[PATCH v2 2/6] mfd: stm32-adc: Add support for stm32 ADC
Jonathan Cameron
jic23 at jic23.retrosnub.co.uk
Tue Nov 15 05:17:06 PST 2016
On 15 November 2016 10:47:52 GMT+00:00, Fabrice Gasnier <fabrice.gasnier at st.com> wrote:
>On 11/14/2016 05:47 PM, Lee Jones wrote:
>> On Sat, 12 Nov 2016, Jonathan Cameron wrote:
>>
>>> On 10/11/16 16:18, 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 at st.com>
>>> Looks good to me (other than the build issue obviously ;)
>
>Hi Jonathan,
>Thanks for your review.
>I'll fix build issue, sure ;-)
>
>>>
>>> The fun bit will be trying to keep the whole thing this clean as you
>>> add the more 'interesting' functionality. *fingers crossed*
>Yes... But in the end, splitting shared resources in core driver makes
>it more simple.
>Not sure there will be more complexity here.
>
>>>
>>> Acked-by: Jonathan Cameron <jic23 at kernel.org>
>> There isn't anything MFD about this driver.
>>
>> Please move it into IIO.
>
>Hmm, there is no other sub sysbtem that may be used here, ADC driver
>belongs to IIO.
>Also, of_platform_populate() is being used here. This can perfectly be
>called from within IIO.
>
>Jonathan, can this "stm32-adc-core" driver be moved to, and live in
>drivers/iio/adc ?
>(e.g. in addition to stm32-adc iio driver)
>Is it ok for you ?
Yes. That's ideal.
>
>Please advise,
>Best Regards,
>Fabrice
>
>>
>>>> ---
>>>> drivers/mfd/Kconfig | 14 ++
>>>> drivers/mfd/Makefile | 1 +
>>>> drivers/mfd/stm32-adc-core.c | 301
>+++++++++++++++++++++++++++++++++++++
>>>> include/linux/mfd/stm32-adc-core.h | 52 +++++++
>>>> 4 files changed, 368 insertions(+)
>>>> create mode 100644 drivers/mfd/stm32-adc-core.c
>>>> create mode 100644 include/linux/mfd/stm32-adc-core.h
>>>>
>>>> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
>>>> index c6df644..2580cee 100644
>>>> --- a/drivers/mfd/Kconfig
>>>> +++ b/drivers/mfd/Kconfig
>>>> @@ -1152,6 +1152,20 @@ config MFD_PALMAS
>>>> If you say yes here you get support for the Palmas
>>>> series of PMIC chips from Texas Instruments.
>>>>
>>>> +config MFD_STM32_ADC
>>>> + tristate "STMicroelectronics STM32 adc"
>>>> + depends on ARCH_STM32 || COMPILE_TEST
>>>> + depends on OF
>>>> + select MFD_CORE
>>>> + 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 TPS6105X
>>>> tristate "TI TPS61050/61052 Boost Converters"
>>>> depends on I2C
>>>> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
>>>> index 9834e66..4571506 100644
>>>> --- a/drivers/mfd/Makefile
>>>> +++ b/drivers/mfd/Makefile
>>>> @@ -185,6 +185,7 @@ obj-$(CONFIG_MFD_INTEL_LPSS_PCI) +=
>intel-lpss-pci.o
>>>> obj-$(CONFIG_MFD_INTEL_LPSS_ACPI) += intel-lpss-acpi.o
>>>> obj-$(CONFIG_MFD_INTEL_MSIC) += intel_msic.o
>>>> obj-$(CONFIG_MFD_PALMAS) += palmas.o
>>>> +obj-$(CONFIG_MFD_STM32_ADC) += stm32-adc-core.o
>>>> obj-$(CONFIG_MFD_VIPERBOARD) += viperboard.o
>>>> obj-$(CONFIG_MFD_RC5T583) += rc5t583.o rc5t583-irq.o
>>>> obj-$(CONFIG_MFD_RK808) += rk808.o
>>>> diff --git a/drivers/mfd/stm32-adc-core.c
>b/drivers/mfd/stm32-adc-core.c
>>>> new file mode 100644
>>>> index 0000000..bcf52fb
>>>> --- /dev/null
>>>> +++ b/drivers/mfd/stm32-adc-core.c
>>>> @@ -0,0 +1,301 @@
>>>> +/*
>>>> + * This file is part of STM32 ADC driver
>>>> + *
>>>> + * Copyright (C) 2016, STMicroelectronics - All Rights Reserved
>>>> + * Author: Fabrice Gasnier <fabrice.gasnier at 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/mfd/stm32-adc-core.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/of_device.h>
>>>> +#include <linux/regulator/consumer.h>
>>>> +#include <linux/slab.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 at st.com>");
>>>> +MODULE_DESCRIPTION("STMicroelectronics STM32 ADC MFD driver");
>>>> +MODULE_LICENSE("GPL v2");
>>>> +MODULE_ALIAS("platform:stm32-adc-core");
>>>> diff --git a/include/linux/mfd/stm32-adc-core.h
>b/include/linux/mfd/stm32-adc-core.h
>>>> new file mode 100644
>>>> index 0000000..081fa5f
>>>> --- /dev/null
>>>> +++ b/include/linux/mfd/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 at 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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