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linux/drivers/iio/adc/imx8qxp-adc.c
Frank Li 0fc3562a99 iio: imx8qxp-adc: fix irq flood when call imx8qxp_adc_read_raw() 
irq flood happen when run
    cat /sys/bus/iio/devices/iio:device0/in_voltage1_raw

imx8qxp_adc_read_raw()
{
	...
	enable irq
	/* adc start */
	writel(1, adc->regs + IMX8QXP_ADR_ADC_SWTRIG);
	^^^^ trigger irq flood.
	wait_for_completion_interruptible_timeout();
	readl(adc->regs + IMX8QXP_ADR_ADC_RESFIFO);
	^^^^ clear irq here.
	...
}

There is only FIFO watermark interrupt at this ADC controller.
IRQ line will be assert until software read data from FIFO.
So IRQ flood happen during wait_for_completion_interruptible_timeout().

Move FIFO read into irq handle to avoid irq flood.

Fixes: 1e23dcaa1a ("iio: imx8qxp-adc: Add driver support for NXP IMX8QXP ADC")
Cc: stable@vger.kernel.org

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Cai Huoqing <cai.huoqing@linux.dev>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Link: https://lore.kernel.org/r/20221201140110.2653501-1-Frank.Li@nxp.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2022-12-28 17:20:03 +00:00

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// SPDX-License-Identifier: GPL-2.0+
/*
* NXP i.MX8QXP ADC driver
*
* Based on the work of Haibo Chen <haibo.chen@nxp.com>
* The initial developer of the original code is Haibo Chen.
* Portions created by Haibo Chen are Copyright (C) 2018 NXP.
* All Rights Reserved.
*
* Copyright (C) 2018 NXP
* Copyright (C) 2021 Cai Huoqing
*/
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>
#include <linux/iio/iio.h>
#define ADC_DRIVER_NAME "imx8qxp-adc"
/* Register map definition */
#define IMX8QXP_ADR_ADC_CTRL 0x10
#define IMX8QXP_ADR_ADC_STAT 0x14
#define IMX8QXP_ADR_ADC_IE 0x18
#define IMX8QXP_ADR_ADC_DE 0x1c
#define IMX8QXP_ADR_ADC_CFG 0x20
#define IMX8QXP_ADR_ADC_FCTRL 0x30
#define IMX8QXP_ADR_ADC_SWTRIG 0x34
#define IMX8QXP_ADR_ADC_TCTRL(tid) (0xc0 + (tid) * 4)
#define IMX8QXP_ADR_ADC_CMDH(cid) (0x100 + (cid) * 8)
#define IMX8QXP_ADR_ADC_CMDL(cid) (0x104 + (cid) * 8)
#define IMX8QXP_ADR_ADC_RESFIFO 0x300
#define IMX8QXP_ADR_ADC_TST 0xffc
/* ADC bit shift */
#define IMX8QXP_ADC_IE_FWMIE_MASK GENMASK(1, 0)
#define IMX8QXP_ADC_CTRL_FIFO_RESET_MASK BIT(8)
#define IMX8QXP_ADC_CTRL_SOFTWARE_RESET_MASK BIT(1)
#define IMX8QXP_ADC_CTRL_ADC_EN_MASK BIT(0)
#define IMX8QXP_ADC_TCTRL_TCMD_MASK GENMASK(31, 24)
#define IMX8QXP_ADC_TCTRL_TDLY_MASK GENMASK(23, 16)
#define IMX8QXP_ADC_TCTRL_TPRI_MASK GENMASK(15, 8)
#define IMX8QXP_ADC_TCTRL_HTEN_MASK GENMASK(7, 0)
#define IMX8QXP_ADC_CMDL_CSCALE_MASK GENMASK(13, 8)
#define IMX8QXP_ADC_CMDL_MODE_MASK BIT(7)
#define IMX8QXP_ADC_CMDL_DIFF_MASK BIT(6)
#define IMX8QXP_ADC_CMDL_ABSEL_MASK BIT(5)
#define IMX8QXP_ADC_CMDL_ADCH_MASK GENMASK(2, 0)
#define IMX8QXP_ADC_CMDH_NEXT_MASK GENMASK(31, 24)
#define IMX8QXP_ADC_CMDH_LOOP_MASK GENMASK(23, 16)
#define IMX8QXP_ADC_CMDH_AVGS_MASK GENMASK(15, 12)
#define IMX8QXP_ADC_CMDH_STS_MASK BIT(8)
#define IMX8QXP_ADC_CMDH_LWI_MASK GENMASK(7, 7)
#define IMX8QXP_ADC_CMDH_CMPEN_MASK GENMASK(0, 0)
#define IMX8QXP_ADC_CFG_PWREN_MASK BIT(28)
#define IMX8QXP_ADC_CFG_PUDLY_MASK GENMASK(23, 16)
#define IMX8QXP_ADC_CFG_REFSEL_MASK GENMASK(7, 6)
#define IMX8QXP_ADC_CFG_PWRSEL_MASK GENMASK(5, 4)
#define IMX8QXP_ADC_CFG_TPRICTRL_MASK GENMASK(3, 0)
#define IMX8QXP_ADC_FCTRL_FWMARK_MASK GENMASK(20, 16)
#define IMX8QXP_ADC_FCTRL_FCOUNT_MASK GENMASK(4, 0)
#define IMX8QXP_ADC_RESFIFO_VAL_MASK GENMASK(18, 3)
/* ADC PARAMETER*/
#define IMX8QXP_ADC_CMDL_CHANNEL_SCALE_FULL GENMASK(5, 0)
#define IMX8QXP_ADC_CMDL_SEL_A_A_B_CHANNEL 0
#define IMX8QXP_ADC_CMDL_STANDARD_RESOLUTION 0
#define IMX8QXP_ADC_CMDL_MODE_SINGLE 0
#define IMX8QXP_ADC_CMDH_LWI_INCREMENT_DIS 0
#define IMX8QXP_ADC_CMDH_CMPEN_DIS 0
#define IMX8QXP_ADC_PAUSE_EN BIT(31)
#define IMX8QXP_ADC_TCTRL_TPRI_PRIORITY_HIGH 0
#define IMX8QXP_ADC_TCTRL_HTEN_HW_TIRG_DIS 0
#define IMX8QXP_ADC_TIMEOUT msecs_to_jiffies(100)
#define IMX8QXP_ADC_MAX_FIFO_SIZE 16
struct imx8qxp_adc {
struct device *dev;
void __iomem *regs;
struct clk *clk;
struct clk *ipg_clk;
struct regulator *vref;
/* Serialise ADC channel reads */
struct mutex lock;
struct completion completion;
u32 fifo[IMX8QXP_ADC_MAX_FIFO_SIZE];
};
#define IMX8QXP_ADC_CHAN(_idx) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (_idx), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
BIT(IIO_CHAN_INFO_SAMP_FREQ), \
}
static const struct iio_chan_spec imx8qxp_adc_iio_channels[] = {
IMX8QXP_ADC_CHAN(0),
IMX8QXP_ADC_CHAN(1),
IMX8QXP_ADC_CHAN(2),
IMX8QXP_ADC_CHAN(3),
IMX8QXP_ADC_CHAN(4),
IMX8QXP_ADC_CHAN(5),
IMX8QXP_ADC_CHAN(6),
IMX8QXP_ADC_CHAN(7),
};
static void imx8qxp_adc_reset(struct imx8qxp_adc *adc)
{
u32 ctrl;
/*software reset, need to clear the set bit*/
ctrl = readl(adc->regs + IMX8QXP_ADR_ADC_CTRL);
ctrl |= FIELD_PREP(IMX8QXP_ADC_CTRL_SOFTWARE_RESET_MASK, 1);
writel(ctrl, adc->regs + IMX8QXP_ADR_ADC_CTRL);
udelay(10);
ctrl &= ~FIELD_PREP(IMX8QXP_ADC_CTRL_SOFTWARE_RESET_MASK, 1);
writel(ctrl, adc->regs + IMX8QXP_ADR_ADC_CTRL);
/* reset the fifo */
ctrl |= FIELD_PREP(IMX8QXP_ADC_CTRL_FIFO_RESET_MASK, 1);
writel(ctrl, adc->regs + IMX8QXP_ADR_ADC_CTRL);
}
static void imx8qxp_adc_reg_config(struct imx8qxp_adc *adc, int channel)
{
u32 adc_cfg, adc_tctrl, adc_cmdl, adc_cmdh;
/* ADC configuration */
adc_cfg = FIELD_PREP(IMX8QXP_ADC_CFG_PWREN_MASK, 1) |
FIELD_PREP(IMX8QXP_ADC_CFG_PUDLY_MASK, 0x80)|
FIELD_PREP(IMX8QXP_ADC_CFG_REFSEL_MASK, 0) |
FIELD_PREP(IMX8QXP_ADC_CFG_PWRSEL_MASK, 3) |
FIELD_PREP(IMX8QXP_ADC_CFG_TPRICTRL_MASK, 0);
writel(adc_cfg, adc->regs + IMX8QXP_ADR_ADC_CFG);
/* config the trigger control */
adc_tctrl = FIELD_PREP(IMX8QXP_ADC_TCTRL_TCMD_MASK, 1) |
FIELD_PREP(IMX8QXP_ADC_TCTRL_TDLY_MASK, 0) |
FIELD_PREP(IMX8QXP_ADC_TCTRL_TPRI_MASK, IMX8QXP_ADC_TCTRL_TPRI_PRIORITY_HIGH) |
FIELD_PREP(IMX8QXP_ADC_TCTRL_HTEN_MASK, IMX8QXP_ADC_TCTRL_HTEN_HW_TIRG_DIS);
writel(adc_tctrl, adc->regs + IMX8QXP_ADR_ADC_TCTRL(0));
/* config the cmd */
adc_cmdl = FIELD_PREP(IMX8QXP_ADC_CMDL_CSCALE_MASK, IMX8QXP_ADC_CMDL_CHANNEL_SCALE_FULL) |
FIELD_PREP(IMX8QXP_ADC_CMDL_MODE_MASK, IMX8QXP_ADC_CMDL_STANDARD_RESOLUTION) |
FIELD_PREP(IMX8QXP_ADC_CMDL_DIFF_MASK, IMX8QXP_ADC_CMDL_MODE_SINGLE) |
FIELD_PREP(IMX8QXP_ADC_CMDL_ABSEL_MASK, IMX8QXP_ADC_CMDL_SEL_A_A_B_CHANNEL) |
FIELD_PREP(IMX8QXP_ADC_CMDL_ADCH_MASK, channel);
writel(adc_cmdl, adc->regs + IMX8QXP_ADR_ADC_CMDL(0));
adc_cmdh = FIELD_PREP(IMX8QXP_ADC_CMDH_NEXT_MASK, 0) |
FIELD_PREP(IMX8QXP_ADC_CMDH_LOOP_MASK, 0) |
FIELD_PREP(IMX8QXP_ADC_CMDH_AVGS_MASK, 7) |
FIELD_PREP(IMX8QXP_ADC_CMDH_STS_MASK, 0) |
FIELD_PREP(IMX8QXP_ADC_CMDH_LWI_MASK, IMX8QXP_ADC_CMDH_LWI_INCREMENT_DIS) |
FIELD_PREP(IMX8QXP_ADC_CMDH_CMPEN_MASK, IMX8QXP_ADC_CMDH_CMPEN_DIS);
writel(adc_cmdh, adc->regs + IMX8QXP_ADR_ADC_CMDH(0));
}
static void imx8qxp_adc_fifo_config(struct imx8qxp_adc *adc)
{
u32 fifo_ctrl, interrupt_en;
fifo_ctrl = readl(adc->regs + IMX8QXP_ADR_ADC_FCTRL);
fifo_ctrl &= ~IMX8QXP_ADC_FCTRL_FWMARK_MASK;
/* set the watermark level to 1 */
fifo_ctrl |= FIELD_PREP(IMX8QXP_ADC_FCTRL_FWMARK_MASK, 0);
writel(fifo_ctrl, adc->regs + IMX8QXP_ADR_ADC_FCTRL);
/* FIFO Watermark Interrupt Enable */
interrupt_en = readl(adc->regs + IMX8QXP_ADR_ADC_IE);
interrupt_en |= FIELD_PREP(IMX8QXP_ADC_IE_FWMIE_MASK, 1);
writel(interrupt_en, adc->regs + IMX8QXP_ADR_ADC_IE);
}
static void imx8qxp_adc_disable(struct imx8qxp_adc *adc)
{
u32 ctrl;
ctrl = readl(adc->regs + IMX8QXP_ADR_ADC_CTRL);
ctrl &= ~FIELD_PREP(IMX8QXP_ADC_CTRL_ADC_EN_MASK, 1);
writel(ctrl, adc->regs + IMX8QXP_ADR_ADC_CTRL);
}
static int imx8qxp_adc_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct imx8qxp_adc *adc = iio_priv(indio_dev);
struct device *dev = adc->dev;
u32 ctrl;
long ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
pm_runtime_get_sync(dev);
mutex_lock(&adc->lock);
reinit_completion(&adc->completion);
imx8qxp_adc_reg_config(adc, chan->channel);
imx8qxp_adc_fifo_config(adc);
/* adc enable */
ctrl = readl(adc->regs + IMX8QXP_ADR_ADC_CTRL);
ctrl |= FIELD_PREP(IMX8QXP_ADC_CTRL_ADC_EN_MASK, 1);
writel(ctrl, adc->regs + IMX8QXP_ADR_ADC_CTRL);
/* adc start */
writel(1, adc->regs + IMX8QXP_ADR_ADC_SWTRIG);
ret = wait_for_completion_interruptible_timeout(&adc->completion,
IMX8QXP_ADC_TIMEOUT);
pm_runtime_mark_last_busy(dev);
pm_runtime_put_sync_autosuspend(dev);
if (ret == 0) {
mutex_unlock(&adc->lock);
return -ETIMEDOUT;
}
if (ret < 0) {
mutex_unlock(&adc->lock);
return ret;
}
*val = adc->fifo[0];
mutex_unlock(&adc->lock);
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
ret = regulator_get_voltage(adc->vref);
if (ret < 0)
return ret;
*val = ret / 1000;
*val2 = 12;
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_SAMP_FREQ:
*val = clk_get_rate(adc->clk) / 3;
return IIO_VAL_INT;
default:
return -EINVAL;
}
}
static irqreturn_t imx8qxp_adc_isr(int irq, void *dev_id)
{
struct imx8qxp_adc *adc = dev_id;
u32 fifo_count;
int i;
fifo_count = FIELD_GET(IMX8QXP_ADC_FCTRL_FCOUNT_MASK,
readl(adc->regs + IMX8QXP_ADR_ADC_FCTRL));
for (i = 0; i < fifo_count; i++)
adc->fifo[i] = FIELD_GET(IMX8QXP_ADC_RESFIFO_VAL_MASK,
readl_relaxed(adc->regs + IMX8QXP_ADR_ADC_RESFIFO));
if (fifo_count)
complete(&adc->completion);
return IRQ_HANDLED;
}
static int imx8qxp_adc_reg_access(struct iio_dev *indio_dev, unsigned int reg,
unsigned int writeval, unsigned int *readval)
{
struct imx8qxp_adc *adc = iio_priv(indio_dev);
struct device *dev = adc->dev;
if (!readval || reg % 4 || reg > IMX8QXP_ADR_ADC_TST)
return -EINVAL;
pm_runtime_get_sync(dev);
*readval = readl(adc->regs + reg);
pm_runtime_mark_last_busy(dev);
pm_runtime_put_sync_autosuspend(dev);
return 0;
}
static const struct iio_info imx8qxp_adc_iio_info = {
.read_raw = &imx8qxp_adc_read_raw,
.debugfs_reg_access = &imx8qxp_adc_reg_access,
};
static int imx8qxp_adc_probe(struct platform_device *pdev)
{
struct imx8qxp_adc *adc;
struct iio_dev *indio_dev;
struct device *dev = &pdev->dev;
int irq;
int ret;
indio_dev = devm_iio_device_alloc(dev, sizeof(*adc));
if (!indio_dev) {
dev_err(dev, "Failed allocating iio device\n");
return -ENOMEM;
}
adc = iio_priv(indio_dev);
adc->dev = dev;
mutex_init(&adc->lock);
adc->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(adc->regs))
return PTR_ERR(adc->regs);
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
adc->clk = devm_clk_get(dev, "per");
if (IS_ERR(adc->clk))
return dev_err_probe(dev, PTR_ERR(adc->clk), "Failed getting clock\n");
adc->ipg_clk = devm_clk_get(dev, "ipg");
if (IS_ERR(adc->ipg_clk))
return dev_err_probe(dev, PTR_ERR(adc->ipg_clk), "Failed getting clock\n");
adc->vref = devm_regulator_get(dev, "vref");
if (IS_ERR(adc->vref))
return dev_err_probe(dev, PTR_ERR(adc->vref), "Failed getting reference voltage\n");
ret = regulator_enable(adc->vref);
if (ret) {
dev_err(dev, "Can't enable adc reference top voltage\n");
return ret;
}
platform_set_drvdata(pdev, indio_dev);
init_completion(&adc->completion);
indio_dev->name = ADC_DRIVER_NAME;
indio_dev->info = &imx8qxp_adc_iio_info;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->channels = imx8qxp_adc_iio_channels;
indio_dev->num_channels = ARRAY_SIZE(imx8qxp_adc_iio_channels);
ret = clk_prepare_enable(adc->clk);
if (ret) {
dev_err(&pdev->dev, "Could not prepare or enable the clock.\n");
goto error_regulator_disable;
}
ret = clk_prepare_enable(adc->ipg_clk);
if (ret) {
dev_err(&pdev->dev, "Could not prepare or enable the clock.\n");
goto error_adc_clk_disable;
}
ret = devm_request_irq(dev, irq, imx8qxp_adc_isr, 0, ADC_DRIVER_NAME, adc);
if (ret < 0) {
dev_err(dev, "Failed requesting irq, irq = %d\n", irq);
goto error_ipg_clk_disable;
}
imx8qxp_adc_reset(adc);
ret = iio_device_register(indio_dev);
if (ret) {
imx8qxp_adc_disable(adc);
dev_err(dev, "Couldn't register the device.\n");
goto error_ipg_clk_disable;
}
pm_runtime_set_active(dev);
pm_runtime_set_autosuspend_delay(dev, 50);
pm_runtime_use_autosuspend(dev);
pm_runtime_enable(dev);
return 0;
error_ipg_clk_disable:
clk_disable_unprepare(adc->ipg_clk);
error_adc_clk_disable:
clk_disable_unprepare(adc->clk);
error_regulator_disable:
regulator_disable(adc->vref);
return ret;
}
static int imx8qxp_adc_remove(struct platform_device *pdev)
{
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
struct imx8qxp_adc *adc = iio_priv(indio_dev);
struct device *dev = adc->dev;
pm_runtime_get_sync(dev);
iio_device_unregister(indio_dev);
imx8qxp_adc_disable(adc);
clk_disable_unprepare(adc->clk);
clk_disable_unprepare(adc->ipg_clk);
regulator_disable(adc->vref);
pm_runtime_disable(dev);
pm_runtime_put_noidle(dev);
return 0;
}
static int imx8qxp_adc_runtime_suspend(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct imx8qxp_adc *adc = iio_priv(indio_dev);
imx8qxp_adc_disable(adc);
clk_disable_unprepare(adc->clk);
clk_disable_unprepare(adc->ipg_clk);
regulator_disable(adc->vref);
return 0;
}
static int imx8qxp_adc_runtime_resume(struct device *dev)
{
struct iio_dev *indio_dev = dev_get_drvdata(dev);
struct imx8qxp_adc *adc = iio_priv(indio_dev);
int ret;
ret = regulator_enable(adc->vref);
if (ret) {
dev_err(dev, "Can't enable adc reference top voltage, err = %d\n", ret);
return ret;
}
ret = clk_prepare_enable(adc->clk);
if (ret) {
dev_err(dev, "Could not prepare or enable clock.\n");
goto err_disable_reg;
}
ret = clk_prepare_enable(adc->ipg_clk);
if (ret) {
dev_err(dev, "Could not prepare or enable clock.\n");
goto err_unprepare_clk;
}
imx8qxp_adc_reset(adc);
return 0;
err_unprepare_clk:
clk_disable_unprepare(adc->clk);
err_disable_reg:
regulator_disable(adc->vref);
return ret;
}
static DEFINE_RUNTIME_DEV_PM_OPS(imx8qxp_adc_pm_ops,
imx8qxp_adc_runtime_suspend,
imx8qxp_adc_runtime_resume, NULL);
static const struct of_device_id imx8qxp_adc_match[] = {
{ .compatible = "nxp,imx8qxp-adc", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, imx8qxp_adc_match);
static struct platform_driver imx8qxp_adc_driver = {
.probe = imx8qxp_adc_probe,
.remove = imx8qxp_adc_remove,
.driver = {
.name = ADC_DRIVER_NAME,
.of_match_table = imx8qxp_adc_match,
.pm = pm_ptr(&imx8qxp_adc_pm_ops),
},
};
module_platform_driver(imx8qxp_adc_driver);
MODULE_DESCRIPTION("i.MX8QuadXPlus ADC driver");
MODULE_LICENSE("GPL v2");
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