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/module.h> 15 #include <linux/of_device.h> 16 #include <linux/of_platform.h> 17 #include <linux/platform_device.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 }; 25 26 struct hmc425a_chip_info { 27 const char *name; 28 const struct iio_chan_spec *channels; 29 unsigned int num_channels; 30 unsigned int num_gpios; 31 int gain_min; 32 int gain_max; 33 int default_gain; 34 }; 35 36 struct hmc425a_state { 37 struct regulator *reg; 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 } 75 76 *val = gain / 1000; 77 *val2 = (gain % 1000) * 1000; 78 79 ret = IIO_VAL_INT_PLUS_MICRO_DB; 80 break; 81 default: 82 ret = -EINVAL; 83 } 84 mutex_unlock(&st->lock); 85 86 return ret; 87 }; 88 89 static int hmc425a_write_raw(struct iio_dev *indio_dev, 90 struct iio_chan_spec const *chan, int val, 91 int val2, long mask) 92 { 93 struct hmc425a_state *st = iio_priv(indio_dev); 94 struct hmc425a_chip_info *inf = st->chip_info; 95 int code = 0, gain; 96 int ret; 97 98 if (val < 0) 99 gain = (val * 1000) - (val2 / 1000); 100 else 101 gain = (val * 1000) + (val2 / 1000); 102 103 if (gain > inf->gain_max || gain < inf->gain_min) 104 return -EINVAL; 105 106 switch (st->type) { 107 case ID_HMC425A: 108 code = ~((abs(gain) / 500) & 0x3F); 109 break; 110 } 111 112 mutex_lock(&st->lock); 113 switch (mask) { 114 case IIO_CHAN_INFO_HARDWAREGAIN: 115 st->gain = code; 116 117 ret = hmc425a_write(indio_dev, st->gain); 118 break; 119 default: 120 ret = -EINVAL; 121 } 122 mutex_unlock(&st->lock); 123 124 return ret; 125 } 126 127 static int hmc425a_write_raw_get_fmt(struct iio_dev *indio_dev, 128 struct iio_chan_spec const *chan, 129 long mask) 130 { 131 switch (mask) { 132 case IIO_CHAN_INFO_HARDWAREGAIN: 133 return IIO_VAL_INT_PLUS_MICRO_DB; 134 default: 135 return -EINVAL; 136 } 137 } 138 139 static const struct iio_info hmc425a_info = { 140 .read_raw = &hmc425a_read_raw, 141 .write_raw = &hmc425a_write_raw, 142 .write_raw_get_fmt = &hmc425a_write_raw_get_fmt, 143 }; 144 145 #define HMC425A_CHAN(_channel) \ 146 { \ 147 .type = IIO_VOLTAGE, \ 148 .output = 1, \ 149 .indexed = 1, \ 150 .channel = _channel, \ 151 .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \ 152 } 153 154 static const struct iio_chan_spec hmc425a_channels[] = { 155 HMC425A_CHAN(0), 156 }; 157 158 /* Match table for of_platform binding */ 159 static const struct of_device_id hmc425a_of_match[] = { 160 { .compatible = "adi,hmc425a", .data = (void *)ID_HMC425A }, 161 {}, 162 }; 163 MODULE_DEVICE_TABLE(of, hmc425a_of_match); 164 165 static void hmc425a_reg_disable(void *data) 166 { 167 struct hmc425a_state *st = data; 168 169 regulator_disable(st->reg); 170 } 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 }; 183 184 static int hmc425a_probe(struct platform_device *pdev) 185 { 186 struct iio_dev *indio_dev; 187 struct hmc425a_state *st; 188 int ret; 189 190 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st)); 191 if (!indio_dev) 192 return -ENOMEM; 193 194 st = iio_priv(indio_dev); 195 st->type = (enum hmc425a_type)of_device_get_match_data(&pdev->dev); 196 197 st->chip_info = &hmc425a_chip_info_tbl[st->type]; 198 indio_dev->num_channels = st->chip_info->num_channels; 199 indio_dev->channels = st->chip_info->channels; 200 indio_dev->name = st->chip_info->name; 201 st->gain = st->chip_info->default_gain; 202 203 st->gpios = devm_gpiod_get_array(&pdev->dev, "ctrl", GPIOD_OUT_LOW); 204 if (IS_ERR(st->gpios)) { 205 ret = PTR_ERR(st->gpios); 206 if (ret != -EPROBE_DEFER) 207 dev_err(&pdev->dev, "failed to get gpios\n"); 208 return ret; 209 } 210 211 if (st->gpios->ndescs != st->chip_info->num_gpios) { 212 dev_err(&pdev->dev, "%d GPIOs needed to operate\n", 213 st->chip_info->num_gpios); 214 return -ENODEV; 215 } 216 217 st->reg = devm_regulator_get(&pdev->dev, "vcc-supply"); 218 if (IS_ERR(st->reg)) 219 return PTR_ERR(st->reg); 220 221 ret = regulator_enable(st->reg); 222 if (ret) 223 return ret; 224 ret = devm_add_action_or_reset(&pdev->dev, hmc425a_reg_disable, st); 225 if (ret) 226 return ret; 227 228 mutex_init(&st->lock); 229 230 indio_dev->dev.parent = &pdev->dev; 231 indio_dev->info = &hmc425a_info; 232 indio_dev->modes = INDIO_DIRECT_MODE; 233 234 return devm_iio_device_register(&pdev->dev, indio_dev); 235 } 236 237 static struct platform_driver hmc425a_driver = { 238 .driver = { 239 .name = KBUILD_MODNAME, 240 .of_match_table = hmc425a_of_match, 241 }, 242 .probe = hmc425a_probe, 243 }; 244 module_platform_driver(hmc425a_driver); 245 246 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>"); 247 MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers"); 248 MODULE_LICENSE("GPL v2"); 249