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Subject[PATCH v2 1/2] iio: adc: add driver for Rockchip saradc
Date
The ADC is a 3-channel signal-ended 10-bit Successive Approximation
Register (SAR) A/D Converter. It uses the supply and ground as its reference
and converts the analog input signal into 10-bit binary digital codes.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
changes since v1:
- address comments from Peter Meerwald

drivers/iio/adc/Kconfig | 10 ++
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/rockchip_saradc.c | 313 ++++++++++++++++++++++++++++++++++++++
3 files changed, 324 insertions(+)
create mode 100644 drivers/iio/adc/rockchip_saradc.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index a80d236..5d36bdb 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -187,6 +187,16 @@ config NAU7802
To compile this driver as a module, choose M here: the
module will be called nau7802.

+config ROCKCHIP_SARADC
+ tristate "Rockchip SARADC driver"
+ depends on ARCH_ROCKCHIP || (OF && COMPILE_TEST)
+ help
+ Say yes here to build support for the SARADC found in SoCs from
+ Rockchip.
+
+ To compile this driver as a module, choose M here: the
+ module will be called rockchip_saradc.
+
config TI_ADC081C
tristate "Texas Instruments ADC081C021/027"
depends on I2C
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 9d60f2d..8e2932d 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_MCP320X) += mcp320x.o
obj-$(CONFIG_MCP3422) += mcp3422.o
obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
obj-$(CONFIG_NAU7802) += nau7802.o
+obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
obj-$(CONFIG_TWL4030_MADC) += twl4030-madc.o
diff --git a/drivers/iio/adc/rockchip_saradc.c b/drivers/iio/adc/rockchip_saradc.c
new file mode 100644
index 0000000..3f0164c
--- /dev/null
+++ b/drivers/iio/adc/rockchip_saradc.c
@@ -0,0 +1,313 @@
+/*
+ * Rockchip Successive Approximation Register (SAR) A/D Converter
+ * Copyright (C) 2014 ROCKCHIP, Inc.
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/regulator/consumer.h>
+#include <linux/iio/iio.h>
+
+#define SARADC_DATA 0x00
+#define SARADC_DATA_MASK 0x3ff
+
+#define SARADC_STAS 0x04
+#define SARADC_STAS_BUSY BIT(0)
+
+#define SARADC_CTRL 0x08
+#define SARADC_CTRL_IRQ_STATUS BIT(6)
+#define SARADC_CTRL_IRQ_ENABLE BIT(5)
+#define SARADC_CTRL_POWER_CTRL BIT(3)
+#define SARADC_CTRL_CHN_MASK 0x7
+
+#define SARADC_DLY_PU_SOC 0x0c
+#define SARADC_DLY_PU_SOC_MASK 0x3f
+
+#define SARADC_BITS 10
+#define SARADC_TIMEOUT msecs_to_jiffies(100)
+
+struct rockchip_saradc {
+ void __iomem *regs;
+ struct clk *pclk;
+ struct clk *clk;
+ struct completion completion;
+ struct regulator *vref;
+ int vref_mv;
+ u16 last_val;
+};
+
+static int rockchip_saradc_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct rockchip_saradc *info = iio_priv(indio_dev);
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&indio_dev->mlock);
+
+ /* Select the channel to be used and trigger conversion */
+ writel_relaxed(0x08, info->regs + SARADC_DLY_PU_SOC);
+ writel(SARADC_CTRL_POWER_CTRL
+ | (chan->channel & SARADC_CTRL_CHN_MASK)
+ | SARADC_CTRL_IRQ_ENABLE,
+ info->regs + SARADC_CTRL);
+
+ if (!wait_for_completion_timeout(&info->completion,
+ SARADC_TIMEOUT)) {
+ writel_relaxed(0, info->regs + SARADC_CTRL);
+ mutex_unlock(&indio_dev->mlock);
+ return -ETIMEDOUT;
+ }
+
+ *val = info->last_val;
+ mutex_unlock(&indio_dev->mlock);
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = info->vref_mv;
+ *val2 = SARADC_BITS;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ default:
+ return -EINVAL;
+ }
+}
+
+static irqreturn_t rockchip_saradc_isr(int irq, void *dev_id)
+{
+ struct rockchip_saradc *info = (struct rockchip_saradc *)dev_id;
+
+ /* Read value */
+ info->last_val = readl_relaxed(info->regs + SARADC_DATA);
+ info->last_val &= SARADC_DATA_MASK;
+
+ /* clear irq & power down adc */
+ writel_relaxed(0, info->regs + SARADC_CTRL);
+
+ complete(&info->completion);
+
+ return IRQ_HANDLED;
+}
+
+static const struct iio_info rockchip_saradc_iio_info = {
+ .read_raw = rockchip_saradc_read_raw,
+ .driver_module = THIS_MODULE,
+};
+
+#define ADC_CHANNEL(_index, _id) { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = _index, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .datasheet_name = _id, \
+}
+
+static const struct iio_chan_spec rockchip_saradc_iio_channels[] = {
+ ADC_CHANNEL(0, "adc0"),
+ ADC_CHANNEL(1, "adc1"),
+ ADC_CHANNEL(2, "adc2"),
+};
+
+static int rockchip_saradc_probe(struct platform_device *pdev)
+{
+ struct rockchip_saradc *info = NULL;
+ struct device_node *np = pdev->dev.of_node;
+ struct iio_dev *indio_dev = NULL;
+ struct resource *mem;
+ int ret = -ENODEV;
+ int irq;
+ u32 rate;
+
+ if (!np)
+ return ret;
+
+ indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
+ 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)
+ return -ENOMEM;
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_err(&pdev->dev, "no irq resource?\n");
+ return irq;
+ }
+
+ ret = devm_request_irq(&pdev->dev, irq, rockchip_saradc_isr,
+ 0, dev_name(&pdev->dev), info);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed requesting irq %d\n", irq);
+ return ret;
+ }
+
+ init_completion(&info->completion);
+
+ info->pclk = devm_clk_get(&pdev->dev, "apb_pclk");
+ if (IS_ERR(info->pclk)) {
+ dev_err(&pdev->dev, "failed to get pclk\n");
+ return PTR_ERR(info->pclk);
+ }
+
+ info->clk = devm_clk_get(&pdev->dev, "saradc");
+ if (IS_ERR(info->clk)) {
+ dev_err(&pdev->dev, "failed to get adc clock\n");
+ return PTR_ERR(info->clk);
+ }
+
+ info->vref = devm_regulator_get(&pdev->dev, "vref");
+ if (IS_ERR(info->vref)) {
+ dev_err(&pdev->dev, "failed to get regulator, %ld\n",
+ PTR_ERR(info->vref));
+ return PTR_ERR(info->vref);
+ }
+
+ /* use a default of 1MHz for the converter clock */
+ if (of_property_read_u32(np, "clock-frequency", &rate))
+ rate = 1000000;
+
+ ret = clk_set_rate(info->clk, rate);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to set adc clk rate, %d\n", ret);
+ return ret;
+ }
+
+ ret = regulator_enable(info->vref);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to enable vref regulator\n");
+ return ret;
+ }
+
+ ret = regulator_get_voltage(info->vref);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to get regulator voltage\n");
+ goto err_reg_voltage;
+ }
+ info->vref_mv = ret / 1000;
+
+ ret = clk_prepare_enable(info->pclk);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to enable pclk\n");
+ goto err_reg_voltage;
+ }
+
+ ret = clk_prepare_enable(info->clk);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to enable converter clock\n");
+ goto err_pclk;
+ }
+
+ 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 = &rockchip_saradc_iio_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ indio_dev->channels = rockchip_saradc_iio_channels;
+ indio_dev->num_channels = ARRAY_SIZE(rockchip_saradc_iio_channels);
+
+ ret = iio_device_register(indio_dev);
+ if (ret)
+ goto err_clk;
+
+ return 0;
+
+err_clk:
+ clk_disable_unprepare(info->clk);
+err_pclk:
+ clk_disable_unprepare(info->pclk);
+err_reg_voltage:
+ regulator_disable(info->vref);
+ return ret;
+}
+
+static int rockchip_saradc_remove(struct platform_device *pdev)
+{
+ struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+ struct rockchip_saradc *info = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+ clk_disable_unprepare(info->clk);
+ clk_disable_unprepare(info->pclk);
+ regulator_disable(info->vref);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int rockchip_saradc_suspend(struct device *dev)
+{
+ struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct rockchip_saradc *info = iio_priv(indio_dev);
+
+ clk_disable_unprepare(info->clk);
+ clk_disable_unprepare(info->pclk);
+ regulator_disable(info->vref);
+
+ return 0;
+}
+
+static int rockchip_saradc_resume(struct device *dev)
+{
+ struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct rockchip_saradc *info = iio_priv(indio_dev);
+ int ret;
+
+ ret = regulator_enable(info->vref);
+ if (ret)
+ return ret;
+
+ ret = clk_prepare_enable(info->pclk);
+ if (ret)
+ return ret;
+
+ ret = clk_prepare_enable(info->clk);
+ if (ret)
+ return ret;
+
+ return ret;
+}
+#endif
+
+static SIMPLE_DEV_PM_OPS(rockchip_saradc_pm_ops,
+ rockchip_saradc_suspend, rockchip_saradc_resume);
+
+static const struct of_device_id rockchip_saradc_match[] = {
+ { .compatible = "rockchip,saradc" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, rockchip_saradc_match);
+
+static struct platform_driver rockchip_saradc_driver = {
+ .probe = rockchip_saradc_probe,
+ .remove = rockchip_saradc_remove,
+ .driver = {
+ .name = "rockchip-saradc",
+ .owner = THIS_MODULE,
+ .of_match_table = rockchip_saradc_match,
+ .pm = &rockchip_saradc_pm_ops,
+ },
+};
+
+module_platform_driver(rockchip_saradc_driver);
--
1.9.0



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