diff options
Diffstat (limited to 'drivers/iio/adc/mt6577_auxadc.c')
| -rw-r--r-- | drivers/iio/adc/mt6577_auxadc.c | 291 |
1 files changed, 291 insertions, 0 deletions
diff --git a/drivers/iio/adc/mt6577_auxadc.c b/drivers/iio/adc/mt6577_auxadc.c new file mode 100644 index 000000000000..2d104c828041 --- /dev/null +++ b/drivers/iio/adc/mt6577_auxadc.c @@ -0,0 +1,291 @@ +/* + * Copyright (c) 2016 MediaTek Inc. + * Author: Zhiyong Tao <zhiyong.tao@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> + +/* Register definitions */ +#define MT6577_AUXADC_CON0 0x00 +#define MT6577_AUXADC_CON1 0x04 +#define MT6577_AUXADC_CON2 0x10 +#define MT6577_AUXADC_STA BIT(0) + +#define MT6577_AUXADC_DAT0 0x14 +#define MT6577_AUXADC_RDY0 BIT(12) + +#define MT6577_AUXADC_MISC 0x94 +#define MT6577_AUXADC_PDN_EN BIT(14) + +#define MT6577_AUXADC_DAT_MASK 0xfff +#define MT6577_AUXADC_SLEEP_US 1000 +#define MT6577_AUXADC_TIMEOUT_US 10000 +#define MT6577_AUXADC_POWER_READY_MS 1 +#define MT6577_AUXADC_SAMPLE_READY_US 25 + +struct mt6577_auxadc_device { + void __iomem *reg_base; + struct clk *adc_clk; + struct mutex lock; +}; + +#define MT6577_AUXADC_CHANNEL(idx) { \ + .type = IIO_VOLTAGE, \ + .indexed = 1, \ + .channel = (idx), \ + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \ +} + +static const struct iio_chan_spec mt6577_auxadc_iio_channels[] = { + MT6577_AUXADC_CHANNEL(0), + MT6577_AUXADC_CHANNEL(1), + MT6577_AUXADC_CHANNEL(2), + MT6577_AUXADC_CHANNEL(3), + MT6577_AUXADC_CHANNEL(4), + MT6577_AUXADC_CHANNEL(5), + MT6577_AUXADC_CHANNEL(6), + MT6577_AUXADC_CHANNEL(7), + MT6577_AUXADC_CHANNEL(8), + MT6577_AUXADC_CHANNEL(9), + MT6577_AUXADC_CHANNEL(10), + MT6577_AUXADC_CHANNEL(11), + MT6577_AUXADC_CHANNEL(12), + MT6577_AUXADC_CHANNEL(13), + MT6577_AUXADC_CHANNEL(14), + MT6577_AUXADC_CHANNEL(15), +}; + +static inline void mt6577_auxadc_mod_reg(void __iomem *reg, + u32 or_mask, u32 and_mask) +{ + u32 val; + + val = readl(reg); + val |= or_mask; + val &= ~and_mask; + writel(val, reg); +} + +static int mt6577_auxadc_read(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan) +{ + u32 val; + void __iomem *reg_channel; + int ret; + struct mt6577_auxadc_device *adc_dev = iio_priv(indio_dev); + + reg_channel = adc_dev->reg_base + MT6577_AUXADC_DAT0 + + chan->channel * 0x04; + + mutex_lock(&adc_dev->lock); + + mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_CON1, + 0, 1 << chan->channel); + + /* read channel and make sure old ready bit == 0 */ + ret = readl_poll_timeout(reg_channel, val, + ((val & MT6577_AUXADC_RDY0) == 0), + MT6577_AUXADC_SLEEP_US, + MT6577_AUXADC_TIMEOUT_US); + if (ret < 0) { + dev_err(indio_dev->dev.parent, + "wait for channel[%d] ready bit clear time out\n", + chan->channel); + goto err_timeout; + } + + /* set bit to trigger sample */ + mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_CON1, + 1 << chan->channel, 0); + + /* we must delay here for hardware sample channel data */ + udelay(MT6577_AUXADC_SAMPLE_READY_US); + + /* check MTK_AUXADC_CON2 if auxadc is idle */ + ret = readl_poll_timeout(adc_dev->reg_base + MT6577_AUXADC_CON2, val, + ((val & MT6577_AUXADC_STA) == 0), + MT6577_AUXADC_SLEEP_US, + MT6577_AUXADC_TIMEOUT_US); + if (ret < 0) { + dev_err(indio_dev->dev.parent, + "wait for auxadc idle time out\n"); + goto err_timeout; + } + + /* read channel and make sure ready bit == 1 */ + ret = readl_poll_timeout(reg_channel, val, + ((val & MT6577_AUXADC_RDY0) != 0), + MT6577_AUXADC_SLEEP_US, + MT6577_AUXADC_TIMEOUT_US); + if (ret < 0) { + dev_err(indio_dev->dev.parent, + "wait for channel[%d] data ready time out\n", + chan->channel); + goto err_timeout; + } + + /* read data */ + val = readl(reg_channel) & MT6577_AUXADC_DAT_MASK; + + mutex_unlock(&adc_dev->lock); + + return val; + +err_timeout: + + mutex_unlock(&adc_dev->lock); + + return -ETIMEDOUT; +} + +static int mt6577_auxadc_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, + int *val2, + long info) +{ + switch (info) { + case IIO_CHAN_INFO_PROCESSED: + *val = mt6577_auxadc_read(indio_dev, chan); + if (*val < 0) { + dev_err(indio_dev->dev.parent, + "failed to sample data on channel[%d]\n", + chan->channel); + return *val; + } + return IIO_VAL_INT; + + default: + return -EINVAL; + } +} + +static const struct iio_info mt6577_auxadc_info = { + .driver_module = THIS_MODULE, + .read_raw = &mt6577_auxadc_read_raw, +}; + +static int mt6577_auxadc_probe(struct platform_device *pdev) +{ + struct mt6577_auxadc_device *adc_dev; + unsigned long adc_clk_rate; + struct resource *res; + struct iio_dev *indio_dev; + int ret; + + 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 = &mt6577_auxadc_info; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = mt6577_auxadc_iio_channels; + indio_dev->num_channels = ARRAY_SIZE(mt6577_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 auxadc clock\n"); + 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) { + ret = -EINVAL; + dev_err(&pdev->dev, "null clock rate\n"); + goto err_disable_clk; + } + + mutex_init(&adc_dev->lock); + + mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_MISC, + MT6577_AUXADC_PDN_EN, 0); + mdelay(MT6577_AUXADC_POWER_READY_MS); + + platform_set_drvdata(pdev, indio_dev); + + ret = iio_device_register(indio_dev); + if (ret < 0) { + dev_err(&pdev->dev, "failed to register iio device\n"); + goto err_power_off; + } + + return 0; + +err_power_off: + mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_MISC, + 0, MT6577_AUXADC_PDN_EN); +err_disable_clk: + clk_disable_unprepare(adc_dev->adc_clk); + return ret; +} + +static int mt6577_auxadc_remove(struct platform_device *pdev) +{ + struct iio_dev *indio_dev = platform_get_drvdata(pdev); + struct mt6577_auxadc_device *adc_dev = iio_priv(indio_dev); + + iio_device_unregister(indio_dev); + + mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_MISC, + 0, MT6577_AUXADC_PDN_EN); + + clk_disable_unprepare(adc_dev->adc_clk); + + return 0; +} + +static const struct of_device_id mt6577_auxadc_of_match[] = { + { .compatible = "mediatek,mt2701-auxadc", }, + { .compatible = "mediatek,mt8173-auxadc", }, + { } +}; +MODULE_DEVICE_TABLE(of, mt6577_auxadc_of_match); + +static struct platform_driver mt6577_auxadc_driver = { + .driver = { + .name = "mt6577-auxadc", + .of_match_table = mt6577_auxadc_of_match, + }, + .probe = mt6577_auxadc_probe, + .remove = mt6577_auxadc_remove, +}; +module_platform_driver(mt6577_auxadc_driver); + +MODULE_AUTHOR("Zhiyong Tao <zhiyong.tao@mediatek.com>"); +MODULE_DESCRIPTION("MTK AUXADC Device Driver"); +MODULE_LICENSE("GPL v2"); |