diff options
Diffstat (limited to 'drivers/iio/adc/sophgo-cv1800b-adc.c')
| -rw-r--r-- | drivers/iio/adc/sophgo-cv1800b-adc.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/drivers/iio/adc/sophgo-cv1800b-adc.c b/drivers/iio/adc/sophgo-cv1800b-adc.c new file mode 100644 index 000000000000..0951deb7b111 --- /dev/null +++ b/drivers/iio/adc/sophgo-cv1800b-adc.c @@ -0,0 +1,227 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Sophgo CV1800B SARADC Driver + * + * Copyright (C) Bootlin 2024 + * Author: Thomas Bonnefille <thomas.bonnefille@bootlin.com> + */ + +#include <linux/array_size.h> +#include <linux/bitfield.h> +#include <linux/bits.h> +#include <linux/cleanup.h> +#include <linux/clk.h> +#include <linux/completion.h> +#include <linux/err.h> +#include <linux/interrupt.h> +#include <linux/iopoll.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/platform_device.h> +#include <linux/types.h> + +#include <linux/iio/iio.h> + +#define CV1800B_ADC_CTRL_REG 0x04 +#define CV1800B_ADC_EN BIT(0) +#define CV1800B_ADC_SEL(x) BIT((x) + 5) +#define CV1800B_ADC_STATUS_REG 0x08 +#define CV1800B_ADC_BUSY BIT(0) +#define CV1800B_ADC_CYC_SET_REG 0x0C +#define CV1800B_MASK_STARTUP_CYCLE GENMASK(4, 0) +#define CV1800B_MASK_SAMPLE_WINDOW GENMASK(11, 8) +#define CV1800B_MASK_CLKDIV GENMASK(15, 12) +#define CV1800B_MASK_COMPARE_CYCLE GENMASK(19, 16) +#define CV1800B_ADC_CH_RESULT_REG(x) (0x14 + 4 * (x)) +#define CV1800B_ADC_CH_RESULT GENMASK(11, 0) +#define CV1800B_ADC_CH_VALID BIT(15) +#define CV1800B_ADC_INTR_EN_REG 0x20 +#define CV1800B_ADC_INTR_CLR_REG 0x24 +#define CV1800B_ADC_INTR_CLR_BIT BIT(0) +#define CV1800B_ADC_INTR_STA_REG 0x28 +#define CV1800B_ADC_INTR_STA_BIT BIT(0) +#define CV1800B_READ_TIMEOUT_MS 1000 +#define CV1800B_READ_TIMEOUT_US (CV1800B_READ_TIMEOUT_MS * 1000) + +#define CV1800B_ADC_CHANNEL(index) \ + { \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = index, \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\ + .scan_index = index, \ + } + +struct cv1800b_adc { + struct completion completion; + void __iomem *regs; + struct mutex lock; /* ADC Control and Result register */ + struct clk *clk; + int irq; +}; + +static const struct iio_chan_spec sophgo_channels[] = { + CV1800B_ADC_CHANNEL(0), + CV1800B_ADC_CHANNEL(1), + CV1800B_ADC_CHANNEL(2), +}; + +static void cv1800b_adc_start_measurement(struct cv1800b_adc *saradc, + int channel) +{ + writel(0, saradc->regs + CV1800B_ADC_CTRL_REG); + writel(CV1800B_ADC_SEL(channel) | CV1800B_ADC_EN, + saradc->regs + CV1800B_ADC_CTRL_REG); +} + +static int cv1800b_adc_wait(struct cv1800b_adc *saradc) +{ + if (saradc->irq < 0) { + u32 reg; + + return readl_poll_timeout(saradc->regs + CV1800B_ADC_STATUS_REG, + reg, !(reg & CV1800B_ADC_BUSY), + 500, CV1800B_READ_TIMEOUT_US); + } + + return wait_for_completion_timeout(&saradc->completion, + msecs_to_jiffies(CV1800B_READ_TIMEOUT_MS)) > 0 ? + 0 : -ETIMEDOUT; +} + +static int cv1800b_adc_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct cv1800b_adc *saradc = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_RAW: { + u32 sample; + + scoped_guard(mutex, &saradc->lock) { + int ret; + + cv1800b_adc_start_measurement(saradc, chan->scan_index); + ret = cv1800b_adc_wait(saradc); + if (ret < 0) + return ret; + + sample = readl(saradc->regs + CV1800B_ADC_CH_RESULT_REG(chan->scan_index)); + } + if (!(sample & CV1800B_ADC_CH_VALID)) + return -ENODATA; + + *val = sample & CV1800B_ADC_CH_RESULT; + return IIO_VAL_INT; + } + case IIO_CHAN_INFO_SCALE: + *val = 3300; + *val2 = 12; + return IIO_VAL_FRACTIONAL_LOG2; + case IIO_CHAN_INFO_SAMP_FREQ: { + u32 status_reg = readl(saradc->regs + CV1800B_ADC_CYC_SET_REG); + unsigned int clk_div = (1 + FIELD_GET(CV1800B_MASK_CLKDIV, status_reg)); + unsigned int freq = clk_get_rate(saradc->clk) / clk_div; + unsigned int nb_startup_cycle = 1 + FIELD_GET(CV1800B_MASK_STARTUP_CYCLE, status_reg); + unsigned int nb_sample_cycle = 1 + FIELD_GET(CV1800B_MASK_SAMPLE_WINDOW, status_reg); + unsigned int nb_compare_cycle = 1 + FIELD_GET(CV1800B_MASK_COMPARE_CYCLE, status_reg); + + *val = freq / (nb_startup_cycle + nb_sample_cycle + nb_compare_cycle); + return IIO_VAL_INT; + } + default: + return -EINVAL; + } +} + +static irqreturn_t cv1800b_adc_interrupt_handler(int irq, void *private) +{ + struct cv1800b_adc *saradc = private; + u32 reg = readl(saradc->regs + CV1800B_ADC_INTR_STA_REG); + + if (!(FIELD_GET(CV1800B_ADC_INTR_STA_BIT, reg))) + return IRQ_NONE; + + writel(CV1800B_ADC_INTR_CLR_BIT, saradc->regs + CV1800B_ADC_INTR_CLR_REG); + complete(&saradc->completion); + + return IRQ_HANDLED; +} + +static const struct iio_info cv1800b_adc_info = { + .read_raw = &cv1800b_adc_read_raw, +}; + +static int cv1800b_adc_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct cv1800b_adc *saradc; + struct iio_dev *indio_dev; + int ret; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*saradc)); + if (!indio_dev) + return -ENOMEM; + + saradc = iio_priv(indio_dev); + indio_dev->name = "sophgo-cv1800b-adc"; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->info = &cv1800b_adc_info; + indio_dev->num_channels = ARRAY_SIZE(sophgo_channels); + indio_dev->channels = sophgo_channels; + + saradc->clk = devm_clk_get_enabled(dev, NULL); + if (IS_ERR(saradc->clk)) + return PTR_ERR(saradc->clk); + + saradc->regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(saradc->regs)) + return PTR_ERR(saradc->regs); + + saradc->irq = platform_get_irq_optional(pdev, 0); + if (saradc->irq > 0) { + init_completion(&saradc->completion); + ret = devm_request_irq(dev, saradc->irq, + cv1800b_adc_interrupt_handler, 0, + dev_name(dev), saradc); + if (ret) + return ret; + + writel(1, saradc->regs + CV1800B_ADC_INTR_EN_REG); + } + + ret = devm_mutex_init(dev, &saradc->lock); + if (ret) + return ret; + + writel(FIELD_PREP(CV1800B_MASK_STARTUP_CYCLE, 15) | + FIELD_PREP(CV1800B_MASK_SAMPLE_WINDOW, 15) | + FIELD_PREP(CV1800B_MASK_CLKDIV, 1) | + FIELD_PREP(CV1800B_MASK_COMPARE_CYCLE, 15), + saradc->regs + CV1800B_ADC_CYC_SET_REG); + + return devm_iio_device_register(dev, indio_dev); +} + +static const struct of_device_id cv1800b_adc_match[] = { + { .compatible = "sophgo,cv1800b-saradc", }, + { } +}; +MODULE_DEVICE_TABLE(of, cv1800b_adc_match); + +static struct platform_driver cv1800b_adc_driver = { + .driver = { + .name = "sophgo-cv1800b-saradc", + .of_match_table = cv1800b_adc_match, + }, + .probe = cv1800b_adc_probe, +}; +module_platform_driver(cv1800b_adc_driver); + +MODULE_AUTHOR("Thomas Bonnefille <thomas.bonnefille@bootlin.com>"); +MODULE_DESCRIPTION("Sophgo CV1800B SARADC driver"); +MODULE_LICENSE("GPL"); |