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linux/drivers/iio/adc/stm32-adc-core.c

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/*
* This file is part of STM32 ADC driver
*
* Copyright (C) 2016, STMicroelectronics - All Rights Reserved
* Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
*
* Inspired from: fsl-imx25-tsadc
*
* License type: GPLv2
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* 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.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdesc.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include "stm32-adc-core.h"
/* STM32F4 - common registers for all ADC instances: 1, 2 & 3 */
#define STM32F4_ADC_CSR (STM32_ADCX_COMN_OFFSET + 0x00)
#define STM32F4_ADC_CCR (STM32_ADCX_COMN_OFFSET + 0x04)
/* STM32F4_ADC_CSR - bit fields */
#define STM32F4_EOC3 BIT(17)
#define STM32F4_EOC2 BIT(9)
#define STM32F4_EOC1 BIT(1)
/* STM32F4_ADC_CCR - bit fields */
#define STM32F4_ADC_ADCPRE_SHIFT 16
#define STM32F4_ADC_ADCPRE_MASK GENMASK(17, 16)
/* STM32 F4 maximum analog clock rate (from datasheet) */
#define STM32F4_ADC_MAX_CLK_RATE 36000000
/**
* struct stm32_adc_priv - stm32 ADC core private data
* @irq: irq for ADC block
* @domain: irq domain reference
* @aclk: clock reference for the analog circuitry
* @vref: regulator reference
* @common: common data for all ADC instances
*/
struct stm32_adc_priv {
int irq;
struct irq_domain *domain;
struct clk *aclk;
struct regulator *vref;
struct stm32_adc_common common;
};
static struct stm32_adc_priv *to_stm32_adc_priv(struct stm32_adc_common *com)
{
return container_of(com, struct stm32_adc_priv, common);
}
/* STM32F4 ADC internal common clock prescaler division ratios */
static int stm32f4_pclk_div[] = {2, 4, 6, 8};
/**
* stm32f4_adc_clk_sel() - Select stm32f4 ADC common clock prescaler
* @priv: stm32 ADC core private data
* Select clock prescaler used for analog conversions, before using ADC.
*/
static int stm32f4_adc_clk_sel(struct platform_device *pdev,
struct stm32_adc_priv *priv)
{
unsigned long rate;
u32 val;
int i;
rate = clk_get_rate(priv->aclk);
for (i = 0; i < ARRAY_SIZE(stm32f4_pclk_div); i++) {
if ((rate / stm32f4_pclk_div[i]) <= STM32F4_ADC_MAX_CLK_RATE)
break;
}
if (i >= ARRAY_SIZE(stm32f4_pclk_div))
return -EINVAL;
val = readl_relaxed(priv->common.base + STM32F4_ADC_CCR);
val &= ~STM32F4_ADC_ADCPRE_MASK;
val |= i << STM32F4_ADC_ADCPRE_SHIFT;
writel_relaxed(val, priv->common.base + STM32F4_ADC_CCR);
dev_dbg(&pdev->dev, "Using analog clock source at %ld kHz\n",
rate / (stm32f4_pclk_div[i] * 1000));
return 0;
}
/* ADC common interrupt for all instances */
static void stm32_adc_irq_handler(struct irq_desc *desc)
{
struct stm32_adc_priv *priv = irq_desc_get_handler_data(desc);
struct irq_chip *chip = irq_desc_get_chip(desc);
u32 status;
chained_irq_enter(chip, desc);
status = readl_relaxed(priv->common.base + STM32F4_ADC_CSR);
if (status & STM32F4_EOC1)
generic_handle_irq(irq_find_mapping(priv->domain, 0));
if (status & STM32F4_EOC2)
generic_handle_irq(irq_find_mapping(priv->domain, 1));
if (status & STM32F4_EOC3)
generic_handle_irq(irq_find_mapping(priv->domain, 2));
chained_irq_exit(chip, desc);
};
static int stm32_adc_domain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq)
{
irq_set_chip_data(irq, d->host_data);
irq_set_chip_and_handler(irq, &dummy_irq_chip, handle_level_irq);
return 0;
}
static void stm32_adc_domain_unmap(struct irq_domain *d, unsigned int irq)
{
irq_set_chip_and_handler(irq, NULL, NULL);
irq_set_chip_data(irq, NULL);
}
static const struct irq_domain_ops stm32_adc_domain_ops = {
.map = stm32_adc_domain_map,
.unmap = stm32_adc_domain_unmap,
.xlate = irq_domain_xlate_onecell,
};
static int stm32_adc_irq_probe(struct platform_device *pdev,
struct stm32_adc_priv *priv)
{
struct device_node *np = pdev->dev.of_node;
priv->irq = platform_get_irq(pdev, 0);
if (priv->irq < 0) {
dev_err(&pdev->dev, "failed to get irq\n");
return priv->irq;
}
priv->domain = irq_domain_add_simple(np, STM32_ADC_MAX_ADCS, 0,
&stm32_adc_domain_ops,
priv);
if (!priv->domain) {
dev_err(&pdev->dev, "Failed to add irq domain\n");
return -ENOMEM;
}
irq_set_chained_handler(priv->irq, stm32_adc_irq_handler);
irq_set_handler_data(priv->irq, priv);
return 0;
}
static void stm32_adc_irq_remove(struct platform_device *pdev,
struct stm32_adc_priv *priv)
{
int hwirq;
for (hwirq = 0; hwirq < STM32_ADC_MAX_ADCS; hwirq++)
irq_dispose_mapping(irq_find_mapping(priv->domain, hwirq));
irq_domain_remove(priv->domain);
irq_set_chained_handler(priv->irq, NULL);
}
static int stm32_adc_probe(struct platform_device *pdev)
{
struct stm32_adc_priv *priv;
struct device_node *np = pdev->dev.of_node;
struct resource *res;
int ret;
if (!pdev->dev.of_node)
return -ENODEV;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->common.base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(priv->common.base))
return PTR_ERR(priv->common.base);
priv->common.phys_base = res->start;
priv->vref = devm_regulator_get(&pdev->dev, "vref");
if (IS_ERR(priv->vref)) {
ret = PTR_ERR(priv->vref);
dev_err(&pdev->dev, "vref get failed, %d\n", ret);
return ret;
}
ret = regulator_enable(priv->vref);
if (ret < 0) {
dev_err(&pdev->dev, "vref enable failed\n");
return ret;
}
ret = regulator_get_voltage(priv->vref);
if (ret < 0) {
dev_err(&pdev->dev, "vref get voltage failed, %d\n", ret);
goto err_regulator_disable;
}
priv->common.vref_mv = ret / 1000;
dev_dbg(&pdev->dev, "vref+=%dmV\n", priv->common.vref_mv);
priv->aclk = devm_clk_get(&pdev->dev, "adc");
if (IS_ERR(priv->aclk)) {
ret = PTR_ERR(priv->aclk);
dev_err(&pdev->dev, "Can't get 'adc' clock\n");
goto err_regulator_disable;
}
ret = clk_prepare_enable(priv->aclk);
if (ret < 0) {
dev_err(&pdev->dev, "adc clk enable failed\n");
goto err_regulator_disable;
}
ret = stm32f4_adc_clk_sel(pdev, priv);
if (ret < 0) {
dev_err(&pdev->dev, "adc clk selection failed\n");
goto err_clk_disable;
}
ret = stm32_adc_irq_probe(pdev, priv);
if (ret < 0)
goto err_clk_disable;
platform_set_drvdata(pdev, &priv->common);
ret = of_platform_populate(np, NULL, NULL, &pdev->dev);
if (ret < 0) {
dev_err(&pdev->dev, "failed to populate DT children\n");
goto err_irq_remove;
}
return 0;
err_irq_remove:
stm32_adc_irq_remove(pdev, priv);
err_clk_disable:
clk_disable_unprepare(priv->aclk);
err_regulator_disable:
regulator_disable(priv->vref);
return ret;
}
static int stm32_adc_remove(struct platform_device *pdev)
{
struct stm32_adc_common *common = platform_get_drvdata(pdev);
struct stm32_adc_priv *priv = to_stm32_adc_priv(common);
of_platform_depopulate(&pdev->dev);
stm32_adc_irq_remove(pdev, priv);
clk_disable_unprepare(priv->aclk);
regulator_disable(priv->vref);
return 0;
}
static const struct of_device_id stm32_adc_of_match[] = {
{ .compatible = "st,stm32f4-adc-core" },
{},
};
MODULE_DEVICE_TABLE(of, stm32_adc_of_match);
static struct platform_driver stm32_adc_driver = {
.probe = stm32_adc_probe,
.remove = stm32_adc_remove,
.driver = {
.name = "stm32-adc-core",
.of_match_table = stm32_adc_of_match,
},
};
module_platform_driver(stm32_adc_driver);
MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
MODULE_DESCRIPTION("STMicroelectronics STM32 ADC core driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:stm32-adc-core");
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