diff options
Diffstat (limited to 'drivers/iio/adc/rockchip_saradc.c')
| -rw-r--r-- | drivers/iio/adc/rockchip_saradc.c | 487 |
1 files changed, 487 insertions, 0 deletions
diff --git a/drivers/iio/adc/rockchip_saradc.c b/drivers/iio/adc/rockchip_saradc.c new file mode 100644 index 000000000..12584f163 --- /dev/null +++ b/drivers/iio/adc/rockchip_saradc.c @@ -0,0 +1,487 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Rockchip Successive Approximation Register (SAR) A/D Converter + * Copyright (C) 2014 ROCKCHIP, Inc. + */ + +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/clk.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/reset.h> +#include <linux/regulator/consumer.h> +#include <linux/iio/buffer.h> +#include <linux/iio/iio.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> + +#define SARADC_DATA 0x00 + +#define SARADC_STAS 0x04 +#define SARADC_STAS_BUSY BIT(0) + +#define SARADC_CTRL 0x08 +#define SARADC_CTRL_IRQ_STATUS BIT(6) +#define SARADC_CTRL_IRQ_ENABLE BIT(5) +#define SARADC_CTRL_POWER_CTRL BIT(3) +#define SARADC_CTRL_CHN_MASK 0x7 + +#define SARADC_DLY_PU_SOC 0x0c +#define SARADC_DLY_PU_SOC_MASK 0x3f + +#define SARADC_TIMEOUT msecs_to_jiffies(100) +#define SARADC_MAX_CHANNELS 6 + +struct rockchip_saradc_data { + const struct iio_chan_spec *channels; + int num_channels; + unsigned long clk_rate; +}; + +struct rockchip_saradc { + void __iomem *regs; + struct clk *pclk; + struct clk *clk; + struct completion completion; + struct regulator *vref; + struct reset_control *reset; + const struct rockchip_saradc_data *data; + u16 last_val; + const struct iio_chan_spec *last_chan; +}; + +static void rockchip_saradc_power_down(struct rockchip_saradc *info) +{ + /* Clear irq & power down adc */ + writel_relaxed(0, info->regs + SARADC_CTRL); +} + +static int rockchip_saradc_conversion(struct rockchip_saradc *info, + struct iio_chan_spec const *chan) +{ + reinit_completion(&info->completion); + + /* 8 clock periods as delay between power up and start cmd */ + writel_relaxed(8, info->regs + SARADC_DLY_PU_SOC); + + info->last_chan = chan; + + /* Select the channel to be used and trigger conversion */ + writel(SARADC_CTRL_POWER_CTRL + | (chan->channel & SARADC_CTRL_CHN_MASK) + | SARADC_CTRL_IRQ_ENABLE, + info->regs + SARADC_CTRL); + + if (!wait_for_completion_timeout(&info->completion, SARADC_TIMEOUT)) + return -ETIMEDOUT; + + return 0; +} + +static int rockchip_saradc_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct rockchip_saradc *info = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&indio_dev->mlock); + + ret = rockchip_saradc_conversion(info, chan); + if (ret) { + rockchip_saradc_power_down(info); + mutex_unlock(&indio_dev->mlock); + return ret; + } + + *val = info->last_val; + mutex_unlock(&indio_dev->mlock); + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + ret = regulator_get_voltage(info->vref); + if (ret < 0) { + dev_err(&indio_dev->dev, "failed to get voltage\n"); + return ret; + } + + *val = ret / 1000; + *val2 = chan->scan_type.realbits; + return IIO_VAL_FRACTIONAL_LOG2; + default: + return -EINVAL; + } +} + +static irqreturn_t rockchip_saradc_isr(int irq, void *dev_id) +{ + struct rockchip_saradc *info = dev_id; + + /* Read value */ + info->last_val = readl_relaxed(info->regs + SARADC_DATA); + info->last_val &= GENMASK(info->last_chan->scan_type.realbits - 1, 0); + + rockchip_saradc_power_down(info); + + complete(&info->completion); + + return IRQ_HANDLED; +} + +static const struct iio_info rockchip_saradc_iio_info = { + .read_raw = rockchip_saradc_read_raw, +}; + +#define SARADC_CHANNEL(_index, _id, _res) { \ + .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), \ + .datasheet_name = _id, \ + .scan_index = _index, \ + .scan_type = { \ + .sign = 'u', \ + .realbits = _res, \ + .storagebits = 16, \ + .endianness = IIO_CPU, \ + }, \ +} + +static const struct iio_chan_spec rockchip_saradc_iio_channels[] = { + SARADC_CHANNEL(0, "adc0", 10), + SARADC_CHANNEL(1, "adc1", 10), + SARADC_CHANNEL(2, "adc2", 10), +}; + +static const struct rockchip_saradc_data saradc_data = { + .channels = rockchip_saradc_iio_channels, + .num_channels = ARRAY_SIZE(rockchip_saradc_iio_channels), + .clk_rate = 1000000, +}; + +static const struct iio_chan_spec rockchip_rk3066_tsadc_iio_channels[] = { + SARADC_CHANNEL(0, "adc0", 12), + SARADC_CHANNEL(1, "adc1", 12), +}; + +static const struct rockchip_saradc_data rk3066_tsadc_data = { + .channels = rockchip_rk3066_tsadc_iio_channels, + .num_channels = ARRAY_SIZE(rockchip_rk3066_tsadc_iio_channels), + .clk_rate = 50000, +}; + +static const struct iio_chan_spec rockchip_rk3399_saradc_iio_channels[] = { + SARADC_CHANNEL(0, "adc0", 10), + SARADC_CHANNEL(1, "adc1", 10), + SARADC_CHANNEL(2, "adc2", 10), + SARADC_CHANNEL(3, "adc3", 10), + SARADC_CHANNEL(4, "adc4", 10), + SARADC_CHANNEL(5, "adc5", 10), +}; + +static const struct rockchip_saradc_data rk3399_saradc_data = { + .channels = rockchip_rk3399_saradc_iio_channels, + .num_channels = ARRAY_SIZE(rockchip_rk3399_saradc_iio_channels), + .clk_rate = 1000000, +}; + +static const struct of_device_id rockchip_saradc_match[] = { + { + .compatible = "rockchip,saradc", + .data = &saradc_data, + }, { + .compatible = "rockchip,rk3066-tsadc", + .data = &rk3066_tsadc_data, + }, { + .compatible = "rockchip,rk3399-saradc", + .data = &rk3399_saradc_data, + }, + {}, +}; +MODULE_DEVICE_TABLE(of, rockchip_saradc_match); + +/* + * Reset SARADC Controller. + */ +static void rockchip_saradc_reset_controller(struct reset_control *reset) +{ + reset_control_assert(reset); + usleep_range(10, 20); + reset_control_deassert(reset); +} + +static void rockchip_saradc_clk_disable(void *data) +{ + struct rockchip_saradc *info = data; + + clk_disable_unprepare(info->clk); +} + +static void rockchip_saradc_pclk_disable(void *data) +{ + struct rockchip_saradc *info = data; + + clk_disable_unprepare(info->pclk); +} + +static void rockchip_saradc_regulator_disable(void *data) +{ + struct rockchip_saradc *info = data; + + regulator_disable(info->vref); +} + +static irqreturn_t rockchip_saradc_trigger_handler(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *i_dev = pf->indio_dev; + struct rockchip_saradc *info = iio_priv(i_dev); + /* + * @values: each channel takes an u16 value + * @timestamp: will be 8-byte aligned automatically + */ + struct { + u16 values[SARADC_MAX_CHANNELS]; + int64_t timestamp; + } data; + int ret; + int i, j = 0; + + mutex_lock(&i_dev->mlock); + + for_each_set_bit(i, i_dev->active_scan_mask, i_dev->masklength) { + const struct iio_chan_spec *chan = &i_dev->channels[i]; + + ret = rockchip_saradc_conversion(info, chan); + if (ret) { + rockchip_saradc_power_down(info); + goto out; + } + + data.values[j] = info->last_val; + j++; + } + + iio_push_to_buffers_with_timestamp(i_dev, &data, iio_get_time_ns(i_dev)); +out: + mutex_unlock(&i_dev->mlock); + + iio_trigger_notify_done(i_dev->trig); + + return IRQ_HANDLED; +} + +static int rockchip_saradc_probe(struct platform_device *pdev) +{ + struct rockchip_saradc *info = NULL; + struct device_node *np = pdev->dev.of_node; + struct iio_dev *indio_dev = NULL; + struct resource *mem; + const struct of_device_id *match; + int ret; + int irq; + + if (!np) + return -ENODEV; + + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info)); + if (!indio_dev) { + dev_err(&pdev->dev, "failed allocating iio device\n"); + return -ENOMEM; + } + info = iio_priv(indio_dev); + + match = of_match_device(rockchip_saradc_match, &pdev->dev); + if (!match) { + dev_err(&pdev->dev, "failed to match device\n"); + return -ENODEV; + } + + info->data = match->data; + + /* Sanity check for possible later IP variants with more channels */ + if (info->data->num_channels > SARADC_MAX_CHANNELS) { + dev_err(&pdev->dev, "max channels exceeded"); + return -EINVAL; + } + + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); + info->regs = devm_ioremap_resource(&pdev->dev, mem); + if (IS_ERR(info->regs)) + return PTR_ERR(info->regs); + + /* + * The reset should be an optional property, as it should work + * with old devicetrees as well + */ + info->reset = devm_reset_control_get_exclusive(&pdev->dev, + "saradc-apb"); + if (IS_ERR(info->reset)) { + ret = PTR_ERR(info->reset); + if (ret != -ENOENT) + return ret; + + dev_dbg(&pdev->dev, "no reset control found\n"); + info->reset = NULL; + } + + init_completion(&info->completion); + + irq = platform_get_irq(pdev, 0); + if (irq < 0) + return irq; + + ret = devm_request_irq(&pdev->dev, irq, rockchip_saradc_isr, + 0, dev_name(&pdev->dev), info); + if (ret < 0) { + dev_err(&pdev->dev, "failed requesting irq %d\n", irq); + return ret; + } + + info->pclk = devm_clk_get(&pdev->dev, "apb_pclk"); + if (IS_ERR(info->pclk)) { + dev_err(&pdev->dev, "failed to get pclk\n"); + return PTR_ERR(info->pclk); + } + + info->clk = devm_clk_get(&pdev->dev, "saradc"); + if (IS_ERR(info->clk)) { + dev_err(&pdev->dev, "failed to get adc clock\n"); + return PTR_ERR(info->clk); + } + + info->vref = devm_regulator_get(&pdev->dev, "vref"); + if (IS_ERR(info->vref)) { + dev_err(&pdev->dev, "failed to get regulator, %ld\n", + PTR_ERR(info->vref)); + return PTR_ERR(info->vref); + } + + if (info->reset) + rockchip_saradc_reset_controller(info->reset); + + /* + * Use a default value for the converter clock. + * This may become user-configurable in the future. + */ + ret = clk_set_rate(info->clk, info->data->clk_rate); + if (ret < 0) { + dev_err(&pdev->dev, "failed to set adc clk rate, %d\n", ret); + return ret; + } + + ret = regulator_enable(info->vref); + if (ret < 0) { + dev_err(&pdev->dev, "failed to enable vref regulator\n"); + return ret; + } + ret = devm_add_action_or_reset(&pdev->dev, + rockchip_saradc_regulator_disable, info); + if (ret) { + dev_err(&pdev->dev, "failed to register devm action, %d\n", + ret); + return ret; + } + + ret = clk_prepare_enable(info->pclk); + if (ret < 0) { + dev_err(&pdev->dev, "failed to enable pclk\n"); + return ret; + } + ret = devm_add_action_or_reset(&pdev->dev, + rockchip_saradc_pclk_disable, info); + if (ret) { + dev_err(&pdev->dev, "failed to register devm action, %d\n", + ret); + return ret; + } + + ret = clk_prepare_enable(info->clk); + if (ret < 0) { + dev_err(&pdev->dev, "failed to enable converter clock\n"); + return ret; + } + ret = devm_add_action_or_reset(&pdev->dev, + rockchip_saradc_clk_disable, info); + if (ret) { + dev_err(&pdev->dev, "failed to register devm action, %d\n", + ret); + return ret; + } + + platform_set_drvdata(pdev, indio_dev); + + indio_dev->name = dev_name(&pdev->dev); + indio_dev->info = &rockchip_saradc_iio_info; + indio_dev->modes = INDIO_DIRECT_MODE; + + indio_dev->channels = info->data->channels; + indio_dev->num_channels = info->data->num_channels; + ret = devm_iio_triggered_buffer_setup(&indio_dev->dev, indio_dev, NULL, + rockchip_saradc_trigger_handler, + NULL); + if (ret) + return ret; + + return devm_iio_device_register(&pdev->dev, indio_dev); +} + +#ifdef CONFIG_PM_SLEEP +static int rockchip_saradc_suspend(struct device *dev) +{ + struct iio_dev *indio_dev = dev_get_drvdata(dev); + struct rockchip_saradc *info = iio_priv(indio_dev); + + clk_disable_unprepare(info->clk); + clk_disable_unprepare(info->pclk); + regulator_disable(info->vref); + + return 0; +} + +static int rockchip_saradc_resume(struct device *dev) +{ + struct iio_dev *indio_dev = dev_get_drvdata(dev); + struct rockchip_saradc *info = iio_priv(indio_dev); + int ret; + + ret = regulator_enable(info->vref); + if (ret) + return ret; + + ret = clk_prepare_enable(info->pclk); + if (ret) + return ret; + + ret = clk_prepare_enable(info->clk); + if (ret) + clk_disable_unprepare(info->pclk); + + return ret; +} +#endif + +static SIMPLE_DEV_PM_OPS(rockchip_saradc_pm_ops, + rockchip_saradc_suspend, rockchip_saradc_resume); + +static struct platform_driver rockchip_saradc_driver = { + .probe = rockchip_saradc_probe, + .driver = { + .name = "rockchip-saradc", + .of_match_table = rockchip_saradc_match, + .pm = &rockchip_saradc_pm_ops, + }, +}; + +module_platform_driver(rockchip_saradc_driver); + +MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>"); +MODULE_DESCRIPTION("Rockchip SARADC driver"); +MODULE_LICENSE("GPL v2"); |