diff options
Diffstat (limited to 'drivers/iio/adc/sc27xx_adc.c')
| -rw-r--r-- | drivers/iio/adc/sc27xx_adc.c | 522 |
1 files changed, 522 insertions, 0 deletions
diff --git a/drivers/iio/adc/sc27xx_adc.c b/drivers/iio/adc/sc27xx_adc.c new file mode 100644 index 000000000000..2b60efea0c39 --- /dev/null +++ b/drivers/iio/adc/sc27xx_adc.c @@ -0,0 +1,522 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2018 Spreadtrum Communications Inc. + +#include <linux/hwspinlock.h> +#include <linux/iio/iio.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> + +/* PMIC global registers definition */ +#define SC27XX_MODULE_EN 0xc08 +#define SC27XX_MODULE_ADC_EN BIT(5) +#define SC27XX_ARM_CLK_EN 0xc10 +#define SC27XX_CLK_ADC_EN BIT(5) +#define SC27XX_CLK_ADC_CLK_EN BIT(6) + +/* ADC controller registers definition */ +#define SC27XX_ADC_CTL 0x0 +#define SC27XX_ADC_CH_CFG 0x4 +#define SC27XX_ADC_DATA 0x4c +#define SC27XX_ADC_INT_EN 0x50 +#define SC27XX_ADC_INT_CLR 0x54 +#define SC27XX_ADC_INT_STS 0x58 +#define SC27XX_ADC_INT_RAW 0x5c + +/* Bits and mask definition for SC27XX_ADC_CTL register */ +#define SC27XX_ADC_EN BIT(0) +#define SC27XX_ADC_CHN_RUN BIT(1) +#define SC27XX_ADC_12BIT_MODE BIT(2) +#define SC27XX_ADC_RUN_NUM_MASK GENMASK(7, 4) +#define SC27XX_ADC_RUN_NUM_SHIFT 4 + +/* Bits and mask definition for SC27XX_ADC_CH_CFG register */ +#define SC27XX_ADC_CHN_ID_MASK GENMASK(4, 0) +#define SC27XX_ADC_SCALE_MASK GENMASK(10, 8) +#define SC27XX_ADC_SCALE_SHIFT 8 + +/* Bits definitions for SC27XX_ADC_INT_EN registers */ +#define SC27XX_ADC_IRQ_EN BIT(0) + +/* Bits definitions for SC27XX_ADC_INT_CLR registers */ +#define SC27XX_ADC_IRQ_CLR BIT(0) + +/* Mask definition for SC27XX_ADC_DATA register */ +#define SC27XX_ADC_DATA_MASK GENMASK(11, 0) + +/* Timeout (ms) for the trylock of hardware spinlocks */ +#define SC27XX_ADC_HWLOCK_TIMEOUT 5000 + +/* Maximum ADC channel number */ +#define SC27XX_ADC_CHANNEL_MAX 32 + +/* ADC voltage ratio definition */ +#define SC27XX_VOLT_RATIO(n, d) \ + (((n) << SC27XX_RATIO_NUMERATOR_OFFSET) | (d)) +#define SC27XX_RATIO_NUMERATOR_OFFSET 16 +#define SC27XX_RATIO_DENOMINATOR_MASK GENMASK(15, 0) + +struct sc27xx_adc_data { + struct device *dev; + struct regmap *regmap; + /* + * One hardware spinlock to synchronize between the multiple + * subsystems which will access the unique ADC controller. + */ + struct hwspinlock *hwlock; + struct completion completion; + int channel_scale[SC27XX_ADC_CHANNEL_MAX]; + u32 base; + int value; + int irq; +}; + +struct sc27xx_adc_linear_graph { + int volt0; + int adc0; + int volt1; + int adc1; +}; + +/* + * According to the datasheet, we can convert one ADC value to one voltage value + * through 2 points in the linear graph. If the voltage is less than 1.2v, we + * should use the small-scale graph, and if more than 1.2v, we should use the + * big-scale graph. + */ +static const struct sc27xx_adc_linear_graph big_scale_graph = { + 4200, 3310, + 3600, 2832, +}; + +static const struct sc27xx_adc_linear_graph small_scale_graph = { + 1000, 3413, + 100, 341, +}; + +static int sc27xx_adc_get_ratio(int channel, int scale) +{ + switch (channel) { + case 1: + case 2: + case 3: + case 4: + return scale ? SC27XX_VOLT_RATIO(400, 1025) : + SC27XX_VOLT_RATIO(1, 1); + case 5: + return SC27XX_VOLT_RATIO(7, 29); + case 6: + return SC27XX_VOLT_RATIO(375, 9000); + case 7: + case 8: + return scale ? SC27XX_VOLT_RATIO(100, 125) : + SC27XX_VOLT_RATIO(1, 1); + case 19: + return SC27XX_VOLT_RATIO(1, 3); + default: + return SC27XX_VOLT_RATIO(1, 1); + } + return SC27XX_VOLT_RATIO(1, 1); +} + +static int sc27xx_adc_read(struct sc27xx_adc_data *data, int channel, + int scale, int *val) +{ + int ret; + u32 tmp; + + reinit_completion(&data->completion); + + ret = hwspin_lock_timeout_raw(data->hwlock, SC27XX_ADC_HWLOCK_TIMEOUT); + if (ret) { + dev_err(data->dev, "timeout to get the hwspinlock\n"); + return ret; + } + + ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL, + SC27XX_ADC_EN, SC27XX_ADC_EN); + if (ret) + goto unlock_adc; + + /* Configure the channel id and scale */ + tmp = (scale << SC27XX_ADC_SCALE_SHIFT) & SC27XX_ADC_SCALE_MASK; + tmp |= channel & SC27XX_ADC_CHN_ID_MASK; + ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CH_CFG, + SC27XX_ADC_CHN_ID_MASK | SC27XX_ADC_SCALE_MASK, + tmp); + if (ret) + goto disable_adc; + + /* Select 12bit conversion mode, and only sample 1 time */ + tmp = SC27XX_ADC_12BIT_MODE; + tmp |= (0 << SC27XX_ADC_RUN_NUM_SHIFT) & SC27XX_ADC_RUN_NUM_MASK; + ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL, + SC27XX_ADC_RUN_NUM_MASK | SC27XX_ADC_12BIT_MODE, + tmp); + if (ret) + goto disable_adc; + + ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL, + SC27XX_ADC_CHN_RUN, SC27XX_ADC_CHN_RUN); + if (ret) + goto disable_adc; + + wait_for_completion(&data->completion); + +disable_adc: + regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL, + SC27XX_ADC_EN, 0); +unlock_adc: + hwspin_unlock_raw(data->hwlock); + + if (!ret) + *val = data->value; + + return ret; +} + +static irqreturn_t sc27xx_adc_isr(int irq, void *dev_id) +{ + struct sc27xx_adc_data *data = dev_id; + int ret; + + ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_INT_CLR, + SC27XX_ADC_IRQ_CLR, SC27XX_ADC_IRQ_CLR); + if (ret) + return IRQ_RETVAL(ret); + + ret = regmap_read(data->regmap, data->base + SC27XX_ADC_DATA, + &data->value); + if (ret) + return IRQ_RETVAL(ret); + + data->value &= SC27XX_ADC_DATA_MASK; + complete(&data->completion); + + return IRQ_HANDLED; +} + +static void sc27xx_adc_volt_ratio(struct sc27xx_adc_data *data, + int channel, int scale, + u32 *div_numerator, u32 *div_denominator) +{ + u32 ratio = sc27xx_adc_get_ratio(channel, scale); + + *div_numerator = ratio >> SC27XX_RATIO_NUMERATOR_OFFSET; + *div_denominator = ratio & SC27XX_RATIO_DENOMINATOR_MASK; +} + +static int sc27xx_adc_to_volt(const struct sc27xx_adc_linear_graph *graph, + int raw_adc) +{ + int tmp; + + tmp = (graph->volt0 - graph->volt1) * (raw_adc - graph->adc1); + tmp /= (graph->adc0 - graph->adc1); + tmp += graph->volt1; + + return tmp < 0 ? 0 : tmp; +} + +static int sc27xx_adc_convert_volt(struct sc27xx_adc_data *data, int channel, + int scale, int raw_adc) +{ + u32 numerator, denominator; + u32 volt; + + /* + * Convert ADC values to voltage values according to the linear graph, + * and channel 5 and channel 1 has been calibrated, so we can just + * return the voltage values calculated by the linear graph. But other + * channels need be calculated to the real voltage values with the + * voltage ratio. + */ + switch (channel) { + case 5: + return sc27xx_adc_to_volt(&big_scale_graph, raw_adc); + + case 1: + return sc27xx_adc_to_volt(&small_scale_graph, raw_adc); + + default: + volt = sc27xx_adc_to_volt(&small_scale_graph, raw_adc); + break; + } + + sc27xx_adc_volt_ratio(data, channel, scale, &numerator, &denominator); + + return (volt * denominator + numerator / 2) / numerator; +} + +static int sc27xx_adc_read_processed(struct sc27xx_adc_data *data, + int channel, int scale, int *val) +{ + int ret, raw_adc; + + ret = sc27xx_adc_read(data, channel, scale, &raw_adc); + if (ret) + return ret; + + *val = sc27xx_adc_convert_volt(data, channel, scale, raw_adc); + return 0; +} + +static int sc27xx_adc_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct sc27xx_adc_data *data = iio_priv(indio_dev); + int scale = data->channel_scale[chan->channel]; + int ret, tmp; + + switch (mask) { + case IIO_CHAN_INFO_PROCESSED: + mutex_lock(&indio_dev->mlock); + ret = sc27xx_adc_read_processed(data, chan->channel, scale, + &tmp); + mutex_unlock(&indio_dev->mlock); + + if (ret) + return ret; + + *val = tmp; + return IIO_VAL_INT; + + case IIO_CHAN_INFO_SCALE: + *val = scale; + return IIO_VAL_INT; + + default: + return -EINVAL; + } +} + +static int sc27xx_adc_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + struct sc27xx_adc_data *data = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_SCALE: + data->channel_scale[chan->channel] = val; + return IIO_VAL_INT; + + default: + return -EINVAL; + } +} + +static const struct iio_info sc27xx_info = { + .read_raw = &sc27xx_adc_read_raw, + .write_raw = &sc27xx_adc_write_raw, +}; + +#define SC27XX_ADC_CHANNEL(index) { \ + .type = IIO_VOLTAGE, \ + .channel = index, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) | \ + BIT(IIO_CHAN_INFO_SCALE), \ + .datasheet_name = "CH##index", \ + .indexed = 1, \ +} + +static const struct iio_chan_spec sc27xx_channels[] = { + SC27XX_ADC_CHANNEL(0), + SC27XX_ADC_CHANNEL(1), + SC27XX_ADC_CHANNEL(2), + SC27XX_ADC_CHANNEL(3), + SC27XX_ADC_CHANNEL(4), + SC27XX_ADC_CHANNEL(5), + SC27XX_ADC_CHANNEL(6), + SC27XX_ADC_CHANNEL(7), + SC27XX_ADC_CHANNEL(8), + SC27XX_ADC_CHANNEL(9), + SC27XX_ADC_CHANNEL(10), + SC27XX_ADC_CHANNEL(11), + SC27XX_ADC_CHANNEL(12), + SC27XX_ADC_CHANNEL(13), + SC27XX_ADC_CHANNEL(14), + SC27XX_ADC_CHANNEL(15), + SC27XX_ADC_CHANNEL(16), + SC27XX_ADC_CHANNEL(17), + SC27XX_ADC_CHANNEL(18), + SC27XX_ADC_CHANNEL(19), + SC27XX_ADC_CHANNEL(20), + SC27XX_ADC_CHANNEL(21), + SC27XX_ADC_CHANNEL(22), + SC27XX_ADC_CHANNEL(23), + SC27XX_ADC_CHANNEL(24), + SC27XX_ADC_CHANNEL(25), + SC27XX_ADC_CHANNEL(26), + SC27XX_ADC_CHANNEL(27), + SC27XX_ADC_CHANNEL(28), + SC27XX_ADC_CHANNEL(29), + SC27XX_ADC_CHANNEL(30), + SC27XX_ADC_CHANNEL(31), +}; + +static int sc27xx_adc_enable(struct sc27xx_adc_data *data) +{ + int ret; + + ret = regmap_update_bits(data->regmap, SC27XX_MODULE_EN, + SC27XX_MODULE_ADC_EN, SC27XX_MODULE_ADC_EN); + if (ret) + return ret; + + /* Enable ADC work clock and controller clock */ + ret = regmap_update_bits(data->regmap, SC27XX_ARM_CLK_EN, + SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN, + SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN); + if (ret) + goto disable_adc; + + ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_INT_EN, + SC27XX_ADC_IRQ_EN, SC27XX_ADC_IRQ_EN); + if (ret) + goto disable_clk; + + return 0; + +disable_clk: + regmap_update_bits(data->regmap, SC27XX_ARM_CLK_EN, + SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN, 0); +disable_adc: + regmap_update_bits(data->regmap, SC27XX_MODULE_EN, + SC27XX_MODULE_ADC_EN, 0); + + return ret; +} + +static void sc27xx_adc_disable(void *_data) +{ + struct sc27xx_adc_data *data = _data; + + regmap_update_bits(data->regmap, data->base + SC27XX_ADC_INT_EN, + SC27XX_ADC_IRQ_EN, 0); + + /* Disable ADC work clock and controller clock */ + regmap_update_bits(data->regmap, SC27XX_ARM_CLK_EN, + SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN, 0); + + regmap_update_bits(data->regmap, SC27XX_MODULE_EN, + SC27XX_MODULE_ADC_EN, 0); +} + +static void sc27xx_adc_free_hwlock(void *_data) +{ + struct hwspinlock *hwlock = _data; + + hwspin_lock_free(hwlock); +} + +static int sc27xx_adc_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct sc27xx_adc_data *sc27xx_data; + struct iio_dev *indio_dev; + int ret; + + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*sc27xx_data)); + if (!indio_dev) + return -ENOMEM; + + sc27xx_data = iio_priv(indio_dev); + + sc27xx_data->regmap = dev_get_regmap(pdev->dev.parent, NULL); + if (!sc27xx_data->regmap) { + dev_err(&pdev->dev, "failed to get ADC regmap\n"); + return -ENODEV; + } + + ret = of_property_read_u32(np, "reg", &sc27xx_data->base); + if (ret) { + dev_err(&pdev->dev, "failed to get ADC base address\n"); + return ret; + } + + sc27xx_data->irq = platform_get_irq(pdev, 0); + if (sc27xx_data->irq < 0) { + dev_err(&pdev->dev, "failed to get ADC irq number\n"); + return sc27xx_data->irq; + } + + ret = of_hwspin_lock_get_id(np, 0); + if (ret < 0) { + dev_err(&pdev->dev, "failed to get hwspinlock id\n"); + return ret; + } + + sc27xx_data->hwlock = hwspin_lock_request_specific(ret); + if (!sc27xx_data->hwlock) { + dev_err(&pdev->dev, "failed to request hwspinlock\n"); + return -ENXIO; + } + + ret = devm_add_action(&pdev->dev, sc27xx_adc_free_hwlock, + sc27xx_data->hwlock); + if (ret) { + sc27xx_adc_free_hwlock(sc27xx_data->hwlock); + dev_err(&pdev->dev, "failed to add hwspinlock action\n"); + return ret; + } + + init_completion(&sc27xx_data->completion); + sc27xx_data->dev = &pdev->dev; + + ret = sc27xx_adc_enable(sc27xx_data); + if (ret) { + dev_err(&pdev->dev, "failed to enable ADC module\n"); + return ret; + } + + ret = devm_add_action(&pdev->dev, sc27xx_adc_disable, sc27xx_data); + if (ret) { + sc27xx_adc_disable(sc27xx_data); + dev_err(&pdev->dev, "failed to add ADC disable action\n"); + return ret; + } + + ret = devm_request_threaded_irq(&pdev->dev, sc27xx_data->irq, NULL, + sc27xx_adc_isr, IRQF_ONESHOT, + pdev->name, sc27xx_data); + if (ret) { + dev_err(&pdev->dev, "failed to request ADC irq\n"); + return ret; + } + + indio_dev->dev.parent = &pdev->dev; + indio_dev->name = dev_name(&pdev->dev); + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->info = &sc27xx_info; + indio_dev->channels = sc27xx_channels; + indio_dev->num_channels = ARRAY_SIZE(sc27xx_channels); + ret = devm_iio_device_register(&pdev->dev, indio_dev); + if (ret) + dev_err(&pdev->dev, "could not register iio (ADC)"); + + return ret; +} + +static const struct of_device_id sc27xx_adc_of_match[] = { + { .compatible = "sprd,sc2731-adc", }, + { } +}; + +static struct platform_driver sc27xx_adc_driver = { + .probe = sc27xx_adc_probe, + .driver = { + .name = "sc27xx-adc", + .of_match_table = sc27xx_adc_of_match, + }, +}; + +module_platform_driver(sc27xx_adc_driver); + +MODULE_AUTHOR("Freeman Liu <freeman.liu@spreadtrum.com>"); +MODULE_DESCRIPTION("Spreadtrum SC27XX ADC Driver"); +MODULE_LICENSE("GPL v2"); |