1 // SPDX-License-Identifier: GPL-2.0
3  * HMC425A and similar Gain Amplifiers
26  * The LTC6373 amplifier supports configuring gain using GPIO's with the following
30  * From here, it is observed that all values are multiples of the '2' gain setting,
56 	int				(*gain_dB_to_code)(int gain, int *code);
63 	struct	gpio_descs *gpios;  member
64 	u32	gain;  member
70 	const struct hmc425a_chip_info *inf = st->chip_info;  in gain_dB_to_code()
71 	int gain;  in gain_dB_to_code()  local
74 		gain = (val * 1000) - (val2 / 1000);  in gain_dB_to_code()
76 		gain = (val * 1000) + (val2 / 1000);  in gain_dB_to_code()
78 	if (gain > inf->gain_max || gain < inf->gain_min)  in gain_dB_to_code()
79 		return -EINVAL;  in gain_dB_to_code()
80 	if (st->powerdown)  in gain_dB_to_code()
81 		return -EPERM;  in gain_dB_to_code()
83 	return st->chip_info->gain_dB_to_code(gain, code);  in gain_dB_to_code()
86 static int hmc425a_gain_dB_to_code(int gain, int *code)  in hmc425a_gain_dB_to_code()  argument
88 	*code = ~((abs(gain) / 500) & 0x3F);  in hmc425a_gain_dB_to_code()
92 static int hmc540s_gain_dB_to_code(int gain, int *code)  in hmc540s_gain_dB_to_code()  argument
94 	*code = ~((abs(gain) / 1000) & 0xF);  in hmc540s_gain_dB_to_code()
98 static int adrf5740_gain_dB_to_code(int gain, int *code)  in adrf5740_gain_dB_to_code()  argument
100 	int temp = (abs(gain) / 2000) & 0xF;  in adrf5740_gain_dB_to_code()
102 	/* Bit [0-3]: 2dB 4dB 8dB 8dB */  in adrf5740_gain_dB_to_code()
107 static int ltc6373_gain_dB_to_code(int gain, int *code)  in ltc6373_gain_dB_to_code()  argument
109 	*code = ~(DIV_ROUND_CLOSEST(gain, LTC6373_CONVERSION_CONSTANT) + 3)  in ltc6373_gain_dB_to_code()
116 	if (st->powerdown)  in code_to_gain_dB()
117 		return -EPERM;  in code_to_gain_dB()
118 	return st->chip_info->code_to_gain_dB(st->gain, val, val2);  in code_to_gain_dB()
123 	*val = (~code * -500) / 1000;  in hmc425a_code_to_gain_dB()
124 	*val2 = ((~code * -500) % 1000) * 1000;  in hmc425a_code_to_gain_dB()
130 	*val = (~code * -1000) / 1000;  in hmc540s_code_to_gain_dB()
131 	*val2 = ((~code * -1000) % 1000) * 1000;  in hmc540s_code_to_gain_dB()
138 	 * Bit [0-3]: 2dB 4dB 8dB 8dB  in adrf5740_code_to_gain_dB()
142 	*val = (code * -2000) / 1000;  in adrf5740_code_to_gain_dB()
143 	*val2 = ((code * -2000) % 1000) * 1000;  in adrf5740_code_to_gain_dB()
149 	int gain = ((~code & LTC6373_CONVERSION_MASK) - 3) *  in ltc6373_code_to_gain_dB()  local
152 	*val = gain / 1000;  in ltc6373_code_to_gain_dB()
153 	*val2 = (gain % 1000) * 1000;  in ltc6373_code_to_gain_dB()
164 	gpiod_set_array_value_cansleep(st->gpios->ndescs, st->gpios->desc,  in hmc425a_write()
176 	mutex_lock(&st->lock);  in hmc425a_read_raw()
185 		ret = -EINVAL;  in hmc425a_read_raw()
187 	mutex_unlock(&st->lock);  in hmc425a_read_raw()
199 	mutex_lock(&st->lock);  in hmc425a_write_raw()
205 		st->gain = code;  in hmc425a_write_raw()
207 		ret = hmc425a_write(indio_dev, st->gain);  in hmc425a_write_raw()
210 		ret = -EINVAL;  in hmc425a_write_raw()
212 	mutex_unlock(&st->lock);  in hmc425a_write_raw()
225 		return -EINVAL;  in hmc425a_write_raw_get_fmt()
242 	return sysfs_emit(buf, "%d\n", st->powerdown);  in ltc6373_read_powerdown()
259 	mutex_lock(&st->lock);  in ltc6373_write_powerdown()
260 	st->powerdown = powerdown;  in ltc6373_write_powerdown()
261 	code = (powerdown) ? LTC6373_SHUTDOWN : st->gain;  in ltc6373_write_powerdown()
263 	mutex_unlock(&st->lock);  in ltc6373_write_powerdown()
310 		.gain_min = -31500,
312 		.default_gain = -0x40, /* set default gain -31.5db*/
321 		.gain_min = -15000,
323 		.default_gain = -0x10, /* set default gain -15.0db*/
332 		.gain_min = -22000,
334 		.default_gain = 0xF, /* set default gain -22.0db*/
343 		.gain_min = -12041, /* gain setting x0.25*/
344 		.gain_max = 24082,  /* gain setting x16  */
359 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));  in hmc425a_probe()
361 		return -ENOMEM;  in hmc425a_probe()
365 	st->chip_info = device_get_match_data(&pdev->dev);  in hmc425a_probe()
366 	indio_dev->num_channels = st->chip_info->num_channels;  in hmc425a_probe()
367 	indio_dev->channels = st->chip_info->channels;  in hmc425a_probe()
368 	indio_dev->name = st->chip_info->name;  in hmc425a_probe()
369 	st->gain = st->chip_info->default_gain;  in hmc425a_probe()
371 	st->gpios = devm_gpiod_get_array(&pdev->dev, "ctrl", GPIOD_OUT_LOW);  in hmc425a_probe()
372 	if (IS_ERR(st->gpios))  in hmc425a_probe()
373 		return dev_err_probe(&pdev->dev, PTR_ERR(st->gpios),  in hmc425a_probe()
374 				     "failed to get gpios\n");  in hmc425a_probe()
376 	if (st->gpios->ndescs != st->chip_info->num_gpios) {  in hmc425a_probe()
377 		dev_err(&pdev->dev, "%d GPIOs needed to operate\n",  in hmc425a_probe()
378 			st->chip_info->num_gpios);  in hmc425a_probe()
379 		return -ENODEV;  in hmc425a_probe()
382 	ret = devm_regulator_get_enable(&pdev->dev, "vcc-supply");  in hmc425a_probe()
386 	mutex_init(&st->lock);  in hmc425a_probe()
388 	indio_dev->info = &hmc425a_info;  in hmc425a_probe()
389 	indio_dev->modes = INDIO_DIRECT_MODE;  in hmc425a_probe()
391 	if (st->chip_info->has_powerdown) {  in hmc425a_probe()
392 		st->powerdown = true;  in hmc425a_probe()
393 		hmc425a_write(indio_dev, st->chip_info->powerdown_val);  in hmc425a_probe()
395 		/* Set default gain */  in hmc425a_probe()
396 		hmc425a_write(indio_dev, st->gain);  in hmc425a_probe()
399 	return devm_iio_device_register(&pdev->dev, indio_dev);  in hmc425a_probe()
426 MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers");