[PATCH v7 5/8] iio: adc: fsl,imx25-gcq driver
Hartmut Knaack
knaack.h at gmx.de
Sat Jun 13 17:04:25 PDT 2015
Markus Pargmann schrieb am 03.03.2015 um 08:58:
> This is a conversion queue driver for the mx25 SoC. It uses the central
> ADC which is used by two seperate independent queues. This driver
> prepares different conversion configurations for each possible input.
> For a conversion it creates a conversionqueue of one item with the
> correct configuration for the chosen channel. It then executes the queue
> once and disables the conversion queue afterwards.
>
> The reference voltages are configurable through devicetree subnodes,
> depending on the connections of the ADC inputs.
>
Hi,
please see my comments inline.
> Signed-off-by: Markus Pargmann <mpa at pengutronix.de>
> Signed-off-by: Denis Carikli <denis at eukrea.com>
> Signed-off-by: Markus Pargmann <mpa at pengutronix.de>
> ---
>
> Notes:
> Changes in v7:
> - Remove separate functions mx25_gcq_disable/enable_eoq() as they were used at
> only one position
> - Enforce an external reference regulator if one of the conversions uses it as
> reference. The devm_regulator_get() call was moved into
> mx25_gcq_setup_cfgs() to be able to acquire the reference regulator when
> necessary.
> - Store indio_dev as platform driver data instead of the private data. This
> was changed in probe() and remove().
>
> Changes in v6:
> - Added defines for a complete list of references in the dt binding macros
>
> drivers/iio/adc/Kconfig | 7 +
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/fsl-imx25-gcq.c | 356 ++++++++++++++++++++++++++++
> include/dt-bindings/iio/adc/fsl-imx25-gcq.h | 18 ++
> 4 files changed, 382 insertions(+)
> create mode 100644 drivers/iio/adc/fsl-imx25-gcq.c
> create mode 100644 include/dt-bindings/iio/adc/fsl-imx25-gcq.h
>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 202daf889be2..947805d03d6c 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -154,6 +154,13 @@ config EXYNOS_ADC
> of SoCs for drivers such as the touchscreen and hwmon to use to share
> this resource.
>
> +config FSL_MX25_ADC
> + tristate "Freescale MX25 ADC driver"
> + depends on MFD_MX25_TSADC
> + help
> + Generic Conversion Queue driver used for general purpose ADC in the
> + MX25. This driver supports single measurements using the MX25 ADC.
> +
> config LP8788_ADC
> tristate "LP8788 ADC driver"
> depends on MFD_LP8788
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 0315af640866..409583975ba0 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -17,6 +17,7 @@ obj-$(CONFIG_AT91_ADC) += at91_adc.o
> obj-$(CONFIG_AXP288_ADC) += axp288_adc.o
> obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
> obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
> +obj-$(CONFIG_FSL_MX25_ADC) += fsl-imx25-gcq.o
> obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
> obj-$(CONFIG_MAX1027) += max1027.o
> obj-$(CONFIG_MAX1363) += max1363.o
> diff --git a/drivers/iio/adc/fsl-imx25-gcq.c b/drivers/iio/adc/fsl-imx25-gcq.c
> new file mode 100644
> index 000000000000..18c21888aa4e
> --- /dev/null
> +++ b/drivers/iio/adc/fsl-imx25-gcq.c
> @@ -0,0 +1,356 @@
> +/*
> + * Copyright (C) 2014-2015 Pengutronix, Markus Pargmann <mpa at pengutronix.de>
> + *
> + * This program is free software; you can redistribute it and/or modify it under
> + * the terms of the GNU General Public License version 2 as published by the
> + * Free Software Foundation.
> + *
> + * 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/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +
> +#define MX25_GCQ_TIMEOUT (msecs_to_jiffies(2000))
> +
> +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;
> + unsigned int settling_time;
settling_time is unused.
> + struct clk *clk;
> + int irq;
> + struct regulator *ext_vref;
> + u32 channel_vref_mv[MX25_NUM_CFGS];
I couldn't see where this array got assigned.
> +};
> +
> +#define MX25_CQG_CHAN(chan, id) {\
> + .type = IIO_VOLTAGE,\
> + .indexed = 1,\
> + .channel = chan,\
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),\
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
> + .datasheet_name = id,\
> +}
> +
> +static const struct iio_chan_spec mx25_gcq_channels[MX25_NUM_CFGS] = {
> + MX25_CQG_CHAN(0, "xp"),
> + MX25_CQG_CHAN(1, "yp"),
> + MX25_CQG_CHAN(2, "xn"),
> + MX25_CQG_CHAN(3, "yn"),
> + MX25_CQG_CHAN(4, "wiper"),
> + MX25_CQG_CHAN(5, "inaux0"),
> + MX25_CQG_CHAN(6, "inaux1"),
> + MX25_CQG_CHAN(7, "inaux2"),
Was it intended to use the entries of enum mx25_gcq_cfgs for chan here?
> +};
> +
> +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_update_bits(priv->regs, MX25_ADCQ_MR,
> + MX25_ADCQ_MR_EOQ_IRQ, MX25_ADCQ_MR_EOQ_IRQ);
> + complete(&priv->completed);
> + }
> +
> + /* Disable conversion queue run */
> + regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FQS, 0);
> +
> + /* 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 timeout;
> + 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_update_bits(priv->regs, MX25_ADCQ_MR, MX25_ADCQ_MR_EOQ_IRQ, 0);
> +
> + /* Trigger queue for one run */
> + regmap_update_bits(priv->regs, MX25_ADCQ_CR, MX25_ADCQ_CR_FQS,
> + MX25_ADCQ_CR_FQS);
> +
> + timeout = wait_for_completion_interruptible_timeout(
> + &priv->completed, MX25_GCQ_TIMEOUT);
> + if (timeout < 0) {
> + dev_err(dev,
> + "ADC wait for measurement failed\n");
This fits in one line.
> + return timeout;
> + } else if (timeout == 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 = 0;
No need to initialize ret.
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + mutex_lock(&indio_dev->mlock);
> + ret = mx25_gcq_get_raw_value(&indio_dev->dev, chan, priv, val);
> + mutex_unlock(&indio_dev->mlock);
> + 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_setup_cfgs(struct platform_device *pdev,
> + struct mx25_gcq_priv *priv)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + struct device_node *child;
> + struct device *dev = &pdev->dev;
> + int ret, i;
> + bool external_ref_used = false;
> +
> + /*
> + * 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);
> +
> + for_each_child_of_node(np, child) {
> + u32 reg;
> + u32 refp = MX25_ADCQ_CFG_REFP_INT;
> + u32 refn = MX25_ADCQ_CFG_REFN_NGND2;
> +
> + ret = of_property_read_u32(child, "reg", ®);
> + if (ret) {
> + dev_err(dev, "Failed to get reg property\n");
> + return ret;
> + }
> +
> + if (reg >= MX25_NUM_CFGS) {
> + dev_err(dev,
> + "reg value is greater than the number of available configuration registers\n");
> + return -EINVAL;
> + }
> +
> + of_property_read_u32(child, "fsl,adc-refp", &refp);
> + of_property_read_u32(child, "fsl,adc-refn", &refn);
> +
> + if (refp == MX25_ADC_REFP_EXT)
> + external_ref_used = true;
> +
> + /*
> + * Shift the read values to the correct positions within the
> + * register.
> + */
> + refp = MX25_ADCQ_CFG_REFP(refp);
> + refn = MX25_ADCQ_CFG_REFN(refn);
This is only valid if reading the of_property was successful!
Better check return value after read and only apply the shift in case of success.
> +
> + if ((refp & MX25_ADCQ_CFG_REFP_MASK) != refp) {
> + dev_err(dev, "Invalid fsl,adc-refp property value\n");
> + return -EINVAL;
> + }
> + if ((refn & MX25_ADCQ_CFG_REFN_MASK) != refn) {
> + dev_err(dev, "Invalid fsl,adc-refn property value");
Missing \n
> + return -EINVAL;
> + }
> +
> + regmap_update_bits(priv->regs, MX25_ADCQ_CFG(reg),
> + MX25_ADCQ_CFG_REFP_MASK |
> + MX25_ADCQ_CFG_REFN_MASK,
> + refp | refn);
> + }
> + regmap_update_bits(priv->regs, MX25_ADCQ_CR,
> + MX25_ADCQ_CR_FRST | MX25_ADCQ_CR_QRST,
> + MX25_ADCQ_CR_FRST | MX25_ADCQ_CR_QRST);
> +
> + regmap_write(priv->regs, MX25_ADCQ_CR,
> + MX25_ADCQ_CR_PDMSK | MX25_ADCQ_CR_QSM_FQS);
> +
> + if (external_ref_used) {
> + priv->ext_vref = devm_regulator_get(&pdev->dev, "vref");
> + if (IS_ERR(priv->ext_vref)) {
> + dev_err(&pdev->dev, "Failed to get regulator for vref although the external reference voltage is used.\n");
> + return PTR_ERR(priv->ext_vref);
You need to restructure your code to set the reference voltage for each channel.
> + }
> + }
> +
> + return 0;
> +}
> +
> +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;
> + struct resource *res;
> + void __iomem *mem;
> + int ret;
> +
> + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + priv = iio_priv(indio_dev);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + mem = devm_ioremap_resource(dev, res);
> + if (!mem)
mem is an ERR_PTR() encoded error code in case of failure.
> + return -ENOMEM;
> +
> + priv->regs = devm_regmap_init_mmio(dev, mem, &mx25_gcq_regconfig);
> + if (IS_ERR(priv->regs)) {
> + dev_err(dev, "Failed to initialize regmap\n");
> + return PTR_ERR(priv->regs);
> + }
> +
> + init_completion(&priv->completed);
> +
> + ret = mx25_gcq_setup_cfgs(pdev, priv);
> + if (ret)
> + return ret;
> +
> + if (!IS_ERR_OR_NULL(priv->ext_vref)) {
> + ret = regulator_enable(priv->ext_vref);
> + if (ret)
> + return ret;
> + }
> +
> + priv->clk = tsadc->clk;
> + ret = clk_prepare_enable(priv->clk);
> + if (ret) {
> + dev_err(dev, "Failed to enable clock\n");
> + return ret;
> + }
> +
> + priv->irq = platform_get_irq(pdev, 0);
> + if (priv->irq <= 0) {
> + dev_err(dev, "Failed to get IRQ\n");
> + ret = priv->irq;
> + goto err_clk_unprepare;
> + }
> +
> + ret = request_irq(priv->irq, mx25_gcq_irq, 0, pdev->name, priv);
> + if (ret) {
> + dev_err(dev, "Failed requesting IRQ\n");
> + goto err_clk_unprepare;
> + }
> +
> + indio_dev->dev.parent = &pdev->dev;
> + indio_dev->channels = mx25_gcq_channels;
> + indio_dev->num_channels = ARRAY_SIZE(mx25_gcq_channels);
> + indio_dev->info = &mx25_gcq_iio_info;
You should also set indio_dev->name and indio_dev->modes.
> +
> + ret = iio_device_register(indio_dev);
> + if (ret) {
> + dev_err(dev, "Failed to register iio device\n");
> + goto err_irq_free;
> + }
> +
> + platform_set_drvdata(pdev, indio_dev);
This should be moved up before iio_device_register.
> +
> + return 0;
> +
> +err_irq_free:
> + free_irq(priv->irq, (void *)priv);
> +err_clk_unprepare:
> + clk_disable_unprepare(priv->clk);
> + return ret;
> +}
> +
> +static int mx25_gcq_remove(struct platform_device *pdev)
> +{
> + struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> + struct mx25_gcq_priv *priv = iio_priv(indio_dev);
> +
> + iio_device_unregister(indio_dev);
> + free_irq(priv->irq, priv);
> + clk_disable_unprepare(priv->clk);
> +
> + return 0;
> +}
> +
> +static struct of_device_id mx25_gcq_ids[] = {
> + { .compatible = "fsl,imx25-gcq", },
> + { /* Sentinel */ }
> +};
> +
> +static struct platform_driver mx25_gcq_driver = {
> + .driver = {
> + .name = "mx25-gcq",
> + .of_match_table = mx25_gcq_ids,
> + },
> + .probe = mx25_gcq_probe,
> + .remove = mx25_gcq_remove,
> +};
> +module_platform_driver(mx25_gcq_driver);
> +
> +MODULE_DESCRIPTION("ADC driver for Freescale mx25");
> +MODULE_AUTHOR("Markus Pargmann <mpa at pengutronix.de>");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/dt-bindings/iio/adc/fsl-imx25-gcq.h b/include/dt-bindings/iio/adc/fsl-imx25-gcq.h
> new file mode 100644
> index 000000000000..4f2f4a9baafe
> --- /dev/null
> +++ b/include/dt-bindings/iio/adc/fsl-imx25-gcq.h
> @@ -0,0 +1,18 @@
> +/*
> + * This header provides constants for configuring the I.MX25 ADC
> + */
> +
> +#ifndef _DT_BINDINGS_IIO_ADC_FS_IMX25_GCQ_H
> +#define _DT_BINDINGS_IIO_ADC_FS_IMX25_GCQ_H
> +
> +#define MX25_ADC_REFP_YP 0 /* YP voltage reference */
> +#define MX25_ADC_REFP_XP 1 /* XP voltage reference */
> +#define MX25_ADC_REFP_INT 2 /* Internal voltage reference */
> +#define MX25_ADC_REFP_EXT 3 /* External voltage reference */
> +
> +#define MX25_ADC_REFN_XN 0
> +#define MX25_ADC_REFN_YN 1
> +#define MX25_ADC_REFN_NGND 2
> +#define MX25_ADC_REFN_NGND2 3
Have some comments for the REFN-block as well?
> +
> +#endif
>
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