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@xxxxxx> --- 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@xxxxxx>. + * + * 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@xxxxxx>"); +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@xxxxxx>. + * + * 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 -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
