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Message-ID: <20230311185719.7af38a8a@jic23-huawei>
Date: Sat, 11 Mar 2023 18:57:19 +0000
From: Jonathan Cameron <jic23@...nel.org>
To: William Breathitt Gray <william.gray@...aro.org>
Cc: lars@...afoo.de, linux-iio@...r.kernel.org,
linux-kernel@...r.kernel.org,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: Re: [PATCH v2] iio: dac: cio-dac: Migrate to the regmap API
On Sat, 11 Mar 2023 09:02:18 -0500
William Breathitt Gray <william.gray@...aro.org> wrote:
> The regmap API supports IO port accessors so we can take advantage of
> regmap abstractions rather than handling access to the device registers
> directly in the driver.
>
> Suggested-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Signed-off-by: William Breathitt Gray <william.gray@...aro.org>
Trivial question inline about the includes changes, otherwise looks good to me.
I'm not that fussed about the includes if there is nothing else requiring
a v3, but obviously want to give it a little time for others to comment.
Jonathan
> ---
> Changes in v2:
> - Remove DAC initialization to 0V in cio_dio_probe() as superfluous now
> that the chan_out_states buffer is gone
>
> drivers/iio/dac/Kconfig | 1 +
> drivers/iio/dac/cio-dac.c | 66 ++++++++++++++++++++++++++-------------
> 2 files changed, 46 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index d3f90cf86143..3acd9c3f388e 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -277,6 +277,7 @@ config CIO_DAC
> tristate "Measurement Computing CIO-DAC IIO driver"
> depends on X86 && (ISA_BUS || PC104)
> select ISA_BUS_API
> + select REGMAP_MMIO
> help
> Say yes here to build support for the Measurement Computing CIO-DAC
> analog output device family (CIO-DAC16, CIO-DAC08, PC104-DAC06). The
> diff --git a/drivers/iio/dac/cio-dac.c b/drivers/iio/dac/cio-dac.c
> index 791dd999cf29..759833a6bd29 100644
> --- a/drivers/iio/dac/cio-dac.c
> +++ b/drivers/iio/dac/cio-dac.c
> @@ -6,16 +6,15 @@
> * This driver supports the following Measurement Computing devices: CIO-DAC16,
> * CIO-DAC06, and PC104-DAC06.
> */
> -#include <linux/bitops.h>
> +#include <linux/bits.h>
I'm not immediately spotting why this change is part of the regmap
conversion.
It may well make sense, but if unrelated, should probably be in a different patch.
> #include <linux/device.h>
> -#include <linux/errno.h>
> +#include <linux/err.h>
> #include <linux/iio/iio.h>
> #include <linux/iio/types.h>
> -#include <linux/io.h>
> -#include <linux/ioport.h>
> #include <linux/isa.h>
> #include <linux/module.h>
> #include <linux/moduleparam.h>
> +#include <linux/regmap.h>
> #include <linux/types.h>
>
> #define CIO_DAC_NUM_CHAN 16
> @@ -35,25 +34,51 @@ static unsigned int num_cio_dac;
> module_param_hw_array(base, uint, ioport, &num_cio_dac, 0);
> MODULE_PARM_DESC(base, "Measurement Computing CIO-DAC base addresses");
>
> +#define CIO_DAC_BASE 0x00
> +#define CIO_DAC_CHANNEL_STRIDE 2
> +
> +static bool cio_dac_precious_reg(struct device *dev, unsigned int reg)
> +{
> + /*
> + * All registers are considered precious; if the XFER jumper is set on
> + * the device, then no update occurs until a DAC register is read.
> + */
> + return true;
> +}
> +
> +static const struct regmap_config cio_dac_regmap_config = {
> + .reg_bits = 16,
> + .reg_stride = 2,
> + .val_bits = 16,
> + .io_port = true,
> + .max_register = 0x1F,
> + .precious_reg = cio_dac_precious_reg,
> +};
> +
> /**
> * struct cio_dac_iio - IIO device private data structure
> - * @chan_out_states: channels' output states
> - * @base: base memory address of the DAC device
> + * @map: Regmap for the device
> */
> struct cio_dac_iio {
> - int chan_out_states[CIO_DAC_NUM_CHAN];
> - u16 __iomem *base;
> + struct regmap *map;
> };
>
> static int cio_dac_read_raw(struct iio_dev *indio_dev,
> struct iio_chan_spec const *chan, int *val, int *val2, long mask)
> {
> struct cio_dac_iio *const priv = iio_priv(indio_dev);
> + const unsigned int offset = chan->channel * CIO_DAC_CHANNEL_STRIDE;
> + int err;
> + unsigned int dac_val;
>
> if (mask != IIO_CHAN_INFO_RAW)
> return -EINVAL;
>
> - *val = priv->chan_out_states[chan->channel];
> + err = regmap_read(priv->map, CIO_DAC_BASE + offset, &dac_val);
> + if (err)
> + return err;
> +
> + *val = dac_val;
>
> return IIO_VAL_INT;
> }
> @@ -62,6 +87,7 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev,
> struct iio_chan_spec const *chan, int val, int val2, long mask)
> {
> struct cio_dac_iio *const priv = iio_priv(indio_dev);
> + const unsigned int offset = chan->channel * CIO_DAC_CHANNEL_STRIDE;
>
> if (mask != IIO_CHAN_INFO_RAW)
> return -EINVAL;
> @@ -70,10 +96,7 @@ static int cio_dac_write_raw(struct iio_dev *indio_dev,
> if ((unsigned int)val > 65535)
> return -EINVAL;
>
> - priv->chan_out_states[chan->channel] = val;
> - iowrite16(val, priv->base + chan->channel);
> -
> - return 0;
> + return regmap_write(priv->map, CIO_DAC_BASE + offset, val);
> }
>
> static const struct iio_info cio_dac_info = {
> @@ -92,7 +115,7 @@ static int cio_dac_probe(struct device *dev, unsigned int id)
> {
> struct iio_dev *indio_dev;
> struct cio_dac_iio *priv;
> - unsigned int i;
> + void __iomem *regs;
>
> indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
> if (!indio_dev)
> @@ -105,21 +128,22 @@ static int cio_dac_probe(struct device *dev, unsigned int id)
> return -EBUSY;
> }
>
> - priv = iio_priv(indio_dev);
> - priv->base = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
> - if (!priv->base)
> + regs = devm_ioport_map(dev, base[id], CIO_DAC_EXTENT);
> + if (!regs)
> return -ENOMEM;
>
> + priv = iio_priv(indio_dev);
> + priv->map = devm_regmap_init_mmio(dev, regs, &cio_dac_regmap_config);
> + if (IS_ERR(priv->map))
> + return dev_err_probe(dev, PTR_ERR(priv->map),
> + "Unable to initialize register map\n");
> +
> indio_dev->info = &cio_dac_info;
> indio_dev->modes = INDIO_DIRECT_MODE;
> indio_dev->channels = cio_dac_channels;
> indio_dev->num_channels = CIO_DAC_NUM_CHAN;
> indio_dev->name = dev_name(dev);
>
> - /* initialize DAC outputs to 0V */
> - for (i = 0; i < CIO_DAC_NUM_CHAN; i++)
> - iowrite16(0, priv->base + i);
> -
> return devm_iio_device_register(dev, indio_dev);
> }
>
>
> base-commit: fe15c26ee26efa11741a7b632e9f23b01aca4cc6
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