clk: sunxi-ng: Add fractional lib

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>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>
Link: lkml.kernel.org/r/20160629190535.11855-4-maxime.ripard@free-electrons.com

diff --git a/drivers/clk/sunxi-ng/Kconfig b/drivers/clk/sunxi-ng/Kconfig
index df5b276..3d117d7 100644 (file)
--- a/drivers/clk/sunxi-ng/Kconfig
+++ b/drivers/clk/sunxi-ng/Kconfig
@@ -1,3 +1,12 @@
 config SUNXI_CCU
        bool "Clock support for Allwinner SoCs"
        default ARCH_SUNXI
+
+if SUNXI_CCU
+
+# Base clock types
+
+config SUNXI_CCU_FRAC
+       bool
+
+endif

diff --git a/drivers/clk/sunxi-ng/Makefile b/drivers/clk/sunxi-ng/Makefile
index 886d078..46f417c 100644 (file)
--- a/drivers/clk/sunxi-ng/Makefile
+++ b/drivers/clk/sunxi-ng/Makefile
@@ -1,3 +1,6 @@
 # Common objects
 obj-$(CONFIG_SUNXI_CCU)                += ccu_common.o
 obj-$(CONFIG_SUNXI_CCU)                += ccu_reset.o
+
+# Base clock types
+obj-$(CONFIG_SUNXI_CCU_FRAC)   += 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 (file)
index 0000000..5c4b10c
--- /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 (file)
index 0000000..e4c670b
--- /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_ */