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path: root/drivers/clk/meson/clk-mpll.c
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-rw-r--r--drivers/clk/meson/clk-mpll.c180
1 files changed, 180 insertions, 0 deletions
diff --git a/drivers/clk/meson/clk-mpll.c b/drivers/clk/meson/clk-mpll.c
new file mode 100644
index 0000000000..20255e129b
--- /dev/null
+++ b/drivers/clk/meson/clk-mpll.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+/*
+ * Copyright (c) 2016 AmLogic, Inc.
+ * Author: Michael Turquette <mturquette@baylibre.com>
+ */
+
+/*
+ * MultiPhase Locked Loops are outputs from a PLL with additional frequency
+ * scaling capabilities. MPLL rates are calculated as:
+ *
+ * f(N2_integer, SDM_IN ) = 2.0G/(N2_integer + SDM_IN/16384)
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+#include <linux/spinlock.h>
+
+#include "clk-regmap.h"
+#include "clk-mpll.h"
+
+#define SDM_DEN 16384
+#define N2_MIN 4
+#define N2_MAX 511
+
+static inline struct meson_clk_mpll_data *
+meson_clk_mpll_data(struct clk_regmap *clk)
+{
+ return (struct meson_clk_mpll_data *)clk->data;
+}
+
+static long rate_from_params(unsigned long parent_rate,
+ unsigned int sdm,
+ unsigned int n2)
+{
+ unsigned long divisor = (SDM_DEN * n2) + sdm;
+
+ if (n2 < N2_MIN)
+ return -EINVAL;
+
+ return DIV_ROUND_UP_ULL((u64)parent_rate * SDM_DEN, divisor);
+}
+
+static void params_from_rate(unsigned long requested_rate,
+ unsigned long parent_rate,
+ unsigned int *sdm,
+ unsigned int *n2,
+ u8 flags)
+{
+ uint64_t div = parent_rate;
+ uint64_t frac = do_div(div, requested_rate);
+
+ frac *= SDM_DEN;
+
+ if (flags & CLK_MESON_MPLL_ROUND_CLOSEST)
+ *sdm = DIV_ROUND_CLOSEST_ULL(frac, requested_rate);
+ else
+ *sdm = DIV_ROUND_UP_ULL(frac, requested_rate);
+
+ if (*sdm == SDM_DEN) {
+ *sdm = 0;
+ div += 1;
+ }
+
+ if (div < N2_MIN) {
+ *n2 = N2_MIN;
+ *sdm = 0;
+ } else if (div > N2_MAX) {
+ *n2 = N2_MAX;
+ *sdm = SDM_DEN - 1;
+ } else {
+ *n2 = div;
+ }
+}
+
+static unsigned long mpll_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
+ unsigned int sdm, n2;
+ long rate;
+
+ sdm = meson_parm_read(clk->map, &mpll->sdm);
+ n2 = meson_parm_read(clk->map, &mpll->n2);
+
+ rate = rate_from_params(parent_rate, sdm, n2);
+ return rate < 0 ? 0 : rate;
+}
+
+static int mpll_determine_rate(struct clk_hw *hw, struct clk_rate_request *req)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
+ unsigned int sdm, n2;
+ long rate;
+
+ params_from_rate(req->rate, req->best_parent_rate, &sdm, &n2,
+ mpll->flags);
+
+ rate = rate_from_params(req->best_parent_rate, sdm, n2);
+ if (rate < 0)
+ return rate;
+
+ req->rate = rate;
+ return 0;
+}
+
+static int mpll_set_rate(struct clk_hw *hw,
+ unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
+ unsigned int sdm, n2;
+ unsigned long flags = 0;
+
+ params_from_rate(rate, parent_rate, &sdm, &n2, mpll->flags);
+
+ if (mpll->lock)
+ spin_lock_irqsave(mpll->lock, flags);
+ else
+ __acquire(mpll->lock);
+
+ /* Set the fractional part */
+ meson_parm_write(clk->map, &mpll->sdm, sdm);
+
+ /* Set the integer divider part */
+ meson_parm_write(clk->map, &mpll->n2, n2);
+
+ if (mpll->lock)
+ spin_unlock_irqrestore(mpll->lock, flags);
+ else
+ __release(mpll->lock);
+
+ return 0;
+}
+
+static int mpll_init(struct clk_hw *hw)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_clk_mpll_data *mpll = meson_clk_mpll_data(clk);
+
+ if (mpll->init_count)
+ regmap_multi_reg_write(clk->map, mpll->init_regs,
+ mpll->init_count);
+
+ /* Enable the fractional part */
+ meson_parm_write(clk->map, &mpll->sdm_en, 1);
+
+ /* Set spread spectrum if possible */
+ if (MESON_PARM_APPLICABLE(&mpll->ssen)) {
+ unsigned int ss =
+ mpll->flags & CLK_MESON_MPLL_SPREAD_SPECTRUM ? 1 : 0;
+ meson_parm_write(clk->map, &mpll->ssen, ss);
+ }
+
+ /* Set the magic misc bit if required */
+ if (MESON_PARM_APPLICABLE(&mpll->misc))
+ meson_parm_write(clk->map, &mpll->misc, 1);
+
+ return 0;
+}
+
+const struct clk_ops meson_clk_mpll_ro_ops = {
+ .recalc_rate = mpll_recalc_rate,
+ .determine_rate = mpll_determine_rate,
+};
+EXPORT_SYMBOL_GPL(meson_clk_mpll_ro_ops);
+
+const struct clk_ops meson_clk_mpll_ops = {
+ .recalc_rate = mpll_recalc_rate,
+ .determine_rate = mpll_determine_rate,
+ .set_rate = mpll_set_rate,
+ .init = mpll_init,
+};
+EXPORT_SYMBOL_GPL(meson_clk_mpll_ops);
+
+MODULE_DESCRIPTION("Amlogic MPLL driver");
+MODULE_AUTHOR("Michael Turquette <mturquette@baylibre.com>");
+MODULE_LICENSE("GPL v2");