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17#include <linux/clk.h>
18#include <linux/err.h>
19#include <linux/iio/iio.h>
20#include <linux/iio/driver.h>
21#include <linux/io.h>
22#include <linux/iopoll.h>
23#include <linux/module.h>
24#include <linux/mutex.h>
25#include <linux/of.h>
26#include <linux/of_device.h>
27#include <linux/platform_device.h>
28#include <linux/regulator/consumer.h>
29
30
31#define LPC18XX_ADC_CR 0x000
32#define LPC18XX_ADC_CR_CLKDIV_SHIFT 8
33#define LPC18XX_ADC_CR_PDN BIT(21)
34#define LPC18XX_ADC_CR_START_NOW (0x1 << 24)
35#define LPC18XX_ADC_GDR 0x004
36
37
38#define LPC18XX_ADC_SAMPLE_SHIFT 6
39#define LPC18XX_ADC_SAMPLE_MASK 0x3ff
40#define LPC18XX_ADC_CONV_DONE BIT(31)
41
42
43#define LPC18XX_ADC_CLK_TARGET 4500000
44
45struct lpc18xx_adc {
46 struct regulator *vref;
47 void __iomem *base;
48 struct device *dev;
49 struct mutex lock;
50 struct clk *clk;
51 u32 cr_reg;
52};
53
54#define LPC18XX_ADC_CHAN(_idx) { \
55 .type = IIO_VOLTAGE, \
56 .indexed = 1, \
57 .channel = _idx, \
58 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
59 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
60}
61
62static const struct iio_chan_spec lpc18xx_adc_iio_channels[] = {
63 LPC18XX_ADC_CHAN(0),
64 LPC18XX_ADC_CHAN(1),
65 LPC18XX_ADC_CHAN(2),
66 LPC18XX_ADC_CHAN(3),
67 LPC18XX_ADC_CHAN(4),
68 LPC18XX_ADC_CHAN(5),
69 LPC18XX_ADC_CHAN(6),
70 LPC18XX_ADC_CHAN(7),
71};
72
73static int lpc18xx_adc_read_chan(struct lpc18xx_adc *adc, unsigned int ch)
74{
75 int ret;
76 u32 reg;
77
78 reg = adc->cr_reg | BIT(ch) | LPC18XX_ADC_CR_START_NOW;
79 writel(reg, adc->base + LPC18XX_ADC_CR);
80
81 ret = readl_poll_timeout(adc->base + LPC18XX_ADC_GDR, reg,
82 reg & LPC18XX_ADC_CONV_DONE, 3, 9);
83 if (ret) {
84 dev_warn(adc->dev, "adc read timed out\n");
85 return ret;
86 }
87
88 return (reg >> LPC18XX_ADC_SAMPLE_SHIFT) & LPC18XX_ADC_SAMPLE_MASK;
89}
90
91static int lpc18xx_adc_read_raw(struct iio_dev *indio_dev,
92 struct iio_chan_spec const *chan,
93 int *val, int *val2, long mask)
94{
95 struct lpc18xx_adc *adc = iio_priv(indio_dev);
96
97 switch (mask) {
98 case IIO_CHAN_INFO_RAW:
99 mutex_lock(&adc->lock);
100 *val = lpc18xx_adc_read_chan(adc, chan->channel);
101 mutex_unlock(&adc->lock);
102 if (*val < 0)
103 return *val;
104
105 return IIO_VAL_INT;
106
107 case IIO_CHAN_INFO_SCALE:
108 *val = regulator_get_voltage(adc->vref) / 1000;
109 *val2 = 10;
110
111 return IIO_VAL_FRACTIONAL_LOG2;
112 }
113
114 return -EINVAL;
115}
116
117static const struct iio_info lpc18xx_adc_info = {
118 .read_raw = lpc18xx_adc_read_raw,
119};
120
121static int lpc18xx_adc_probe(struct platform_device *pdev)
122{
123 struct iio_dev *indio_dev;
124 struct lpc18xx_adc *adc;
125 struct resource *res;
126 unsigned int clkdiv;
127 unsigned long rate;
128 int ret;
129
130 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
131 if (!indio_dev)
132 return -ENOMEM;
133
134 platform_set_drvdata(pdev, indio_dev);
135 adc = iio_priv(indio_dev);
136 adc->dev = &pdev->dev;
137 mutex_init(&adc->lock);
138
139 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
140 adc->base = devm_ioremap_resource(&pdev->dev, res);
141 if (IS_ERR(adc->base))
142 return PTR_ERR(adc->base);
143
144 adc->clk = devm_clk_get(&pdev->dev, NULL);
145 if (IS_ERR(adc->clk)) {
146 dev_err(&pdev->dev, "error getting clock\n");
147 return PTR_ERR(adc->clk);
148 }
149
150 rate = clk_get_rate(adc->clk);
151 clkdiv = DIV_ROUND_UP(rate, LPC18XX_ADC_CLK_TARGET);
152
153 adc->vref = devm_regulator_get(&pdev->dev, "vref");
154 if (IS_ERR(adc->vref)) {
155 dev_err(&pdev->dev, "error getting regulator\n");
156 return PTR_ERR(adc->vref);
157 }
158
159 indio_dev->name = dev_name(&pdev->dev);
160 indio_dev->dev.parent = &pdev->dev;
161 indio_dev->info = &lpc18xx_adc_info;
162 indio_dev->modes = INDIO_DIRECT_MODE;
163 indio_dev->channels = lpc18xx_adc_iio_channels;
164 indio_dev->num_channels = ARRAY_SIZE(lpc18xx_adc_iio_channels);
165
166 ret = regulator_enable(adc->vref);
167 if (ret) {
168 dev_err(&pdev->dev, "unable to enable regulator\n");
169 return ret;
170 }
171
172 ret = clk_prepare_enable(adc->clk);
173 if (ret) {
174 dev_err(&pdev->dev, "unable to enable clock\n");
175 goto dis_reg;
176 }
177
178 adc->cr_reg = (clkdiv << LPC18XX_ADC_CR_CLKDIV_SHIFT) |
179 LPC18XX_ADC_CR_PDN;
180 writel(adc->cr_reg, adc->base + LPC18XX_ADC_CR);
181
182 ret = iio_device_register(indio_dev);
183 if (ret) {
184 dev_err(&pdev->dev, "unable to register device\n");
185 goto dis_clk;
186 }
187
188 return 0;
189
190dis_clk:
191 writel(0, adc->base + LPC18XX_ADC_CR);
192 clk_disable_unprepare(adc->clk);
193dis_reg:
194 regulator_disable(adc->vref);
195 return ret;
196}
197
198static int lpc18xx_adc_remove(struct platform_device *pdev)
199{
200 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
201 struct lpc18xx_adc *adc = iio_priv(indio_dev);
202
203 iio_device_unregister(indio_dev);
204
205 writel(0, adc->base + LPC18XX_ADC_CR);
206 clk_disable_unprepare(adc->clk);
207 regulator_disable(adc->vref);
208
209 return 0;
210}
211
212static const struct of_device_id lpc18xx_adc_match[] = {
213 { .compatible = "nxp,lpc1850-adc" },
214 { }
215};
216MODULE_DEVICE_TABLE(of, lpc18xx_adc_match);
217
218static struct platform_driver lpc18xx_adc_driver = {
219 .probe = lpc18xx_adc_probe,
220 .remove = lpc18xx_adc_remove,
221 .driver = {
222 .name = "lpc18xx-adc",
223 .of_match_table = lpc18xx_adc_match,
224 },
225};
226module_platform_driver(lpc18xx_adc_driver);
227
228MODULE_DESCRIPTION("LPC18xx ADC driver");
229MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
230MODULE_LICENSE("GPL v2");
231
