Re: [PATCH v5 1/2] iio: adc: add driver for Rockchip saradc
From: Hartmut Knaack
Date: Sun Jul 20 2014 - 06:07:56 EST
Heiko StÃbner schrieb:
> 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@xxxxxxxxx>
Reviewed-by: Hartmut Knaack <knaack.h@xxxxxx>
> ---
Looks good to me. The fact, that SARADC_DLY_PU_SOC_MASK is defined but never used should be fine under the given circumstances, that no datasheet with register definitions is publicly available.
> changes since v4:
> - address comments from Hartmut Knaack
> - explain the DLY_PU_SOC value
> - determine regulator voltage in IIO_CHAN_INFO_SCALE
> - return ENODEV directly in the !np case
> changes since v3:
> - address comments from Jonathan Cameron
> - explicitly check for negative values in error checks
> - change Kconfig depends to ARCH_ROCKCHIP || (ARM && COMPILE_TEST)
> to prevent issues due to undefined writel_relaxed functions
> The previous check for OF was unecessary, as the only used function
> is of_property_read_u32, for which a stub is defined for the !OF case.
> changes since v2:
> - address more comments from Peter Meerwald
> mainly the missing info_mask_shared_by_type element
> changes since v1:
> - address comments from Peter Meerwald
>
> drivers/iio/adc/Kconfig | 10 ++
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/rockchip_saradc.c | 316 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 327 insertions(+)
> create mode 100644 drivers/iio/adc/rockchip_saradc.c
>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index a80d236..01c6ed6 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 || (ARM && 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..9fa5653
> --- /dev/null
> +++ b/drivers/iio/adc/rockchip_saradc.c
> @@ -0,0 +1,316 @@
> +/*
> + * 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;
> + 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);
> + int ret;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + mutex_lock(&indio_dev->mlock);
> +
> + /* 8 clock periods as delay between power up and start cmd */
> + writel_relaxed(8, info->regs + SARADC_DLY_PU_SOC);
> +
> + /* Select the channel to be used and trigger conversion */
> + 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:
> + ret = regulator_get_voltage(info->vref);
> + if (ret < 0) {
> + dev_err(&indio_dev->dev, "failed to get voltage\n");
> + return ret;
> + }
> +
> + *val = ret / 1000;
> + *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), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> + .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;
> + int irq;
> + u32 rate;
> +
> + if (!np)
> + return -ENODEV;
> +
> + 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 */
> + ret = of_property_read_u32(np, "clock-frequency", &rate);
> + if (ret < 0)
> + rate = 1000000;
> +
> + ret = clk_set_rate(info->clk, rate);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to set adc clk rate, %d\n", ret);
> + return ret;
> + }
> +
> + ret = regulator_enable(info->vref);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to enable vref regulator\n");
> + return ret;
> + }
> +
> + ret = clk_prepare_enable(info->pclk);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to enable pclk\n");
> + goto err_reg_voltage;
> + }
> +
> + ret = clk_prepare_enable(info->clk);
> + if (ret < 0) {
> + 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);
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