1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * TI gate clock support
4 *
5 * Copyright (C) 2020 Dario Binacchi <dariobin@libero.it>
6 *
7 * Loosely based on Linux kernel drivers/clk/ti/gate.c
8 */
9
10 #include <common.h>
11 #include <dm.h>
12 #include <dm/device_compat.h>
13 #include <clk-uclass.h>
14 #include <asm/io.h>
15 #include <linux/clk-provider.h>
16 #include "clk.h"
17
18 struct clk_ti_gate_priv {
19 struct clk_ti_reg reg;
20 u8 enable_bit;
21 u32 flags;
22 bool invert_enable;
23 };
24
clk_ti_gate_disable(struct clk * clk)25 static int clk_ti_gate_disable(struct clk *clk)
26 {
27 struct clk_ti_gate_priv *priv = dev_get_priv(clk->dev);
28 u32 v;
29
30 v = clk_ti_readl(&priv->reg);
31 if (priv->invert_enable)
32 v |= (1 << priv->enable_bit);
33 else
34 v &= ~(1 << priv->enable_bit);
35
36 clk_ti_writel(v, &priv->reg);
37 /* No OCP barrier needed here since it is a disable operation */
38 return 0;
39 }
40
clk_ti_gate_enable(struct clk * clk)41 static int clk_ti_gate_enable(struct clk *clk)
42 {
43 struct clk_ti_gate_priv *priv = dev_get_priv(clk->dev);
44 u32 v;
45
46 v = clk_ti_readl(&priv->reg);
47 if (priv->invert_enable)
48 v &= ~(1 << priv->enable_bit);
49 else
50 v |= (1 << priv->enable_bit);
51
52 clk_ti_writel(v, &priv->reg);
53 /* OCP barrier */
54 v = clk_ti_readl(&priv->reg);
55 return 0;
56 }
57
clk_ti_gate_of_to_plat(struct udevice * dev)58 static int clk_ti_gate_of_to_plat(struct udevice *dev)
59 {
60 struct clk_ti_gate_priv *priv = dev_get_priv(dev);
61 int err;
62
63 err = clk_ti_get_reg_addr(dev, 0, &priv->reg);
64 if (err) {
65 dev_err(dev, "failed to get control register address\n");
66 return err;
67 }
68
69 priv->enable_bit = dev_read_u32_default(dev, "ti,bit-shift", 0);
70 if (dev_read_bool(dev, "ti,set-rate-parent"))
71 priv->flags |= CLK_SET_RATE_PARENT;
72
73 priv->invert_enable = dev_read_bool(dev, "ti,set-bit-to-disable");
74 return 0;
75 }
76
77 static struct clk_ops clk_ti_gate_ops = {
78 .enable = clk_ti_gate_enable,
79 .disable = clk_ti_gate_disable,
80 };
81
82 static const struct udevice_id clk_ti_gate_of_match[] = {
83 { .compatible = "ti,gate-clock" },
84 { },
85 };
86
87 U_BOOT_DRIVER(clk_ti_gate) = {
88 .name = "ti_gate_clock",
89 .id = UCLASS_CLK,
90 .of_match = clk_ti_gate_of_match,
91 .of_to_plat = clk_ti_gate_of_to_plat,
92 .priv_auto = sizeof(struct clk_ti_gate_priv),
93 .ops = &clk_ti_gate_ops,
94 };
95