1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (C) 2018, STMicroelectronics - All Rights Reserved
4 * Author(s): Patrice Chotard, <patrice.chotard@st.com> for STMicroelectronics.
5 */
6
7 #include <common.h>
8 #include <clk.h>
9 #include <dm.h>
10 #include <fdtdec.h>
11 #include <timer.h>
12
13 #include <asm/io.h>
14
15 /* Timer control1 register */
16 #define CR1_CEN BIT(0)
17 #define CR1_ARPE BIT(7)
18
19 /* Event Generation Register register */
20 #define EGR_UG BIT(0)
21
22 /* Auto reload register for free running config */
23 #define GPT_FREE_RUNNING 0xFFFFFFFF
24
25 struct stm32_timer_regs {
26 u32 cr1;
27 u32 cr2;
28 u32 smcr;
29 u32 dier;
30 u32 sr;
31 u32 egr;
32 u32 ccmr1;
33 u32 ccmr2;
34 u32 ccer;
35 u32 cnt;
36 u32 psc;
37 u32 arr;
38 u32 reserved;
39 u32 ccr1;
40 u32 ccr2;
41 u32 ccr3;
42 u32 ccr4;
43 u32 reserved1;
44 u32 dcr;
45 u32 dmar;
46 u32 tim2_5_or;
47 };
48
49 struct stm32_timer_priv {
50 struct stm32_timer_regs *base;
51 };
52
stm32_timer_get_count(struct udevice * dev,u64 * count)53 static int stm32_timer_get_count(struct udevice *dev, u64 *count)
54 {
55 struct stm32_timer_priv *priv = dev_get_priv(dev);
56 struct stm32_timer_regs *regs = priv->base;
57
58 *count = readl(®s->cnt);
59
60 return 0;
61 }
62
stm32_timer_probe(struct udevice * dev)63 static int stm32_timer_probe(struct udevice *dev)
64 {
65 struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
66 struct stm32_timer_priv *priv = dev_get_priv(dev);
67 struct stm32_timer_regs *regs;
68 struct clk clk;
69 fdt_addr_t addr;
70 int ret;
71 u32 rate, psc;
72
73 addr = dev_read_addr(dev);
74 if (addr == FDT_ADDR_T_NONE)
75 return -EINVAL;
76
77 priv->base = (struct stm32_timer_regs *)addr;
78
79 ret = clk_get_by_index(dev, 0, &clk);
80 if (ret < 0)
81 return ret;
82
83 ret = clk_enable(&clk);
84 if (ret) {
85 dev_err(dev, "failed to enable clock\n");
86 return ret;
87 }
88
89 regs = priv->base;
90
91 /* Stop the timer */
92 clrbits_le32(®s->cr1, CR1_CEN);
93
94 /* get timer clock */
95 rate = clk_get_rate(&clk);
96
97 /* we set timer prescaler to obtain a 1MHz timer counter frequency */
98 psc = (rate / CONFIG_SYS_HZ_CLOCK) - 1;
99 writel(psc, ®s->psc);
100
101 /* Set timer frequency to 1MHz */
102 uc_priv->clock_rate = CONFIG_SYS_HZ_CLOCK;
103
104 /* Configure timer for auto-reload */
105 setbits_le32(®s->cr1, CR1_ARPE);
106
107 /* load value for auto reload */
108 writel(GPT_FREE_RUNNING, ®s->arr);
109
110 /* start timer */
111 setbits_le32(®s->cr1, CR1_CEN);
112
113 /* Update generation */
114 setbits_le32(®s->egr, EGR_UG);
115
116 return 0;
117 }
118
119 static const struct timer_ops stm32_timer_ops = {
120 .get_count = stm32_timer_get_count,
121 };
122
123 static const struct udevice_id stm32_timer_ids[] = {
124 { .compatible = "st,stm32-timer" },
125 {}
126 };
127
128 U_BOOT_DRIVER(stm32_timer) = {
129 .name = "stm32_timer",
130 .id = UCLASS_TIMER,
131 .of_match = stm32_timer_ids,
132 .priv_auto_alloc_size = sizeof(struct stm32_timer_priv),
133 .probe = stm32_timer_probe,
134 .ops = &stm32_timer_ops,
135 };
136
137