[PATCH 2/3] auxadc: Add Mediatek auxadc driver for mt2701.
Peter Meerwald-Stadler
pmeerw at pmeerw.net
Fri Jun 24 01:51:19 PDT 2016
> Add Mediatek auxadc driver in iio.
> It will register a device in iio and support iio.
> So thermal can read auxadc channel to sample data by iio device.
> It is tested successfully on mt2701 platform.
> Mt8173 platform is not tested. But the expectation is compatible.
some reference to iio would be nice in the subject line
comments below
> Signed-off-by: Zhiyong Tao <zhiyong.tao at mediatek.com>
> ---
> drivers/iio/adc/Kconfig | 11 ++
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/mt65xx_auxadc.c | 269
> +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 281 insertions(+)
> create mode 100644 drivers/iio/adc/mt65xx_auxadc.c
>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 25378c5..7684849 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -315,6 +315,17 @@ config MEN_Z188_ADC
> This driver can also be built as a module. If so, the module will be
> called men_z188_adc.
>
> +config MEDIATEK_MT65XX_AUXADC
> + tristate "MediaTek AUXADC driver"
maybe some 'depends on' here so the driver is just visible for relevant
configs? see below, MXR_LRADC, for an example
> + help
> + Say yes here to enable support for MediaTek mt65xx AUXADC.
> +
> + The driver supports immediate mode operation to read from one of sixteen
> + channels (external or internal).
> +
> + This driver can also be built as a module. If so, the module will be
> + called mt65xx_auxadc.
> +
> config MXS_LRADC
> tristate "Freescale i.MX23/i.MX28 LRADC"
> depends on (ARCH_MXS || COMPILE_TEST) && HAS_IOMEM
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 38638d4..bc62209 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -31,6 +31,7 @@ obj-$(CONFIG_MAX1363) += max1363.o
> obj-$(CONFIG_MCP320X) += mcp320x.o
> obj-$(CONFIG_MCP3422) += mcp3422.o
> obj-$(CONFIG_MEN_Z188_ADC) += men_z188_adc.o
> +obj-$(CONFIG_MEDIATEK_MT65XX_AUXADC) += mt65xx_auxadc.o
> obj-$(CONFIG_MXS_LRADC) += mxs-lradc.o
> obj-$(CONFIG_NAU7802) += nau7802.o
> obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
> diff --git a/drivers/iio/adc/mt65xx_auxadc.c
> b/drivers/iio/adc/mt65xx_auxadc.c
> new file mode 100644
> index 0000000..b3c059c
> --- /dev/null
> +++ b/drivers/iio/adc/mt65xx_auxadc.c
> @@ -0,0 +1,269 @@
> +/*
> + * Copyright (c) 2016 MediaTek Inc.
> + * Author: Zhiyong Tao <zhiyong.tao at mediatek.com>
> + *
> + * 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.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/iopoll.h>
> +#include <linux/io.h>
> +#include <linux/iio/iio.h>
> +
> +/* Registers define*/
delete one space before define, add a space after define; maybe 'Register
definitions' or 'Register defines' would read smoother
> +#define MT65XX_AUXADC_CON0 0x00
> +#define MT65XX_AUXADC_CON1 0x04
> +#define MT65XX_AUXADC_CON2 0x10
> +#define MT65XX_AUXADC_STA BIT(0)
> +
> +#define MT65XX_AUXADC_DAT0 0x14
> +#define MT65XX_AUXADC_RDY0 BIT(12)
> +
> +#define MT65XX_AUXADC_MISC 0x94
> +#define MT65XX_AUXADC_PDN_EN BIT(14)
> +
> +#define MT65XX_AUXADC_DAT_MASK 0xfff
> +#define MT65XX_AUXADC_SLEEP_US 1000
> +#define MT65XX_AUXADC_TIMEOUT_US 10000
> +#define MT65XX_AUXADC_POWER_READY_MS 1
> +#define MT65XX_AUXADC_SAMPLE_READY_US 25
> +
> +struct mt65xx_auxadc_device {
> + void __iomem *reg_base;
> + struct clk *adc_clk;
> + struct mutex lock; /*generic mutex for auxadc driver*/
comment needed?
> + unsigned int power_ready_ms;
> + unsigned int sample_ready_us;
> +};
> +
> +#define MT65xx_AUXADC_CHANNEL(idx) { \
XX uppercase
> + .type = IIO_VOLTAGE, \
> + .indexed = 1, \
> + .channel = (idx), \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
> + BIT(IIO_CHAN_INFO_OFFSET), \
> +}
> +
> +static const struct iio_chan_spec mt65xx_auxadc_iio_channels[] = {
> + MT65xx_AUXADC_CHANNEL(0),
> + MT65xx_AUXADC_CHANNEL(1),
> + MT65xx_AUXADC_CHANNEL(2),
> + MT65xx_AUXADC_CHANNEL(3),
> + MT65xx_AUXADC_CHANNEL(4),
> + MT65xx_AUXADC_CHANNEL(5),
> + MT65xx_AUXADC_CHANNEL(6),
> + MT65xx_AUXADC_CHANNEL(7),
> + MT65xx_AUXADC_CHANNEL(8),
> + MT65xx_AUXADC_CHANNEL(9),
> + MT65xx_AUXADC_CHANNEL(10),
> + MT65xx_AUXADC_CHANNEL(11),
> + MT65xx_AUXADC_CHANNEL(12),
> + MT65xx_AUXADC_CHANNEL(13),
> + MT65xx_AUXADC_CHANNEL(14),
> + MT65xx_AUXADC_CHANNEL(15),
> +};
> +
> +static int mt65xx_auxadc_read(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan)
> +{
> + u32 rawdata, val;
> + void __iomem *reg_channel;
> + struct mt65xx_auxadc_device *adc_dev = iio_priv(indio_dev);
> +
> + reg_channel = adc_dev->reg_base + MT65XX_AUXADC_DAT0 +
> + chan->channel * 0x04;
> +
> + mutex_lock(&adc_dev->lock);
> +
> + val = readl(adc_dev->reg_base + MT65XX_AUXADC_CON1);
> + val &= ~(1 << chan->channel);
> + writel(val, adc_dev->reg_base + MT65XX_AUXADC_CON1);
> +
> + /* read channel and make sure old ready bit ==0 */
> + readl_poll_timeout(reg_channel, val,
> + ((val & MT65XX_AUXADC_RDY0) == 0),
> + MT65XX_AUXADC_SLEEP_US,
> + MT65XX_AUXADC_TIMEOUT_US);
this returns a code 0 or -ETIMEDOUT that probably should be checked
> +
> + /* set bit to trigger sample */
double space after bit
> + val = readl(adc_dev->reg_base + MT65XX_AUXADC_CON1);
> + val |= 1 << chan->channel;
> + writel(val, adc_dev->reg_base + MT65XX_AUXADC_CON1);
> +
> + /* we must delay here for hardware sample channel data */
> + udelay(adc_dev->sample_ready_us);
> +
> + /* check MTK_AUXADC_CON2 if auxadc is idle */
> + readl_poll_timeout(adc_dev->reg_base + MT65XX_AUXADC_CON2, val,
> + ((val & MT65XX_AUXADC_STA) == 0),
> + MT65XX_AUXADC_SLEEP_US,
> + MT65XX_AUXADC_TIMEOUT_US);
> +
> + /* read channel and make sure ready bit ==1 */
> + readl_poll_timeout(reg_channel, val,
> + ((val & MT65XX_AUXADC_RDY0) == 1),
> + MT65XX_AUXADC_SLEEP_US,
> + MT65XX_AUXADC_TIMEOUT_US);
> +
> + /* read data */
> + rawdata = readl(reg_channel) & MT65XX_AUXADC_DAT_MASK;
> +
> + mutex_unlock(&adc_dev->lock);
> +
> + return rawdata;
> +}
> +
> +static int mt65xx_auxadc_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val,
> + int *val2,
> + long info)
> +{
> + int ret;
> +
> + switch (info) {
> + case IIO_CHAN_INFO_RAW:
> + *val = mt65xx_auxadc_read(indio_dev, chan);
> + ret = IIO_VAL_INT;
> + break;
> + case IIO_CHAN_INFO_SCALE:
> + *val = 1;
no point in returning 1 and 0 for SCALE and OFFSET, these are the
default/assumed values if not given
> + ret = IIO_VAL_INT;
> + break;
> + case IIO_CHAN_INFO_OFFSET:
> + *val = 0;
> + ret = IIO_VAL_INT;
> + break;
> + default:
> + ret = -EINVAL;
> + break;
> + }
> +
> + return ret;
> +}
> +
> +static const struct iio_info mt65xx_auxadc_info = {
> + .driver_module = THIS_MODULE,
> + .read_raw = &mt65xx_auxadc_read_raw,
> +};
> +
> +static int mt65xx_auxadc_probe(struct platform_device *pdev)
> +{
> + struct mt65xx_auxadc_device *adc_dev;
> + unsigned long adc_clk_rate;
> + struct resource *res;
> + struct iio_dev *indio_dev;
> + int ret;
> + u32 val;
> +
> + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc_dev));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + adc_dev = iio_priv(indio_dev);
> + indio_dev->dev.parent = &pdev->dev;
> + indio_dev->name = dev_name(&pdev->dev);
> + indio_dev->info = &mt65xx_auxadc_info;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->channels = mt65xx_auxadc_iio_channels;
> + indio_dev->num_channels = ARRAY_SIZE(mt65xx_auxadc_iio_channels);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + adc_dev->reg_base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(adc_dev->reg_base)) {
> + dev_err(&pdev->dev, "failed to get auxadc base address.\n");
> + return PTR_ERR(adc_dev->reg_base);
> + }
> +
> + adc_dev->adc_clk = devm_clk_get(&pdev->dev, "main");
> + if (IS_ERR(adc_dev->adc_clk)) {
> + dev_err(&pdev->dev, "failed to get axuadc clock\n");
spelling: auxadc
> + return PTR_ERR(adc_dev->adc_clk);
> + }
> +
> + ret = clk_prepare_enable(adc_dev->adc_clk);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to enable auxadc clock\n");
> + return ret;
> + }
> +
> + adc_clk_rate = clk_get_rate(adc_dev->adc_clk);
> + if (!adc_clk_rate) {
> + dev_err(&pdev->dev, "null clock rate!\n");
> + clk_disable_unprepare(adc_dev->adc_clk);
> + return -EINVAL;
> + }
> +
> + adc_dev->power_ready_ms = MT65XX_AUXADC_POWER_READY_MS;
> + adc_dev->sample_ready_us = MT65XX_AUXADC_SAMPLE_READY_US;
> +
> + mutex_init(&adc_dev->lock);
> +
> + val = readl(adc_dev->reg_base + MT65XX_AUXADC_MISC);
> + val |= MT65XX_AUXADC_PDN_EN;
> + writel(val, adc_dev->reg_base + MT65XX_AUXADC_MISC);
> + mdelay(adc_dev->power_ready_ms);
> +
> + ret = iio_device_register(indio_dev);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to register iio device!\n");
power down on failure?
clk_disable_unprepare()?
> + return ret;
> + }
> +
> + platform_set_drvdata(pdev, indio_dev);
I'd rather put this before iio_device_register() to avoid a potential race
window
> +
> + return 0;
> +}
> +
> +static int mt65xx_auxadc_remove(struct platform_device *pdev)
> +{
> + struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> + struct mt65xx_auxadc_device *adc_dev = iio_priv(indio_dev);
> + u32 val;
> +
> + iio_device_unregister(indio_dev);
> +
> + val = readl(adc_dev->reg_base + MT65XX_AUXADC_MISC);
> + val &= ~MT65XX_AUXADC_PDN_EN;
> + writel(val, adc_dev->reg_base + MT65XX_AUXADC_MISC);
> +
> + clk_disable_unprepare(adc_dev->adc_clk);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id mt65xx_auxadc_of_match[] = {
> + { .compatible = "mediatek,mt2701-auxadc", },
> + { .compatible = "mediatek,mt8173-auxadc", },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, mt65xx_auxadc_of_match);
> +
> +static struct platform_driver mt65xx_auxadc_driver = {
> + .driver = {
> + .name = "mt65xx-auxadc",
> + .of_match_table = mt65xx_auxadc_of_match,
> + },
> + .probe = mt65xx_auxadc_probe,
> + .remove = mt65xx_auxadc_remove,
> +};
> +module_platform_driver(mt65xx_auxadc_driver);
> +
> +MODULE_AUTHOR("Zhiyong Tao <zhiyong.tao at mediatek.com>");
> +MODULE_DESCRIPTION("MTK AUXADC Device Driver");
> +MODULE_LICENSE("GPL v2");
>
--
Peter Meerwald-Stadler
+43-664-2444418 (mobile)
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