100_get_parent(struct clk_hw *hw)
-{
-       struct ar100_clk *clk = to_ar100_clk(hw);
-       return (readl(clk->reg) >> SUN6I_AR100_MUX_SHIFT) &
-              SUN6I_AR100_MUX_MASK;
-}
-
-static int ar100_set_rate(struct clk_hw *hw, unsigned long rate,
-                         unsigned long parent_rate)
+/**
+ * sun6i_get_ar100_factors - Calculates factors p, m for AR100
+ *
+ * AR100 rate is calculated as follows
+ * rate = (parent_rate >> p) / (m + 1);
+ */
+static void sun6i_get_ar100_factors(struct factors_request *req)
 {
-       unsigned long div = parent_rate / rate;
-       struct ar100_clk *clk = to_ar100_clk(hw);
-       u32 val = readl(clk->reg);
+       unsigned long div;
        int shift;
 
-       if (parent_rate % rate)
-               return -EINVAL;
+       /* clock only divides */
+       if (req->rate > req->parent_rate)
+               req->rate = req->parent_rate;
 
-       shift = ffs(div) - 1;
-       if (shift > SUN6I_AR100_SHIFT_MAX)
-               shift = SUN6I_AR100_SHIFT_MAX;
+       div = DIV_ROUND_UP(req->parent_rate, req->rate);
 
-       div >>= shift;
+       if (div < 32)
+               shift = 0;
+       else if (div >> 1 < 32)
+               shift = 1;
+       else if (div >> 2 < 32)
+               shift = 2;
+       else
+               shift = 3;
 
-       if (div > SUN6I_AR100_DIV_MAX)
-               return -EINVAL;
+       div >>= shift;
 
-       val &= ~((SUN6I_AR100_SHIFT_MASK << SUN6I_AR100_SHIFT_SHIFT) |
-                (SUN6I_AR100_DIV_MASK << SUN6I_AR100_DIV_SHIFT));
-       val |= (shift << SUN6I_AR100_SHIFT_SHIFT) |
-              (div << SUN6I_AR100_DIV_SHIFT);
-       writel(val, clk->reg);
+       if (div > 32)
+               div = 32;
 
-       return 0;
+       req->rate = (req->parent_rate >> shift) / div;
+       req->m = div - 1;
+       req->p = shift;
 }
 
-static struct clk_ops ar100_ops = {
-       .recalc_rate = ar100_recalc_rate,
-       .determine_rate = ar100_determine_rate,
-       .set_parent = ar100_set_parent,
-       .get_parent = ar100_get_parent,
-       .set_rate = ar100_set_rate,
+static const struct clk_factors_config sun6i_ar100_config = {
+       .mwidth = 5,
+       .mshift = 8,
+       .pwidth = 2,
+       .pshift = 4,
 };
 
+static const struct factors_data sun6i_ar100_data __initconst = {
+       .mux = 16,
+       .muxmask = GENMASK(1, 0),
+       .table = &sun6i_ar100_config,
+       .getter = sun6i_get_ar100_factors,
+};
+
+static DEFINE_SPINLOCK(sun6i_ar100_lock);
+
 static int sun6i_a31_ar100_clk_probe(struct platform_device *pdev)
 {
-       const char *parents[SUN6I_AR100_MAX_PARENTS];
        struct device_node *np = pdev->dev.of_node;
-       const char *clk_name = np->name;
-       struct clk_init_data init;
-       struct ar100_clk *ar100;
        struct resource *r;
+       void __iomem *reg;
        struct clk *clk;
-       int nparents;
-
-       ar100 = devm_kzalloc(&pdev->dev, sizeof(*ar100), GFP_KERNEL);
-       if (!ar100)
-               return -ENOMEM;
 
        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-       ar100->reg = devm_ioremap_resource(&pdev->dev, r);
-       if (IS_ERR(ar100->reg))
-               return PTR_ERR(ar100->reg);
+       reg = devm_ioremap_resource(&pdev->dev, r);
+       if (IS_ERR(reg))
+               return PTR_ERR(reg);
 
-       nparents = of_clk_get_parent_count(np);
-       if (nparents > SUN6I_AR100_MAX_PARENTS)
-               nparents = SUN6I_AR100_MAX_PARENTS;
-
-       of_clk_parent_fill(np, parents, nparents);
+       clk = sunxi_factors_register(np, &sun6i_ar100_data, &sun6i_ar100_lock,
+                                    reg);
+       if (!clk)
+               return -ENOMEM;
 
-       of_property_read_string(np, "clock-output-names", &clk_name);
+       platform_set_drvdata(pdev, clk);
 
-       init.name = clk_name;
-       init.ops = &ar100_ops;
-       init.parent_names = parents;
-       init.num_parents = nparents;
-       init.flags = 0;
+       return 0;
+}
 
-       ar100->hw.init = &init;
+static int sun6i_a31_ar100_clk_remove(struct platform_device *pdev)
+{
+       struct device_node *np = pdev->dev.of_node;
+       struct clk *clk = platform_get_drvdata(pdev);
 
-       clk = clk_register(&pdev->dev, &ar100->hw);
-       if (IS_ERR(clk))
-               return PTR_ERR(clk);
+       sunxi_factors_unregister(np, clk);
 
-       return of_clk_add_provider(np, of_clk_src_simple_get, clk);
+       return 0;
 }
 
 static const struct of_device_id sun6i_a31_ar100_clk_dt_ids[] = {
@@ -227,6 +113,7 @@ static struct platform_driver sun6i_a31_ar100_clk_driver = {
                .of_match_table = sun6i_a31_ar100_clk_dt_ids,
        },
        .probe = sun6i_a31_ar100_clk_probe,
+       .remove = sun6i_a31_ar100_clk_remove,
 };
 module_platform_driver(sun6i_a31_ar100_clk_driver);