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-rw-r--r--drivers/clk/meson/sclk-div.c253
1 files changed, 253 insertions, 0 deletions
diff --git a/drivers/clk/meson/sclk-div.c b/drivers/clk/meson/sclk-div.c
new file mode 100644
index 000000000..76d31c0a3
--- /dev/null
+++ b/drivers/clk/meson/sclk-div.c
@@ -0,0 +1,253 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/*
+ * Copyright (c) 2018 BayLibre, SAS.
+ * Author: Jerome Brunet <jbrunet@baylibre.com>
+ *
+ * Sample clock generator divider:
+ * This HW divider gates with value 0 but is otherwise a zero based divider:
+ *
+ * val >= 1
+ * divider = val + 1
+ *
+ * The duty cycle may also be set for the LR clock variant. The duty cycle
+ * ratio is:
+ *
+ * hi = [0 - val]
+ * duty_cycle = (1 + hi) / (1 + val)
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/module.h>
+
+#include "clk-regmap.h"
+#include "sclk-div.h"
+
+static inline struct meson_sclk_div_data *
+meson_sclk_div_data(struct clk_regmap *clk)
+{
+ return (struct meson_sclk_div_data *)clk->data;
+}
+
+static int sclk_div_maxval(struct meson_sclk_div_data *sclk)
+{
+ return (1 << sclk->div.width) - 1;
+}
+
+static int sclk_div_maxdiv(struct meson_sclk_div_data *sclk)
+{
+ return sclk_div_maxval(sclk) + 1;
+}
+
+static int sclk_div_getdiv(struct clk_hw *hw, unsigned long rate,
+ unsigned long prate, int maxdiv)
+{
+ int div = DIV_ROUND_CLOSEST_ULL((u64)prate, rate);
+
+ return clamp(div, 2, maxdiv);
+}
+
+static int sclk_div_bestdiv(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate,
+ struct meson_sclk_div_data *sclk)
+{
+ struct clk_hw *parent = clk_hw_get_parent(hw);
+ int bestdiv = 0, i;
+ unsigned long maxdiv, now, parent_now;
+ unsigned long best = 0, best_parent = 0;
+
+ if (!rate)
+ rate = 1;
+
+ maxdiv = sclk_div_maxdiv(sclk);
+
+ if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT))
+ return sclk_div_getdiv(hw, rate, *prate, maxdiv);
+
+ /*
+ * The maximum divider we can use without overflowing
+ * unsigned long in rate * i below
+ */
+ maxdiv = min(ULONG_MAX / rate, maxdiv);
+
+ for (i = 2; i <= maxdiv; i++) {
+ /*
+ * It's the most ideal case if the requested rate can be
+ * divided from parent clock without needing to change
+ * parent rate, so return the divider immediately.
+ */
+ if (rate * i == *prate)
+ return i;
+
+ parent_now = clk_hw_round_rate(parent, rate * i);
+ now = DIV_ROUND_UP_ULL((u64)parent_now, i);
+
+ if (abs(rate - now) < abs(rate - best)) {
+ bestdiv = i;
+ best = now;
+ best_parent = parent_now;
+ }
+ }
+
+ if (!bestdiv)
+ bestdiv = sclk_div_maxdiv(sclk);
+ else
+ *prate = best_parent;
+
+ return bestdiv;
+}
+
+static long sclk_div_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_sclk_div_data *sclk = meson_sclk_div_data(clk);
+ int div;
+
+ div = sclk_div_bestdiv(hw, rate, prate, sclk);
+
+ return DIV_ROUND_UP_ULL((u64)*prate, div);
+}
+
+static void sclk_apply_ratio(struct clk_regmap *clk,
+ struct meson_sclk_div_data *sclk)
+{
+ unsigned int hi = DIV_ROUND_CLOSEST(sclk->cached_div *
+ sclk->cached_duty.num,
+ sclk->cached_duty.den);
+
+ if (hi)
+ hi -= 1;
+
+ meson_parm_write(clk->map, &sclk->hi, hi);
+}
+
+static int sclk_div_set_duty_cycle(struct clk_hw *hw,
+ struct clk_duty *duty)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_sclk_div_data *sclk = meson_sclk_div_data(clk);
+
+ if (MESON_PARM_APPLICABLE(&sclk->hi)) {
+ memcpy(&sclk->cached_duty, duty, sizeof(*duty));
+ sclk_apply_ratio(clk, sclk);
+ }
+
+ return 0;
+}
+
+static int sclk_div_get_duty_cycle(struct clk_hw *hw,
+ struct clk_duty *duty)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_sclk_div_data *sclk = meson_sclk_div_data(clk);
+ int hi;
+
+ if (!MESON_PARM_APPLICABLE(&sclk->hi)) {
+ duty->num = 1;
+ duty->den = 2;
+ return 0;
+ }
+
+ hi = meson_parm_read(clk->map, &sclk->hi);
+ duty->num = hi + 1;
+ duty->den = sclk->cached_div;
+ return 0;
+}
+
+static void sclk_apply_divider(struct clk_regmap *clk,
+ struct meson_sclk_div_data *sclk)
+{
+ if (MESON_PARM_APPLICABLE(&sclk->hi))
+ sclk_apply_ratio(clk, sclk);
+
+ meson_parm_write(clk->map, &sclk->div, sclk->cached_div - 1);
+}
+
+static int sclk_div_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long prate)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_sclk_div_data *sclk = meson_sclk_div_data(clk);
+ unsigned long maxdiv = sclk_div_maxdiv(sclk);
+
+ sclk->cached_div = sclk_div_getdiv(hw, rate, prate, maxdiv);
+
+ if (clk_hw_is_enabled(hw))
+ sclk_apply_divider(clk, sclk);
+
+ return 0;
+}
+
+static unsigned long sclk_div_recalc_rate(struct clk_hw *hw,
+ unsigned long prate)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_sclk_div_data *sclk = meson_sclk_div_data(clk);
+
+ return DIV_ROUND_UP_ULL((u64)prate, sclk->cached_div);
+}
+
+static int sclk_div_enable(struct clk_hw *hw)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_sclk_div_data *sclk = meson_sclk_div_data(clk);
+
+ sclk_apply_divider(clk, sclk);
+
+ return 0;
+}
+
+static void sclk_div_disable(struct clk_hw *hw)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_sclk_div_data *sclk = meson_sclk_div_data(clk);
+
+ meson_parm_write(clk->map, &sclk->div, 0);
+}
+
+static int sclk_div_is_enabled(struct clk_hw *hw)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_sclk_div_data *sclk = meson_sclk_div_data(clk);
+
+ if (meson_parm_read(clk->map, &sclk->div))
+ return 1;
+
+ return 0;
+}
+
+static int sclk_div_init(struct clk_hw *hw)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_sclk_div_data *sclk = meson_sclk_div_data(clk);
+ unsigned int val;
+
+ val = meson_parm_read(clk->map, &sclk->div);
+
+ /* if the divider is initially disabled, assume max */
+ if (!val)
+ sclk->cached_div = sclk_div_maxdiv(sclk);
+ else
+ sclk->cached_div = val + 1;
+
+ sclk_div_get_duty_cycle(hw, &sclk->cached_duty);
+
+ return 0;
+}
+
+const struct clk_ops meson_sclk_div_ops = {
+ .recalc_rate = sclk_div_recalc_rate,
+ .round_rate = sclk_div_round_rate,
+ .set_rate = sclk_div_set_rate,
+ .enable = sclk_div_enable,
+ .disable = sclk_div_disable,
+ .is_enabled = sclk_div_is_enabled,
+ .get_duty_cycle = sclk_div_get_duty_cycle,
+ .set_duty_cycle = sclk_div_set_duty_cycle,
+ .init = sclk_div_init,
+};
+EXPORT_SYMBOL_GPL(meson_sclk_div_ops);
+
+MODULE_DESCRIPTION("Amlogic Sample divider driver");
+MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
+MODULE_LICENSE("GPL v2");