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Date: Tue, 4 Dec 2018 17:53:08 +0100
From: Jerome Brunet <jbrunet@...libre.com>
To: Neil Armstrong <narmstrong@...libre.com>,
Kevin Hilman <khilman@...libre.com>,
Carlo Caione <carlo@...one.org>
Cc: Jerome Brunet <jbrunet@...libre.com>, linux-clk@...r.kernel.org,
linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org,
devicetree@...r.kernel.org
Subject: [PATCH 3/5] clk: meson: add dual divider clock driver
Add the dual divider driver. This special divider make a weighted
average between 2 dividers to reach fractional divider values.
Signed-off-by: Jerome Brunet <jbrunet@...libre.com>
---
drivers/clk/meson/Makefile | 1 +
drivers/clk/meson/clk-dualdiv.c | 130 ++++++++++++++++++++++++++++++++
drivers/clk/meson/clkc.h | 19 +++++
3 files changed, 150 insertions(+)
create mode 100644 drivers/clk/meson/clk-dualdiv.c
diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
index 0234767f6cfc..ae3fa2a127d5 100644
--- a/drivers/clk/meson/Makefile
+++ b/drivers/clk/meson/Makefile
@@ -3,6 +3,7 @@
#
obj-$(CONFIG_COMMON_CLK_AMLOGIC) += clk-pll.o clk-mpll.o clk-phase.o vid-pll-div.o
+obj-$(CONFIG_COMMON_CLK_AMLOGIC) += clk-dualdiv.o
obj-$(CONFIG_COMMON_CLK_AMLOGIC_AUDIO) += clk-triphase.o sclk-div.o
obj-$(CONFIG_COMMON_CLK_MESON_AO) += meson-aoclk.o
obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o
diff --git a/drivers/clk/meson/clk-dualdiv.c b/drivers/clk/meson/clk-dualdiv.c
new file mode 100644
index 000000000000..4d9e161de627
--- /dev/null
+++ b/drivers/clk/meson/clk-dualdiv.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2017 BayLibre, SAS
+ * Author: Neil Armstrong <narmstrong@...libre.com>
+ * Author: Jerome Brunet <jbrunet@...libre.com>
+ */
+
+/*
+ * The AO Domain embeds a dual/divider to generate a more precise
+ * 32,768KHz clock for low-power suspend mode and CEC.
+ * ______ ______
+ * | | | |
+ * | Div1 |-| Cnt1 |
+ * /|______| |______|\
+ * -| ______ ______ X--> Out
+ * \| | | |/
+ * | Div2 |-| Cnt2 |
+ * |______| |______|
+ *
+ * The dividing can be switched to single or dual, with a counter
+ * for each divider to set when the switching is done.
+ */
+
+#include <linux/clk-provider.h>
+#include "clkc.h"
+
+static inline struct meson_clk_dualdiv_data *
+meson_clk_dualdiv_data(struct clk_regmap *clk)
+{
+ return (struct meson_clk_dualdiv_data *)clk->data;
+}
+
+static unsigned long
+__dualdiv_param_to_rate(unsigned long parent_rate,
+ const struct meson_clk_dualdiv_param *p)
+{
+ if (!p->dual)
+ return DIV_ROUND_CLOSEST(parent_rate, p->n1);
+
+ return DIV_ROUND_CLOSEST(parent_rate * (p->m1 + p->m2),
+ p->n1 * p->m1 + p->n2 * p->m2);
+}
+
+static unsigned long meson_clk_dualdiv_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_clk_dualdiv_data *dualdiv = meson_clk_dualdiv_data(clk);
+ struct meson_clk_dualdiv_param setting;
+
+ setting.dual = meson_parm_read(clk->map, &dualdiv->dual);
+ setting.n1 = meson_parm_read(clk->map, &dualdiv->n1) + 1;
+ setting.m1 = meson_parm_read(clk->map, &dualdiv->m1) + 1;
+ setting.n2 = meson_parm_read(clk->map, &dualdiv->n2) + 1;
+ setting.m2 = meson_parm_read(clk->map, &dualdiv->m2) + 1;
+
+ return __dualdiv_param_to_rate(parent_rate, &setting);
+}
+
+static const struct meson_clk_dualdiv_param *
+__dualdiv_get_setting(unsigned long rate, unsigned long parent_rate,
+ struct meson_clk_dualdiv_data *dualdiv)
+{
+ const struct meson_clk_dualdiv_param *table = dualdiv->table;
+ unsigned long best = 0, now = 0;
+ unsigned int i, best_i = 0;
+
+ if (!table)
+ return NULL;
+
+ for (i = 0; table[i].n1; i++) {
+ now = __dualdiv_param_to_rate(parent_rate, &table[i]);
+
+ /* If we get an exact match, don't bother any further */
+ if (now == rate) {
+ return &table[i];
+ } else if (abs(now - rate) < abs(best - rate)) {
+ best = now;
+ best_i = i;
+ }
+ }
+
+ return (struct meson_clk_dualdiv_param *)&table[best_i];
+}
+
+static long meson_clk_dualdiv_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *parent_rate)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_clk_dualdiv_data *dualdiv = meson_clk_dualdiv_data(clk);
+ const struct meson_clk_dualdiv_param *setting =
+ __dualdiv_get_setting(rate, *parent_rate, dualdiv);
+
+ if (!setting)
+ return meson_clk_dualdiv_recalc_rate(hw, *parent_rate);
+
+ return __dualdiv_param_to_rate(*parent_rate, setting);
+}
+
+static int meson_clk_dualdiv_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ struct clk_regmap *clk = to_clk_regmap(hw);
+ struct meson_clk_dualdiv_data *dualdiv = meson_clk_dualdiv_data(clk);
+ const struct meson_clk_dualdiv_param *setting =
+ __dualdiv_get_setting(rate, parent_rate, dualdiv);
+
+ if (!setting)
+ return -EINVAL;
+
+ meson_parm_write(clk->map, &dualdiv->dual, setting->dual);
+ meson_parm_write(clk->map, &dualdiv->n1, setting->n1 - 1);
+ meson_parm_write(clk->map, &dualdiv->m1, setting->m1 - 1);
+ meson_parm_write(clk->map, &dualdiv->n2, setting->n2 - 1);
+ meson_parm_write(clk->map, &dualdiv->m2, setting->m2 - 1);
+
+ return 0;
+}
+
+const struct clk_ops meson_clk_dualdiv_ops = {
+ .recalc_rate = meson_clk_dualdiv_recalc_rate,
+ .round_rate = meson_clk_dualdiv_round_rate,
+ .set_rate = meson_clk_dualdiv_set_rate,
+};
+EXPORT_SYMBOL_GPL(meson_clk_dualdiv_ops);
+
+const struct clk_ops meson_clk_dualdiv_ro_ops = {
+ .recalc_rate = meson_clk_dualdiv_recalc_rate,
+};
+EXPORT_SYMBOL_GPL(meson_clk_dualdiv_ro_ops);
diff --git a/drivers/clk/meson/clkc.h b/drivers/clk/meson/clkc.h
index 91666055c75a..1efa6be9cfe4 100644
--- a/drivers/clk/meson/clkc.h
+++ b/drivers/clk/meson/clkc.h
@@ -110,6 +110,23 @@ struct clk_regmap _name = { \
}, \
};
+struct meson_clk_dualdiv_param {
+ unsigned int n1;
+ unsigned int n2;
+ unsigned int m1;
+ unsigned int m2;
+ unsigned int dual;
+};
+
+struct meson_clk_dualdiv_data {
+ struct parm n1;
+ struct parm n2;
+ struct parm m1;
+ struct parm m2;
+ struct parm dual;
+ const struct meson_clk_dualdiv_param *table;
+};
+
/* clk_ops */
extern const struct clk_ops meson_clk_pll_ro_ops;
extern const struct clk_ops meson_clk_pll_ops;
@@ -118,5 +135,7 @@ extern const struct clk_ops meson_clk_mpll_ro_ops;
extern const struct clk_ops meson_clk_mpll_ops;
extern const struct clk_ops meson_clk_phase_ops;
extern const struct clk_ops meson_vid_pll_div_ro_ops;
+extern const struct clk_ops meson_clk_dualdiv_ops;
+extern const struct clk_ops meson_clk_dualdiv_ro_ops;
#endif /* __CLKC_H */
--
2.19.1
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