clk: sunxi-ng: Add N-M-factor clock support

Introduce support for clocks that multiply and divide using linear factors.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20160629190535.11855-11-maxime.ripard@free-electrons.com

1 files changed, 114 insertions, 0 deletions

diff --git a/drivers/clk/sunxi-ng/ccu_nm.c b/drivers/clk/sunxi-ng/ccu_nm.c
new file mode 100644
index 000000000000..e35ddd8eec8b
--- /dev/null
+++ b/drivers/clk/sunxi-ng/ccu_nm.c
@@ -0,0 +1,114 @@
+/*
+ * 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_frac.h"
+#include "ccu_gate.h"
+#include "ccu_nm.h"
+
+static void ccu_nm_disable(struct clk_hw *hw)
+{
+	struct ccu_nm *nm = hw_to_ccu_nm(hw);
+
+	return ccu_gate_helper_disable(&nm->common, nm->enable);
+}
+
+static int ccu_nm_enable(struct clk_hw *hw)
+{
+	struct ccu_nm *nm = hw_to_ccu_nm(hw);
+
+	return ccu_gate_helper_enable(&nm->common, nm->enable);
+}
+
+static int ccu_nm_is_enabled(struct clk_hw *hw)
+{
+	struct ccu_nm *nm = hw_to_ccu_nm(hw);
+
+	return ccu_gate_helper_is_enabled(&nm->common, nm->enable);
+}
+
+static unsigned long ccu_nm_recalc_rate(struct clk_hw *hw,
+					unsigned long parent_rate)
+{
+	struct ccu_nm *nm = hw_to_ccu_nm(hw);
+	unsigned long n, m;
+	u32 reg;
+
+	if (ccu_frac_helper_is_enabled(&nm->common, &nm->frac))
+		return ccu_frac_helper_read_rate(&nm->common, &nm->frac);
+
+	reg = readl(nm->common.base + nm->common.reg);
+
+	n = reg >> nm->n.shift;
+	n &= (1 << nm->n.width) - 1;
+
+	m = reg >> nm->m.shift;
+	m &= (1 << nm->m.width) - 1;
+
+	return parent_rate * (n + 1) / (m + 1);
+}
+
+static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
+			      unsigned long *parent_rate)
+{
+	struct ccu_nm *nm = hw_to_ccu_nm(hw);
+	unsigned long n, m;
+
+	rational_best_approximation(rate, *parent_rate,
+				    1 << nm->n.width, 1 << nm->m.width,
+				    &n, &m);
+
+	return *parent_rate * n / m;
+}
+
+static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate,
+			   unsigned long parent_rate)
+{
+	struct ccu_nm *nm = hw_to_ccu_nm(hw);
+	unsigned long flags;
+	unsigned long n, m;
+	u32 reg;
+
+	if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate))
+		return ccu_frac_helper_set_rate(&nm->common, &nm->frac, rate);
+	else
+		ccu_frac_helper_disable(&nm->common, &nm->frac);
+
+	rational_best_approximation(rate, parent_rate,
+				    1 << nm->n.width, 1 << nm->m.width,
+				    &n, &m);
+
+	spin_lock_irqsave(nm->common.lock, flags);
+
+	reg = readl(nm->common.base + nm->common.reg);
+	reg &= ~GENMASK(nm->n.width + nm->n.shift - 1, nm->n.shift);
+	reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
+
+	writel(reg | ((m - 1) << nm->m.shift) | ((n - 1) << nm->n.shift),
+	       nm->common.base + nm->common.reg);
+
+	spin_unlock_irqrestore(nm->common.lock, flags);
+
+	ccu_helper_wait_for_lock(&nm->common, nm->lock);
+
+	return 0;
+}
+
+const struct clk_ops ccu_nm_ops = {
+	.disable	= ccu_nm_disable,
+	.enable		= ccu_nm_enable,
+	.is_enabled	= ccu_nm_is_enabled,
+
+	.recalc_rate	= ccu_nm_recalc_rate,
+	.round_rate	= ccu_nm_round_rate,
+	.set_rate	= ccu_nm_set_rate,
+};