iio: adc: add exynos adc driver under iio framwork
This patch adds New driver to support:
1. Supports ADC IF found on EXYNOS4412/EXYNOS5250
and future SoCs from Samsung
2. Add ADC driver under iio/adc framework
3. Also adds the Documentation for device tree bindings
Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@samsung.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c
new file mode 100644
index 0000000..ed6fdd7
--- /dev/null
+++ b/drivers/iio/adc/exynos_adc.c
@@ -0,0 +1,440 @@
+/*
+ * exynos_adc.c - Support for ADC in EXYNOS SoCs
+ *
+ * 8 ~ 10 channel, 10/12-bit ADC
+ *
+ * Copyright (C) 2013 Naveen Krishna Chatradhi <ch.naveen@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/regulator/consumer.h>
+#include <linux/of_platform.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/machine.h>
+#include <linux/iio/driver.h>
+
+enum adc_version {
+ ADC_V1,
+ ADC_V2
+};
+
+/* EXYNOS4412/5250 ADC_V1 registers definitions */
+#define ADC_V1_CON(x) ((x) + 0x00)
+#define ADC_V1_DLY(x) ((x) + 0x08)
+#define ADC_V1_DATX(x) ((x) + 0x0C)
+#define ADC_V1_INTCLR(x) ((x) + 0x18)
+#define ADC_V1_MUX(x) ((x) + 0x1c)
+
+/* Future ADC_V2 registers definitions */
+#define ADC_V2_CON1(x) ((x) + 0x00)
+#define ADC_V2_CON2(x) ((x) + 0x04)
+#define ADC_V2_STAT(x) ((x) + 0x08)
+#define ADC_V2_INT_EN(x) ((x) + 0x10)
+#define ADC_V2_INT_ST(x) ((x) + 0x14)
+#define ADC_V2_VER(x) ((x) + 0x20)
+
+/* Bit definitions for ADC_V1 */
+#define ADC_V1_CON_RES (1u << 16)
+#define ADC_V1_CON_PRSCEN (1u << 14)
+#define ADC_V1_CON_PRSCLV(x) (((x) & 0xFF) << 6)
+#define ADC_V1_CON_STANDBY (1u << 2)
+
+/* Bit definitions for ADC_V2 */
+#define ADC_V2_CON1_SOFT_RESET (1u << 2)
+
+#define ADC_V2_CON2_OSEL (1u << 10)
+#define ADC_V2_CON2_ESEL (1u << 9)
+#define ADC_V2_CON2_HIGHF (1u << 8)
+#define ADC_V2_CON2_C_TIME(x) (((x) & 7) << 4)
+#define ADC_V2_CON2_ACH_SEL(x) (((x) & 0xF) << 0)
+#define ADC_V2_CON2_ACH_MASK 0xF
+
+#define MAX_ADC_V2_CHANNELS 10
+#define MAX_ADC_V1_CHANNELS 8
+
+/* Bit definitions common for ADC_V1 and ADC_V2 */
+#define ADC_CON_EN_START (1u << 0)
+#define ADC_DATX_MASK 0xFFF
+
+#define EXYNOS_ADC_TIMEOUT (msecs_to_jiffies(1000))
+
+struct exynos_adc {
+ void __iomem *regs;
+ struct clk *clk;
+ unsigned int irq;
+ struct regulator *vdd;
+
+ struct completion completion;
+
+ u32 value;
+ unsigned int version;
+};
+
+static const struct of_device_id exynos_adc_match[] = {
+ { .compatible = "samsung,exynos-adc-v1", .data = (void *)ADC_V1 },
+ { .compatible = "samsung,exynos-adc-v2", .data = (void *)ADC_V2 },
+ {},
+};
+MODULE_DEVICE_TABLE(of, exynos_adc_match);
+
+static inline unsigned int exynos_adc_get_version(struct platform_device *pdev)
+{
+ const struct of_device_id *match;
+
+ match = of_match_node(exynos_adc_match, pdev->dev.of_node);
+ return (unsigned int)match->data;
+}
+
+static int exynos_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val,
+ int *val2,
+ long mask)
+{
+ struct exynos_adc *info = iio_priv(indio_dev);
+ unsigned long timeout;
+ u32 con1, con2;
+
+ if (mask != IIO_CHAN_INFO_RAW)
+ return -EINVAL;
+
+ mutex_lock(&indio_dev->mlock);
+
+ /* Select the channel to be used and Trigger conversion */
+ if (info->version == ADC_V2) {
+ con2 = readl(ADC_V2_CON2(info->regs));
+ con2 &= ~ADC_V2_CON2_ACH_MASK;
+ con2 |= ADC_V2_CON2_ACH_SEL(chan->address);
+ writel(con2, ADC_V2_CON2(info->regs));
+
+ con1 = readl(ADC_V2_CON1(info->regs));
+ writel(con1 | ADC_CON_EN_START,
+ ADC_V2_CON1(info->regs));
+ } else {
+ writel(chan->address, ADC_V1_MUX(info->regs));
+
+ con1 = readl(ADC_V1_CON(info->regs));
+ writel(con1 | ADC_CON_EN_START,
+ ADC_V1_CON(info->regs));
+ }
+
+ timeout = wait_for_completion_interruptible_timeout
+ (&info->completion, EXYNOS_ADC_TIMEOUT);
+ *val = info->value;
+
+ mutex_unlock(&indio_dev->mlock);
+
+ if (timeout == 0)
+ return -ETIMEDOUT;
+
+ return IIO_VAL_INT;
+}
+
+static irqreturn_t exynos_adc_isr(int irq, void *dev_id)
+{
+ struct exynos_adc *info = (struct exynos_adc *)dev_id;
+
+ /* Read value */
+ info->value = readl(ADC_V1_DATX(info->regs)) &
+ ADC_DATX_MASK;
+ /* clear irq */
+ if (info->version == ADC_V2)
+ writel(1, ADC_V2_INT_ST(info->regs));
+ else
+ writel(1, ADC_V1_INTCLR(info->regs));
+
+ complete(&info->completion);
+
+ return IRQ_HANDLED;
+}
+
+static int exynos_adc_reg_access(struct iio_dev *indio_dev,
+ unsigned reg, unsigned writeval,
+ unsigned *readval)
+{
+ struct exynos_adc *info = iio_priv(indio_dev);
+
+ if (readval == NULL)
+ return -EINVAL;
+
+ *readval = readl(info->regs + reg);
+
+ return 0;
+}
+
+static const struct iio_info exynos_adc_iio_info = {
+ .read_raw = &exynos_read_raw,
+ .debugfs_reg_access = &exynos_adc_reg_access,
+ .driver_module = THIS_MODULE,
+};
+
+#define ADC_CHANNEL(_index, _id) { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = _index, \
+ .address = _index, \
+ .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT, \
+ .datasheet_name = _id, \
+}
+
+static const struct iio_chan_spec exynos_adc_iio_channels[] = {
+ ADC_CHANNEL(0, "adc0"),
+ ADC_CHANNEL(1, "adc1"),
+ ADC_CHANNEL(2, "adc2"),
+ ADC_CHANNEL(3, "adc3"),
+ ADC_CHANNEL(4, "adc4"),
+ ADC_CHANNEL(5, "adc5"),
+ ADC_CHANNEL(6, "adc6"),
+ ADC_CHANNEL(7, "adc7"),
+ ADC_CHANNEL(8, "adc8"),
+ ADC_CHANNEL(9, "adc9"),
+};
+
+static int exynos_adc_remove_devices(struct device *dev, void *c)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+
+ platform_device_unregister(pdev);
+
+ return 0;
+}
+
+static void exynos_adc_hw_init(struct exynos_adc *info)
+{
+ u32 con1, con2;
+
+ if (info->version == ADC_V2) {
+ con1 = ADC_V2_CON1_SOFT_RESET;
+ writel(con1, ADC_V2_CON1(info->regs));
+
+ con2 = ADC_V2_CON2_OSEL | ADC_V2_CON2_ESEL |
+ ADC_V2_CON2_HIGHF | ADC_V2_CON2_C_TIME(0);
+ writel(con2, ADC_V2_CON2(info->regs));
+
+ /* Enable interrupts */
+ writel(1, ADC_V2_INT_EN(info->regs));
+ } else {
+ /* set default prescaler values and Enable prescaler */
+ con1 = ADC_V1_CON_PRSCLV(49) | ADC_V1_CON_PRSCEN;
+
+ /* Enable 12-bit ADC resolution */
+ con1 |= ADC_V1_CON_RES;
+ writel(con1, ADC_V1_CON(info->regs));
+ }
+}
+
+static int exynos_adc_probe(struct platform_device *pdev)
+{
+ struct exynos_adc *info = NULL;
+ struct device_node *np = pdev->dev.of_node;
+ struct iio_dev *indio_dev = NULL;
+ struct resource *mem;
+ int ret = -ENODEV;
+ int irq;
+
+ if (!np)
+ return ret;
+
+ indio_dev = iio_device_alloc(sizeof(struct exynos_adc));
+ if (!indio_dev) {
+ dev_err(&pdev->dev, "failed allocating iio device\n");
+ return -ENOMEM;
+ }
+
+ info = iio_priv(indio_dev);
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+ info->regs = devm_request_and_ioremap(&pdev->dev, mem);
+ if (!info->regs) {
+ ret = -ENOMEM;
+ goto err_iio;
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "no irq resource?\n");
+ ret = irq;
+ goto err_iio;
+ }
+
+ info->irq = irq;
+
+ init_completion(&info->completion);
+
+ ret = request_irq(info->irq, exynos_adc_isr,
+ 0, dev_name(&pdev->dev), info);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed requesting irq, irq = %d\n",
+ info->irq);
+ goto err_iio;
+ }
+
+ info->clk = devm_clk_get(&pdev->dev, "adc");
+ if (IS_ERR(info->clk)) {
+ dev_err(&pdev->dev, "failed getting clock, err = %ld\n",
+ PTR_ERR(info->clk));
+ ret = PTR_ERR(info->clk);
+ goto err_irq;
+ }
+
+ info->vdd = devm_regulator_get(&pdev->dev, "vdd");
+ if (IS_ERR(info->vdd)) {
+ dev_err(&pdev->dev, "failed getting regulator, err = %ld\n",
+ PTR_ERR(info->vdd));
+ ret = PTR_ERR(info->vdd);
+ goto err_irq;
+ }
+
+ info->version = exynos_adc_get_version(pdev);
+
+ platform_set_drvdata(pdev, indio_dev);
+
+ indio_dev->name = dev_name(&pdev->dev);
+ indio_dev->dev.parent = &pdev->dev;
+ indio_dev->dev.of_node = pdev->dev.of_node;
+ indio_dev->info = &exynos_adc_iio_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = exynos_adc_iio_channels;
+
+ if (info->version == ADC_V1)
+ indio_dev->num_channels = MAX_ADC_V1_CHANNELS;
+ else
+ indio_dev->num_channels = MAX_ADC_V2_CHANNELS;
+
+ ret = iio_device_register(indio_dev);
+ if (ret)
+ goto err_irq;
+
+ ret = regulator_enable(info->vdd);
+ if (ret)
+ goto err_iio_dev;
+
+ clk_prepare_enable(info->clk);
+
+ exynos_adc_hw_init(info);
+
+ ret = of_platform_populate(np, exynos_adc_match, NULL, &pdev->dev);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed adding child nodes\n");
+ goto err_of_populate;
+ }
+
+ return 0;
+
+err_of_populate:
+ device_for_each_child(&pdev->dev, NULL,
+ exynos_adc_remove_devices);
+ regulator_disable(info->vdd);
+ clk_disable_unprepare(info->clk);
+err_iio_dev:
+ iio_device_unregister(indio_dev);
+err_irq:
+ free_irq(info->irq, info);
+err_iio:
+ iio_device_free(indio_dev);
+ return ret;
+}
+
+static int exynos_adc_remove(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct exynos_adc *info = iio_priv(indio_dev);
+
+ device_for_each_child(&pdev->dev, NULL,
+ exynos_adc_remove_devices);
+ regulator_disable(info->vdd);
+ clk_disable_unprepare(info->clk);
+ iio_device_unregister(indio_dev);
+ free_irq(info->irq, info);
+ iio_device_free(indio_dev);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int exynos_adc_suspend(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct exynos_adc *info = platform_get_drvdata(pdev);
+ u32 con;
+
+ if (info->version == ADC_V2) {
+ con = readl(ADC_V2_CON1(info->regs));
+ con &= ~ADC_CON_EN_START;
+ writel(con, ADC_V2_CON1(info->regs));
+ } else {
+ con = readl(ADC_V1_CON(info->regs));
+ con |= ADC_V1_CON_STANDBY;
+ writel(con, ADC_V1_CON(info->regs));
+ }
+
+ clk_disable_unprepare(info->clk);
+ regulator_disable(info->vdd);
+
+ return 0;
+}
+
+static int exynos_adc_resume(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct exynos_adc *info = platform_get_drvdata(pdev);
+ int ret;
+
+ ret = regulator_enable(info->vdd);
+ if (ret)
+ return ret;
+
+ clk_prepare_enable(info->clk);
+
+ exynos_adc_hw_init(info);
+
+ return 0;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(exynos_adc_pm_ops,
+ exynos_adc_suspend,
+ exynos_adc_resume);
+
+static struct platform_driver exynos_adc_driver = {
+ .probe = exynos_adc_probe,
+ .remove = exynos_adc_remove,
+ .driver = {
+ .name = "exynos-adc",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(exynos_adc_match),
+ .pm = &exynos_adc_pm_ops,
+ },
+};
+
+module_platform_driver(exynos_adc_driver);
+
+MODULE_AUTHOR("Naveen Krishna Chatradhi <ch.naveen@samsung.com>");
+MODULE_DESCRIPTION("Samsung EXYNOS5 ADC driver");
+MODULE_LICENSE("GPL v2");