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gerrit.devboardsforandroid.linaro.org / platform / external / u-boot / 47b1cbaf02a3960f4eb5b0e3b71a963d5b6e13df / . / drivers / power / regulator / stm32-vrefbuf.c
blob: 0ad6833ed0413d68a38e287e702e74ec2350425a [file] [log] [blame]
Fabrice Gasnier93cf0ae2018-04-26 17:00:46 +0200[diff] [blame]1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2018, STMicroelectronics - All Rights Reserved
4 * Author: Fabrice Gasnier <fabrice.gasnier@st.com>
5 *
6 * Originally based on the Linux kernel v4.16 drivers/regulator/stm32-vrefbuf.c
7 */
8
9#include <common.h>
10#include <clk.h>
11#include <dm.h>
12#include <asm/io.h>
13#include <linux/iopoll.h>
14#include <linux/kernel.h>
15#include <power/regulator.h>
16
17/* STM32 VREFBUF registers */
18#define STM32_VREFBUF_CSR 0x00
19
20/* STM32 VREFBUF CSR bitfields */
21#define STM32_VRS GENMASK(6, 4)
22#define STM32_VRS_SHIFT 4
23#define STM32_VRR BIT(3)
24#define STM32_HIZ BIT(1)
25#define STM32_ENVR BIT(0)
26
27struct stm32_vrefbuf {
28 void __iomem *base;
29 struct clk clk;
30 struct udevice *vdda_supply;
31};
32
33static const unsigned int stm32_vrefbuf_voltages[] = {
34 /* Matches resp. VRS = 000b, 001b, 010b, 011b */
35 2500000, 2048000, 1800000, 1500000,
36};
37
38static int stm32_vrefbuf_set_enable(struct udevice *dev, bool enable)
39{
40 struct stm32_vrefbuf *priv = dev_get_priv(dev);
41 u32 val;
42 int ret;
43
44 clrsetbits_le32(priv->base + STM32_VREFBUF_CSR, STM32_HIZ | STM32_ENVR,
45 enable ? STM32_ENVR : STM32_HIZ);
46 if (!enable)
47 return 0;
48
49 /*
50 * Vrefbuf startup time depends on external capacitor: wait here for
51 * VRR to be set. That means output has reached expected value.
52 * ~650us sleep should be enough for caps up to 1.5uF. Use 10ms as
53 * arbitrary timeout.
54 */
55 ret = readl_poll_timeout(priv->base + STM32_VREFBUF_CSR, val,
56 val & STM32_VRR, 10000);
57 if (ret < 0) {
58 dev_err(dev, "stm32 vrefbuf timed out: %d\n", ret);
59 clrsetbits_le32(priv->base + STM32_VREFBUF_CSR, STM32_ENVR,
60 STM32_HIZ);
61 return ret;
62 }
63
64 return 0;
65}
66
67static int stm32_vrefbuf_get_enable(struct udevice *dev)
68{
69 struct stm32_vrefbuf *priv = dev_get_priv(dev);
70
71 return readl(priv->base + STM32_VREFBUF_CSR) & STM32_ENVR;
72}
73
74static int stm32_vrefbuf_set_value(struct udevice *dev, int uV)
75{
76 struct stm32_vrefbuf *priv = dev_get_priv(dev);
77 unsigned int i;
78
79 for (i = 0; i < ARRAY_SIZE(stm32_vrefbuf_voltages); i++) {
80 if (uV == stm32_vrefbuf_voltages[i]) {
81 clrsetbits_le32(priv->base + STM32_VREFBUF_CSR,
82 STM32_VRS, i << STM32_VRS_SHIFT);
83 return 0;
84 }
85 }
86
87 return -EINVAL;
88}
89
90static int stm32_vrefbuf_get_value(struct udevice *dev)
91{
92 struct stm32_vrefbuf *priv = dev_get_priv(dev);
93 u32 val;
94
95 val = readl(priv->base + STM32_VREFBUF_CSR) & STM32_VRS;
96 val >>= STM32_VRS_SHIFT;
97
98 return stm32_vrefbuf_voltages[val];
99}
100
101static const struct dm_regulator_ops stm32_vrefbuf_ops = {
102 .get_value = stm32_vrefbuf_get_value,
103 .set_value = stm32_vrefbuf_set_value,
104 .get_enable = stm32_vrefbuf_get_enable,
105 .set_enable = stm32_vrefbuf_set_enable,
106};
107
108static int stm32_vrefbuf_probe(struct udevice *dev)
109{
110 struct stm32_vrefbuf *priv = dev_get_priv(dev);
111 int ret;
112
113 priv->base = dev_read_addr_ptr(dev);
114
115 ret = clk_get_by_index(dev, 0, &priv->clk);
116 if (ret) {
117 dev_err(dev, "Can't get clock: %d\n", ret);
118 return ret;
119 }
120
121 ret = clk_enable(&priv->clk);
122 if (ret) {
123 dev_err(dev, "Can't enable clock: %d\n", ret);
124 return ret;
125 }
126
127 ret = device_get_supply_regulator(dev, "vdda-supply",
128 &priv->vdda_supply);
129 if (ret) {
130 dev_dbg(dev, "No vdda-supply: %d\n", ret);
131 return 0;
132 }
133
134 ret = regulator_set_enable(priv->vdda_supply, true);
135 if (ret) {
136 dev_err(dev, "Can't enable vdda-supply: %d\n", ret);
137 clk_disable(&priv->clk);
138 }
139
140 return ret;
141}
142
143static const struct udevice_id stm32_vrefbuf_ids[] = {
144 { .compatible = "st,stm32-vrefbuf" },
145 { }
146};
147
148U_BOOT_DRIVER(stm32_vrefbuf) = {
149 .name = "stm32-vrefbuf",
150 .id = UCLASS_REGULATOR,
151 .of_match = stm32_vrefbuf_ids,
152 .probe = stm32_vrefbuf_probe,
153 .ops = &stm32_vrefbuf_ops,
154 .priv_auto_alloc_size = sizeof(struct stm32_vrefbuf),
155};