Re: [PATCH v3 2/2] iio: twl6030-gpadc: TWL6030, TWL6032 GPADC driver
From: Grygorii Strashko
Date: Mon Jul 15 2013 - 07:58:20 EST
Hi All,
I have a question regarding this patch and IIO in general
- Does IIO provide sync mechanism with system wide suspend/resume or
this should be handled by each driver itself?
What if during system suspend iio_read_channel_raw() (or any other
consumer API) will be called after gpadc driver have been suspended
already? (I did some investigation and seems it's possible - Am I right?)
If no, could "info_exist_lock" be reused for such purposes?
Regards,
-grygorii
On 07/12/2013 10:56 PM, Lars-Peter Clausen wrote:
A couple of comments inline.
On 07/12/2013 09:18 AM, Oleksandr Kozaruk wrote:
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index ab0767e6..87d699e 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -157,4 +157,12 @@ config VIPERBOARD_ADC
Say yes here to access the ADC part of the Nano River
Technologies Viperboard.
+config TWL6030_GPADC
+ tristate "TWL6030 GPADC (General Purpose A/D Convertor) Support"
+ depends on TWL4030_CORE
+ default n
+ help
+ Say yes here if you want support for the TWL6030 General Purpose
+ A/D Convertor.
+
Keep it in alphabetical order
endmenu
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 0a825be..8b05633 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -17,3 +17,4 @@ obj-$(CONFIG_MAX1363) += max1363.o
obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o
+obj-$(CONFIG_TWL6030_GPADC) += twl6030-gpadc.o
Same here.
diff --git a/drivers/iio/adc/twl6030-gpadc.c
b/drivers/iio/adc/twl6030-gpadc.c
new file mode 100644
index 0000000..6ceb789
--- /dev/null
+++ b/drivers/iio/adc/twl6030-gpadc.c
@@ -0,0 +1,1019 @@
[...]
+static u8 twl6032_channel_to_reg(int channel)
+{
+ return TWL6032_GPADC_GPCH0_LSB;
There is more than one channel, isn't there?
[...]
> +static int twl6030_gpadc_read_raw(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan,
> + int *val, int *val2, long mask)
> +{
> + struct twl6030_gpadc_data *gpadc = iio_priv(indio_dev);
> + int ret = -EINVAL;
> +
> + mutex_lock(&gpadc->lock);
> +
> + ret = gpadc->pdata->start_conversion(chan->channel);
> + if (ret) {
> + dev_err(gpadc->dev, "failed to start conversion\n");
> + goto err;
> + }
> + /* wait for conversion to complete */
> + wait_for_completion_interruptible_timeout(&gpadc->irq_complete,
> + msecs_to_jiffies(5000));
wait_for_completion_interruptible_timeout() can return either a negative
error code if it was interrupted, 0 if it timed out, or a positive value
if it was successfully completed. You need to handle all three cases.
Have a look at other existing drivers to see how to do this properly.
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + ret = twl6030_gpadc_get_raw(gpadc, chan->channel, val);
> + ret = ret ? -EIO : IIO_VAL_INT;
> + break;
> +
> + case IIO_CHAN_INFO_PROCESSED:
> + ret = twl6030_gpadc_get_processed(gpadc, chan->channel, val);
> + ret = ret ? -EIO : IIO_VAL_INT;
> + break;
> +
> + default:
> + break;
> + }
> +err:
> + mutex_unlock(&gpadc->lock);
> +
> + return ret;
> +}
+}
+
[...]
+static int twl6030_gpadc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct twl6030_gpadc_data *gpadc;
+ const struct twl6030_gpadc_platform_data *pdata;
+ const struct of_device_id *match;
+ struct iio_dev *indio_dev;
+ int irq;
+ int ret = 0;
+
+ match = of_match_device(of_match_ptr(of_twl6030_match_tbl), dev);
+ pdata = match ? match->data : dev->platform_data;
+
+ if (!pdata)
+ return -EINVAL;
+
+ indio_dev = iio_device_alloc(sizeof(struct twl6030_gpadc_data));
sizeof(*gpadc)
+ if (!indio_dev) {
+ dev_err(dev, "failed allocating iio device\n");
+ ret = -ENOMEM;
+ }
+
+ gpadc = iio_priv(indio_dev);
+
+ gpadc->twl6030_cal_tbl = devm_kzalloc(dev,
+ sizeof(struct twl6030_chnl_calib) *
+ pdata->nchannels, GFP_KERNEL);
+ if (!gpadc->twl6030_cal_tbl)
+ goto err;
+
+ gpadc->dev = dev;
+ gpadc->pdata = pdata;
+
+ platform_set_drvdata(pdev, indio_dev);
+ mutex_init(&gpadc->lock);
+ init_completion(&gpadc->irq_complete);
+
+ ret = pdata->calibrate(gpadc);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to read calibration registers\n");
+ goto err;
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "failed to get irq\n");
+ goto err;
+ }
+
+ ret = devm_request_threaded_irq(dev, irq, NULL,
+ twl6030_gpadc_irq_handler,
+ IRQF_ONESHOT, "twl6030_gpadc", gpadc);
You access memory in the interrupt handler which is freed before the
interrupt handler is freed.
+ if (ret) {
+ dev_dbg(&pdev->dev, "could not request irq\n");
+ goto err;
+ }
+
+ ret = twl6030_gpadc_enable_irq(TWL6030_GPADC_RT_SW1_EOC_MASK);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to enable GPADC interrupt\n");
+ goto err;
+ }
+ ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCS,
+ TWL6030_REG_TOGGLE1);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to enable GPADC module\n");
+ goto err;
+ }
+
+ indio_dev->name = DRIVER_NAME;
+ indio_dev->dev.parent = dev;
+ indio_dev->info = &twl6030_gpadc_iio_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = pdata->iio_channels;
+ indio_dev->num_channels = pdata->nchannels;
+
+ ret = iio_device_register(indio_dev);
+ if (ret)
+ goto err;
+
+ return ret;
+err:
+ iio_device_free(indio_dev);
+ return ret;
+}
+
[...]
+static int twl6030_gpadc_suspend(struct device *pdev)
+{
+ int ret;
+
+ ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCR,
+ TWL6030_REG_TOGGLE1);
+ if (ret)
+ dev_err(pdev, "error reseting GPADC (%d)!\n", ret);
+
+ return 0;
+};
+
+static int twl6030_gpadc_resume(struct device *pdev)
+{
+ int ret;
+
+ ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, TWL6030_GPADCS,
+ TWL6030_REG_TOGGLE1);
+ if (ret)
+ dev_err(pdev, "error setting GPADC (%d)!\n", ret);
+
+ return 0;
+};
+
+static const struct dev_pm_ops twl6030_gpadc_pm_ops = {
+ .suspend = twl6030_gpadc_suspend,
+ .resume = twl6030_gpadc_resume,
+};
SIMPLE_DEV_PM_OPS?
[...]
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