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gerrit.devboardsforandroid.linaro.org / platform / external / u-boot / 54925327fa11779112bfc947a0c0a0f30623bbc6 / . / drivers / adc / exynos-adc.c
blob: 534e68db8b575c7a174bde024c0b1d1d3e94623d [file] [log] [blame]
Przemyslaw Marczak3b3ad902015-10-27 13:08:01 +0100[diff] [blame]1/*
2 * Copyright (C) 2015 Samsung Electronics
3 * Przemyslaw Marczak <p.marczak@samsung.com>
4 *
5 * SPDX-License-Identifier: GPL-2.0+
6 */
7#include <common.h>
8#include <errno.h>
9#include <dm.h>
10#include <adc.h>
11#include <asm/arch/adc.h>
12
13struct exynos_adc_priv {
14 int active_channel;
15 struct exynos_adc_v2 *regs;
16};
17
18int exynos_adc_channel_data(struct udevice *dev, int channel,
19 unsigned int *data)
20{
21 struct exynos_adc_priv *priv = dev_get_priv(dev);
22 struct exynos_adc_v2 *regs = priv->regs;
23
24 if (channel != priv->active_channel) {
25 error("Requested channel is not active!");
26 return -EINVAL;
27 }
28
29 if (ADC_V2_GET_STATUS_FLAG(readl(&regs->status)) != FLAG_CONV_END)
30 return -EBUSY;
31
32 *data = readl(&regs->dat) & ADC_V2_DAT_MASK;
33
34 return 0;
35}
36
37int exynos_adc_start_channel(struct udevice *dev, int channel)
38{
39 struct exynos_adc_priv *priv = dev_get_priv(dev);
40 struct exynos_adc_v2 *regs = priv->regs;
41 unsigned int cfg;
42
43 /* Choose channel */
44 cfg = readl(&regs->con2);
45 cfg &= ~ADC_V2_CON2_CHAN_SEL_MASK;
46 cfg |= ADC_V2_CON2_CHAN_SEL(channel);
47 writel(cfg, &regs->con2);
48
49 /* Start conversion */
50 cfg = readl(&regs->con1);
51 writel(cfg | ADC_V2_CON1_STC_EN, &regs->con1);
52
53 priv->active_channel = channel;
54
55 return 0;
56}
57
58int exynos_adc_stop(struct udevice *dev)
59{
60 struct exynos_adc_priv *priv = dev_get_priv(dev);
61 struct exynos_adc_v2 *regs = priv->regs;
62 unsigned int cfg;
63
64 /* Stop conversion */
65 cfg = readl(&regs->con1);
66 cfg |= ~ADC_V2_CON1_STC_EN;
67
68 writel(cfg, &regs->con1);
69
70 priv->active_channel = -1;
71
72 return 0;
73}
74
75int exynos_adc_probe(struct udevice *dev)
76{
77 struct exynos_adc_priv *priv = dev_get_priv(dev);
78 struct exynos_adc_v2 *regs = priv->regs;
79 unsigned int cfg;
80
81 /* Check HW version */
82 if (readl(&regs->version) != ADC_V2_VERSION) {
83 error("This driver supports only ADC v2!");
84 return -ENXIO;
85 }
86
87 /* ADC Reset */
88 writel(ADC_V2_CON1_SOFT_RESET, &regs->con1);
89
90 /* Disable INT - will read status only */
91 writel(0x0, &regs->int_en);
92
93 /* CON2 - set conversion parameters */
94 cfg = ADC_V2_CON2_C_TIME(3); /* Conversion times: (1 << 3) = 8 */
95 cfg |= ADC_V2_CON2_OSEL(OSEL_BINARY);
96 cfg |= ADC_V2_CON2_ESEL(ESEL_ADC_EVAL_TIME_20CLK);
97 cfg |= ADC_V2_CON2_HIGHF(HIGHF_CONV_RATE_600KSPS);
98 writel(cfg, &regs->con2);
99
100 priv->active_channel = -1;
101
102 return 0;
103}
104
105int exynos_adc_ofdata_to_platdata(struct udevice *dev)
106{
107 struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev);
108 struct exynos_adc_priv *priv = dev_get_priv(dev);
109
110 priv->regs = (struct exynos_adc_v2 *)dev_get_addr(dev);
111 if (priv->regs == (struct exynos_adc_v2 *)FDT_ADDR_T_NONE) {
112 error("Dev: %s - can't get address!", dev->name);
113 return -ENODATA;
114 }
115
116 uc_pdata->data_mask = ADC_V2_DAT_MASK;
117 uc_pdata->data_format = ADC_DATA_FORMAT_BIN;
118 uc_pdata->data_timeout_us = ADC_V2_CONV_TIMEOUT_US;
119
120 /* Mask available channel bits: [0:9] */
121 uc_pdata->channel_mask = (2 << ADC_V2_MAX_CHANNEL) - 1;
122
123 return 0;
124}
125
126static const struct adc_ops exynos_adc_ops = {
127 .start_channel = exynos_adc_start_channel,
128 .channel_data = exynos_adc_channel_data,
129 .stop = exynos_adc_stop,
130};
131
132static const struct udevice_id exynos_adc_ids[] = {
133 { .compatible = "samsung,exynos-adc-v2" },
134 { }
135};
136
137U_BOOT_DRIVER(exynos_adc) = {
138 .name = "exynos-adc",
139 .id = UCLASS_ADC,
140 .of_match = exynos_adc_ids,
141 .ops = &exynos_adc_ops,
142 .probe = exynos_adc_probe,
143 .ofdata_to_platdata = exynos_adc_ofdata_to_platdata,
144 .priv_auto_alloc_size = sizeof(struct exynos_adc_priv),
145};