Message-ID: <BCC00D81-A139-4C23-8A04-1A3A48419A53@jic23.retrosnub.co.uk>
Date:   Tue, 15 Nov 2016 13:17:06 +0000
From:   Jonathan Cameron <jic23@...23.retrosnub.co.uk>
To:     Fabrice Gasnier <fabrice.gasnier@...com>,
        Lee Jones <lee.jones@...aro.org>,
        Jonathan Cameron <jic23@...nel.org>
CC:     linux-iio@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux@...linux.org.uk, robh+dt@...nel.org, mark.rutland@....com,
        mcoquelin.stm32@...il.com, alexandre.torgue@...com,
        lars@...afoo.de, knaack.h@....de, pmeerw@...erw.net
Subject: Re: [PATCH v2 2/6] mfd: stm32-adc: Add support for stm32 ADC



On 15 November 2016 10:47:52 GMT+00:00, Fabrice Gasnier <fabrice.gasnier@...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@...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@...nel.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@...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@...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@...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
>>>>
>
>--
>To unsubscribe from this list: send the line "unsubscribe linux-iio" in
>the body of a message to majordomo@...r.kernel.org
>More majordomo info at  http://vger.kernel.org/majordomo-info.html

-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.

Powered by blists - more mailing lists