diff options
| -rw-r--r-- | drivers/clk/Makefile | 2 | ||||
| -rw-r--r-- | drivers/clk/clk-gate.c | 148 | ||||
| -rw-r--r-- | include/linux/clk-provider.h | 18 |
3 files changed, 167 insertions, 1 deletions
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index b7fec605c6c..39154eca59c 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile @@ -7,7 +7,7 @@ obj-$(CONFIG_$(SPL_TPL_)CLK) += clk-uclass.o obj-$(CONFIG_$(SPL_TPL_)CLK) += clk_fixed_rate.o obj-$(CONFIG_$(SPL_TPL_)CLK) += clk_fixed_factor.o -obj-$(CONFIG_$(SPL_TPL_)CLK_CCF) += clk.o clk-divider.o clk-mux.o +obj-$(CONFIG_$(SPL_TPL_)CLK_CCF) += clk.o clk-divider.o clk-mux.o clk-gate.o obj-$(CONFIG_$(SPL_TPL_)CLK_CCF) += clk-fixed-factor.o obj-y += analogbits/ diff --git a/drivers/clk/clk-gate.c b/drivers/clk/clk-gate.c new file mode 100644 index 00000000000..a3a1fdd3b2f --- /dev/null +++ b/drivers/clk/clk-gate.c @@ -0,0 +1,148 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com> + * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org> + * Copyright 2019 NXP + * + * Gated clock implementation + */ + +#include <common.h> +#include <asm/io.h> +#include <malloc.h> +#include <clk-uclass.h> +#include <dm/device.h> +#include <linux/clk-provider.h> +#include <clk.h> +#include "clk.h" + +#define UBOOT_DM_CLK_GATE "clk_gate" + +/** + * DOC: basic gatable clock which can gate and ungate it's output + * + * Traits of this clock: + * prepare - clk_(un)prepare only ensures parent is (un)prepared + * enable - clk_enable and clk_disable are functional & control gating + * rate - inherits rate from parent. No clk_set_rate support + * parent - fixed parent. No clk_set_parent support + */ + +/* + * It works on following logic: + * + * For enabling clock, enable = 1 + * set2dis = 1 -> clear bit -> set = 0 + * set2dis = 0 -> set bit -> set = 1 + * + * For disabling clock, enable = 0 + * set2dis = 1 -> set bit -> set = 1 + * set2dis = 0 -> clear bit -> set = 0 + * + * So, result is always: enable xor set2dis. + */ +static void clk_gate_endisable(struct clk *clk, int enable) +{ + struct clk_gate *gate = to_clk_gate(clk_dev_binded(clk) ? + dev_get_clk_ptr(clk->dev) : clk); + int set = gate->flags & CLK_GATE_SET_TO_DISABLE ? 1 : 0; + u32 reg; + + set ^= enable; + + if (gate->flags & CLK_GATE_HIWORD_MASK) { + reg = BIT(gate->bit_idx + 16); + if (set) + reg |= BIT(gate->bit_idx); + } else { + reg = readl(gate->reg); + + if (set) + reg |= BIT(gate->bit_idx); + else + reg &= ~BIT(gate->bit_idx); + } + + writel(reg, gate->reg); +} + +static int clk_gate_enable(struct clk *clk) +{ + clk_gate_endisable(clk, 1); + + return 0; +} + +static int clk_gate_disable(struct clk *clk) +{ + clk_gate_endisable(clk, 0); + + return 0; +} + +int clk_gate_is_enabled(struct clk *clk) +{ + struct clk_gate *gate = to_clk_gate(clk_dev_binded(clk) ? + dev_get_clk_ptr(clk->dev) : clk); + u32 reg; + + reg = readl(gate->reg); + + /* if a set bit disables this clk, flip it before masking */ + if (gate->flags & CLK_GATE_SET_TO_DISABLE) + reg ^= BIT(gate->bit_idx); + + reg &= BIT(gate->bit_idx); + + return reg ? 1 : 0; +} + +const struct clk_ops clk_gate_ops = { + .enable = clk_gate_enable, + .disable = clk_gate_disable, + .get_rate = clk_generic_get_rate, +}; + +struct clk *clk_register_gate(struct device *dev, const char *name, + const char *parent_name, unsigned long flags, + void __iomem *reg, u8 bit_idx, + u8 clk_gate_flags, spinlock_t *lock) +{ + struct clk_gate *gate; + struct clk *clk; + int ret; + + if (clk_gate_flags & CLK_GATE_HIWORD_MASK) { + if (bit_idx > 15) { + pr_err("gate bit exceeds LOWORD field\n"); + return ERR_PTR(-EINVAL); + } + } + + /* allocate the gate */ + gate = kzalloc(sizeof(*gate), GFP_KERNEL); + if (!gate) + return ERR_PTR(-ENOMEM); + + /* struct clk_gate assignments */ + gate->reg = reg; + gate->bit_idx = bit_idx; + gate->flags = clk_gate_flags; + + clk = &gate->clk; + + ret = clk_register(clk, UBOOT_DM_CLK_GATE, name, parent_name); + if (ret) { + kfree(gate); + return ERR_PTR(ret); + } + + return clk; +} + +U_BOOT_DRIVER(clk_gate) = { + .name = UBOOT_DM_CLK_GATE, + .id = UCLASS_CLK, + .ops = &clk_gate_ops, + .flags = DM_FLAG_PRE_RELOC, +}; diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h index 6d62f862d2a..8b04ecd7a5c 100644 --- a/include/linux/clk-provider.h +++ b/include/linux/clk-provider.h @@ -69,6 +69,24 @@ struct clk_mux { extern const struct clk_ops clk_mux_ops; u8 clk_mux_get_parent(struct clk *clk); +struct clk_gate { + struct clk clk; + void __iomem *reg; + u8 bit_idx; + u8 flags; +}; + +#define to_clk_gate(_clk) container_of(_clk, struct clk_gate, clk) + +#define CLK_GATE_SET_TO_DISABLE BIT(0) +#define CLK_GATE_HIWORD_MASK BIT(1) + +extern const struct clk_ops clk_gate_ops; +struct clk *clk_register_gate(struct device *dev, const char *name, + const char *parent_name, unsigned long flags, + void __iomem *reg, u8 bit_idx, + u8 clk_gate_flags, spinlock_t *lock); + struct clk_div_table { unsigned int val; unsigned int div; |