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author | Shawn Guo <shawn.guo@freescale.com> | 2014-08-26 15:06:33 +0800 |
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committer | Shawn Guo <shawn.guo@freescale.com> | 2014-09-16 10:06:48 +0800 |
commit | 19d863446a6b75b2f97b3012acf67c40b9f2ea1f (patch) | |
tree | 2e5c01c62795c0e0a2d33ba5f2f2bb0f00a2b43d /arch/arm/mach-imx/clk-gate-exclusive.c | |
parent | bd404b1d337b960c44b75fcb01e3170f1d41ae80 (diff) | |
download | op-kernel-dev-19d863446a6b75b2f97b3012acf67c40b9f2ea1f.zip op-kernel-dev-19d863446a6b75b2f97b3012acf67c40b9f2ea1f.tar.gz |
ARM: imx: add an exclusive gate clock type
There are a couple of gate clocks are mutually exclusive on i.MX6, i.e.
LVDSCLK1_IBEN and LVDSCLK1_OBEN. They cannot be enabled simultaneously.
This patches adds an exclusive gate clock type specifically for such
case. The clock driver will need to call imx_clk_gate_exclusive() to
register a gate clock with parameter exclusive_mask indicating the mask
of gate bits which are mutually exclusive to this gate clock.
Right now, it only handles the exclusive gate clocks which are defined
in a single hardware register, which is the case we're running into
today. But it can be extended to handle exclusive gate clocks defined
in different registers later if needed.
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
Diffstat (limited to 'arch/arm/mach-imx/clk-gate-exclusive.c')
-rw-r--r-- | arch/arm/mach-imx/clk-gate-exclusive.c | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/arch/arm/mach-imx/clk-gate-exclusive.c b/arch/arm/mach-imx/clk-gate-exclusive.c new file mode 100644 index 0000000..c12f5f2 --- /dev/null +++ b/arch/arm/mach-imx/clk-gate-exclusive.c @@ -0,0 +1,94 @@ +/* + * Copyright 2014 Freescale Semiconductor, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/clk-provider.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/slab.h> +#include "clk.h" + +/** + * struct clk_gate_exclusive - i.MX specific gate clock which is mutually + * exclusive with other gate clocks + * + * @gate: the parent class + * @exclusive_mask: mask of gate bits which are mutually exclusive to this + * gate clock + * + * The imx exclusive gate clock is a subclass of basic clk_gate + * with an addtional mask to indicate which other gate bits in the same + * register is mutually exclusive to this gate clock. + */ +struct clk_gate_exclusive { + struct clk_gate gate; + u32 exclusive_mask; +}; + +static int clk_gate_exclusive_enable(struct clk_hw *hw) +{ + struct clk_gate *gate = container_of(hw, struct clk_gate, hw); + struct clk_gate_exclusive *exgate = container_of(gate, + struct clk_gate_exclusive, gate); + u32 val = readl(gate->reg); + + if (val & exgate->exclusive_mask) + return -EBUSY; + + return clk_gate_ops.enable(hw); +} + +static void clk_gate_exclusive_disable(struct clk_hw *hw) +{ + clk_gate_ops.disable(hw); +} + +static int clk_gate_exclusive_is_enabled(struct clk_hw *hw) +{ + return clk_gate_ops.is_enabled(hw); +} + +static const struct clk_ops clk_gate_exclusive_ops = { + .enable = clk_gate_exclusive_enable, + .disable = clk_gate_exclusive_disable, + .is_enabled = clk_gate_exclusive_is_enabled, +}; + +struct clk *imx_clk_gate_exclusive(const char *name, const char *parent, + void __iomem *reg, u8 shift, u32 exclusive_mask) +{ + struct clk_gate_exclusive *exgate; + struct clk_gate *gate; + struct clk *clk; + struct clk_init_data init; + + if (exclusive_mask == 0) + return ERR_PTR(-EINVAL); + + exgate = kzalloc(sizeof(*exgate), GFP_KERNEL); + if (!exgate) + return ERR_PTR(-ENOMEM); + gate = &exgate->gate; + + init.name = name; + init.ops = &clk_gate_exclusive_ops; + init.flags = CLK_SET_RATE_PARENT; + init.parent_names = parent ? &parent : NULL; + init.num_parents = parent ? 1 : 0; + + gate->reg = reg; + gate->bit_idx = shift; + gate->lock = &imx_ccm_lock; + gate->hw.init = &init; + exgate->exclusive_mask = exclusive_mask; + + clk = clk_register(NULL, &gate->hw); + if (IS_ERR(clk)) + kfree(exgate); + + return clk; +} |