[PATCH v2 03/15] clk: sunxi-ng: Add fractional lib

Maxime Ripard
2016-06-07T20:41:42Z

Some clocks can be switched to a mode called fractional that have two fixed
output rate you can choose from.

Add a small library to deal with those clocks.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
---
drivers/clk/sunxi-ng/Makefile | 2 +
drivers/clk/sunxi-ng/ccu_frac.c | 110 ++++++++++++++++++++++++++++++++++++++++
drivers/clk/sunxi-ng/ccu_frac.h | 53 +++++++++++++++++++
3 files changed, 165 insertions(+)
create mode 100644 drivers/clk/sunxi-ng/ccu_frac.c
create mode 100644 drivers/clk/sunxi-ng/ccu_frac.h

diff --git a/drivers/clk/sunxi-ng/Makefile b/drivers/clk/sunxi-ng/Makefile
index bd3461b0f38c..4585443b3771 100644
--- a/drivers/clk/sunxi-ng/Makefile
+++ b/drivers/clk/sunxi-ng/Makefile
@@ -1,2 +1,4 @@
obj-y += ccu_common.o
obj-y += ccu_reset.o
+
+obj-y += ccu_frac.o
diff --git a/drivers/clk/sunxi-ng/ccu_frac.c b/drivers/clk/sunxi-ng/ccu_frac.c
new file mode 100644
index 000000000000..5c4b10cd15b5
--- /dev/null
+++ b/drivers/clk/sunxi-ng/ccu_frac.c
@@ -0,0 +1,110 @@
+/*
+ * 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/spinlock.h>
+
+#include "ccu_frac.h"
+
+bool ccu_frac_helper_is_enabled(struct ccu_common *common,
+ struct _ccu_frac *cf)
+{
+ if (!(common->features & CCU_FEATURE_FRACTIONAL))
+ return false;
+
+ return !(readl(common->base + common->reg) & cf->enable);
+}
+
+void ccu_frac_helper_enable(struct ccu_common *common,
+ struct _ccu_frac *cf)
+{
+ unsigned long flags;
+ u32 reg;
+
+ if (!(common->features & CCU_FEATURE_FRACTIONAL))
+ return;
+
+ spin_lock_irqsave(common->lock, flags);
+ reg = readl(common->base + common->reg);
+ writel(reg & ~cf->enable, common->base + common->reg);
+ spin_unlock_irqrestore(common->lock, flags);
+}
+
+void ccu_frac_helper_disable(struct ccu_common *common,
+ struct _ccu_frac *cf)
+{
+ unsigned long flags;
+ u32 reg;
+
+ if (!(common->features & CCU_FEATURE_FRACTIONAL))
+ return;
+
+ spin_lock_irqsave(common->lock, flags);
+ reg = readl(common->base + common->reg);
+ writel(reg | cf->enable, common->base + common->reg);
+ spin_unlock_irqrestore(common->lock, flags);
+}
+
+bool ccu_frac_helper_has_rate(struct ccu_common *common,
+ struct _ccu_frac *cf,
+ unsigned long rate)
+{
+ if (!(common->features & CCU_FEATURE_FRACTIONAL))
+ return false;
+
+ return (cf->rates[0] == rate) || (cf->rates[1] == rate);
+}
+
+unsigned long ccu_frac_helper_read_rate(struct ccu_common *common,
+ struct _ccu_frac *cf)
+{
+ u32 reg;
+
+ printk("%s: Read fractional\n", clk_hw_get_name(&common->hw));
+
+ if (!(common->features & CCU_FEATURE_FRACTIONAL))
+ return 0;
+
+ printk("%s: clock is fractional (rates %lu and %lu)\n",
+ clk_hw_get_name(&common->hw), cf->rates[0], cf->rates[1]);
+
+ reg = readl(common->base + common->reg);
+
+ printk("%s: clock reg is 0x%x (select is 0x%x)\n",
+ clk_hw_get_name(&common->hw), reg, cf->select);
+
+ return (reg & cf->select) ? cf->rates[1] : cf->rates[0];
+}
+
+int ccu_frac_helper_set_rate(struct ccu_common *common,
+ struct _ccu_frac *cf,
+ unsigned long rate)
+{
+ unsigned long flags;
+ u32 reg, sel;
+
+ if (!(common->features & CCU_FEATURE_FRACTIONAL))
+ return -EINVAL;
+
+ if (cf->rates[0] == rate)
+ sel = 0;
+ else if (cf->rates[1] == rate)
+ sel = cf->select;
+ else
+ return -EINVAL;
+
+ spin_lock_irqsave(common->lock, flags);
+ reg = readl(common->base + common->reg);
+ reg &= ~cf->select;
+ writel(reg | sel, common->base + common->reg);
+ spin_unlock_irqrestore(common->lock, flags);
+
+ return 0;
+}
diff --git a/drivers/clk/sunxi-ng/ccu_frac.h b/drivers/clk/sunxi-ng/ccu_frac.h
new file mode 100644
index 000000000000..e4c670b1cdfe
--- /dev/null
+++ b/drivers/clk/sunxi-ng/ccu_frac.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2016 Maxime Ripard. All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _CCU_FRAC_H_
+#define _CCU_FRAC_H_
+
+#include <linux/clk-provider.h>
+
+#include "ccu_common.h"
+
+struct _ccu_frac {
+ u32 enable;
+ u32 select;
+
+ unsigned long rates[2];
+};
+
+#define _SUNXI_CCU_FRAC(_enable, _select, _rate1, _rate2) \
+ { \
+ .enable = _enable, \
+ .select = _select, \
+ .rates = { _rate1, _rate2 }, \
+ }
+
+bool ccu_frac_helper_is_enabled(struct ccu_common *common,
+ struct _ccu_frac *cf);
+void ccu_frac_helper_enable(struct ccu_common *common,
+ struct _ccu_frac *cf);
+void ccu_frac_helper_disable(struct ccu_common *common,
+ struct _ccu_frac *cf);
+
+bool ccu_frac_helper_has_rate(struct ccu_common *common,
+ struct _ccu_frac *cf,
+ unsigned long rate);
+
+unsigned long ccu_frac_helper_read_rate(struct ccu_common *common,
+ struct _ccu_frac *cf);
+
+int ccu_frac_helper_set_rate(struct ccu_common *common,
+ struct _ccu_frac *cf,
+ unsigned long rate);
+
+#endif /* _CCU_FRAC_H_ */
--
2.8.3