This source file includes following definitions.
- lpc18xx_adc_read_chan
- lpc18xx_adc_read_raw
- lpc18xx_adc_probe
- lpc18xx_adc_remove
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14 #include <linux/clk.h>
15 #include <linux/err.h>
16 #include <linux/iio/iio.h>
17 #include <linux/iio/driver.h>
18 #include <linux/io.h>
19 #include <linux/iopoll.h>
20 #include <linux/module.h>
21 #include <linux/mutex.h>
22 #include <linux/of.h>
23 #include <linux/of_device.h>
24 #include <linux/platform_device.h>
25 #include <linux/regulator/consumer.h>
26
27
28 #define LPC18XX_ADC_CR 0x000
29 #define LPC18XX_ADC_CR_CLKDIV_SHIFT 8
30 #define LPC18XX_ADC_CR_PDN BIT(21)
31 #define LPC18XX_ADC_CR_START_NOW (0x1 << 24)
32 #define LPC18XX_ADC_GDR 0x004
33
34
35 #define LPC18XX_ADC_SAMPLE_SHIFT 6
36 #define LPC18XX_ADC_SAMPLE_MASK 0x3ff
37 #define LPC18XX_ADC_CONV_DONE BIT(31)
38
39
40 #define LPC18XX_ADC_CLK_TARGET 4500000
41
42 struct lpc18xx_adc {
43 struct regulator *vref;
44 void __iomem *base;
45 struct device *dev;
46 struct mutex lock;
47 struct clk *clk;
48 u32 cr_reg;
49 };
50
51 #define LPC18XX_ADC_CHAN(_idx) { \
52 .type = IIO_VOLTAGE, \
53 .indexed = 1, \
54 .channel = _idx, \
55 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
56 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
57 }
58
59 static const struct iio_chan_spec lpc18xx_adc_iio_channels[] = {
60 LPC18XX_ADC_CHAN(0),
61 LPC18XX_ADC_CHAN(1),
62 LPC18XX_ADC_CHAN(2),
63 LPC18XX_ADC_CHAN(3),
64 LPC18XX_ADC_CHAN(4),
65 LPC18XX_ADC_CHAN(5),
66 LPC18XX_ADC_CHAN(6),
67 LPC18XX_ADC_CHAN(7),
68 };
69
70 static int lpc18xx_adc_read_chan(struct lpc18xx_adc *adc, unsigned int ch)
71 {
72 int ret;
73 u32 reg;
74
75 reg = adc->cr_reg | BIT(ch) | LPC18XX_ADC_CR_START_NOW;
76 writel(reg, adc->base + LPC18XX_ADC_CR);
77
78 ret = readl_poll_timeout(adc->base + LPC18XX_ADC_GDR, reg,
79 reg & LPC18XX_ADC_CONV_DONE, 3, 9);
80 if (ret) {
81 dev_warn(adc->dev, "adc read timed out\n");
82 return ret;
83 }
84
85 return (reg >> LPC18XX_ADC_SAMPLE_SHIFT) & LPC18XX_ADC_SAMPLE_MASK;
86 }
87
88 static int lpc18xx_adc_read_raw(struct iio_dev *indio_dev,
89 struct iio_chan_spec const *chan,
90 int *val, int *val2, long mask)
91 {
92 struct lpc18xx_adc *adc = iio_priv(indio_dev);
93
94 switch (mask) {
95 case IIO_CHAN_INFO_RAW:
96 mutex_lock(&adc->lock);
97 *val = lpc18xx_adc_read_chan(adc, chan->channel);
98 mutex_unlock(&adc->lock);
99 if (*val < 0)
100 return *val;
101
102 return IIO_VAL_INT;
103
104 case IIO_CHAN_INFO_SCALE:
105 *val = regulator_get_voltage(adc->vref) / 1000;
106 *val2 = 10;
107
108 return IIO_VAL_FRACTIONAL_LOG2;
109 }
110
111 return -EINVAL;
112 }
113
114 static const struct iio_info lpc18xx_adc_info = {
115 .read_raw = lpc18xx_adc_read_raw,
116 };
117
118 static int lpc18xx_adc_probe(struct platform_device *pdev)
119 {
120 struct iio_dev *indio_dev;
121 struct lpc18xx_adc *adc;
122 struct resource *res;
123 unsigned int clkdiv;
124 unsigned long rate;
125 int ret;
126
127 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
128 if (!indio_dev)
129 return -ENOMEM;
130
131 platform_set_drvdata(pdev, indio_dev);
132 adc = iio_priv(indio_dev);
133 adc->dev = &pdev->dev;
134 mutex_init(&adc->lock);
135
136 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
137 adc->base = devm_ioremap_resource(&pdev->dev, res);
138 if (IS_ERR(adc->base))
139 return PTR_ERR(adc->base);
140
141 adc->clk = devm_clk_get(&pdev->dev, NULL);
142 if (IS_ERR(adc->clk)) {
143 dev_err(&pdev->dev, "error getting clock\n");
144 return PTR_ERR(adc->clk);
145 }
146
147 rate = clk_get_rate(adc->clk);
148 clkdiv = DIV_ROUND_UP(rate, LPC18XX_ADC_CLK_TARGET);
149
150 adc->vref = devm_regulator_get(&pdev->dev, "vref");
151 if (IS_ERR(adc->vref)) {
152 dev_err(&pdev->dev, "error getting regulator\n");
153 return PTR_ERR(adc->vref);
154 }
155
156 indio_dev->name = dev_name(&pdev->dev);
157 indio_dev->dev.parent = &pdev->dev;
158 indio_dev->info = &lpc18xx_adc_info;
159 indio_dev->modes = INDIO_DIRECT_MODE;
160 indio_dev->channels = lpc18xx_adc_iio_channels;
161 indio_dev->num_channels = ARRAY_SIZE(lpc18xx_adc_iio_channels);
162
163 ret = regulator_enable(adc->vref);
164 if (ret) {
165 dev_err(&pdev->dev, "unable to enable regulator\n");
166 return ret;
167 }
168
169 ret = clk_prepare_enable(adc->clk);
170 if (ret) {
171 dev_err(&pdev->dev, "unable to enable clock\n");
172 goto dis_reg;
173 }
174
175 adc->cr_reg = (clkdiv << LPC18XX_ADC_CR_CLKDIV_SHIFT) |
176 LPC18XX_ADC_CR_PDN;
177 writel(adc->cr_reg, adc->base + LPC18XX_ADC_CR);
178
179 ret = iio_device_register(indio_dev);
180 if (ret) {
181 dev_err(&pdev->dev, "unable to register device\n");
182 goto dis_clk;
183 }
184
185 return 0;
186
187 dis_clk:
188 writel(0, adc->base + LPC18XX_ADC_CR);
189 clk_disable_unprepare(adc->clk);
190 dis_reg:
191 regulator_disable(adc->vref);
192 return ret;
193 }
194
195 static int lpc18xx_adc_remove(struct platform_device *pdev)
196 {
197 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
198 struct lpc18xx_adc *adc = iio_priv(indio_dev);
199
200 iio_device_unregister(indio_dev);
201
202 writel(0, adc->base + LPC18XX_ADC_CR);
203 clk_disable_unprepare(adc->clk);
204 regulator_disable(adc->vref);
205
206 return 0;
207 }
208
209 static const struct of_device_id lpc18xx_adc_match[] = {
210 { .compatible = "nxp,lpc1850-adc" },
211 { }
212 };
213 MODULE_DEVICE_TABLE(of, lpc18xx_adc_match);
214
215 static struct platform_driver lpc18xx_adc_driver = {
216 .probe = lpc18xx_adc_probe,
217 .remove = lpc18xx_adc_remove,
218 .driver = {
219 .name = "lpc18xx-adc",
220 .of_match_table = lpc18xx_adc_match,
221 },
222 };
223 module_platform_driver(lpc18xx_adc_driver);
224
225 MODULE_DESCRIPTION("LPC18xx ADC driver");
226 MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
227 MODULE_LICENSE("GPL v2");