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12#include <linux/clk.h>
13#include <linux/err.h>
14#include <linux/iio/iio.h>
15#include <linux/iio/driver.h>
16#include <linux/io.h>
17#include <linux/iopoll.h>
18#include <linux/module.h>
19#include <linux/mutex.h>
20#include <linux/of.h>
21#include <linux/of_device.h>
22#include <linux/platform_device.h>
23#include <linux/regulator/consumer.h>
24
25
26#define LPC18XX_DAC_CR 0x000
27#define LPC18XX_DAC_CR_VALUE_SHIFT 6
28#define LPC18XX_DAC_CR_VALUE_MASK 0x3ff
29#define LPC18XX_DAC_CR_BIAS BIT(16)
30#define LPC18XX_DAC_CTRL 0x004
31#define LPC18XX_DAC_CTRL_DMA_ENA BIT(3)
32
33struct lpc18xx_dac {
34 struct regulator *vref;
35 void __iomem *base;
36 struct mutex lock;
37 struct clk *clk;
38};
39
40static const struct iio_chan_spec lpc18xx_dac_iio_channels[] = {
41 {
42 .type = IIO_VOLTAGE,
43 .output = 1,
44 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
45 BIT(IIO_CHAN_INFO_SCALE),
46 },
47};
48
49static int lpc18xx_dac_read_raw(struct iio_dev *indio_dev,
50 struct iio_chan_spec const *chan,
51 int *val, int *val2, long mask)
52{
53 struct lpc18xx_dac *dac = iio_priv(indio_dev);
54 u32 reg;
55
56 switch (mask) {
57 case IIO_CHAN_INFO_RAW:
58 reg = readl(dac->base + LPC18XX_DAC_CR);
59 *val = reg >> LPC18XX_DAC_CR_VALUE_SHIFT;
60 *val &= LPC18XX_DAC_CR_VALUE_MASK;
61
62 return IIO_VAL_INT;
63
64 case IIO_CHAN_INFO_SCALE:
65 *val = regulator_get_voltage(dac->vref) / 1000;
66 *val2 = 10;
67
68 return IIO_VAL_FRACTIONAL_LOG2;
69 }
70
71 return -EINVAL;
72}
73
74static int lpc18xx_dac_write_raw(struct iio_dev *indio_dev,
75 struct iio_chan_spec const *chan,
76 int val, int val2, long mask)
77{
78 struct lpc18xx_dac *dac = iio_priv(indio_dev);
79 u32 reg;
80
81 switch (mask) {
82 case IIO_CHAN_INFO_RAW:
83 if (val < 0 || val > LPC18XX_DAC_CR_VALUE_MASK)
84 return -EINVAL;
85
86 reg = LPC18XX_DAC_CR_BIAS;
87 reg |= val << LPC18XX_DAC_CR_VALUE_SHIFT;
88
89 mutex_lock(&dac->lock);
90 writel(reg, dac->base + LPC18XX_DAC_CR);
91 writel(LPC18XX_DAC_CTRL_DMA_ENA, dac->base + LPC18XX_DAC_CTRL);
92 mutex_unlock(&dac->lock);
93
94 return 0;
95 }
96
97 return -EINVAL;
98}
99
100static const struct iio_info lpc18xx_dac_info = {
101 .read_raw = lpc18xx_dac_read_raw,
102 .write_raw = lpc18xx_dac_write_raw,
103};
104
105static int lpc18xx_dac_probe(struct platform_device *pdev)
106{
107 struct iio_dev *indio_dev;
108 struct lpc18xx_dac *dac;
109 int ret;
110
111 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*dac));
112 if (!indio_dev)
113 return -ENOMEM;
114
115 platform_set_drvdata(pdev, indio_dev);
116 dac = iio_priv(indio_dev);
117 mutex_init(&dac->lock);
118
119 dac->base = devm_platform_ioremap_resource(pdev, 0);
120 if (IS_ERR(dac->base))
121 return PTR_ERR(dac->base);
122
123 dac->clk = devm_clk_get(&pdev->dev, NULL);
124 if (IS_ERR(dac->clk)) {
125 dev_err(&pdev->dev, "error getting clock\n");
126 return PTR_ERR(dac->clk);
127 }
128
129 dac->vref = devm_regulator_get(&pdev->dev, "vref");
130 if (IS_ERR(dac->vref)) {
131 dev_err(&pdev->dev, "error getting regulator\n");
132 return PTR_ERR(dac->vref);
133 }
134
135 indio_dev->name = dev_name(&pdev->dev);
136 indio_dev->info = &lpc18xx_dac_info;
137 indio_dev->modes = INDIO_DIRECT_MODE;
138 indio_dev->channels = lpc18xx_dac_iio_channels;
139 indio_dev->num_channels = ARRAY_SIZE(lpc18xx_dac_iio_channels);
140
141 ret = regulator_enable(dac->vref);
142 if (ret) {
143 dev_err(&pdev->dev, "unable to enable regulator\n");
144 return ret;
145 }
146
147 ret = clk_prepare_enable(dac->clk);
148 if (ret) {
149 dev_err(&pdev->dev, "unable to enable clock\n");
150 goto dis_reg;
151 }
152
153 writel(0, dac->base + LPC18XX_DAC_CTRL);
154 writel(0, dac->base + LPC18XX_DAC_CR);
155
156 ret = iio_device_register(indio_dev);
157 if (ret) {
158 dev_err(&pdev->dev, "unable to register device\n");
159 goto dis_clk;
160 }
161
162 return 0;
163
164dis_clk:
165 clk_disable_unprepare(dac->clk);
166dis_reg:
167 regulator_disable(dac->vref);
168 return ret;
169}
170
171static int lpc18xx_dac_remove(struct platform_device *pdev)
172{
173 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
174 struct lpc18xx_dac *dac = iio_priv(indio_dev);
175
176 iio_device_unregister(indio_dev);
177
178 writel(0, dac->base + LPC18XX_DAC_CTRL);
179 clk_disable_unprepare(dac->clk);
180 regulator_disable(dac->vref);
181
182 return 0;
183}
184
185static const struct of_device_id lpc18xx_dac_match[] = {
186 { .compatible = "nxp,lpc1850-dac" },
187 { }
188};
189MODULE_DEVICE_TABLE(of, lpc18xx_dac_match);
190
191static struct platform_driver lpc18xx_dac_driver = {
192 .probe = lpc18xx_dac_probe,
193 .remove = lpc18xx_dac_remove,
194 .driver = {
195 .name = "lpc18xx-dac",
196 .of_match_table = lpc18xx_dac_match,
197 },
198};
199module_platform_driver(lpc18xx_dac_driver);
200
201MODULE_DESCRIPTION("LPC18xx DAC driver");
202MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
203MODULE_LICENSE("GPL v2");
204
