[PATCH v3 2/6] iio: adc: Add support for STM32 ADC core
Fabrice Gasnier
fabrice.gasnier at st.com
Tue Nov 15 07:30:57 PST 2016
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>
---
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 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/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 at 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 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
--
1.9.1
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