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SubjectRe: [PATCH v3 2/6] iio: adc: Add support for STM32 ADC core
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On 11/19/2016 01:17 PM, Jonathan Cameron wrote:
> On 15/11/16 15:30, Fabrice Gasnier wrote:
>> Add core driver for STMicroelectronics STM32 ADC (Analog to Digital
>> Converter). STM32 ADC can be composed of up to 3 ADCs with shared
>> resources like clock prescaler, common interrupt line and analog
>> reference voltage.
>> This core driver basically manages shared resources.
>>
>> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
> There is nothing in here that demands selecting a fixed regulator.
> I've also switched the select regulator over to depends on inline with
> other drivers in IIO that have a hard dependency on regulators.
> Other than that which showed up during build tests, looks good to me.
> Shout if I've broken anything with this change.

Hi Jonathan, All,

First many thanks.
This is not a big deal. Only thing is: I think patch 4 of this series
(on stm32_defconfig) need to be updated
to accommodate this change. E.g. :
+CONFIG_REGULATOR=y
+CONFIG_REGULATOR_FIXED_VOLTAGE=y

Shall I send a new version of this series (all patches), including your
changes, with updated defconfig as well ?
Or only updated patch on defconfig is enough ?

Please advise,
Fabrice
>
> Applied to the togreg branch of iio.git and pushed out as testing for
> the autobuilders to play with it.
>
> Thanks,
>
> Jonathan
>> ---
>> drivers/iio/adc/Kconfig | 13 ++
>> drivers/iio/adc/Makefile | 1 +
>> drivers/iio/adc/stm32-adc-core.c | 303 +++++++++++++++++++++++++++++++++++++++
>> drivers/iio/adc/stm32-adc-core.h | 52 +++++++
>> 4 files changed, 369 insertions(+)
>> create mode 100644 drivers/iio/adc/stm32-adc-core.c
>> create mode 100644 drivers/iio/adc/stm32-adc-core.h
>>
>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
>> index 7edcf32..ff30239 100644
>> --- a/drivers/iio/adc/Kconfig
>> +++ b/drivers/iio/adc/Kconfig
>> @@ -419,6 +419,19 @@ config ROCKCHIP_SARADC
>> To compile this driver as a module, choose M here: the
>> module will be called rockchip_saradc.
>>
>> +config STM32_ADC_CORE
>> + tristate "STMicroelectronics STM32 adc core"
>> + depends on ARCH_STM32 || COMPILE_TEST
>> + depends on OF
>> + select REGULATOR
>> + select REGULATOR_FIXED_VOLTAGE
>> + help
>> + Select this option to enable the core driver for STMicroelectronics
>> + STM32 analog-to-digital converter (ADC).
>> +
>> + This driver can also be built as a module. If so, the module
>> + will be called stm32-adc-core.
>> +
>> config STX104
>> tristate "Apex Embedded Systems STX104 driver"
>> depends on X86 && ISA_BUS_API
>> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
>> index 7a40c04..a1e8f44 100644
>> --- a/drivers/iio/adc/Makefile
>> +++ b/drivers/iio/adc/Makefile
>> @@ -41,6 +41,7 @@ obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o
>> obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
>> obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
>> obj-$(CONFIG_STX104) += stx104.o
>> +obj-$(CONFIG_STM32_ADC_CORE) += stm32-adc-core.o
>> obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
>> obj-$(CONFIG_TI_ADC0832) += ti-adc0832.o
>> obj-$(CONFIG_TI_ADC12138) += ti-adc12138.o
>> diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c
>> new file mode 100644
>> index 0000000..4214b0c
>> --- /dev/null
>> +++ b/drivers/iio/adc/stm32-adc-core.c
>> @@ -0,0 +1,303 @@
>> +/*
>> + * 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->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");
>> diff --git a/drivers/iio/adc/stm32-adc-core.h b/drivers/iio/adc/stm32-adc-core.h
>> new file mode 100644
>> index 0000000..081fa5f
>> --- /dev/null
>> +++ b/drivers/iio/adc/stm32-adc-core.h
>> @@ -0,0 +1,52 @@
>> +/*
>> + * This file is part of STM32 ADC driver
>> + *
>> + * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
>> + * Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
>> + *
>> + * 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/>.
>> + */
>> +
>> +#ifndef __STM32_ADC_H
>> +#define __STM32_ADC_H
>> +
>> +/*
>> + * STM32 - ADC global register map
>> + * ________________________________________________________
>> + * | Offset | Register |
>> + * --------------------------------------------------------
>> + * | 0x000 | Master ADC1 |
>> + * --------------------------------------------------------
>> + * | 0x100 | Slave ADC2 |
>> + * --------------------------------------------------------
>> + * | 0x200 | Slave ADC3 |
>> + * --------------------------------------------------------
>> + * | 0x300 | Master & Slave common regs |
>> + * --------------------------------------------------------
>> + */
>> +#define STM32_ADC_MAX_ADCS 3
>> +#define STM32_ADCX_COMN_OFFSET 0x300
>> +
>> +/**
>> + * struct stm32_adc_common - stm32 ADC driver common data (for all instances)
>> + * @base: control registers base cpu addr
>> + * @vref_mv: vref voltage (mv)
>> + */
>> +struct stm32_adc_common {
>> + void __iomem *base;
>> + int vref_mv;
>> +};
>> +
>> +#endif
>>

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