Unverified Commit bed73904 authored by Arnaud Pouliquen's avatar Arnaud Pouliquen Committed by Mark Brown

IIO: ADC: add stm32 DFSDM core support

Add driver for stm32 DFSDM pheripheral. Its converts a sigma delta
stream in n bit samples through a low pass filter and an integrator.
stm32-dfsdm-core driver is the core part supporting the filter
instances dedicated to sigma-delta ADC or audio PDM microphone purpose.
Signed-off-by: default avatarArnaud Pouliquen <arnaud.pouliquen@st.com>
Reviewed-by: default avatarJonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 6c82f947
......@@ -668,6 +668,18 @@ config STM32_ADC
This driver can also be built as a module. If so, the module
will be called stm32-adc.
config STM32_DFSDM_CORE
tristate "STMicroelectronics STM32 DFSDM core"
depends on (ARCH_STM32 && OF) || COMPILE_TEST
select REGMAP
select REGMAP_MMIO
help
Select this option to enable the driver for STMicroelectronics
STM32 digital filter for sigma delta converter.
This driver can also be built as a module. If so, the module
will be called stm32-dfsdm-core.
config STX104
tristate "Apex Embedded Systems STX104 driver"
depends on PC104 && X86 && ISA_BUS_API
......
......@@ -64,6 +64,7 @@ obj-$(CONFIG_STX104) += stx104.o
obj-$(CONFIG_SUN4I_GPADC) += sun4i-gpadc-iio.o
obj-$(CONFIG_STM32_ADC_CORE) += stm32-adc-core.o
obj-$(CONFIG_STM32_ADC) += stm32-adc.o
obj-$(CONFIG_STM32_DFSDM_CORE) += stm32-dfsdm-core.o
obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
obj-$(CONFIG_TI_ADC0832) += ti-adc0832.o
obj-$(CONFIG_TI_ADC084S021) += ti-adc084s021.o
......
// SPDX-License-Identifier: GPL-2.0
/*
* This file is part the core part STM32 DFSDM driver
*
* Copyright (C) 2017, STMicroelectronics - All Rights Reserved
* Author(s): Arnaud Pouliquen <arnaud.pouliquen@st.com> for STMicroelectronics.
*/
#include <linux/clk.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include "stm32-dfsdm.h"
struct stm32_dfsdm_dev_data {
unsigned int num_filters;
unsigned int num_channels;
const struct regmap_config *regmap_cfg;
};
#define STM32H7_DFSDM_NUM_FILTERS 4
#define STM32H7_DFSDM_NUM_CHANNELS 8
static bool stm32_dfsdm_volatile_reg(struct device *dev, unsigned int reg)
{
if (reg < DFSDM_FILTER_BASE_ADR)
return false;
/*
* Mask is done on register to avoid to list registers of all
* filter instances.
*/
switch (reg & DFSDM_FILTER_REG_MASK) {
case DFSDM_CR1(0) & DFSDM_FILTER_REG_MASK:
case DFSDM_ISR(0) & DFSDM_FILTER_REG_MASK:
case DFSDM_JDATAR(0) & DFSDM_FILTER_REG_MASK:
case DFSDM_RDATAR(0) & DFSDM_FILTER_REG_MASK:
return true;
}
return false;
}
static const struct regmap_config stm32h7_dfsdm_regmap_cfg = {
.reg_bits = 32,
.val_bits = 32,
.reg_stride = sizeof(u32),
.max_register = 0x2B8,
.volatile_reg = stm32_dfsdm_volatile_reg,
.fast_io = true,
};
static const struct stm32_dfsdm_dev_data stm32h7_dfsdm_data = {
.num_filters = STM32H7_DFSDM_NUM_FILTERS,
.num_channels = STM32H7_DFSDM_NUM_CHANNELS,
.regmap_cfg = &stm32h7_dfsdm_regmap_cfg,
};
struct dfsdm_priv {
struct platform_device *pdev; /* platform device */
struct stm32_dfsdm dfsdm; /* common data exported for all instances */
unsigned int spi_clk_out_div; /* SPI clkout divider value */
atomic_t n_active_ch; /* number of current active channels */
struct clk *clk; /* DFSDM clock */
struct clk *aclk; /* audio clock */
};
/**
* stm32_dfsdm_start_dfsdm - start global dfsdm interface.
*
* Enable interface if n_active_ch is not null.
* @dfsdm: Handle used to retrieve dfsdm context.
*/
int stm32_dfsdm_start_dfsdm(struct stm32_dfsdm *dfsdm)
{
struct dfsdm_priv *priv = container_of(dfsdm, struct dfsdm_priv, dfsdm);
struct device *dev = &priv->pdev->dev;
unsigned int clk_div = priv->spi_clk_out_div;
int ret;
if (atomic_inc_return(&priv->n_active_ch) == 1) {
ret = clk_prepare_enable(priv->clk);
if (ret < 0) {
dev_err(dev, "Failed to start clock\n");
goto error_ret;
}
if (priv->aclk) {
ret = clk_prepare_enable(priv->aclk);
if (ret < 0) {
dev_err(dev, "Failed to start audio clock\n");
goto disable_clk;
}
}
/* Output the SPI CLKOUT (if clk_div == 0 clock if OFF) */
ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
DFSDM_CHCFGR1_CKOUTDIV_MASK,
DFSDM_CHCFGR1_CKOUTDIV(clk_div));
if (ret < 0)
goto disable_aclk;
/* Global enable of DFSDM interface */
ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
DFSDM_CHCFGR1_DFSDMEN_MASK,
DFSDM_CHCFGR1_DFSDMEN(1));
if (ret < 0)
goto disable_aclk;
}
dev_dbg(dev, "%s: n_active_ch %d\n", __func__,
atomic_read(&priv->n_active_ch));
return 0;
disable_aclk:
clk_disable_unprepare(priv->aclk);
disable_clk:
clk_disable_unprepare(priv->clk);
error_ret:
atomic_dec(&priv->n_active_ch);
return ret;
}
EXPORT_SYMBOL_GPL(stm32_dfsdm_start_dfsdm);
/**
* stm32_dfsdm_stop_dfsdm - stop global DFSDM interface.
*
* Disable interface if n_active_ch is null
* @dfsdm: Handle used to retrieve dfsdm context.
*/
int stm32_dfsdm_stop_dfsdm(struct stm32_dfsdm *dfsdm)
{
struct dfsdm_priv *priv = container_of(dfsdm, struct dfsdm_priv, dfsdm);
int ret;
if (atomic_dec_and_test(&priv->n_active_ch)) {
/* Global disable of DFSDM interface */
ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
DFSDM_CHCFGR1_DFSDMEN_MASK,
DFSDM_CHCFGR1_DFSDMEN(0));
if (ret < 0)
return ret;
/* Stop SPI CLKOUT */
ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
DFSDM_CHCFGR1_CKOUTDIV_MASK,
DFSDM_CHCFGR1_CKOUTDIV(0));
if (ret < 0)
return ret;
clk_disable_unprepare(priv->clk);
if (priv->aclk)
clk_disable_unprepare(priv->aclk);
}
dev_dbg(&priv->pdev->dev, "%s: n_active_ch %d\n", __func__,
atomic_read(&priv->n_active_ch));
return 0;
}
EXPORT_SYMBOL_GPL(stm32_dfsdm_stop_dfsdm);
static int stm32_dfsdm_parse_of(struct platform_device *pdev,
struct dfsdm_priv *priv)
{
struct device_node *node = pdev->dev.of_node;
struct resource *res;
unsigned long clk_freq;
unsigned int spi_freq, rem;
int ret;
if (!node)
return -EINVAL;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "Failed to get memory resource\n");
return -ENODEV;
}
priv->dfsdm.phys_base = res->start;
priv->dfsdm.base = devm_ioremap_resource(&pdev->dev, res);
/*
* "dfsdm" clock is mandatory for DFSDM peripheral clocking.
* "dfsdm" or "audio" clocks can be used as source clock for
* the SPI clock out signal and internal processing, depending
* on use case.
*/
priv->clk = devm_clk_get(&pdev->dev, "dfsdm");
if (IS_ERR(priv->clk)) {
dev_err(&pdev->dev, "No stm32_dfsdm_clk clock found\n");
return -EINVAL;
}
priv->aclk = devm_clk_get(&pdev->dev, "audio");
if (IS_ERR(priv->aclk))
priv->aclk = NULL;
if (priv->aclk)
clk_freq = clk_get_rate(priv->aclk);
else
clk_freq = clk_get_rate(priv->clk);
/* SPI clock out frequency */
ret = of_property_read_u32(pdev->dev.of_node, "spi-max-frequency",
&spi_freq);
if (ret < 0) {
/* No SPI master mode */
return 0;
}
priv->spi_clk_out_div = div_u64_rem(clk_freq, spi_freq, &rem) - 1;
priv->dfsdm.spi_master_freq = spi_freq;
if (rem) {
dev_warn(&pdev->dev, "SPI clock not accurate\n");
dev_warn(&pdev->dev, "%ld = %d * %d + %d\n",
clk_freq, spi_freq, priv->spi_clk_out_div + 1, rem);
}
return 0;
};
static const struct of_device_id stm32_dfsdm_of_match[] = {
{
.compatible = "st,stm32h7-dfsdm",
.data = &stm32h7_dfsdm_data,
},
{}
};
MODULE_DEVICE_TABLE(of, stm32_dfsdm_of_match);
static int stm32_dfsdm_probe(struct platform_device *pdev)
{
struct dfsdm_priv *priv;
struct device_node *pnode = pdev->dev.of_node;
const struct of_device_id *of_id;
const struct stm32_dfsdm_dev_data *dev_data;
struct stm32_dfsdm *dfsdm;
int ret;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->pdev = pdev;
of_id = of_match_node(stm32_dfsdm_of_match, pnode);
if (!of_id->data) {
dev_err(&pdev->dev, "Data associated to device is missing\n");
return -EINVAL;
}
dev_data = (const struct stm32_dfsdm_dev_data *)of_id->data;
dfsdm = &priv->dfsdm;
dfsdm->fl_list = devm_kcalloc(&pdev->dev, dev_data->num_filters,
sizeof(*dfsdm->fl_list), GFP_KERNEL);
if (!dfsdm->fl_list)
return -ENOMEM;
dfsdm->num_fls = dev_data->num_filters;
dfsdm->ch_list = devm_kcalloc(&pdev->dev, dev_data->num_channels,
sizeof(*dfsdm->ch_list),
GFP_KERNEL);
if (!dfsdm->ch_list)
return -ENOMEM;
dfsdm->num_chs = dev_data->num_channels;
ret = stm32_dfsdm_parse_of(pdev, priv);
if (ret < 0)
return ret;
dfsdm->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "dfsdm",
dfsdm->base,
&stm32h7_dfsdm_regmap_cfg);
if (IS_ERR(dfsdm->regmap)) {
ret = PTR_ERR(dfsdm->regmap);
dev_err(&pdev->dev, "%s: Failed to allocate regmap: %d\n",
__func__, ret);
return ret;
}
platform_set_drvdata(pdev, dfsdm);
return devm_of_platform_populate(&pdev->dev);
}
static struct platform_driver stm32_dfsdm_driver = {
.probe = stm32_dfsdm_probe,
.driver = {
.name = "stm32-dfsdm",
.of_match_table = stm32_dfsdm_of_match,
},
};
module_platform_driver(stm32_dfsdm_driver);
MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@st.com>");
MODULE_DESCRIPTION("STMicroelectronics STM32 dfsdm driver");
MODULE_LICENSE("GPL v2");
This diff is collapsed.
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment