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authorChao Xie <chao.xie@marvell.com>2014-10-31 10:13:48 +0800
committerMichael Turquette <mturquette@linaro.org>2014-11-12 16:34:10 -0800
commitae32a5b321c8484294d129e7980f8fcf35aa42af (patch)
tree65e22e25fb37606baecdb530d6005d5ab6b19332 /drivers/clk/mmp
parent4661fda10f8bd57fceef8349d10900e165a0a548 (diff)
clk: mmp: add reset support
Some clock control regsiter has bit to reset the cotroller. So before enable the clock, we need deassert the reset pin. Make use of reset controller framework to export reset interface for device drivers, then device driver can control the reset action. Signed-off-by: Chao Xie <chao.xie@marvell.com> Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> Signed-off-by: Michael Turquette <mturquette@linaro.org>
Diffstat (limited to 'drivers/clk/mmp')
-rw-r--r--drivers/clk/mmp/Makefile2
-rw-r--r--drivers/clk/mmp/reset.c99
-rw-r--r--drivers/clk/mmp/reset.h31
3 files changed, 132 insertions, 0 deletions
diff --git a/drivers/clk/mmp/Makefile b/drivers/clk/mmp/Makefile
index 32b5b90c9fa9..2573d7c6198e 100644
--- a/drivers/clk/mmp/Makefile
+++ b/drivers/clk/mmp/Makefile
@@ -4,6 +4,8 @@
obj-y += clk-apbc.o clk-apmu.o clk-frac.o clk-mix.o clk-gate.o clk.o
+obj-$(CONFIG_RESET_CONTROLLER) += reset.o
+
obj-$(CONFIG_CPU_PXA168) += clk-pxa168.o
obj-$(CONFIG_CPU_PXA910) += clk-pxa910.o
obj-$(CONFIG_CPU_MMP2) += clk-mmp2.o
diff --git a/drivers/clk/mmp/reset.c b/drivers/clk/mmp/reset.c
new file mode 100644
index 000000000000..b54da1fe73f0
--- /dev/null
+++ b/drivers/clk/mmp/reset.c
@@ -0,0 +1,99 @@
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/reset-controller.h>
+
+#include "reset.h"
+
+#define rcdev_to_unit(rcdev) container_of(rcdev, struct mmp_clk_reset_unit, rcdev)
+
+static int mmp_of_reset_xlate(struct reset_controller_dev *rcdev,
+ const struct of_phandle_args *reset_spec)
+{
+ struct mmp_clk_reset_unit *unit = rcdev_to_unit(rcdev);
+ struct mmp_clk_reset_cell *cell;
+ int i;
+
+ if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells))
+ return -EINVAL;
+
+ for (i = 0; i < rcdev->nr_resets; i++) {
+ cell = &unit->cells[i];
+ if (cell->clk_id == reset_spec->args[0])
+ break;
+ }
+
+ if (i == rcdev->nr_resets)
+ return -EINVAL;
+
+ return i;
+}
+
+static int mmp_clk_reset_assert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct mmp_clk_reset_unit *unit = rcdev_to_unit(rcdev);
+ struct mmp_clk_reset_cell *cell;
+ unsigned long flags = 0;
+ u32 val;
+
+ cell = &unit->cells[id];
+ if (cell->lock)
+ spin_lock_irqsave(cell->lock, flags);
+
+ val = readl(cell->reg);
+ val |= cell->bits;
+ writel(val, cell->reg);
+
+ if (cell->lock)
+ spin_unlock_irqrestore(cell->lock, flags);
+
+ return 0;
+}
+
+static int mmp_clk_reset_deassert(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ struct mmp_clk_reset_unit *unit = rcdev_to_unit(rcdev);
+ struct mmp_clk_reset_cell *cell;
+ unsigned long flags = 0;
+ u32 val;
+
+ cell = &unit->cells[id];
+ if (cell->lock)
+ spin_lock_irqsave(cell->lock, flags);
+
+ val = readl(cell->reg);
+ val &= ~cell->bits;
+ writel(val, cell->reg);
+
+ if (cell->lock)
+ spin_unlock_irqrestore(cell->lock, flags);
+
+ return 0;
+}
+
+static struct reset_control_ops mmp_clk_reset_ops = {
+ .assert = mmp_clk_reset_assert,
+ .deassert = mmp_clk_reset_deassert,
+};
+
+void mmp_clk_reset_register(struct device_node *np,
+ struct mmp_clk_reset_cell *cells, int nr_resets)
+{
+ struct mmp_clk_reset_unit *unit;
+
+ unit = kzalloc(sizeof(*unit), GFP_KERNEL);
+ if (!unit)
+ return;
+
+ unit->cells = cells;
+ unit->rcdev.of_reset_n_cells = 1;
+ unit->rcdev.nr_resets = nr_resets;
+ unit->rcdev.ops = &mmp_clk_reset_ops;
+ unit->rcdev.of_node = np;
+ unit->rcdev.of_xlate = mmp_of_reset_xlate;
+
+ reset_controller_register(&unit->rcdev);
+}
diff --git a/drivers/clk/mmp/reset.h b/drivers/clk/mmp/reset.h
new file mode 100644
index 000000000000..be8b1a7000f7
--- /dev/null
+++ b/drivers/clk/mmp/reset.h
@@ -0,0 +1,31 @@
+#ifndef __MACH_MMP_CLK_RESET_H
+#define __MACH_MMP_CLK_RESET_H
+
+#include <linux/reset-controller.h>
+
+#define MMP_RESET_INVERT 1
+
+struct mmp_clk_reset_cell {
+ unsigned int clk_id;
+ void __iomem *reg;
+ u32 bits;
+ unsigned int flags;
+ spinlock_t *lock;
+};
+
+struct mmp_clk_reset_unit {
+ struct reset_controller_dev rcdev;
+ struct mmp_clk_reset_cell *cells;
+};
+
+#ifdef CONFIG_RESET_CONTROLLER
+void mmp_clk_reset_register(struct device_node *np,
+ struct mmp_clk_reset_cell *cells, int nr_resets);
+#else
+static inline void mmp_clk_reset_register(struct device_node *np,
+ struct mmp_clk_reset_cell *cells, int nr_resets)
+{
+}
+#endif
+
+#endif