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path: root/drivers/clk/sunxi/clk-sun6i-ar100.c
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Diffstat (limited to 'drivers/clk/sunxi/clk-sun6i-ar100.c')
-rw-r--r--drivers/clk/sunxi/clk-sun6i-ar100.c233
1 files changed, 233 insertions, 0 deletions
diff --git a/drivers/clk/sunxi/clk-sun6i-ar100.c b/drivers/clk/sunxi/clk-sun6i-ar100.c
new file mode 100644
index 00000000000..eca8ca025b6
--- /dev/null
+++ b/drivers/clk/sunxi/clk-sun6i-ar100.c
@@ -0,0 +1,233 @@
+/*
+ * Copyright (C) 2014 Free Electrons
+ *
+ * License Terms: GNU General Public License v2
+ * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
+ *
+ * Allwinner A31 AR100 clock driver
+ *
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.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 long ar100_determine_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *best_parent_rate,
+ struct clk **best_parent_clk)
+{
+ int nparents = __clk_get_num_parents(hw->clk);
+ long best_rate = -EINVAL;
+ int i;
+
+ *best_parent_clk = NULL;
+
+ for (i = 0; i < nparents; i++) {
+ unsigned long parent_rate;
+ unsigned long tmp_rate;
+ struct clk *parent;
+ unsigned long div;
+ int shift;
+
+ parent = clk_get_parent_by_index(hw->clk, i);
+ parent_rate = __clk_get_rate(parent);
+ div = DIV_ROUND_UP(parent_rate, 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 (!*best_parent_clk || tmp_rate > best_rate) {
+ *best_parent_clk = parent;
+ *best_parent_rate = parent_rate;
+ best_rate = tmp_rate;
+ }
+ }
+
+ return best_rate;
+}
+
+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;
+}
+
+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)
+{
+ unsigned long div = parent_rate / rate;
+ struct ar100_clk *clk = to_ar100_clk(hw);
+ u32 val = readl(clk->reg);
+ int shift;
+
+ if (parent_rate % rate)
+ return -EINVAL;
+
+ shift = ffs(div) - 1;
+ if (shift > SUN6I_AR100_SHIFT_MAX)
+ shift = SUN6I_AR100_SHIFT_MAX;
+
+ div >>= shift;
+
+ if (div > SUN6I_AR100_DIV_MAX)
+ return -EINVAL;
+
+ 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);
+
+ return 0;
+}
+
+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 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;
+ struct clk *clk;
+ int nparents;
+ int i;
+
+ 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);
+
+ nparents = of_clk_get_parent_count(np);
+ if (nparents > SUN6I_AR100_MAX_PARENTS)
+ nparents = SUN6I_AR100_MAX_PARENTS;
+
+ for (i = 0; i < nparents; i++)
+ parents[i] = of_clk_get_parent_name(np, i);
+
+ of_property_read_string(np, "clock-output-names", &clk_name);
+
+ init.name = clk_name;
+ init.ops = &ar100_ops;
+ init.parent_names = parents;
+ init.num_parents = nparents;
+ init.flags = 0;
+
+ ar100->hw.init = &init;
+
+ clk = clk_register(&pdev->dev, &ar100->hw);
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+
+ return of_clk_add_provider(np, of_clk_src_simple_get, clk);
+}
+
+static const struct of_device_id sun6i_a31_ar100_clk_dt_ids[] = {
+ { .compatible = "allwinner,sun6i-a31-ar100-clk" },
+ { /* sentinel */ }
+};
+
+static struct platform_driver sun6i_a31_ar100_clk_driver = {
+ .driver = {
+ .name = "sun6i-a31-ar100-clk",
+ .owner = THIS_MODULE,
+ .of_match_table = sun6i_a31_ar100_clk_dt_ids,
+ },
+ .probe = sun6i_a31_ar100_clk_probe,
+};
+module_platform_driver(sun6i_a31_ar100_clk_driver);
+
+MODULE_AUTHOR("Boris BREZILLON <boris.brezillon@free-electrons.com>");
+MODULE_DESCRIPTION("Allwinner A31 AR100 clock Driver");
+MODULE_LICENSE("GPL v2");
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-28 05:23:37 +0000