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Message-ID: <alpine.DEB.2.02.1508031716370.12576@pmeerw.net>
Date: Mon, 3 Aug 2015 17:24:48 +0200 (CEST)
From: Peter Meerwald <pmeerw@...erw.net>
To: Sanchayan Maity <maitysanchayan@...il.com>
cc: jic23@...nel.org, linux-iio@...r.kernel.org, stefan@...er.ch,
B38611@...escale.com, hofrat@...dl.org, sanjeev_sharma@...tor.com,
fabio.estevam@...escale.com, knaack.h@....de, lars@...afoo.de,
antoine.tenart@...e-electrons.com, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] iio: adc: vf610: Add IIO buffer support for Vybrid ADC
On Mon, 3 Aug 2015, Sanchayan Maity wrote:
> This patch adds support for IIO buffer to the Vybrid ADC driver.
> IIO triggered buffer infrastructure along with iio sysfs trigger
> is used to leverage continuous sampling support provided by the
> ADC block.
comments below
> Signed-off-by: Sanchayan Maity <maitysanchayan@...il.com>
> ---
> drivers/iio/adc/Kconfig | 4 ++
> drivers/iio/adc/vf610_adc.c | 122 +++++++++++++++++++++++++++++++++++++++++---
> 2 files changed, 120 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 7c55658..4661241 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -337,6 +337,10 @@ config TWL6030_GPADC
> config VF610_ADC
> tristate "Freescale vf610 ADC driver"
> depends on OF
> + select IIO_BUFFER
> + select IIO_TRIGGER
> + select IIO_SYSFS_TRIGGER
> + select IIO_TRIGGERED_BUFFER
> help
> Say yes here to support for Vybrid board analog-to-digital converter.
> Since the IP is used for i.MX6SLX, the driver also support i.MX6SLX.
> diff --git a/drivers/iio/adc/vf610_adc.c b/drivers/iio/adc/vf610_adc.c
> index 23b8fb9..af72b9a 100644
> --- a/drivers/iio/adc/vf610_adc.c
> +++ b/drivers/iio/adc/vf610_adc.c
> @@ -34,8 +34,11 @@
> #include <linux/err.h>
>
> #include <linux/iio/iio.h>
> +#include <linux/iio/buffer.h>
> #include <linux/iio/sysfs.h>
> -#include <linux/iio/driver.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
>
> /* This will be the driver name the kernel reports */
> #define DRIVER_NAME "vf610-adc"
> @@ -170,6 +173,7 @@ struct vf610_adc {
> u32 sample_freq_avail[5];
>
> struct completion completion;
> + u16 *buffer;
> };
>
> static const u32 vf610_hw_avgs[] = { 1, 4, 8, 16, 32 };
> @@ -505,12 +509,22 @@ static const struct iio_chan_spec_ext_info vf610_ext_info[] = {
> .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
> BIT(IIO_CHAN_INFO_SAMP_FREQ), \
> .ext_info = vf610_ext_info, \
> + .address = (_idx), \
address is not used, no need to set it
> + .scan_index = (_idx), \
often this is written .scan_type = {.sign = 'u', ...}
> + .scan_type.sign = 'u', \
> + .scan_type.realbits = 12, \
> + .scan_type.storagebits = 16, \
> }
>
> #define VF610_ADC_TEMPERATURE_CHAN(_idx, _chan_type) { \
> .type = (_chan_type), \
> .channel = (_idx), \
> .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
> + .address = (_idx), \
> + .scan_index = (_idx), \
> + .scan_type.sign = 'u', \
> + .scan_type.realbits = 12, \
> + .scan_type.storagebits = 16, \
> }
>
> static const struct iio_chan_spec vf610_adc_iio_channels[] = {
> @@ -531,6 +545,7 @@ static const struct iio_chan_spec vf610_adc_iio_channels[] = {
> VF610_ADC_CHAN(14, IIO_VOLTAGE),
> VF610_ADC_CHAN(15, IIO_VOLTAGE),
> VF610_ADC_TEMPERATURE_CHAN(26, IIO_TEMP),
> + IIO_CHAN_SOFT_TIMESTAMP(32),
> /* sentinel */
> };
>
> @@ -559,13 +574,21 @@ static int vf610_adc_read_data(struct vf610_adc *info)
>
> static irqreturn_t vf610_adc_isr(int irq, void *dev_id)
> {
> - struct vf610_adc *info = (struct vf610_adc *)dev_id;
> + struct iio_dev *indio_dev = (struct iio_dev *)dev_id;
> + struct vf610_adc *info = iio_priv(indio_dev);
> int coco;
>
> coco = readl(info->regs + VF610_REG_ADC_HS);
> if (coco & VF610_ADC_HS_COCO0) {
> info->value = vf610_adc_read_data(info);
> - complete(&info->completion);
> + if (iio_buffer_enabled(indio_dev)) {
> + info->buffer[0] = info->value;
> + writel(0, info->regs + VF610_REG_ADC_HS);
> + iio_push_to_buffers_with_timestamp(indio_dev,
> + info->buffer, iio_get_time_ns());
> + iio_trigger_notify_done(indio_dev->trig);
> + } else
> + complete(&info->completion);
> }
>
> return IRQ_HANDLED;
> @@ -612,6 +635,9 @@ static int vf610_read_raw(struct iio_dev *indio_dev,
> switch (mask) {
> case IIO_CHAN_INFO_RAW:
> case IIO_CHAN_INFO_PROCESSED:
> + if (iio_buffer_enabled(indio_dev))
> + return -EBUSY;
> +
> mutex_lock(&indio_dev->mlock);
> reinit_completion(&info->completion);
>
> @@ -694,6 +720,81 @@ static int vf610_write_raw(struct iio_dev *indio_dev,
> return -EINVAL;
> }
>
> +static int vf610_adc_buffer_postenable(struct iio_dev *indio_dev)
> +{
> + struct vf610_adc *info = iio_priv(indio_dev);
> + unsigned int channel;
> + int ret;
> + int val;
> +
> + ret = iio_triggered_buffer_postenable(indio_dev);
> + if (ret)
> + return ret;
> +
> + val = readl(info->regs + VF610_REG_ADC_GC);
> + val |= VF610_ADC_ADCON;
> + writel(val, info->regs + VF610_REG_ADC_GC);
> +
> + channel = find_first_bit(indio_dev->active_scan_mask,
> + indio_dev->masklength);
> +
> + val = VF610_ADC_ADCHC(channel);
> + val |= VF610_ADC_AIEN;
> +
> + writel(val, info->regs + VF610_REG_ADC_HC0);
> +
> + return 0;
> +}
> +
> +static int vf610_adc_buffer_postdisable(struct iio_dev *indio_dev)
> +{
> + struct vf610_adc *info = iio_priv(indio_dev);
> + unsigned int hc_cfg = 0;
> + int val;
> +
> + val = readl(info->regs + VF610_REG_ADC_GC);
> + val &= ~VF610_ADC_ADCON;
> + writel(val, info->regs + VF610_REG_ADC_GC);
> +
> + hc_cfg |= VF610_ADC_CONV_DISABLE;
> + hc_cfg &= ~VF610_ADC_AIEN;
> +
> + writel(hc_cfg, info->regs + VF610_REG_ADC_HC0);
> +
> + return 0;
> +}
> +
> +static int vf610_adc_update_scan_mode(struct iio_dev *indio_dev,
> + const unsigned long *scan_mask)
> +{
> + struct vf610_adc *info = iio_priv(indio_dev);
> +
> + kfree(info->buffer);
only one channel can be read (onehot), why not use a fixed size buffer
(one u16, perhaps as a local variable in _adc_isr()?
> + info->buffer = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
> + if (!info->buffer)
> + return -ENOMEM;
> +
> + return 0;
> +}
> +
> +static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
> + .postenable = &vf610_adc_buffer_postenable,
> + .predisable = &iio_triggered_buffer_predisable,
> + .postdisable = &vf610_adc_buffer_postdisable,
> + .validate_scan_mask = &iio_validate_scan_mask_onehot,
> +};
> +
> +static int vf610_adc_buffer_init(struct iio_dev *indio_dev)
> +{
> + return iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
> + NULL, &iio_triggered_buffer_setup_ops);
> +}
> +
> +static void vf610_adc_buffer_remove(struct iio_dev *indio_dev)
> +{
> + iio_triggered_buffer_cleanup(indio_dev);
> +}
> +
> static int vf610_adc_reg_access(struct iio_dev *indio_dev,
> unsigned reg, unsigned writeval,
> unsigned *readval)
> @@ -714,6 +815,7 @@ static const struct iio_info vf610_adc_iio_info = {
> .read_raw = &vf610_read_raw,
> .write_raw = &vf610_write_raw,
> .debugfs_reg_access = &vf610_adc_reg_access,
> + .update_scan_mode = &vf610_adc_update_scan_mode,
> .attrs = &vf610_attribute_group,
> };
>
> @@ -753,7 +855,7 @@ static int vf610_adc_probe(struct platform_device *pdev)
>
> ret = devm_request_irq(info->dev, irq,
> vf610_adc_isr, 0,
> - dev_name(&pdev->dev), info);
> + dev_name(&pdev->dev), indio_dev);
> if (ret < 0) {
> dev_err(&pdev->dev, "failed requesting irq, irq = %d\n", irq);
> return ret;
> @@ -806,15 +908,22 @@ static int vf610_adc_probe(struct platform_device *pdev)
> vf610_adc_cfg_init(info);
> vf610_adc_hw_init(info);
>
> + ret = vf610_adc_buffer_init(indio_dev);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "Couldn't initialise the buffer\n");
> + goto error_iio_device_register;
> + }
> +
> ret = iio_device_register(indio_dev);
> if (ret) {
> dev_err(&pdev->dev, "Couldn't register the device.\n");
> - goto error_iio_device_register;
> + goto error_adc_buffer_init;
> }
>
> return 0;
>
> -
> +error_adc_buffer_init:
> + vf610_adc_buffer_remove(indio_dev);
> error_iio_device_register:
> clk_disable_unprepare(info->clk);
> error_adc_clk_enable:
> @@ -829,6 +938,7 @@ static int vf610_adc_remove(struct platform_device *pdev)
> struct vf610_adc *info = iio_priv(indio_dev);
>
> iio_device_unregister(indio_dev);
> + vf610_adc_buffer_remove(indio_dev);
> regulator_disable(info->vref);
> clk_disable_unprepare(info->clk);
>
>
--
Peter Meerwald
+43-664-2444418 (mobile)
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