diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/iio/adc/qcom-spmi-iadc.c | 595 |
1 files changed, 595 insertions, 0 deletions
diff --git a/drivers/iio/adc/qcom-spmi-iadc.c b/drivers/iio/adc/qcom-spmi-iadc.c new file mode 100644 index 000000000..3f062cd61 --- /dev/null +++ b/drivers/iio/adc/qcom-spmi-iadc.c @@ -0,0 +1,595 @@ +/* + * Copyright (c) 2012-2014, The Linux Foundation. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/bitops.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/iio/iio.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/mutex.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> +#include <linux/slab.h> + +/* IADC register and bit definition */ +#define IADC_REVISION2 0x1 +#define IADC_REVISION2_SUPPORTED_IADC 1 + +#define IADC_PERPH_TYPE 0x4 +#define IADC_PERPH_TYPE_ADC 8 + +#define IADC_PERPH_SUBTYPE 0x5 +#define IADC_PERPH_SUBTYPE_IADC 3 + +#define IADC_STATUS1 0x8 +#define IADC_STATUS1_OP_MODE 4 +#define IADC_STATUS1_REQ_STS BIT(1) +#define IADC_STATUS1_EOC BIT(0) +#define IADC_STATUS1_REQ_STS_EOC_MASK 0x3 + +#define IADC_MODE_CTL 0x40 +#define IADC_OP_MODE_SHIFT 3 +#define IADC_OP_MODE_NORMAL 0 +#define IADC_TRIM_EN BIT(0) + +#define IADC_EN_CTL1 0x46 +#define IADC_EN_CTL1_SET BIT(7) + +#define IADC_CH_SEL_CTL 0x48 + +#define IADC_DIG_PARAM 0x50 +#define IADC_DIG_DEC_RATIO_SEL_SHIFT 2 + +#define IADC_HW_SETTLE_DELAY 0x51 + +#define IADC_CONV_REQ 0x52 +#define IADC_CONV_REQ_SET BIT(7) + +#define IADC_FAST_AVG_CTL 0x5a +#define IADC_FAST_AVG_EN 0x5b +#define IADC_FAST_AVG_EN_SET BIT(7) + +#define IADC_PERH_RESET_CTL3 0xda +#define IADC_FOLLOW_WARM_RB BIT(2) + +#define IADC_DATA 0x60 /* 16 bits */ + +#define IADC_SEC_ACCESS 0xd0 +#define IADC_SEC_ACCESS_DATA 0xa5 + +#define IADC_NOMINAL_RSENSE 0xf4 +#define IADC_NOMINAL_RSENSE_SIGN_MASK BIT(7) + +#define IADC_REF_GAIN_MICRO_VOLTS 17857 + +#define IADC_INT_RSENSE_DEVIATION 15625 /* nano Ohms per bit */ + +#define IADC_INT_RSENSE_IDEAL_VALUE 10000 /* micro Ohms */ +#define IADC_INT_RSENSE_DEFAULT_VALUE 7800 /* micro Ohms */ +#define IADC_INT_RSENSE_DEFAULT_GF 9000 /* micro Ohms */ +#define IADC_INT_RSENSE_DEFAULT_SMIC 9700 /* micro Ohms */ + +#define IADC_CONV_TIME_MIN_US 2000 +#define IADC_CONV_TIME_MAX_US 2100 + +#define IADC_DEF_PRESCALING 0 /* 1:1 */ +#define IADC_DEF_DECIMATION 0 /* 512 */ +#define IADC_DEF_HW_SETTLE_TIME 0 /* 0 us */ +#define IADC_DEF_AVG_SAMPLES 0 /* 1 sample */ + +/* IADC channel list */ +#define IADC_INT_RSENSE 0 +#define IADC_EXT_RSENSE 1 +#define IADC_GAIN_17P857MV 3 +#define IADC_EXT_OFFSET_CSP_CSN 5 +#define IADC_INT_OFFSET_CSP2_CSN2 6 + +/** + * struct iadc_chip - IADC Current ADC device structure. + * @regmap: regmap for register read/write. + * @dev: This device pointer. + * @base: base offset for the ADC peripheral. + * @rsense: Values of the internal and external sense resister in micro Ohms. + * @poll_eoc: Poll for end of conversion instead of waiting for IRQ. + * @offset: Raw offset values for the internal and external channels. + * @gain: Raw gain of the channels. + * @lock: ADC lock for access to the peripheral. + * @complete: ADC notification after end of conversion interrupt is received. + */ +struct iadc_chip { + struct regmap *regmap; + struct device *dev; + u16 base; + bool poll_eoc; + u32 rsense[2]; + u16 offset[2]; + u16 gain; + struct mutex lock; + struct completion complete; +}; + +static int iadc_read(struct iadc_chip *iadc, u16 offset, u8 *data) +{ + unsigned int val; + int ret; + + ret = regmap_read(iadc->regmap, iadc->base + offset, &val); + if (ret < 0) + return ret; + + *data = val; + return 0; +} + +static int iadc_write(struct iadc_chip *iadc, u16 offset, u8 data) +{ + return regmap_write(iadc->regmap, iadc->base + offset, data); +} + +static int iadc_reset(struct iadc_chip *iadc) +{ + u8 data; + int ret; + + ret = iadc_write(iadc, IADC_SEC_ACCESS, IADC_SEC_ACCESS_DATA); + if (ret < 0) + return ret; + + ret = iadc_read(iadc, IADC_PERH_RESET_CTL3, &data); + if (ret < 0) + return ret; + + ret = iadc_write(iadc, IADC_SEC_ACCESS, IADC_SEC_ACCESS_DATA); + if (ret < 0) + return ret; + + data |= IADC_FOLLOW_WARM_RB; + + return iadc_write(iadc, IADC_PERH_RESET_CTL3, data); +} + +static int iadc_set_state(struct iadc_chip *iadc, bool state) +{ + return iadc_write(iadc, IADC_EN_CTL1, state ? IADC_EN_CTL1_SET : 0); +} + +static void iadc_status_show(struct iadc_chip *iadc) +{ + u8 mode, sta1, chan, dig, en, req; + int ret; + + ret = iadc_read(iadc, IADC_MODE_CTL, &mode); + if (ret < 0) + return; + + ret = iadc_read(iadc, IADC_DIG_PARAM, &dig); + if (ret < 0) + return; + + ret = iadc_read(iadc, IADC_CH_SEL_CTL, &chan); + if (ret < 0) + return; + + ret = iadc_read(iadc, IADC_CONV_REQ, &req); + if (ret < 0) + return; + + ret = iadc_read(iadc, IADC_STATUS1, &sta1); + if (ret < 0) + return; + + ret = iadc_read(iadc, IADC_EN_CTL1, &en); + if (ret < 0) + return; + + dev_err(iadc->dev, + "mode:%02x en:%02x chan:%02x dig:%02x req:%02x sta1:%02x\n", + mode, en, chan, dig, req, sta1); +} + +static int iadc_configure(struct iadc_chip *iadc, int channel) +{ + u8 decim, mode; + int ret; + + /* Mode selection */ + mode = (IADC_OP_MODE_NORMAL << IADC_OP_MODE_SHIFT) | IADC_TRIM_EN; + ret = iadc_write(iadc, IADC_MODE_CTL, mode); + if (ret < 0) + return ret; + + /* Channel selection */ + ret = iadc_write(iadc, IADC_CH_SEL_CTL, channel); + if (ret < 0) + return ret; + + /* Digital parameter setup */ + decim = IADC_DEF_DECIMATION << IADC_DIG_DEC_RATIO_SEL_SHIFT; + ret = iadc_write(iadc, IADC_DIG_PARAM, decim); + if (ret < 0) + return ret; + + /* HW settle time delay */ + ret = iadc_write(iadc, IADC_HW_SETTLE_DELAY, IADC_DEF_HW_SETTLE_TIME); + if (ret < 0) + return ret; + + ret = iadc_write(iadc, IADC_FAST_AVG_CTL, IADC_DEF_AVG_SAMPLES); + if (ret < 0) + return ret; + + if (IADC_DEF_AVG_SAMPLES) + ret = iadc_write(iadc, IADC_FAST_AVG_EN, IADC_FAST_AVG_EN_SET); + else + ret = iadc_write(iadc, IADC_FAST_AVG_EN, 0); + + if (ret < 0) + return ret; + + if (!iadc->poll_eoc) + reinit_completion(&iadc->complete); + + ret = iadc_set_state(iadc, true); + if (ret < 0) + return ret; + + /* Request conversion */ + return iadc_write(iadc, IADC_CONV_REQ, IADC_CONV_REQ_SET); +} + +static int iadc_poll_wait_eoc(struct iadc_chip *iadc, unsigned int interval_us) +{ + unsigned int count, retry; + int ret; + u8 sta1; + + retry = interval_us / IADC_CONV_TIME_MIN_US; + + for (count = 0; count < retry; count++) { + ret = iadc_read(iadc, IADC_STATUS1, &sta1); + if (ret < 0) + return ret; + + sta1 &= IADC_STATUS1_REQ_STS_EOC_MASK; + if (sta1 == IADC_STATUS1_EOC) + return 0; + + usleep_range(IADC_CONV_TIME_MIN_US, IADC_CONV_TIME_MAX_US); + } + + iadc_status_show(iadc); + + return -ETIMEDOUT; +} + +static int iadc_read_result(struct iadc_chip *iadc, u16 *data) +{ + return regmap_bulk_read(iadc->regmap, iadc->base + IADC_DATA, data, 2); +} + +static int iadc_do_conversion(struct iadc_chip *iadc, int chan, u16 *data) +{ + unsigned int wait; + int ret; + + ret = iadc_configure(iadc, chan); + if (ret < 0) + goto exit; + + wait = BIT(IADC_DEF_AVG_SAMPLES) * IADC_CONV_TIME_MIN_US * 2; + + if (iadc->poll_eoc) { + ret = iadc_poll_wait_eoc(iadc, wait); + } else { + ret = wait_for_completion_timeout(&iadc->complete, + usecs_to_jiffies(wait)); + if (!ret) + ret = -ETIMEDOUT; + else + /* double check conversion status */ + ret = iadc_poll_wait_eoc(iadc, IADC_CONV_TIME_MIN_US); + } + + if (!ret) + ret = iadc_read_result(iadc, data); +exit: + iadc_set_state(iadc, false); + if (ret < 0) + dev_err(iadc->dev, "conversion failed\n"); + + return ret; +} + +static int iadc_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct iadc_chip *iadc = iio_priv(indio_dev); + s32 isense_ua, vsense_uv; + u16 adc_raw, vsense_raw; + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&iadc->lock); + ret = iadc_do_conversion(iadc, chan->channel, &adc_raw); + mutex_unlock(&iadc->lock); + if (ret < 0) + return ret; + + vsense_raw = adc_raw - iadc->offset[chan->channel]; + + vsense_uv = vsense_raw * IADC_REF_GAIN_MICRO_VOLTS; + vsense_uv /= (s32)iadc->gain - iadc->offset[chan->channel]; + + isense_ua = vsense_uv / iadc->rsense[chan->channel]; + + dev_dbg(iadc->dev, "off %d gain %d adc %d %duV I %duA\n", + iadc->offset[chan->channel], iadc->gain, + adc_raw, vsense_uv, isense_ua); + + *val = isense_ua; + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + *val = 0; + *val2 = 1000; + return IIO_VAL_INT_PLUS_MICRO; + } + + return -EINVAL; +} + +static const struct iio_info iadc_info = { + .read_raw = iadc_read_raw, +}; + +static irqreturn_t iadc_isr(int irq, void *dev_id) +{ + struct iadc_chip *iadc = dev_id; + + complete(&iadc->complete); + + return IRQ_HANDLED; +} + +static int iadc_update_offset(struct iadc_chip *iadc) +{ + int ret; + + ret = iadc_do_conversion(iadc, IADC_GAIN_17P857MV, &iadc->gain); + if (ret < 0) + return ret; + + ret = iadc_do_conversion(iadc, IADC_INT_OFFSET_CSP2_CSN2, + &iadc->offset[IADC_INT_RSENSE]); + if (ret < 0) + return ret; + + if (iadc->gain == iadc->offset[IADC_INT_RSENSE]) { + dev_err(iadc->dev, "error: internal offset == gain %d\n", + iadc->gain); + return -EINVAL; + } + + ret = iadc_do_conversion(iadc, IADC_EXT_OFFSET_CSP_CSN, + &iadc->offset[IADC_EXT_RSENSE]); + if (ret < 0) + return ret; + + if (iadc->gain == iadc->offset[IADC_EXT_RSENSE]) { + dev_err(iadc->dev, "error: external offset == gain %d\n", + iadc->gain); + return -EINVAL; + } + + return 0; +} + +static int iadc_version_check(struct iadc_chip *iadc) +{ + u8 val; + int ret; + + ret = iadc_read(iadc, IADC_PERPH_TYPE, &val); + if (ret < 0) + return ret; + + if (val < IADC_PERPH_TYPE_ADC) { + dev_err(iadc->dev, "%d is not ADC\n", val); + return -EINVAL; + } + + ret = iadc_read(iadc, IADC_PERPH_SUBTYPE, &val); + if (ret < 0) + return ret; + + if (val < IADC_PERPH_SUBTYPE_IADC) { + dev_err(iadc->dev, "%d is not IADC\n", val); + return -EINVAL; + } + + ret = iadc_read(iadc, IADC_REVISION2, &val); + if (ret < 0) + return ret; + + if (val < IADC_REVISION2_SUPPORTED_IADC) { + dev_err(iadc->dev, "revision %d not supported\n", val); + return -EINVAL; + } + + return 0; +} + +static int iadc_rsense_read(struct iadc_chip *iadc, struct device_node *node) +{ + int ret, sign, int_sense; + u8 deviation; + + ret = of_property_read_u32(node, "qcom,external-resistor-micro-ohms", + &iadc->rsense[IADC_EXT_RSENSE]); + if (ret < 0) + iadc->rsense[IADC_EXT_RSENSE] = IADC_INT_RSENSE_IDEAL_VALUE; + + if (!iadc->rsense[IADC_EXT_RSENSE]) { + dev_err(iadc->dev, "external resistor can't be zero Ohms"); + return -EINVAL; + } + + ret = iadc_read(iadc, IADC_NOMINAL_RSENSE, &deviation); + if (ret < 0) + return ret; + + /* + * Deviation value stored is an offset from 10 mili Ohms, bit 7 is + * the sign, the remaining bits have an LSB of 15625 nano Ohms. + */ + sign = (deviation & IADC_NOMINAL_RSENSE_SIGN_MASK) ? -1 : 1; + + deviation &= ~IADC_NOMINAL_RSENSE_SIGN_MASK; + + /* Scale it to nono Ohms */ + int_sense = IADC_INT_RSENSE_IDEAL_VALUE * 1000; + int_sense += sign * deviation * IADC_INT_RSENSE_DEVIATION; + int_sense /= 1000; /* micro Ohms */ + + iadc->rsense[IADC_INT_RSENSE] = int_sense; + return 0; +} + +static const struct iio_chan_spec iadc_channels[] = { + { + .type = IIO_CURRENT, + .datasheet_name = "INTERNAL_RSENSE", + .channel = 0, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE), + .indexed = 1, + }, + { + .type = IIO_CURRENT, + .datasheet_name = "EXTERNAL_RSENSE", + .channel = 1, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | + BIT(IIO_CHAN_INFO_SCALE), + .indexed = 1, + }, +}; + +static int iadc_probe(struct platform_device *pdev) +{ + struct device_node *node = pdev->dev.of_node; + struct device *dev = &pdev->dev; + struct iio_dev *indio_dev; + struct iadc_chip *iadc; + int ret, irq_eoc; + u32 res; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*iadc)); + if (!indio_dev) + return -ENOMEM; + + iadc = iio_priv(indio_dev); + iadc->dev = dev; + + iadc->regmap = dev_get_regmap(dev->parent, NULL); + if (!iadc->regmap) + return -ENODEV; + + init_completion(&iadc->complete); + mutex_init(&iadc->lock); + + ret = of_property_read_u32(node, "reg", &res); + if (ret < 0) + return -ENODEV; + + iadc->base = res; + + ret = iadc_version_check(iadc); + if (ret < 0) + return -ENODEV; + + ret = iadc_rsense_read(iadc, node); + if (ret < 0) + return -ENODEV; + + dev_dbg(iadc->dev, "sense resistors %d and %d micro Ohm\n", + iadc->rsense[IADC_INT_RSENSE], + iadc->rsense[IADC_EXT_RSENSE]); + + irq_eoc = platform_get_irq(pdev, 0); + if (irq_eoc == -EPROBE_DEFER) + return irq_eoc; + + if (irq_eoc < 0) + iadc->poll_eoc = true; + + ret = iadc_reset(iadc); + if (ret < 0) { + dev_err(dev, "reset failed\n"); + return ret; + } + + if (!iadc->poll_eoc) { + ret = devm_request_irq(dev, irq_eoc, iadc_isr, 0, + "spmi-iadc", iadc); + if (!ret) + enable_irq_wake(irq_eoc); + else + return ret; + } else { + device_init_wakeup(iadc->dev, 1); + } + + ret = iadc_update_offset(iadc); + if (ret < 0) { + dev_err(dev, "failed offset calibration\n"); + return ret; + } + + indio_dev->dev.parent = dev; + indio_dev->dev.of_node = node; + indio_dev->name = pdev->name; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->info = &iadc_info; + indio_dev->channels = iadc_channels; + indio_dev->num_channels = ARRAY_SIZE(iadc_channels); + + return devm_iio_device_register(dev, indio_dev); +} + +static const struct of_device_id iadc_match_table[] = { + { .compatible = "qcom,spmi-iadc" }, + { } +}; + +MODULE_DEVICE_TABLE(of, iadc_match_table); + +static struct platform_driver iadc_driver = { + .driver = { + .name = "qcom-spmi-iadc", + .of_match_table = iadc_match_table, + }, + .probe = iadc_probe, +}; + +module_platform_driver(iadc_driver); + +MODULE_ALIAS("platform:qcom-spmi-iadc"); +MODULE_DESCRIPTION("Qualcomm SPMI PMIC current ADC driver"); +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Ivan T. Ivanov <iivanov@mm-sol.com>"); |