Version:  2.0.40 2.2.26 2.4.37 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17

Linux/drivers/staging/iio/adc/lpc32xx_adc.c

  1 /*
  2  *  lpc32xx_adc.c - Support for ADC in LPC32XX
  3  *
  4  *  3-channel, 10-bit ADC
  5  *
  6  *  Copyright (C) 2011, 2012 Roland Stigge <stigge@antcom.de>
  7  *
  8  *  This program is free software; you can redistribute it and/or modify
  9  *  it under the terms of the GNU General Public License as published by
 10  *  the Free Software Foundation; either version 2 of the License, or
 11  *  (at your option) any later version.
 12  *
 13  *  This program is distributed in the hope that it will be useful,
 14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 16  *  GNU General Public License for more details.
 17  *
 18  *  You should have received a copy of the GNU General Public License
 19  *  along with this program; if not, write to the Free Software
 20  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 21  */
 22 
 23 #include <linux/module.h>
 24 #include <linux/platform_device.h>
 25 #include <linux/interrupt.h>
 26 #include <linux/device.h>
 27 #include <linux/kernel.h>
 28 #include <linux/slab.h>
 29 #include <linux/io.h>
 30 #include <linux/clk.h>
 31 #include <linux/err.h>
 32 #include <linux/completion.h>
 33 #include <linux/of.h>
 34 
 35 #include <linux/iio/iio.h>
 36 #include <linux/iio/sysfs.h>
 37 
 38 /*
 39  * LPC32XX registers definitions
 40  */
 41 #define LPC32XX_ADC_SELECT(x)   ((x) + 0x04)
 42 #define LPC32XX_ADC_CTRL(x)     ((x) + 0x08)
 43 #define LPC32XX_ADC_VALUE(x)    ((x) + 0x48)
 44 
 45 /* Bit definitions for LPC32XX_ADC_SELECT: */
 46 #define AD_REFm         0x00000200 /* constant, always write this value! */
 47 #define AD_REFp         0x00000080 /* constant, always write this value! */
 48 #define AD_IN           0x00000010 /* multiple of this is the */
 49                                    /* channel number: 0, 1, 2 */
 50 #define AD_INTERNAL     0x00000004 /* constant, always write this value! */
 51 
 52 /* Bit definitions for LPC32XX_ADC_CTRL: */
 53 #define AD_STROBE       0x00000002
 54 #define AD_PDN_CTRL     0x00000004
 55 
 56 /* Bit definitions for LPC32XX_ADC_VALUE: */
 57 #define ADC_VALUE_MASK  0x000003FF
 58 
 59 #define MOD_NAME "lpc32xx-adc"
 60 
 61 struct lpc32xx_adc_info {
 62         void __iomem *adc_base;
 63         struct clk *clk;
 64         struct completion completion;
 65 
 66         u32 value;
 67 };
 68 
 69 static int lpc32xx_read_raw(struct iio_dev *indio_dev,
 70                                 struct iio_chan_spec const *chan,
 71                                 int *val,
 72                                 int *val2,
 73                                 long mask)
 74 {
 75         struct lpc32xx_adc_info *info = iio_priv(indio_dev);
 76 
 77         if (mask == IIO_CHAN_INFO_RAW) {
 78                 mutex_lock(&indio_dev->mlock);
 79                 clk_enable(info->clk);
 80                 /* Measurement setup */
 81                 __raw_writel(AD_INTERNAL | (chan->address) | AD_REFp | AD_REFm,
 82                         LPC32XX_ADC_SELECT(info->adc_base));
 83                 /* Trigger conversion */
 84                 __raw_writel(AD_PDN_CTRL | AD_STROBE,
 85                         LPC32XX_ADC_CTRL(info->adc_base));
 86                 wait_for_completion(&info->completion); /* set by ISR */
 87                 clk_disable(info->clk);
 88                 *val = info->value;
 89                 mutex_unlock(&indio_dev->mlock);
 90 
 91                 return IIO_VAL_INT;
 92         }
 93 
 94         return -EINVAL;
 95 }
 96 
 97 static const struct iio_info lpc32xx_adc_iio_info = {
 98         .read_raw = &lpc32xx_read_raw,
 99         .driver_module = THIS_MODULE,
100 };
101 
102 #define LPC32XX_ADC_CHANNEL(_index) {                   \
103         .type = IIO_VOLTAGE,                            \
104         .indexed = 1,                                   \
105         .channel = _index,                              \
106         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
107         .address = AD_IN * _index,                      \
108         .scan_index = _index,                           \
109 }
110 
111 static const struct iio_chan_spec lpc32xx_adc_iio_channels[] = {
112         LPC32XX_ADC_CHANNEL(0),
113         LPC32XX_ADC_CHANNEL(1),
114         LPC32XX_ADC_CHANNEL(2),
115 };
116 
117 static irqreturn_t lpc32xx_adc_isr(int irq, void *dev_id)
118 {
119         struct lpc32xx_adc_info *info = (struct lpc32xx_adc_info *) dev_id;
120 
121         /* Read value and clear irq */
122         info->value = __raw_readl(LPC32XX_ADC_VALUE(info->adc_base)) &
123                                 ADC_VALUE_MASK;
124         complete(&info->completion);
125 
126         return IRQ_HANDLED;
127 }
128 
129 static int lpc32xx_adc_probe(struct platform_device *pdev)
130 {
131         struct lpc32xx_adc_info *info = NULL;
132         struct resource *res;
133         int retval = -ENODEV;
134         struct iio_dev *iodev = NULL;
135         int irq;
136 
137         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
138         if (!res) {
139                 dev_err(&pdev->dev, "failed to get platform I/O memory\n");
140                 return -EBUSY;
141         }
142 
143         iodev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
144         if (!iodev)
145                 return -ENOMEM;
146 
147         info = iio_priv(iodev);
148 
149         info->adc_base = devm_ioremap(&pdev->dev, res->start,
150                                                 resource_size(res));
151         if (!info->adc_base) {
152                 dev_err(&pdev->dev, "failed mapping memory\n");
153                 return -EBUSY;
154         }
155 
156         info->clk = devm_clk_get(&pdev->dev, NULL);
157         if (IS_ERR(info->clk)) {
158                 dev_err(&pdev->dev, "failed getting clock\n");
159                 return PTR_ERR(info->clk);
160         }
161 
162         irq = platform_get_irq(pdev, 0);
163         if (irq <= 0) {
164                 dev_err(&pdev->dev, "failed getting interrupt resource\n");
165                 return -EINVAL;
166         }
167 
168         retval = devm_request_irq(&pdev->dev, irq, lpc32xx_adc_isr, 0,
169                                                                 MOD_NAME, info);
170         if (retval < 0) {
171                 dev_err(&pdev->dev, "failed requesting interrupt\n");
172                 return retval;
173         }
174 
175         platform_set_drvdata(pdev, iodev);
176 
177         init_completion(&info->completion);
178 
179         iodev->name = MOD_NAME;
180         iodev->dev.parent = &pdev->dev;
181         iodev->info = &lpc32xx_adc_iio_info;
182         iodev->modes = INDIO_DIRECT_MODE;
183         iodev->channels = lpc32xx_adc_iio_channels;
184         iodev->num_channels = ARRAY_SIZE(lpc32xx_adc_iio_channels);
185 
186         retval = devm_iio_device_register(&pdev->dev, iodev);
187         if (retval)
188                 return retval;
189 
190         dev_info(&pdev->dev, "LPC32XX ADC driver loaded, IRQ %d\n", irq);
191 
192         return 0;
193 }
194 
195 #ifdef CONFIG_OF
196 static const struct of_device_id lpc32xx_adc_match[] = {
197         { .compatible = "nxp,lpc3220-adc" },
198         {},
199 };
200 MODULE_DEVICE_TABLE(of, lpc32xx_adc_match);
201 #endif
202 
203 static struct platform_driver lpc32xx_adc_driver = {
204         .probe          = lpc32xx_adc_probe,
205         .driver         = {
206                 .name   = MOD_NAME,
207                 .owner  = THIS_MODULE,
208                 .of_match_table = of_match_ptr(lpc32xx_adc_match),
209         },
210 };
211 
212 module_platform_driver(lpc32xx_adc_driver);
213 
214 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
215 MODULE_DESCRIPTION("LPC32XX ADC driver");
216 MODULE_LICENSE("GPL");
217 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us