1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * IIO driver for the Measurement Computing CIO-DAC 4 * Copyright (C) 2016 William Breathitt Gray 5 * 6 * This driver supports the following Measurement Computing devices: CIO-DAC16, 7 * CIO-DAC08, and PC104-DAC06. 8 */ 9 #include <linux/bits.h> 10 #include <linux/device.h> 11 #include <linux/err.h> 12 #include <linux/iio/iio.h> 13 #include <linux/iio/types.h> 14 #include <linux/isa.h> 15 #include <linux/module.h> 16 #include <linux/moduleparam.h> 17 #include <linux/regmap.h> 18 #include <linux/types.h> 19 20 #define CIO_DAC_NUM_CHAN 16 21 22 #define CIO_DAC_CHAN(chan) { \ 23 .type = IIO_VOLTAGE, \ 24 .channel = chan, \ 25 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 26 .indexed = 1, \ 27 .output = 1 \ 28 } 29 30 #define CIO_DAC_EXTENT 32 31 32 static unsigned int base[max_num_isa_dev(CIO_DAC_EXTENT)]; 33 static unsigned int num_cio_dac; 34 module_param_hw_array(base, uint, ioport, &num_cio_dac, 0); 35 MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses"); 36 37 #define CIO_DAC_BASE 0x00 38 #define CIO_DAC_CHANNEL_STRIDE 2 39 40 static bool cio_dac_precious_reg(struct device *dev, unsigned int reg) 41 { 42 /* 43 * All registers are considered precious; if the XFER jumper is set on 44 * the device, then no update occurs until a DAC register is read. 45 */ 46 return true; 47 } 48 49 static const struct regmap_config cio_dac_regmap_config = { 50 .reg_bits = 16, 51 .reg_stride = 2, 52 .val_bits = 16, 53 .io_port = true, 54 .max_register = 0x1F, 55 .precious_reg = cio_dac_precious_reg, 56 }; 57 58 /** 59 * struct cio_dac_iio - IIO device private data structure 60 * @map: Regmap for the device 61 */ 62 struct cio_dac_iio { 63 struct regmap *map; 64 }; 65 66 static int cio_dac_read_raw(struct iio_dev *indio_dev, 67 struct iio_chan_spec const *chan, int *val, int *val2, long mask) 68 { 69 struct cio_dac_iio *const priv = iio_priv(indio_dev); 70 const unsigned int offset = chan->channel * CIO_DAC_CHANNEL_STRIDE; 71 int err; 72 unsigned int dac_val; 73 74 if (mask != IIO_CHAN_INFO_RAW) 75 return -EINVAL; 76 77 err = regmap_read(priv->map, CIO_DAC_BASE + offset, &dac_val); 78 if (err) 79 return err; 80 81 *val = dac_val; 82 83 return IIO_VAL_INT; 84 } 85 86 static int cio_dac_write_raw(struct iio_dev *indio_dev, 87 struct iio_chan_spec const *chan, int val, int val2, long mask) 88 { 89 struct cio_dac_iio *const priv = iio_priv(indio_dev); 90 const unsigned int offset = chan->channel * CIO_DAC_CHANNEL_STRIDE; 91 92 if (mask != IIO_CHAN_INFO_RAW) 93 return -EINVAL; 94 95 /* DAC can only accept up to a 12-bit value */ 96 if ((unsigned int)val > 4095) 97 return -EINVAL; 98 99 return regmap_write(priv->map, CIO_DAC_BASE + offset, val); 100 } 101 102 static const struct iio_info cio_dac_info = { 103 .read_raw = cio_dac_read_raw, 104 .write_raw = cio_dac_write_raw 105 }; 106 107 static const struct iio_chan_spec cio_dac_channels[CIO_DAC_NUM_CHAN] = { 108 CIO_DAC_CHAN(0), CIO_DAC_CHAN(1), CIO_DAC_CHAN(2), CIO_DAC_CHAN(3), 109 CIO_DAC_CHAN(4), CIO_DAC_CHAN(5), CIO_DAC_CHAN(6), CIO_DAC_CHAN(7), 110 CIO_DAC_CHAN(8), CIO_DAC_CHAN(9), CIO_DAC_CHAN(10), CIO_DAC_CHAN(11), 111 CIO_DAC_CHAN(12), CIO_DAC_CHAN(13), CIO_DAC_CHAN(14), CIO_DAC_CHAN(15) 112 }; 113 114 static int cio_dac_probe(struct device *dev, unsigned int id) 115 { 116 struct iio_dev *indio_dev; 117 struct cio_dac_iio *priv; 118 void __iomem *regs; 119 120 indio_dev = devm_iio_device_alloc(dev, sizeof(*priv)); 121 if (!indio_dev) 122 return -ENOMEM; 123 124 if (!devm_request_region(dev, base[id], CIO_DAC_EXTENT, 125 dev_name(dev))) { 126 dev_err(dev, "Unable to request port addresses (0x%X-0x%X)\n", 127 base[id], base[id] + CIO_DAC_EXTENT); 128 return -EBUSY; 129 } 130 131 regs = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT); 132 if (!regs) 133 return -ENOMEM; 134 135 priv = iio_priv(indio_dev); 136 priv->map = devm_regmap_init_mmio(dev, regs, &cio_dac_regmap_config); 137 if (IS_ERR(priv->map)) 138 return dev_err_probe(dev, PTR_ERR(priv->map), 139 "Unable to initialize register map\n"); 140 141 indio_dev->info = &cio_dac_info; 142 indio_dev->modes = INDIO_DIRECT_MODE; 143 indio_dev->channels = cio_dac_channels; 144 indio_dev->num_channels = CIO_DAC_NUM_CHAN; 145 indio_dev->name = dev_name(dev); 146 147 return devm_iio_device_register(dev, indio_dev); 148 } 149 150 static struct isa_driver cio_dac_driver = { 151 .probe = cio_dac_probe, 152 .driver = { 153 .name = "cio-dac" 154 } 155 }; 156 157 module_isa_driver(cio_dac_driver, num_cio_dac); 158 159 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); 160 MODULE_DESCRIPTION("Measurement Computing CIO-DAC IIO driver"); 161 MODULE_LICENSE("GPL v2"); 162