[PATCH v1 2/2] iio: dac: vf610_dac: Add IIO DAC driver for Vybrid SoC
Peter Meerwald-Stadler
pmeerw at pmeerw.net
Mon Feb 8 22:43:14 PST 2016
On Tue, 9 Feb 2016, Sanchayan Maity wrote:
> Add driver support for DAC peripheral on Vybrid SoC.
comments below
> Signed-off-by: Sanchayan Maity <maitysanchayan at gmail.com>
> ---
> .../devicetree/bindings/iio/dac/vf610-dac.txt | 20 ++
> drivers/iio/dac/Kconfig | 8 +
> drivers/iio/dac/Makefile | 1 +
> drivers/iio/dac/vf610_dac.c | 302 +++++++++++++++++++++
> 4 files changed, 331 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/devicetree/bindings/iio/dac/vf610-dac.txt b/Documentation/devicetree/bindings/iio/dac/vf610-dac.txt
> new file mode 100644
> index 0000000..97d7a40
> --- /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.
the last sentence is not quite clear; is the comma needed?
> +
> +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..775b349
> --- /dev/null
> +++ b/drivers/iio/dac/vf610_dac.c
> @@ -0,0 +1,302 @@
> +/*
> + * 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 DRIVER_NAME "vf610-dac"
VF610_ prefix
> +
> +#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 conversion_mode_sel {
vf610_ prefix
> + VF610_DAC_CONV_HIGH_POWER,
> + VF610_DAC_CONV_LOW_POWER,
> +};
> +
> +struct vf610_dac {
> + struct clk *clk;
> + struct device *dev;
> + enum conversion_mode_sel conv_mode;
> + void __iomem *regs;
> + int irq;
> +};
> +
> +static int vf610_dac_init(struct vf610_dac *info)
should be void, or check the return value
> +{
> + 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);
> +
> + return 0;
> +}
> +
> +static int vf610_set_conversion_mode(struct iio_dev *indio_dev,
> + const struct iio_chan_spec *chan,
> + unsigned int mode)
mode should be enum conversion_mode_sel?
> +{
> + 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,
return of type enum conversion_mode_sel?
> + 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"};
this should be documented in sysfs-bus-iio-vf610; maybe high-power should
be high-speed
probably this interface should have been exposed as a settable
conversion rate
> +
> +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), \
> + .indexed = -1, \
indexed should be 0 (or not specified) if no indexing is to be used
> + .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:
> + break;
just return -EINVAL here?
and remove it below below
> + }
> +
> + 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:
> + break;
return -EINVAL here should save two lines
> + }
> +
> + 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",
"Failed getting ..."
> + 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;
> + }
> +
> + ret = iio_device_register(indio_dev);
> + if (ret) {
> + dev_err(&pdev->dev, "Couldn't register the device\n");
> + goto error_iio_device_register;
> + }
> +
> + vf610_dac_init(info);
there is a race here, move _dac_init() before _register()
return value is not checked (or use void)
> +
> + 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);
> +
> + 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);
> + int val;
> +
> + val = readl(info->regs + VF610_DACx_STATCTRL);
> + val &= ~VF610_DAC_DACEN;
> + writel(val, info->regs + VF610_DACx_STATCTRL);
> +
> + 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 = DRIVER_NAME,
> + .of_match_table = vf610_dac_match,
> + .pm = &vf610_dac_pm_ops,
> + },
> +};
> +module_platform_driver(vf610_dac_driver);
> +
> +MODULE_AUTHOR("Sanchayan Maity <sanchayan.maity at toradex.com");
> +MODULE_DESCRIPTION("Freescale VF610 DAC driver");
> +MODULE_LICENSE("GPL v2");
>
--
Peter Meerwald-Stadler
+43-664-2444418 (mobile)
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