diff options
Diffstat (limited to 'drivers/iio/adc/fsl-imx25-gcq.c')
| -rw-r--r-- | drivers/iio/adc/fsl-imx25-gcq.c | 390 |
1 files changed, 390 insertions, 0 deletions
diff --git a/drivers/iio/adc/fsl-imx25-gcq.c b/drivers/iio/adc/fsl-imx25-gcq.c new file mode 100644 index 000000000000..f8c220f6a7b4 --- /dev/null +++ b/drivers/iio/adc/fsl-imx25-gcq.c @@ -0,0 +1,390 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2014-2015 Pengutronix, Markus Pargmann <mpa@pengutronix.de> + * + * This is the driver for the imx25 GCQ (Generic Conversion Queue) + * connected to the imx25 ADC. + */ + +#include <dt-bindings/iio/adc/fsl-imx25-gcq.h> +#include <linux/clk.h> +#include <linux/iio/iio.h> +#include <linux/interrupt.h> +#include <linux/mfd/imx25-tsadc.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/platform_device.h> +#include <linux/property.h> +#include <linux/regmap.h> +#include <linux/regulator/consumer.h> + +#define MX25_GCQ_TIMEOUT (msecs_to_jiffies(2000)) + +static const char * const driver_name = "mx25-gcq"; + +enum mx25_gcq_cfgs { + MX25_CFG_XP = 0, + MX25_CFG_YP, + MX25_CFG_XN, + MX25_CFG_YN, + MX25_CFG_WIPER, + MX25_CFG_INAUX0, + MX25_CFG_INAUX1, + MX25_CFG_INAUX2, + MX25_NUM_CFGS, +}; + +struct mx25_gcq_priv { + struct regmap *regs; + struct completion completed; + struct clk *clk; + int irq; + struct regulator *vref[4]; + u32 channel_vref_mv[MX25_NUM_CFGS]; + /* + * Lock to protect the device state during a potential concurrent + * read access from userspace. Reading a raw value requires a sequence + * of register writes, then a wait for a completion callback, + * and finally a register read, during which userspace could issue + * another read request. This lock protects a read access from + * ocurring before another one has finished. + */ + struct mutex lock; +}; + +#define MX25_CQG_CHAN(chan, id) {\ + .type = IIO_VOLTAGE,\ + .indexed = 1,\ + .channel = chan,\ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \ + BIT(IIO_CHAN_INFO_SCALE),\ + .datasheet_name = id,\ +} + +static const struct iio_chan_spec mx25_gcq_channels[MX25_NUM_CFGS] = { + MX25_CQG_CHAN(MX25_CFG_XP, "xp"), + MX25_CQG_CHAN(MX25_CFG_YP, "yp"), + MX25_CQG_CHAN(MX25_CFG_XN, "xn"), + MX25_CQG_CHAN(MX25_CFG_YN, "yn"), + MX25_CQG_CHAN(MX25_CFG_WIPER, "wiper"), + MX25_CQG_CHAN(MX25_CFG_INAUX0, "inaux0"), + MX25_CQG_CHAN(MX25_CFG_INAUX1, "inaux1"), + MX25_CQG_CHAN(MX25_CFG_INAUX2, "inaux2"), +}; + +static const char * const mx25_gcq_refp_names[] = { + [MX25_ADC_REFP_YP] = "yp", + [MX25_ADC_REFP_XP] = "xp", + [MX25_ADC_REFP_INT] = "int", + [MX25_ADC_REFP_EXT] = "ext", +}; + +static irqreturn_t mx25_gcq_irq(int irq, void *data) +{ + struct mx25_gcq_priv *priv = data; + u32 stats; + + regmap_read(priv->regs, MX25_ADCQ_SR, &stats); + + if (stats & MX25_ADCQ_SR_EOQ) { + regmap_set_bits(priv->regs, MX25_ADCQ_MR, + MX25_ADCQ_MR_EOQ_IRQ); + complete(&priv->completed); + } + + /* Disable conversion queue run */ + regmap_clear_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FQS); + + /* Acknowledge all possible irqs */ + regmap_write(priv->regs, MX25_ADCQ_SR, MX25_ADCQ_SR_FRR | + MX25_ADCQ_SR_FUR | MX25_ADCQ_SR_FOR | + MX25_ADCQ_SR_EOQ | MX25_ADCQ_SR_PD); + + return IRQ_HANDLED; +} + +static int mx25_gcq_get_raw_value(struct device *dev, + struct iio_chan_spec const *chan, + struct mx25_gcq_priv *priv, + int *val) +{ + long time_left; + u32 data; + + /* Setup the configuration we want to use */ + regmap_write(priv->regs, MX25_ADCQ_ITEM_7_0, + MX25_ADCQ_ITEM(0, chan->channel)); + + regmap_clear_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_EOQ_IRQ); + + /* Trigger queue for one run */ + regmap_set_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FQS); + + time_left = wait_for_completion_interruptible_timeout( + &priv->completed, MX25_GCQ_TIMEOUT); + if (time_left < 0) { + dev_err(dev, "ADC wait for measurement failed\n"); + return time_left; + } else if (time_left == 0) { + dev_err(dev, "ADC timed out\n"); + return -ETIMEDOUT; + } + + regmap_read(priv->regs, MX25_ADCQ_FIFO, &data); + + *val = MX25_ADCQ_FIFO_DATA(data); + + return IIO_VAL_INT; +} + +static int mx25_gcq_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, int *val, + int *val2, long mask) +{ + struct mx25_gcq_priv *priv = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&priv->lock); + ret = mx25_gcq_get_raw_value(&indio_dev->dev, chan, priv, val); + mutex_unlock(&priv->lock); + return ret; + + case IIO_CHAN_INFO_SCALE: + *val = priv->channel_vref_mv[chan->channel]; + *val2 = 12; + return IIO_VAL_FRACTIONAL_LOG2; + + default: + return -EINVAL; + } +} + +static const struct iio_info mx25_gcq_iio_info = { + .read_raw = mx25_gcq_read_raw, +}; + +static const struct regmap_config mx25_gcq_regconfig = { + .max_register = 0x5c, + .reg_bits = 32, + .val_bits = 32, + .reg_stride = 4, +}; + +static int mx25_gcq_ext_regulator_setup(struct device *dev, + struct mx25_gcq_priv *priv, u32 refp) +{ + char reg_name[12]; + int ret; + + if (priv->vref[refp]) + return 0; + + ret = snprintf(reg_name, sizeof(reg_name), "vref-%s", + mx25_gcq_refp_names[refp]); + if (ret < 0) + return ret; + + priv->vref[refp] = devm_regulator_get_optional(dev, reg_name); + if (IS_ERR(priv->vref[refp])) + return dev_err_probe(dev, PTR_ERR(priv->vref[refp]), + "Error, trying to use external voltage reference without a %s regulator.", + reg_name); + + return 0; +} + +static int mx25_gcq_setup_cfgs(struct platform_device *pdev, + struct mx25_gcq_priv *priv) +{ + struct device *dev = &pdev->dev; + int ret, i; + + /* + * Setup all configurations registers with a default conversion + * configuration for each input + */ + for (i = 0; i < MX25_NUM_CFGS; ++i) + regmap_write(priv->regs, MX25_ADCQ_CFG(i), + MX25_ADCQ_CFG_YPLL_OFF | + MX25_ADCQ_CFG_XNUR_OFF | + MX25_ADCQ_CFG_XPUL_OFF | + MX25_ADCQ_CFG_REFP_INT | + MX25_ADCQ_CFG_IN(i) | + MX25_ADCQ_CFG_REFN_NGND2); + + device_for_each_child_node_scoped(dev, child) { + u32 reg; + u32 refp = MX25_ADCQ_CFG_REFP_INT; + u32 refn = MX25_ADCQ_CFG_REFN_NGND2; + + ret = fwnode_property_read_u32(child, "reg", ®); + if (ret) + return dev_err_probe(dev, ret, + "Failed to get reg property\n"); + + if (reg >= MX25_NUM_CFGS) + return dev_err_probe(dev, -EINVAL, + "reg value is greater than the number of available configuration registers\n"); + + fwnode_property_read_u32(child, "fsl,adc-refp", &refp); + fwnode_property_read_u32(child, "fsl,adc-refn", &refn); + + switch (refp) { + case MX25_ADC_REFP_EXT: + case MX25_ADC_REFP_XP: + case MX25_ADC_REFP_YP: + ret = mx25_gcq_ext_regulator_setup(&pdev->dev, priv, refp); + if (ret) + return ret; + priv->channel_vref_mv[reg] = + regulator_get_voltage(priv->vref[refp]); + /* Conversion from uV to mV */ + priv->channel_vref_mv[reg] /= 1000; + break; + case MX25_ADC_REFP_INT: + priv->channel_vref_mv[reg] = 2500; + break; + default: + return dev_err_probe(dev, -EINVAL, + "Invalid positive reference %d\n", refp); + } + + /* + * Shift the read values to the correct positions within the + * register. + */ + refp = MX25_ADCQ_CFG_REFP(refp); + refn = MX25_ADCQ_CFG_REFN(refn); + + if ((refp & MX25_ADCQ_CFG_REFP_MASK) != refp) + return dev_err_probe(dev, -EINVAL, + "Invalid fsl,adc-refp property value\n"); + + if ((refn & MX25_ADCQ_CFG_REFN_MASK) != refn) + return dev_err_probe(dev, -EINVAL, + "Invalid fsl,adc-refn property value\n"); + + regmap_update_bits(priv->regs, MX25_ADCQ_CFG(reg), + MX25_ADCQ_CFG_REFP_MASK | + MX25_ADCQ_CFG_REFN_MASK, + refp | refn); + } + regmap_set_bits(priv->regs, MX25_ADCQ_CR, + MX25_ADCQ_CR_FRST | MX25_ADCQ_CR_QRST); + + regmap_write(priv->regs, MX25_ADCQ_CR, + MX25_ADCQ_CR_PDMSK | MX25_ADCQ_CR_QSM_FQS); + + return 0; +} + +static void mx25_gcq_reg_disable(void *reg) +{ + regulator_disable(reg); +} + +/* Custom handling needed as this driver doesn't own the clock */ +static void mx25_gcq_clk_disable(void *clk) +{ + clk_disable_unprepare(clk); +} + +static int mx25_gcq_probe(struct platform_device *pdev) +{ + struct iio_dev *indio_dev; + struct mx25_gcq_priv *priv; + struct mx25_tsadc *tsadc = dev_get_drvdata(pdev->dev.parent); + struct device *dev = &pdev->dev; + void __iomem *mem; + int ret; + int i; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*priv)); + if (!indio_dev) + return -ENOMEM; + + priv = iio_priv(indio_dev); + + mem = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(mem)) + return PTR_ERR(mem); + + priv->regs = devm_regmap_init_mmio(dev, mem, &mx25_gcq_regconfig); + if (IS_ERR(priv->regs)) + return dev_err_probe(dev, PTR_ERR(priv->regs), + "Failed to initialize regmap\n"); + + mutex_init(&priv->lock); + + init_completion(&priv->completed); + + ret = mx25_gcq_setup_cfgs(pdev, priv); + if (ret) + return ret; + + for (i = 0; i != 4; ++i) { + if (!priv->vref[i]) + continue; + + ret = regulator_enable(priv->vref[i]); + if (ret) + return ret; + + ret = devm_add_action_or_reset(dev, mx25_gcq_reg_disable, + priv->vref[i]); + if (ret) + return ret; + } + + priv->clk = tsadc->clk; + ret = clk_prepare_enable(priv->clk); + if (ret) + return dev_err_probe(dev, ret, "Failed to enable clock\n"); + + ret = devm_add_action_or_reset(dev, mx25_gcq_clk_disable, + priv->clk); + if (ret) + return ret; + + ret = platform_get_irq(pdev, 0); + if (ret < 0) + return ret; + + priv->irq = ret; + ret = devm_request_irq(dev, priv->irq, mx25_gcq_irq, 0, pdev->name, + priv); + if (ret) + return dev_err_probe(dev, ret, "Failed requesting IRQ\n"); + + indio_dev->channels = mx25_gcq_channels; + indio_dev->num_channels = ARRAY_SIZE(mx25_gcq_channels); + indio_dev->info = &mx25_gcq_iio_info; + indio_dev->name = driver_name; + + ret = devm_iio_device_register(dev, indio_dev); + if (ret) + return dev_err_probe(dev, ret, "Failed to register iio device\n"); + + return 0; +} + +static const struct of_device_id mx25_gcq_ids[] = { + { .compatible = "fsl,imx25-gcq", }, + { } +}; +MODULE_DEVICE_TABLE(of, mx25_gcq_ids); + +static struct platform_driver mx25_gcq_driver = { + .driver = { + .name = "mx25-gcq", + .of_match_table = mx25_gcq_ids, + }, + .probe = mx25_gcq_probe, +}; +module_platform_driver(mx25_gcq_driver); + +MODULE_DESCRIPTION("ADC driver for Freescale mx25"); +MODULE_AUTHOR("Markus Pargmann <mpa@pengutronix.de>"); +MODULE_LICENSE("GPL v2"); |