1 /* 2 * MEN 16z188 Analog to Digial Converter 3 * 4 * Copyright (C) 2014 MEN Mikroelektronik GmbH (www.men.de) 5 * Author: Johannes Thumshirn <johannes.thumshirn@men.de> 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License as published by the Free 9 * Software Foundation; version 2 of the License. 10 */ 11 12 #include <linux/kernel.h> 13 #include <linux/module.h> 14 #include <linux/mcb.h> 15 #include <linux/io.h> 16 #include <linux/iio/iio.h> 17 18 #define Z188_ADC_MAX_CHAN 8 19 #define Z188_ADC_GAIN 0x0700000 20 #define Z188_MODE_VOLTAGE BIT(27) 21 #define Z188_CFG_AUTO 0x1 22 #define Z188_CTRL_REG 0x40 23 24 #define ADC_DATA(x) (((x) >> 2) & 0x7ffffc) 25 #define ADC_OVR(x) ((x) & 0x1) 26 27 struct z188_adc { 28 struct resource *mem; 29 void __iomem *base; 30 }; 31 32 #define Z188_ADC_CHANNEL(idx) { \ 33 .type = IIO_VOLTAGE, \ 34 .indexed = 1, \ 35 .channel = (idx), \ 36 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 37 } 38 39 static const struct iio_chan_spec z188_adc_iio_channels[] = { 40 Z188_ADC_CHANNEL(0), 41 Z188_ADC_CHANNEL(1), 42 Z188_ADC_CHANNEL(2), 43 Z188_ADC_CHANNEL(3), 44 Z188_ADC_CHANNEL(4), 45 Z188_ADC_CHANNEL(5), 46 Z188_ADC_CHANNEL(6), 47 Z188_ADC_CHANNEL(7), 48 }; 49 50 static int z188_iio_read_raw(struct iio_dev *iio_dev, 51 struct iio_chan_spec const *chan, 52 int *val, 53 int *val2, 54 long info) 55 { 56 struct z188_adc *adc = iio_priv(iio_dev); 57 int ret; 58 u16 tmp; 59 60 switch (info) { 61 case IIO_CHAN_INFO_RAW: 62 tmp = readw(adc->base + chan->channel * 4); 63 64 if (ADC_OVR(tmp)) { 65 dev_info(&iio_dev->dev, 66 "Oversampling error on ADC channel %d\n", 67 chan->channel); 68 return -EIO; 69 } 70 *val = ADC_DATA(tmp); 71 ret = IIO_VAL_INT; 72 break; 73 default: 74 ret = -EINVAL; 75 break; 76 } 77 78 return ret; 79 } 80 81 static struct iio_info z188_adc_info = { 82 .read_raw = &z188_iio_read_raw, 83 .driver_module = THIS_MODULE, 84 }; 85 86 static void men_z188_config_channels(void __iomem *addr) 87 { 88 int i; 89 u32 cfg; 90 u32 ctl; 91 92 ctl = readl(addr + Z188_CTRL_REG); 93 ctl |= Z188_CFG_AUTO; 94 writel(ctl, addr + Z188_CTRL_REG); 95 96 for (i = 0; i < Z188_ADC_MAX_CHAN; i++) { 97 cfg = readl(addr + i); 98 cfg &= ~Z188_ADC_GAIN; 99 cfg |= Z188_MODE_VOLTAGE; 100 writel(cfg, addr + i); 101 } 102 } 103 104 static int men_z188_probe(struct mcb_device *dev, 105 const struct mcb_device_id *id) 106 { 107 struct z188_adc *adc; 108 struct iio_dev *indio_dev; 109 struct resource *mem; 110 111 indio_dev = devm_iio_device_alloc(&dev->dev, sizeof(struct z188_adc)); 112 if (!indio_dev) 113 return -ENOMEM; 114 115 adc = iio_priv(indio_dev); 116 indio_dev->name = "z188-adc"; 117 indio_dev->dev.parent = &dev->dev; 118 indio_dev->info = &z188_adc_info; 119 indio_dev->modes = INDIO_DIRECT_MODE; 120 indio_dev->channels = z188_adc_iio_channels; 121 indio_dev->num_channels = ARRAY_SIZE(z188_adc_iio_channels); 122 123 mem = mcb_request_mem(dev, "z188-adc"); 124 if (IS_ERR(mem)) 125 return PTR_ERR(mem); 126 127 adc->base = ioremap(mem->start, resource_size(mem)); 128 if (adc->base == NULL) 129 goto err; 130 131 men_z188_config_channels(adc->base); 132 133 adc->mem = mem; 134 mcb_set_drvdata(dev, indio_dev); 135 136 return iio_device_register(indio_dev); 137 138 err: 139 mcb_release_mem(mem); 140 return -ENXIO; 141 } 142 143 static void men_z188_remove(struct mcb_device *dev) 144 { 145 struct iio_dev *indio_dev = mcb_get_drvdata(dev); 146 struct z188_adc *adc = iio_priv(indio_dev); 147 148 iio_device_unregister(indio_dev); 149 iounmap(adc->base); 150 mcb_release_mem(adc->mem); 151 } 152 153 static const struct mcb_device_id men_z188_ids[] = { 154 { .device = 0xbc }, 155 { } 156 }; 157 MODULE_DEVICE_TABLE(mcb, men_z188_ids); 158 159 static struct mcb_driver men_z188_driver = { 160 .driver = { 161 .name = "z188-adc", 162 .owner = THIS_MODULE, 163 }, 164 .probe = men_z188_probe, 165 .remove = men_z188_remove, 166 .id_table = men_z188_ids, 167 }; 168 module_mcb_driver(men_z188_driver); 169 170 MODULE_AUTHOR("Johannes Thumshirn <johannes.thumshirn@men.de>"); 171 MODULE_LICENSE("GPL"); 172 MODULE_DESCRIPTION("IIO ADC driver for MEN 16z188 ADC Core"); 173 MODULE_ALIAS("mcb:16z188"); 174