Subject: [PATCH v2 2/2] iio: dac: vf610_dac: Add IIO DAC driver for Vybrid SoC

From: [email-masked] (Jonathan Cameron)
Date: Sun, 21 Feb 2016 19:37:16 +0000

On 21/02/16 16:48, Jonathan Cameron wrote:
> 
> 
> On 15 February 2016 06:42:33 GMT+00:00, Sanchayan Maity <[email-masked]> wrote:
>> Add driver support for DAC peripheral on Vybrid SoC.
>>
>> Signed-off-by: Sanchayan Maity <[email-masked]>
>> Acked-by: Rob Herring <[email-masked]>
> Ordering is wrong in remove. I may well fix this up and apply later today. 
I also note that the Kconfig dependencies are rather sparse.  Presumably needs
depends on HAS_IOMEM at the very least.  Anyhow, changes are getting less
trivial so I'm  not going to apply this without another revision.

Jonathan
>  Otherwise looks good to me.
>> ---
>> Documentation/ABI/testing/sysfs-bus-iio-vf610      |   9 +
>> .../devicetree/bindings/iio/dac/vf610-dac.txt      |  20 ++
>> drivers/iio/dac/Kconfig                            |   8 +
>> drivers/iio/dac/Makefile                           |   1 +
>> drivers/iio/dac/vf610_dac.c                        | 298
>> +++++++++++++++++++++
>> 5 files changed, 336 insertions(+)
>> create mode 100644
>> Documentation/devicetree/bindings/iio/dac/vf610-dac.txt
>> create mode 100644 drivers/iio/dac/vf610_dac.c
>>
>> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-vf610
>> b/Documentation/ABI/testing/sysfs-bus-iio-vf610
>> index ecbc1f4..5ea809c 100644
>> --- a/Documentation/ABI/testing/sysfs-bus-iio-vf610
>> +++ b/Documentation/ABI/testing/sysfs-bus-iio-vf610
>> @@ -5,3 +5,12 @@ Description:
>> 		Specifies the hardware conversion mode used. The three
>> 		available modes are "normal", "high-speed" and "low-power",
>> 		where the last is the default mode.
>> +
>> +
>> +What:		/sys/bus/iio/devices/iio:deviceX/out_conversion_mode
>> +KernelVersion:	4.6
>> +Contact:	linux-iio at vger.kernel.org
>> +Description:
>> +		Specifies the hardware conversion mode used within DAC.
>> +		The two available modes are "high-power" and "low-power",
>> +		where "low-power" mode is the default mode.
>> \ No newline at end of file
>> diff --git a/Documentation/devicetree/bindings/iio/dac/vf610-dac.txt
>> b/Documentation/devicetree/bindings/iio/dac/vf610-dac.txt
>> new file mode 100644
>> index 0000000..20c6c7a
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iio/dac/vf610-dac.txt
>> @@ -0,0 +1,20 @@
>> +Freescale vf610 Digital to Analog Converter bindings
>> +
>> +The devicetree bindings are for the new DAC driver written for
>> +vf610 SoCs from Freescale.
>> +
>> +Required properties:
>> +- compatible: Should contain "fsl,vf610-dac"
>> +- reg: Offset and length of the register set for the device
>> +- interrupts: Should contain the interrupt for the device
>> +- clocks: The clock is needed by the DAC controller
>> +- clock-names: Must contain "dac" matching entry in the clocks
>> property.
>> +
>> +Example:
>> +dac0: dac at 400cc000 {
>> +	compatible = "fsl,vf610-dac";
>> +	reg = <0x400cc000 0x1000>;
>> +	interrupts = <55 IRQ_TYPE_LEVEL_HIGH>;
>> +	clock-names = "dac";
>> +	clocks = <&clks VF610_CLK_DAC0>;
>> +};
>> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
>> index e701e28..8eb0502 100644
>> --- a/drivers/iio/dac/Kconfig
>> +++ b/drivers/iio/dac/Kconfig
>> @@ -196,4 +196,12 @@ config MCP4922
>> 	  To compile this driver as a module, choose M here: the module
>> 	  will be called mcp4922.
>>
>> +config VF610_DAC
>> +	tristate "Vybrid vf610 DAC driver"
>> +	help
>> +	  Say yes here to support Vybrid board digital-to-analog converter.
>> +
>> +	  This driver can also be built as a module. If so, the module will
>> +	  be called vf610_dac.
>> +
>> endmenu
>> diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
>> index 63ae056..93feb27 100644
>> --- a/drivers/iio/dac/Makefile
>> +++ b/drivers/iio/dac/Makefile
>> @@ -21,3 +21,4 @@ obj-$(CONFIG_MAX517) += max517.o
>> obj-$(CONFIG_MAX5821) += max5821.o
>> obj-$(CONFIG_MCP4725) += mcp4725.o
>> obj-$(CONFIG_MCP4922) += mcp4922.o
>> +obj-$(CONFIG_VF610_DAC) += vf610_dac.o
>> diff --git a/drivers/iio/dac/vf610_dac.c b/drivers/iio/dac/vf610_dac.c
>> new file mode 100644
>> index 0000000..3f70f96
>> --- /dev/null
>> +++ b/drivers/iio/dac/vf610_dac.c
>> @@ -0,0 +1,298 @@
>> +/*
>> + * Freescale Vybrid vf610 DAC driver
>> + *
>> + * Copyright 2016 Toradex AG
>> + *
>> + * This program is free software; you can redistribute it and/or
>> modify
>> + * it under the terms of the GNU General Public License as published
>> by
>> + * the Free Software Foundation; either version 2 of the License, or
>> + * (at your option) any later version.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>> + * GNU General Public License for more details.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/err.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/io.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regulator/consumer.h>
>> +#include <linux/slab.h>
>> +
>> +#include <linux/iio/iio.h>
>> +#include <linux/iio/sysfs.h>
>> +
>> +#define VF610_DACx_STATCTRL		0x20
>> +
>> +#define VF610_DAC_DACEN			BIT(15)
>> +#define VF610_DAC_DACRFS		BIT(14)
>> +#define VF610_DAC_LPEN			BIT(11)
>> +
>> +#define VF610_DAC_DAT0(x)		((x) & 0xFFF)
>> +
>> +enum vf610_conversion_mode_sel {
>> +	VF610_DAC_CONV_HIGH_POWER,
>> +	VF610_DAC_CONV_LOW_POWER,
>> +};
>> +
>> +struct vf610_dac {
>> +	struct clk *clk;
>> +	struct device *dev;
>> +	enum vf610_conversion_mode_sel conv_mode;
>> +	void __iomem *regs;
>> +};
>> +
>> +static void vf610_dac_init(struct vf610_dac *info)
>> +{
>> +	int val;
>> +
>> +	info->conv_mode = VF610_DAC_CONV_LOW_POWER;
>> +	val = VF610_DAC_DACEN | VF610_DAC_DACRFS |
>> +		VF610_DAC_LPEN;
>> +	writel(val, info->regs + VF610_DACx_STATCTRL);
>> +}
>> +
>> +static void vf610_dac_exit(struct vf610_dac *info)
>> +{
>> +	int val;
>> +
>> +	val = readl(info->regs + VF610_DACx_STATCTRL);
>> +	val &= ~VF610_DAC_DACEN;
>> +	writel(val, info->regs + VF610_DACx_STATCTRL);
>> +}
>> +
>> +static int vf610_set_conversion_mode(struct iio_dev *indio_dev,
>> +				const struct iio_chan_spec *chan,
>> +				unsigned int mode)
>> +{
>> +	struct vf610_dac *info = iio_priv(indio_dev);
>> +	int val;
>> +
>> +	mutex_lock(&indio_dev->mlock);
>> +	info->conv_mode = mode;
>> +	val = readl(info->regs + VF610_DACx_STATCTRL);
>> +	if (mode)
>> +		val |= VF610_DAC_LPEN;
>> +	else
>> +		val &= ~VF610_DAC_LPEN;
>> +	writel(val, info->regs + VF610_DACx_STATCTRL);
>> +	mutex_unlock(&indio_dev->mlock);
>> +
>> +	return 0;
>> +}
>> +
>> +static int vf610_get_conversion_mode(struct iio_dev *indio_dev,
>> +				const struct iio_chan_spec *chan)
>> +{
>> +	struct vf610_dac *info = iio_priv(indio_dev);
>> +
>> +	return info->conv_mode;
>> +}
>> +
>> +static const char * const vf610_conv_modes[] = { "high-power",
>> "low-power" };
>> +
>> +static const struct iio_enum vf610_conversion_mode = {
>> +	.items = vf610_conv_modes,
>> +	.num_items = ARRAY_SIZE(vf610_conv_modes),
>> +	.get = vf610_get_conversion_mode,
>> +	.set = vf610_set_conversion_mode,
>> +};
>> +
>> +static const struct iio_chan_spec_ext_info vf610_ext_info[] = {
>> +	IIO_ENUM("conversion_mode", IIO_SHARED_BY_DIR,
>> +		&vf610_conversion_mode),
>> +	{},
>> +};
>> +
>> +#define VF610_DAC_CHAN(_chan_type) { \
>> +	.type = (_chan_type), \
>> +	.output = 1, \
>> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
>> +	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
>> +	.ext_info = vf610_ext_info, \
>> +}
>> +
>> +static const struct iio_chan_spec vf610_dac_iio_channels[] = {
>> +	VF610_DAC_CHAN(IIO_VOLTAGE),
>> +};
>> +
>> +static int vf610_read_raw(struct iio_dev *indio_dev,
>> +			struct iio_chan_spec const *chan,
>> +			int *val, int *val2,
>> +			long mask)
>> +{
>> +	struct vf610_dac *info = iio_priv(indio_dev);
>> +
>> +	switch (mask) {
>> +	case IIO_CHAN_INFO_RAW:
>> +		*val = VF610_DAC_DAT0(readl(info->regs));
>> +		return IIO_VAL_INT;
>> +	case IIO_CHAN_INFO_SCALE:
>> +		/*
>> +		 * DACRFS is always 1 for valid reference and typical
>> +		 * reference voltage as per Vybrid datasheet is 3.3V
>> +		 * from section 9.1.2.1 of Vybrid datasheet
>> +		 */
>> +		*val = 3300 /* mV */;
>> +		*val2 = 12;
>> +		return IIO_VAL_FRACTIONAL_LOG2;
>> +
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +}
>> +
>> +static int vf610_write_raw(struct iio_dev *indio_dev,
>> +			struct iio_chan_spec const *chan,
>> +			int val, int val2,
>> +			long mask)
>> +{
>> +	struct vf610_dac *info = iio_priv(indio_dev);
>> +
>> +	switch (mask) {
>> +	case IIO_CHAN_INFO_RAW:
>> +		mutex_lock(&indio_dev->mlock);
>> +		writel(VF610_DAC_DAT0(val), info->regs);
>> +		mutex_unlock(&indio_dev->mlock);
>> +		return 0;
>> +
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +}
>> +
>> +static const struct iio_info vf610_dac_iio_info = {
>> +	.driver_module = THIS_MODULE,
>> +	.read_raw = &vf610_read_raw,
>> +	.write_raw = &vf610_write_raw,
>> +};
>> +
>> +static const struct of_device_id vf610_dac_match[] = {
>> +	{ .compatible = "fsl,vf610-dac", },
>> +	{ /* sentinel */ }
>> +};
>> +MODULE_DEVICE_TABLE(of, vf610_dac_match);
>> +
>> +static int vf610_dac_probe(struct platform_device *pdev)
>> +{
>> +	struct iio_dev *indio_dev;
>> +	struct vf610_dac *info;
>> +	struct resource *mem;
>> +	int ret;
>> +
>> +	indio_dev = devm_iio_device_alloc(&pdev->dev,
>> +					sizeof(struct vf610_dac));
>> +	if (!indio_dev) {
>> +		dev_err(&pdev->dev, "Failed allocating iio device\n");
>> +		return -ENOMEM;
>> +	}
>> +
>> +	info = iio_priv(indio_dev);
>> +	info->dev = &pdev->dev;
>> +
>> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +	info->regs = devm_ioremap_resource(&pdev->dev, mem);
>> +	if (IS_ERR(info->regs))
>> +		return PTR_ERR(info->regs);
>> +
>> +	info->clk = devm_clk_get(&pdev->dev, "dac");
>> +	if (IS_ERR(info->clk)) {
>> +		dev_err(&pdev->dev, "Failed getting clock, err = %ld\n",
>> +			PTR_ERR(info->clk));
>> +		return PTR_ERR(info->clk);
>> +	}
>> +
>> +	platform_set_drvdata(pdev, indio_dev);
>> +
>> +	indio_dev->name = dev_name(&pdev->dev);
>> +	indio_dev->dev.parent = &pdev->dev;
>> +	indio_dev->dev.of_node = pdev->dev.of_node;
>> +	indio_dev->info = &vf610_dac_iio_info;
>> +	indio_dev->modes = INDIO_DIRECT_MODE;
>> +	indio_dev->channels = vf610_dac_iio_channels;
>> +	indio_dev->num_channels = ARRAY_SIZE(vf610_dac_iio_channels);
>> +
>> +	ret = clk_prepare_enable(info->clk);
>> +	if (ret) {
>> +		dev_err(&pdev->dev,
>> +			"Could not prepare or enable the clock\n");
>> +		return ret;
>> +	}
>> +
>> +	vf610_dac_init(info);
>> +
>> +	ret = iio_device_register(indio_dev);
>> +	if (ret) {
>> +		dev_err(&pdev->dev, "Couldn't register the device\n");
>> +		goto error_iio_device_register;
>> +	}
>> +
>> +	return 0;
>> +
>> +error_iio_device_register:
>> +	clk_disable_unprepare(info->clk);
>> +
>> +	return ret;
>> +}
>> +
>> +static int vf610_dac_remove(struct platform_device *pdev)
>> +{
>> +	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
>> +	struct vf610_dac *info = iio_priv(indio_dev);
>> +
>> +	vf610_dac_exit(info);
> Should be reverse order of probe so exit after the unregister below.
> Right now you are disabling the hardware before removing the userspace interfaces.
>> +	iio_device_unregister(indio_dev);
>> +	clk_disable_unprepare(info->clk);
>> +
>> +	return 0;
>> +}
>> +
>> +#ifdef CONFIG_PM_SLEEP
>> +static int vf610_dac_suspend(struct device *dev)
>> +{
>> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
>> +	struct vf610_dac *info = iio_priv(indio_dev);
>> +
>> +	vf610_dac_exit(info);
>> +	clk_disable_unprepare(info->clk);
>> +
>> +	return 0;
>> +}
>> +
>> +static int vf610_dac_resume(struct device *dev)
>> +{
>> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
>> +	struct vf610_dac *info = iio_priv(indio_dev);
>> +	int ret;
>> +
>> +	ret = clk_prepare_enable(info->clk);
>> +	if (ret)
>> +		return ret;
>> +
>> +	vf610_dac_init(info);
>> +
>> +	return 0;
>> +}
>> +#endif
>> +
>> +static SIMPLE_DEV_PM_OPS(vf610_dac_pm_ops, vf610_dac_suspend,
>> vf610_dac_resume);
>> +
>> +static struct platform_driver vf610_dac_driver = {
>> +	.probe          = vf610_dac_probe,
>> +	.remove         = vf610_dac_remove,
>> +	.driver         = {
>> +		.name   = "vf610-dac",
>> +		.of_match_table = vf610_dac_match,
>> +		.pm     = &vf610_dac_pm_ops,
>> +	},
>> +};
>> +module_platform_driver(vf610_dac_driver);
>> +
>> +MODULE_AUTHOR("Sanchayan Maity <[email-masked]");
>> +MODULE_DESCRIPTION("Freescale VF610 DAC driver");
>> +MODULE_LICENSE("GPL v2");
>