1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * HMC425A and similar Gain Amplifiers 4 * 5 * Copyright 2020 Analog Devices Inc. 6 */ 7 8 #include <linux/device.h> 9 #include <linux/err.h> 10 #include <linux/gpio/consumer.h> 11 #include <linux/iio/iio.h> 12 #include <linux/iio/sysfs.h> 13 #include <linux/kernel.h> 14 #include <linux/mod_devicetable.h> 15 #include <linux/module.h> 16 #include <linux/platform_device.h> 17 #include <linux/property.h> 18 #include <linux/slab.h> 19 #include <linux/regulator/consumer.h> 20 #include <linux/sysfs.h> 21 22 enum hmc425a_type { 23 ID_HMC425A, 24 ID_HMC540S, 25 }; 26 27 struct hmc425a_chip_info { 28 const char *name; 29 const struct iio_chan_spec *channels; 30 unsigned int num_channels; 31 unsigned int num_gpios; 32 int gain_min; 33 int gain_max; 34 int default_gain; 35 }; 36 37 struct hmc425a_state { 38 struct mutex lock; /* protect sensor state */ 39 struct hmc425a_chip_info *chip_info; 40 struct gpio_descs *gpios; 41 enum hmc425a_type type; 42 u32 gain; 43 }; 44 45 static int hmc425a_write(struct iio_dev *indio_dev, u32 value) 46 { 47 struct hmc425a_state *st = iio_priv(indio_dev); 48 DECLARE_BITMAP(values, BITS_PER_TYPE(value)); 49 50 values[0] = value; 51 52 gpiod_set_array_value_cansleep(st->gpios->ndescs, st->gpios->desc, 53 NULL, values); 54 return 0; 55 } 56 57 static int hmc425a_read_raw(struct iio_dev *indio_dev, 58 struct iio_chan_spec const *chan, int *val, 59 int *val2, long m) 60 { 61 struct hmc425a_state *st = iio_priv(indio_dev); 62 int code, gain = 0; 63 int ret; 64 65 mutex_lock(&st->lock); 66 switch (m) { 67 case IIO_CHAN_INFO_HARDWAREGAIN: 68 code = st->gain; 69 70 switch (st->type) { 71 case ID_HMC425A: 72 gain = ~code * -500; 73 break; 74 case ID_HMC540S: 75 gain = ~code * -1000; 76 break; 77 } 78 79 *val = gain / 1000; 80 *val2 = (gain % 1000) * 1000; 81 82 ret = IIO_VAL_INT_PLUS_MICRO_DB; 83 break; 84 default: 85 ret = -EINVAL; 86 } 87 mutex_unlock(&st->lock); 88 89 return ret; 90 }; 91 92 static int hmc425a_write_raw(struct iio_dev *indio_dev, 93 struct iio_chan_spec const *chan, int val, 94 int val2, long mask) 95 { 96 struct hmc425a_state *st = iio_priv(indio_dev); 97 struct hmc425a_chip_info *inf = st->chip_info; 98 int code = 0, gain; 99 int ret; 100 101 if (val < 0) 102 gain = (val * 1000) - (val2 / 1000); 103 else 104 gain = (val * 1000) + (val2 / 1000); 105 106 if (gain > inf->gain_max || gain < inf->gain_min) 107 return -EINVAL; 108 109 switch (st->type) { 110 case ID_HMC425A: 111 code = ~((abs(gain) / 500) & 0x3F); 112 break; 113 case ID_HMC540S: 114 code = ~((abs(gain) / 1000) & 0xF); 115 break; 116 } 117 118 mutex_lock(&st->lock); 119 switch (mask) { 120 case IIO_CHAN_INFO_HARDWAREGAIN: 121 st->gain = code; 122 123 ret = hmc425a_write(indio_dev, st->gain); 124 break; 125 default: 126 ret = -EINVAL; 127 } 128 mutex_unlock(&st->lock); 129 130 return ret; 131 } 132 133 static int hmc425a_write_raw_get_fmt(struct iio_dev *indio_dev, 134 struct iio_chan_spec const *chan, 135 long mask) 136 { 137 switch (mask) { 138 case IIO_CHAN_INFO_HARDWAREGAIN: 139 return IIO_VAL_INT_PLUS_MICRO_DB; 140 default: 141 return -EINVAL; 142 } 143 } 144 145 static const struct iio_info hmc425a_info = { 146 .read_raw = &hmc425a_read_raw, 147 .write_raw = &hmc425a_write_raw, 148 .write_raw_get_fmt = &hmc425a_write_raw_get_fmt, 149 }; 150 151 #define HMC425A_CHAN(_channel) \ 152 { \ 153 .type = IIO_VOLTAGE, \ 154 .output = 1, \ 155 .indexed = 1, \ 156 .channel = _channel, \ 157 .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \ 158 } 159 160 static const struct iio_chan_spec hmc425a_channels[] = { 161 HMC425A_CHAN(0), 162 }; 163 164 /* Match table for of_platform binding */ 165 static const struct of_device_id hmc425a_of_match[] = { 166 { .compatible = "adi,hmc425a", .data = (void *)ID_HMC425A }, 167 { .compatible = "adi,hmc540s", .data = (void *)ID_HMC540S }, 168 {}, 169 }; 170 MODULE_DEVICE_TABLE(of, hmc425a_of_match); 171 172 static struct hmc425a_chip_info hmc425a_chip_info_tbl[] = { 173 [ID_HMC425A] = { 174 .name = "hmc425a", 175 .channels = hmc425a_channels, 176 .num_channels = ARRAY_SIZE(hmc425a_channels), 177 .num_gpios = 6, 178 .gain_min = -31500, 179 .gain_max = 0, 180 .default_gain = -0x40, /* set default gain -31.5db*/ 181 }, 182 [ID_HMC540S] = { 183 .name = "hmc540s", 184 .channels = hmc425a_channels, 185 .num_channels = ARRAY_SIZE(hmc425a_channels), 186 .num_gpios = 4, 187 .gain_min = -15000, 188 .gain_max = 0, 189 .default_gain = -0x10, /* set default gain -15.0db*/ 190 }, 191 }; 192 193 static int hmc425a_probe(struct platform_device *pdev) 194 { 195 struct iio_dev *indio_dev; 196 struct hmc425a_state *st; 197 int ret; 198 199 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st)); 200 if (!indio_dev) 201 return -ENOMEM; 202 203 st = iio_priv(indio_dev); 204 st->type = (uintptr_t)device_get_match_data(&pdev->dev); 205 206 st->chip_info = &hmc425a_chip_info_tbl[st->type]; 207 indio_dev->num_channels = st->chip_info->num_channels; 208 indio_dev->channels = st->chip_info->channels; 209 indio_dev->name = st->chip_info->name; 210 st->gain = st->chip_info->default_gain; 211 212 st->gpios = devm_gpiod_get_array(&pdev->dev, "ctrl", GPIOD_OUT_LOW); 213 if (IS_ERR(st->gpios)) 214 return dev_err_probe(&pdev->dev, PTR_ERR(st->gpios), 215 "failed to get gpios\n"); 216 217 if (st->gpios->ndescs != st->chip_info->num_gpios) { 218 dev_err(&pdev->dev, "%d GPIOs needed to operate\n", 219 st->chip_info->num_gpios); 220 return -ENODEV; 221 } 222 223 ret = devm_regulator_get_enable(&pdev->dev, "vcc-supply"); 224 if (ret) 225 return ret; 226 227 mutex_init(&st->lock); 228 229 indio_dev->info = &hmc425a_info; 230 indio_dev->modes = INDIO_DIRECT_MODE; 231 232 return devm_iio_device_register(&pdev->dev, indio_dev); 233 } 234 235 static struct platform_driver hmc425a_driver = { 236 .driver = { 237 .name = KBUILD_MODNAME, 238 .of_match_table = hmc425a_of_match, 239 }, 240 .probe = hmc425a_probe, 241 }; 242 module_platform_driver(hmc425a_driver); 243 244 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>"); 245 MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers"); 246 MODULE_LICENSE("GPL v2"); 247