[PATCH v9 7/7] iio: adc: adi-axi-adc: move to backend framework

Nuno Sa via B4 Relay
2024-02-06T10:08:44Z

From: Nuno Sa <nuno.sa@analog.com>

Move to the IIO backend framework. Devices supported by adi-axi-adc now
register themselves as backend devices.

Signed-off-by: Nuno Sa <nuno.sa@analog.com>
---
drivers/iio/adc/Kconfig | 2 +-
drivers/iio/adc/adi-axi-adc.c | 378 +++++++++---------------------------
include/linux/iio/adc/adi-axi-adc.h | 68 -------
3 files changed, 92 insertions(+), 356 deletions(-)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 61736dc21d2a..977832d797e1 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -325,7 +325,7 @@ config ADI_AXI_ADC
select IIO_BUFFER_HW_CONSUMER
select IIO_BUFFER_DMAENGINE
select REGMAP_MMIO
- depends on OF
+ select IIO_BACKEND
help
Say yes here to build support for Analog Devices Generic
AXI ADC IP core. The IP core is used for interfacing with
diff --git a/drivers/iio/adc/adi-axi-adc.c b/drivers/iio/adc/adi-axi-adc.c
index 0f21d1d98b9f..cb28b25e97a4 100644
--- a/drivers/iio/adc/adi-axi-adc.c
+++ b/drivers/iio/adc/adi-axi-adc.c
@@ -8,6 +8,7 @@

#include <linux/bitfield.h>
#include <linux/clk.h>
+#include <linux/err.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/module.h>
@@ -17,13 +18,11 @@
#include <linux/regmap.h>
#include <linux/slab.h>

-#include <linux/iio/iio.h>
-#include <linux/iio/sysfs.h>
-#include <linux/iio/buffer.h>
-#include <linux/iio/buffer-dmaengine.h>
-
#include <linux/fpga/adi-axi-common.h>
-#include <linux/iio/adc/adi-axi-adc.h>
+#include <linux/iio/backend.h>
+#include <linux/iio/buffer-dmaengine.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>

/*
* Register definitions:
@@ -44,6 +43,7 @@
#define ADI_AXI_REG_CHAN_CTRL_PN_SEL_OWR BIT(10)
#define ADI_AXI_REG_CHAN_CTRL_IQCOR_EN BIT(9)
#define ADI_AXI_REG_CHAN_CTRL_DCFILT_EN BIT(8)
+#define ADI_AXI_REG_CHAN_CTRL_FMT_MASK GENMASK(6, 4)
#define ADI_AXI_REG_CHAN_CTRL_FMT_SIGNEXT BIT(6)
#define ADI_AXI_REG_CHAN_CTRL_FMT_TYPE BIT(5)
#define ADI_AXI_REG_CHAN_CTRL_FMT_EN BIT(4)
@@ -55,286 +55,100 @@
ADI_AXI_REG_CHAN_CTRL_FMT_EN | \
ADI_AXI_REG_CHAN_CTRL_ENABLE)

-struct adi_axi_adc_core_info {
- unsigned int version;
-};
-
struct adi_axi_adc_state {
- struct mutex lock;
-
- struct adi_axi_adc_client *client;
struct regmap *regmap;
-};
-
-struct adi_axi_adc_client {
- struct list_head entry;
- struct adi_axi_adc_conv conv;
- struct adi_axi_adc_state *state;
struct device *dev;
- const struct adi_axi_adc_core_info *info;
};

-static LIST_HEAD(registered_clients);
-static DEFINE_MUTEX(registered_clients_lock);
-
-static struct adi_axi_adc_client *conv_to_client(struct adi_axi_adc_conv *conv)
-{
- return container_of(conv, struct adi_axi_adc_client, conv);
-}
-
-void *adi_axi_adc_conv_priv(struct adi_axi_adc_conv *conv)
-{
- struct adi_axi_adc_client *cl = conv_to_client(conv);
-
- return (char *)cl + ALIGN(sizeof(struct adi_axi_adc_client),
- IIO_DMA_MINALIGN);
-}
-EXPORT_SYMBOL_NS_GPL(adi_axi_adc_conv_priv, IIO_ADI_AXI);
-
-static int adi_axi_adc_config_dma_buffer(struct device *dev,
- struct iio_dev *indio_dev)
-{
- const char *dma_name;
-
- if (!device_property_present(dev, "dmas"))
- return 0;
-
- if (device_property_read_string(dev, "dma-names", &dma_name))
- dma_name = "rx";
-
- return devm_iio_dmaengine_buffer_setup(indio_dev->dev.parent,
- indio_dev, dma_name);
-}
-
-static int adi_axi_adc_read_raw(struct iio_dev *indio_dev,
- struct iio_chan_spec const *chan,
- int *val, int *val2, long mask)
-{
- struct adi_axi_adc_state *st = iio_priv(indio_dev);
- struct adi_axi_adc_conv *conv = &st->client->conv;
-
- if (!conv->read_raw)
- return -EOPNOTSUPP;
-
- return conv->read_raw(conv, chan, val, val2, mask);
-}
-
-static int adi_axi_adc_write_raw(struct iio_dev *indio_dev,
- struct iio_chan_spec const *chan,
- int val, int val2, long mask)
-{
- struct adi_axi_adc_state *st = iio_priv(indio_dev);
- struct adi_axi_adc_conv *conv = &st->client->conv;
-
- if (!conv->write_raw)
- return -EOPNOTSUPP;
-
- return conv->write_raw(conv, chan, val, val2, mask);
-}
-
-static int adi_axi_adc_read_avail(struct iio_dev *indio_dev,
- struct iio_chan_spec const *chan,
- const int **vals, int *type, int *length,
- long mask)
+static int axi_adc_enable(struct iio_backend *back)
{
- struct adi_axi_adc_state *st = iio_priv(indio_dev);
- struct adi_axi_adc_conv *conv = &st->client->conv;
-
- if (!conv->read_avail)
- return -EOPNOTSUPP;
-
- return conv->read_avail(conv, chan, vals, type, length, mask);
-}
-
-static int adi_axi_adc_update_scan_mode(struct iio_dev *indio_dev,
- const unsigned long *scan_mask)
-{
- struct adi_axi_adc_state *st = iio_priv(indio_dev);
- struct adi_axi_adc_conv *conv = &st->client->conv;
- unsigned int i;
+ struct adi_axi_adc_state *st = iio_backend_get_priv(back);
int ret;

- for (i = 0; i < conv->chip_info->num_channels; i++) {
- if (test_bit(i, scan_mask))
- ret = regmap_set_bits(st->regmap,
- ADI_AXI_REG_CHAN_CTRL(i),
- ADI_AXI_REG_CHAN_CTRL_ENABLE);
- else
- ret = regmap_clear_bits(st->regmap,
- ADI_AXI_REG_CHAN_CTRL(i),
- ADI_AXI_REG_CHAN_CTRL_ENABLE);
- if (ret)
- return ret;
- }
+ ret = regmap_set_bits(st->regmap, ADI_AXI_REG_RSTN,
+ ADI_AXI_REG_RSTN_MMCM_RSTN);
+ if (ret)
+ return ret;

- return 0;
+ fsleep(10);
+ return regmap_set_bits(st->regmap, ADI_AXI_REG_RSTN,
+ ADI_AXI_REG_RSTN_RSTN | ADI_AXI_REG_RSTN_MMCM_RSTN);
}

-static struct adi_axi_adc_conv *adi_axi_adc_conv_register(struct device *dev,
- size_t sizeof_priv)
+static void axi_adc_disable(struct iio_backend *back)
{
- struct adi_axi_adc_client *cl;
- size_t alloc_size;
-
- alloc_size = ALIGN(sizeof(struct adi_axi_adc_client), IIO_DMA_MINALIGN);
- if (sizeof_priv)
- alloc_size += ALIGN(sizeof_priv, IIO_DMA_MINALIGN);
+ struct adi_axi_adc_state *st = iio_backend_get_priv(back);

- cl = kzalloc(alloc_size, GFP_KERNEL);
- if (!cl)
- return ERR_PTR(-ENOMEM);
-
- mutex_lock(&registered_clients_lock);
-
- cl->dev = get_device(dev);
-
- list_add_tail(&cl->entry, &registered_clients);
-
- mutex_unlock(&registered_clients_lock);
-
- return &cl->conv;
+ regmap_write(st->regmap, ADI_AXI_REG_RSTN, 0);
}

-static void adi_axi_adc_conv_unregister(struct adi_axi_adc_conv *conv)
+static int axi_adc_data_format_set(struct iio_backend *back, unsigned int chan,
+ const struct iio_backend_data_fmt *data)
{
- struct adi_axi_adc_client *cl = conv_to_client(conv);
-
- mutex_lock(&registered_clients_lock);
+ struct adi_axi_adc_state *st = iio_backend_get_priv(back);
+ u32 val;

- list_del(&cl->entry);
- put_device(cl->dev);
+ if (!data->enable)
+ return regmap_clear_bits(st->regmap,
+ ADI_AXI_REG_CHAN_CTRL(chan),
+ ADI_AXI_REG_CHAN_CTRL_FMT_EN);

- mutex_unlock(&registered_clients_lock);
+ val = FIELD_PREP(ADI_AXI_REG_CHAN_CTRL_FMT_EN, true);
+ if (data->sign_extend)
+ val |= FIELD_PREP(ADI_AXI_REG_CHAN_CTRL_FMT_SIGNEXT, true);
+ if (data->type == IIO_BACKEND_OFFSET_BINARY)
+ val |= FIELD_PREP(ADI_AXI_REG_CHAN_CTRL_FMT_TYPE, true);

- kfree(cl);
+ return regmap_update_bits(st->regmap, ADI_AXI_REG_CHAN_CTRL(chan),
+ ADI_AXI_REG_CHAN_CTRL_FMT_MASK, val);
}

-static void devm_adi_axi_adc_conv_release(void *conv)
+static int axi_adc_chan_enable(struct iio_backend *back, unsigned int chan)
{
- adi_axi_adc_conv_unregister(conv);
-}
-
-struct adi_axi_adc_conv *devm_adi_axi_adc_conv_register(struct device *dev,
- size_t sizeof_priv)
-{
- struct adi_axi_adc_conv *conv;
- int ret;
-
- conv = adi_axi_adc_conv_register(dev, sizeof_priv);
- if (IS_ERR(conv))
- return conv;
-
- ret = devm_add_action_or_reset(dev, devm_adi_axi_adc_conv_release,
- conv);
- if (ret)
- return ERR_PTR(ret);
+ struct adi_axi_adc_state *st = iio_backend_get_priv(back);

- return conv;
+ return regmap_set_bits(st->regmap, ADI_AXI_REG_CHAN_CTRL(chan),
+ ADI_AXI_REG_CHAN_CTRL_ENABLE);
}
-EXPORT_SYMBOL_NS_GPL(devm_adi_axi_adc_conv_register, IIO_ADI_AXI);
-
-static const struct iio_info adi_axi_adc_info = {
- .read_raw = &adi_axi_adc_read_raw,
- .write_raw = &adi_axi_adc_write_raw,
- .update_scan_mode = &adi_axi_adc_update_scan_mode,
- .read_avail = &adi_axi_adc_read_avail,
-};

-static const struct adi_axi_adc_core_info adi_axi_adc_10_0_a_info = {
- .version = ADI_AXI_PCORE_VER(10, 0, 'a'),
-};
-
-static struct adi_axi_adc_client *adi_axi_adc_attach_client(struct device *dev)
+static int axi_adc_chan_disable(struct iio_backend *back, unsigned int chan)
{
- const struct adi_axi_adc_core_info *info;
- struct adi_axi_adc_client *cl;
- struct device_node *cln;
-
- info = of_device_get_match_data(dev);
- if (!info)
- return ERR_PTR(-ENODEV);
-
- cln = of_parse_phandle(dev->of_node, "adi,adc-dev", 0);
- if (!cln) {
- dev_err(dev, "No 'adi,adc-dev' node defined\n");
- return ERR_PTR(-ENODEV);
- }
-
- mutex_lock(&registered_clients_lock);
+ struct adi_axi_adc_state *st = iio_backend_get_priv(back);

- list_for_each_entry(cl, &registered_clients, entry) {
- if (!cl->dev)
- continue;
-
- if (cl->dev->of_node != cln)
- continue;
-
- if (!try_module_get(cl->dev->driver->owner)) {
- mutex_unlock(&registered_clients_lock);
- of_node_put(cln);
- return ERR_PTR(-ENODEV);
- }
-
- get_device(cl->dev);
- cl->info = info;
- mutex_unlock(&registered_clients_lock);
- of_node_put(cln);
- return cl;
- }
-
- mutex_unlock(&registered_clients_lock);
- of_node_put(cln);
-
- return ERR_PTR(-EPROBE_DEFER);
+ return regmap_clear_bits(st->regmap, ADI_AXI_REG_CHAN_CTRL(chan),
+ ADI_AXI_REG_CHAN_CTRL_ENABLE);
}

-static int adi_axi_adc_setup_channels(struct device *dev,
- struct adi_axi_adc_state *st)
+static struct iio_buffer *axi_adc_request_buffer(struct iio_backend *back,
+ struct iio_dev *indio_dev)
{
- struct adi_axi_adc_conv *conv = &st->client->conv;
- int i, ret;
+ struct adi_axi_adc_state *st = iio_backend_get_priv(back);
+ struct iio_buffer *buffer;
+ const char *dma_name;
+ int ret;

- if (conv->preenable_setup) {
- ret = conv->preenable_setup(conv);
- if (ret)
- return ret;
- }
+ if (device_property_read_string(st->dev, "dma-names", &dma_name))
+ dma_name = "rx";

- for (i = 0; i < conv->chip_info->num_channels; i++) {
- ret = regmap_write(st->regmap, ADI_AXI_REG_CHAN_CTRL(i),
- ADI_AXI_REG_CHAN_CTRL_DEFAULTS);
- if (ret)
- return ret;
+ buffer = iio_dmaengine_buffer_alloc(st->dev, dma_name);
+ if (IS_ERR(buffer)) {
+ dev_err(st->dev, "Could not get DMA buffer, %ld\n",
+ PTR_ERR(buffer));
+ return ERR_CAST(buffer);
}

- return 0;
-}
-
-static int axi_adc_reset(struct adi_axi_adc_state *st)
-{
- int ret;
-
- ret = regmap_write(st->regmap, ADI_AXI_REG_RSTN, 0);
- if (ret)
- return ret;
-
- mdelay(10);
- ret = regmap_write(st->regmap, ADI_AXI_REG_RSTN,
- ADI_AXI_REG_RSTN_MMCM_RSTN);
+ indio_dev->modes |= INDIO_BUFFER_HARDWARE;
+ ret = iio_device_attach_buffer(indio_dev, buffer);
if (ret)
- return ret;
+ return ERR_PTR(ret);

- mdelay(10);
- return regmap_write(st->regmap, ADI_AXI_REG_RSTN,
- ADI_AXI_REG_RSTN_RSTN | ADI_AXI_REG_RSTN_MMCM_RSTN);
+ return buffer;
}

-static void adi_axi_adc_cleanup(void *data)
+static void axi_adc_free_buffer(struct iio_backend *back,
+ struct iio_buffer *buffer)
{
- struct adi_axi_adc_client *cl = data;
-
- put_device(cl->dev);
- module_put(cl->dev->driver->owner);
+ iio_dmaengine_buffer_free(buffer);
}

static const struct regmap_config axi_adc_regmap_config = {
@@ -344,45 +158,46 @@ static const struct regmap_config axi_adc_regmap_config = {
.max_register = 0x0800,
};

+static const struct iio_backend_ops adi_axi_adc_generic = {
+ .enable = axi_adc_enable,
+ .disable = axi_adc_disable,
+ .data_format_set = axi_adc_data_format_set,
+ .chan_enable = axi_adc_chan_enable,
+ .chan_disable = axi_adc_chan_disable,
+ .request_buffer = axi_adc_request_buffer,
+ .free_buffer = axi_adc_free_buffer,
+};
+
static int adi_axi_adc_probe(struct platform_device *pdev)
{
- struct adi_axi_adc_conv *conv;
- struct iio_dev *indio_dev;
- struct adi_axi_adc_client *cl;
struct adi_axi_adc_state *st;
void __iomem *base;
- unsigned int ver;
+ unsigned int ver, *expected_ver;
int ret;

- cl = adi_axi_adc_attach_client(&pdev->dev);
- if (IS_ERR(cl))
- return PTR_ERR(cl);
-
- ret = devm_add_action_or_reset(&pdev->dev, adi_axi_adc_cleanup, cl);
- if (ret)
- return ret;
-
- indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
- if (indio_dev == NULL)
+ st = devm_kzalloc(&pdev->dev, sizeof(*st), GFP_KERNEL);
+ if (!st)
return -ENOMEM;

- st = iio_priv(indio_dev);
- st->client = cl;
- cl->state = st;
- mutex_init(&st->lock);
-
base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(base))
return PTR_ERR(base);

+ st->dev = &pdev->dev;
st->regmap = devm_regmap_init_mmio(&pdev->dev, base,
&axi_adc_regmap_config);
if (IS_ERR(st->regmap))
return PTR_ERR(st->regmap);

- conv = &st->client->conv;
+ expected_ver = (unsigned int *)device_get_match_data(&pdev->dev);
+ if (!expected_ver)
+ return -ENODEV;

- ret = axi_adc_reset(st);
+ /*
+ * Force disable the core. Up to the frontend to enable us. And we can
+ * still read/write registers...
+ */
+ ret = regmap_write(st->regmap, ADI_AXI_REG_RSTN, 0);
if (ret)
return ret;

@@ -390,33 +205,19 @@ static int adi_axi_adc_probe(struct platform_device *pdev)
if (ret)
return ret;

- if (cl->info->version > ver) {
+ if (*expected_ver > ver) {
dev_err(&pdev->dev,
"IP core version is too old. Expected %d.%.2d.%c, Reported %d.%.2d.%c\n",
- ADI_AXI_PCORE_VER_MAJOR(cl->info->version),
- ADI_AXI_PCORE_VER_MINOR(cl->info->version),
- ADI_AXI_PCORE_VER_PATCH(cl->info->version),
+ ADI_AXI_PCORE_VER_MAJOR(*expected_ver),
+ ADI_AXI_PCORE_VER_MINOR(*expected_ver),
+ ADI_AXI_PCORE_VER_PATCH(*expected_ver),
ADI_AXI_PCORE_VER_MAJOR(ver),
ADI_AXI_PCORE_VER_MINOR(ver),
ADI_AXI_PCORE_VER_PATCH(ver));
return -ENODEV;
}

- indio_dev->info = &adi_axi_adc_info;
- indio_dev->name = "adi-axi-adc";
- indio_dev->modes = INDIO_DIRECT_MODE;
- indio_dev->num_channels = conv->chip_info->num_channels;
- indio_dev->channels = conv->chip_info->channels;
-
- ret = adi_axi_adc_config_dma_buffer(&pdev->dev, indio_dev);
- if (ret)
- return ret;
-
- ret = adi_axi_adc_setup_channels(&pdev->dev, st);
- if (ret)
- return ret;
-
- ret = devm_iio_device_register(&pdev->dev, indio_dev);
+ ret = devm_iio_backend_register(&pdev->dev, &adi_axi_adc_generic, st);
if (ret)
return ret;

@@ -428,6 +229,8 @@ static int adi_axi_adc_probe(struct platform_device *pdev)
return 0;
}

+static unsigned int adi_axi_adc_10_0_a_info = ADI_AXI_PCORE_VER(10, 0, 'a');
+
/* Match table for of_platform binding */
static const struct of_device_id adi_axi_adc_of_match[] = {
{ .compatible = "adi,axi-adc-10.0.a", .data = &adi_axi_adc_10_0_a_info },
@@ -448,3 +251,4 @@ MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
MODULE_DESCRIPTION("Analog Devices Generic AXI ADC IP core driver");
MODULE_LICENSE("GPL v2");
MODULE_IMPORT_NS(IIO_DMAENGINE_BUFFER);
+MODULE_IMPORT_NS(IIO_BACKEND);
diff --git a/include/linux/iio/adc/adi-axi-adc.h b/include/linux/iio/adc/adi-axi-adc.h
deleted file mode 100644
index b7904992d561..000000000000
--- a/include/linux/iio/adc/adi-axi-adc.h
+++ /dev/null
@@ -1,68 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * Analog Devices Generic AXI ADC IP core driver/library
- * Link: https://wiki.analog.com/resources/fpga/docs/axi_adc_ip
- *
- * Copyright 2012-2020 Analog Devices Inc.
- */
-#ifndef __ADI_AXI_ADC_H__
-#define __ADI_AXI_ADC_H__
-
-struct device;
-struct iio_chan_spec;
-
-/**
- * struct adi_axi_adc_chip_info - Chip specific information
- * @name Chip name
- * @id Chip ID (usually product ID)
- * @channels Channel specifications of type @struct iio_chan_spec
- * @num_channels Number of @channels
- * @scale_table Supported scales by the chip; tuples of 2 ints
- * @num_scales Number of scales in the table
- * @max_rate Maximum sampling rate supported by the device
- */
-struct adi_axi_adc_chip_info {
- const char *name;
- unsigned int id;
-
- const struct iio_chan_spec *channels;
- unsigned int num_channels;
-
- const unsigned int (*scale_table)[2];
- int num_scales;
-
- unsigned long max_rate;
-};
-
-/**
- * struct adi_axi_adc_conv - data of the ADC attached to the AXI ADC
- * @chip_info chip info details for the client ADC
- * @preenable_setup op to run in the client before enabling the AXI ADC
- * @reg_access IIO debugfs_reg_access hook for the client ADC
- * @read_raw IIO read_raw hook for the client ADC
- * @write_raw IIO write_raw hook for the client ADC
- * @read_avail IIO read_avail hook for the client ADC
- */
-struct adi_axi_adc_conv {
- const struct adi_axi_adc_chip_info *chip_info;
-
- int (*preenable_setup)(struct adi_axi_adc_conv *conv);
- int (*reg_access)(struct adi_axi_adc_conv *conv, unsigned int reg,
- unsigned int writeval, unsigned int *readval);
- int (*read_raw)(struct adi_axi_adc_conv *conv,
- struct iio_chan_spec const *chan,
- int *val, int *val2, long mask);
- int (*write_raw)(struct adi_axi_adc_conv *conv,
- struct iio_chan_spec const *chan,
- int val, int val2, long mask);
- int (*read_avail)(struct adi_axi_adc_conv *conv,
- struct iio_chan_spec const *chan,
- const int **val, int *type, int *length, long mask);
-};
-
-struct adi_axi_adc_conv *devm_adi_axi_adc_conv_register(struct device *dev,
- size_t sizeof_priv);
-
-void *adi_axi_adc_conv_priv(struct adi_axi_adc_conv *conv);
-
-#endif

--
2.43.0