clk: sunxi-ng: Add N-K-M Factor clock
Introduce support for clocks that multiply and divide using two linear
multipliers and one linear divider.
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20160629190535.11855-12-maxime.ripard@free-electrons.com
diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c
new file mode 100644
index 0000000..2071822
--- /dev/null
+++ b/drivers/clk/sunxi-ng/ccu_nkm.c
@@ -0,0 +1,153 @@
+/*
+ * Copyright (C) 2016 Maxime Ripard
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/rational.h>
+
+#include "ccu_gate.h"
+#include "ccu_nkm.h"
+
+struct _ccu_nkm {
+ unsigned long n, max_n;
+ unsigned long k, max_k;
+ unsigned long m, max_m;
+};
+
+static void ccu_nkm_find_best(unsigned long parent, unsigned long rate,
+ struct _ccu_nkm *nkm)
+{
+ unsigned long best_rate = 0;
+ unsigned long best_n = 0, best_k = 0, best_m = 0;
+ unsigned long _n, _k, _m;
+
+ for (_k = 1; _k <= nkm->max_k; _k++) {
+ unsigned long tmp_rate;
+
+ rational_best_approximation(rate / _k, parent,
+ nkm->max_n, nkm->max_m, &_n, &_m);
+
+ tmp_rate = parent * _n * _k / _m;
+
+ if (tmp_rate > rate)
+ continue;
+
+ if ((rate - tmp_rate) < (rate - best_rate)) {
+ best_rate = tmp_rate;
+ best_n = _n;
+ best_k = _k;
+ best_m = _m;
+ }
+ }
+
+ nkm->n = best_n;
+ nkm->k = best_k;
+ nkm->m = best_m;
+}
+
+static void ccu_nkm_disable(struct clk_hw *hw)
+{
+ struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
+
+ return ccu_gate_helper_disable(&nkm->common, nkm->enable);
+}
+
+static int ccu_nkm_enable(struct clk_hw *hw)
+{
+ struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
+
+ return ccu_gate_helper_enable(&nkm->common, nkm->enable);
+}
+
+static int ccu_nkm_is_enabled(struct clk_hw *hw)
+{
+ struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
+
+ return ccu_gate_helper_is_enabled(&nkm->common, nkm->enable);
+}
+
+static unsigned long ccu_nkm_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
+ unsigned long n, m, k;
+ u32 reg;
+
+ reg = readl(nkm->common.base + nkm->common.reg);
+
+ n = reg >> nkm->n.shift;
+ n &= (1 << nkm->n.width) - 1;
+
+ k = reg >> nkm->k.shift;
+ k &= (1 << nkm->k.width) - 1;
+
+ m = reg >> nkm->m.shift;
+ m &= (1 << nkm->m.width) - 1;
+
+ return parent_rate * (n + 1) * (k + 1) / (m + 1);
+}
+
+static long ccu_nkm_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
+ struct _ccu_nkm _nkm;
+
+ _nkm.max_n = 1 << nkm->n.width;
+ _nkm.max_k = 1 << nkm->k.width;
+ _nkm.max_m = 1 << nkm->m.width;
+
+ ccu_nkm_find_best(*parent_rate, rate, &_nkm);
+
+ return *parent_rate * _nkm.n * _nkm.k / _nkm.m;
+}
+
+static int ccu_nkm_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
+ struct _ccu_nkm _nkm;
+ unsigned long flags;
+ u32 reg;
+
+ _nkm.max_n = 1 << nkm->n.width;
+ _nkm.max_k = 1 << nkm->k.width;
+ _nkm.max_m = 1 << nkm->m.width;
+
+ ccu_nkm_find_best(parent_rate, rate, &_nkm);
+
+ spin_lock_irqsave(nkm->common.lock, flags);
+
+ reg = readl(nkm->common.base + nkm->common.reg);
+ reg &= ~GENMASK(nkm->n.width + nkm->n.shift - 1, nkm->n.shift);
+ reg &= ~GENMASK(nkm->k.width + nkm->k.shift - 1, nkm->k.shift);
+ reg &= ~GENMASK(nkm->m.width + nkm->m.shift - 1, nkm->m.shift);
+
+ reg |= (_nkm.n - 1) << nkm->n.shift;
+ reg |= (_nkm.k - 1) << nkm->k.shift;
+ reg |= (_nkm.m - 1) << nkm->m.shift;
+
+ writel(reg, nkm->common.base + nkm->common.reg);
+
+ spin_unlock_irqrestore(nkm->common.lock, flags);
+
+ ccu_helper_wait_for_lock(&nkm->common, nkm->lock);
+
+ return 0;
+}
+
+const struct clk_ops ccu_nkm_ops = {
+ .disable = ccu_nkm_disable,
+ .enable = ccu_nkm_enable,
+ .is_enabled = ccu_nkm_is_enabled,
+
+ .recalc_rate = ccu_nkm_recalc_rate,
+ .round_rate = ccu_nkm_round_rate,
+ .set_rate = ccu_nkm_set_rate,
+};