Hi,
On 01/21/2013 02:37 PM, Naveen Krishna Chatradhi wrote:
> This patch add an ADC IP found on EXYNOS5 series socs from Samsung.
> Also adds the Documentation for device tree bindings.
>[...]
> diff --git a/drivers/iio/adc/exynos5_adc.c b/drivers/iio/adc/exynos5_adc.c
> new file mode 100644
> index 0000000..cd33ea2
> --- /dev/null
> +++ b/drivers/iio/adc/exynos5_adc.c
> @@ -0,0 +1,412 @@
> +/*
> + * exynos5_adc.c - Support for ADC in EXYNOS5 SoCs
> + *
> + * 8-channel, 10/12-bit ADC
> + *
> + * Copyright (C) 2013 Naveen Krishna Chatradhi <ch.naveen@xxxxxxxxxxx>
> + *
> + * 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>
> +
> +/* Samsung ADC registers definitions */
> +#define EXYNOS_ADC_CON(x) ((x) + 0x00)
> +#define EXYNOS_ADC_DLY(x) ((x) + 0x08)
> +#define EXYNOS_ADC_DATX(x) ((x) + 0x0C)
> +#define EXYNOS_ADC_INTCLR(x) ((x) + 0x18)
> +#define EXYNOS_ADC_MUX(x) ((x) + 0x1c)
> +
> +/* Bit definitions for EXYNOS_ADC_MUX: */
> +#define ADC_RES (1u << 16)
> +#define ADC_ECFLG (1u << 15)
> +#define ADC_PRSCEN (1u << 14)
> +#define ADC_PRSCLV(x) (((x) & 0xFF) << 6)
> +#define ADC_PRSCVLMASK (0xFF << 6)
> +#define ADC_STANDBY (1u << 2)
> +#define ADC_READ_START (1u << 1)
> +#define ADC_EN_START (1u << 0)
You are a bit inconsistent with your prefixes, sometimes you use EXYNOS_ADC,
sometimes just ADC, it would be better to use the same prefix all the time.
> +
> +#define ADC_DATX_MASK 0xFFF
> +
> +struct exynos5_adc {
> + void __iomem *regs;
> + struct clk *clk;
> + unsigned int irq;
> + struct regulator *vdd;
> +
> + struct completion completion;
> +
> + struct iio_map *map;
> + u32 value;
> + u32 prescale;
> +};
> +
> +static const struct of_device_id exynos5_adc_match[] = {
> + { .compatible = "samsung,exynos5250-adc" },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, exynos5_adc_match);
> +
> +/* default maps used by iio consumer (ex: ntc-thermistor driver) */
> +static struct iio_map exynos5_adc_iio_maps[] = {
> + {
> + .consumer_dev_name = "0.ncp15wb473",
> + .consumer_channel = "adc_user3",
> + .adc_channel_label = "adc3",
> + },
> + {},
> +};
Hm... this should not be in the driver itself.
> +
> +static int exynos5_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val,
> + int *val2,
> + long mask)
> +{
> + struct exynos5_adc *info = iio_priv(indio_dev);
> + u32 con;
> +
> + if (mask == IIO_CHAN_INFO_RAW) {
> + mutex_lock(&indio_dev->mlock);
> +
> + /* Select the channel to be used */
> + writel(chan->address, EXYNOS_ADC_MUX(info->regs));
> + /* Trigger conversion */
> + con = readl(EXYNOS_ADC_CON(info->regs));
> + writel(con | ADC_EN_START, EXYNOS_ADC_CON(info->regs));
> +
> + wait_for_completion(&info->completion);
> + *val = info->value;
> +
> + mutex_unlock(&indio_dev->mlock);
> +
> + return IIO_VAL_INT;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static irqreturn_t exynos5_adc_isr(int irq, void *dev_id)
> +{
> + struct exynos5_adc *info = (struct exynos5_adc *)dev_id;
> +
> + /* Read value and clear irq */
> + info->value = readl(EXYNOS_ADC_DATX(info->regs)) &
> + ADC_DATX_MASK;
> + writel(0, EXYNOS_ADC_INTCLR(info->regs));
> +
> + complete(&info->completion);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int exynos5_adc_reg_access(struct iio_dev *indio_dev,
> + unsigned reg, unsigned writeval,
> + unsigned *readval)
> +{
> + struct exynos5_adc *info = iio_priv(indio_dev);
> + u32 ret;
> +
> + mutex_lock(&indio_dev->mlock);
Do we really need to take the lock here?
> +
> + if (readval != NULL) {
> + if (reg == 0x08)
> + ret = readl(EXYNOS_ADC_DLY(info->regs));
> + else if (reg == 0x0C)
> + ret = readl(EXYNOS_ADC_DATX(info->regs));
> + else if (reg == 0x1C)
> + ret = readl(EXYNOS_ADC_MUX(info->regs));
> + else
> + ret = readl(EXYNOS_ADC_CON(info->regs));
How about
ret = readl(info->regs + reg)
instead of the whole if ... else if ... else if ...
> +
> + readval = &ret;
Uhm, I'm pretty sure that the line above does not work. At least it won't do
what you want it to do.
> + } else
> + ret = -EINVAL;
> +
> + mutex_unlock(&indio_dev->mlock);
> +
> + return ret;
> +}
> +
> +static const struct iio_info exynos5_adc_iio_info = {
> + .read_raw = &exynos5_read_raw,
> + .debugfs_reg_access = &exynos5_adc_reg_access,
> + .driver_module = THIS_MODULE,
> +};
> +
> +#define EXYNOS_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 exynos5_adc_iio_channels[] = {
> + EXYNOS_ADC_CHANNEL(0, "adc0"),
> + EXYNOS_ADC_CHANNEL(1, "adc1"),
> + EXYNOS_ADC_CHANNEL(2, "adc2"),
> + EXYNOS_ADC_CHANNEL(3, "adc3"),
> + EXYNOS_ADC_CHANNEL(4, "adc4"),
> + EXYNOS_ADC_CHANNEL(5, "adc5"),
> + EXYNOS_ADC_CHANNEL(6, "adc6"),
> + EXYNOS_ADC_CHANNEL(7, "adc7"),
> +};
> +
> +static int exynos5_adc_iio_map_register(struct iio_dev *indio_dev,
> + struct exynos5_adc *adc)
> +{
> + int ret;
> +
> + adc->map = exynos5_adc_iio_maps;
> +
> + ret = iio_map_array_register(indio_dev, adc->map);
> + if (ret) {
> + dev_err(&indio_dev->dev, "iio map err: %d\n", ret);
> + return ret;
> + }
> +
> + return 0;
> +}
Just use iio_map_array_register instead of exynos5_adc_iio_map_register
> +
> +static inline void exynos5_adc_iio_map_unregister(struct iio_dev *indio_dev,
> + struct exynos5_adc *adc)
> +{
> + iio_map_array_unregister(indio_dev, adc->map);
> +}
Just use iio_map_array_unregister directly instead of
exynos5_adc_iio_map_unregister
> +
> +static int exynos5_adc_remove_devices(struct device *dev, void *c)
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> +
> + platform_device_unregister(pdev);
> +
> + return 0;
> +}
Again, a single line wrapper function...
> +
> +static int exynos5_adc_probe(struct platform_device *pdev)
> +{
> + struct exynos5_adc *info = NULL;
> + struct device_node *np = pdev->dev.of_node;
> + struct iio_dev *iodev = NULL;
this is usually called indio_dev, would be good to be consistent across dirvers.
> + struct resource *mem;
> + int ret = -ENODEV;
> + int irq;
> + u32 con;
> +
> + iodev = iio_device_alloc(sizeof(struct exynos5_adc));
> + if (!iodev) {
> + dev_err(&pdev->dev, "failed allocating iio device\n");
> + return -ENOMEM;
> + }
> +
> + info = iio_priv(iodev);
> +
> + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!mem) {
devm_request_and_ioremap will check if mem is NULL, so you don't need to do
this manually.
> + dev_err(&pdev->dev, "no mem resource?\n");
> + goto err_iio;
> + }
> +
> + info->regs = devm_request_and_ioremap(&pdev->dev, mem);
> + if (!info->regs) {
> + dev_err(&pdev->dev, "cannot map EXYNOS5 ADC registers\n");
devm_request_and_ioremap already prints an error message.
> + 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;
> +
> + ret = devm_request_irq(&pdev->dev, info->irq, exynos5_adc_isr,
> + 0, dev_name(&pdev->dev), info);
Using devm_request_irq is racy in this case, since the IRQ will be freed
after the device has been freed, while it needs to be freed before the devie
has been freed.
> + if (ret < 0) {
> + dev_err(&pdev->dev, "cannot request Samsung ADC 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\n");
I think it is a good idea to include the error code in the error message.
> + ret = PTR_ERR(info->clk);
> + goto err_iio;
> + }
> +
> + clk_enable(info->clk);
> +
> + info->vdd = devm_regulator_get(&pdev->dev, "vdd");
> + if (IS_ERR(info->vdd)) {
> + dev_err(&pdev->dev, "operating without regulator \"vdd\" .\n");
Same here.
> + ret = PTR_ERR(info->vdd);
> + goto err_iio;
> + }
> +
> + platform_set_drvdata(pdev, iodev);
> +
> + init_completion(&info->completion);
> +
> + iodev->name = dev_name(&pdev->dev);
> + iodev->dev.parent = &pdev->dev;
> + iodev->dev.of_node = pdev->dev.of_node;
> + iodev->info = &exynos5_adc_iio_info;
> + iodev->modes = INDIO_DIRECT_MODE;
> + iodev->channels = exynos5_adc_iio_channels;
> + iodev->num_channels = ARRAY_SIZE(exynos5_adc_iio_channels);
> +
> + /* Enable prescaler and set platform default */
> + info->prescale = ADC_PRSCLV(49);
> + con = info->prescale | ADC_PRSCEN;
> +
> + /* Enable 12-bit ADC resolution */
> + con |= ADC_RES;
> +
> + writel(con, EXYNOS_ADC_CON(info->regs));
> +
> + ret = exynos5_adc_iio_map_register(iodev, info);
> + if (ret)
> + goto err_iio;
> +
> + ret = iio_device_register(iodev);
> + if (ret)
> + goto err_map;
> +
> + ret = regulator_enable(info->vdd);
> + if (ret)
> + goto err_iio_dev;
> +
> + ret = of_platform_populate(np, exynos5_adc_match, NULL, &pdev->dev);
Which kind of child nodes to you expect it to have? There is nothing about
this in your dt bindings documentation.
> + if (ret < 0) {
> + dev_err(&pdev->dev, "failed to add child nodes\n");
> + goto err_of_populate;
> + }
> +
> + dev_info(&pdev->dev, "EXYNOS5 ADC driver loaded.\n");
That's just noise, please remove it.
> +
> + return 0;
> +
> +err_of_populate:
> + device_for_each_child(&pdev->dev, NULL, exynos5_adc_remove_devices);
> +err_iio_dev:
> + iio_device_unregister(iodev);
> +err_map:
> + exynos5_adc_iio_map_unregister(iodev, info);
> +err_iio:
> + iio_device_free(iodev);
> + return ret;
> +}
> +
> +static int exynos5_adc_remove(struct platform_device *pdev)
> +{
> + struct iio_dev *iodev = platform_get_drvdata(pdev);
> + struct exynos5_adc *info = iio_priv(iodev);
> +
> + platform_set_drvdata(pdev, NULL);
The line above should not be needed
> + iio_device_unregister(iodev);
> + exynos5_adc_iio_map_unregister(iodev, info);
> + iio_device_free(iodev);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM
CONFIG_PM_SLEEP
> +static int exynos5_adc_suspend(struct device *dev)
> +{
> + struct platform_device *pdev = container_of(dev,
> + struct platform_device, dev);
to_platform_device
> + struct exynos5_adc *info = platform_get_drvdata(pdev);
Although using dev_get_data(dev) here would also be ok I guess.
> + u32 con;
> +
> + con = readl(EXYNOS_ADC_CON(info->regs));
> + con |= ADC_STANDBY;
> + writel(con, EXYNOS_ADC_CON(info->regs));
> +
> + clk_disable(info->clk);
clk_unprepare_disable
> + regulator_disable(info->vdd);
> +
> + return 0;
> +}
> +
> +static int exynos5_adc_resume(struct device *dev)
> +{
> + struct platform_device *pdev = container_of(dev,
> + struct platform_device, dev);
Same as above.
> + struct exynos5_adc *info = platform_get_drvdata(pdev);
> + unsigned int con;
> + int ret;
> +
> + ret = regulator_enable(info->vdd);
> + if (ret)
> + return ret;
> +
> + clk_enable(info->clk);
clk_prepare_enable
> +
> + /* TODO: Enable prescalar */
> + con = info->prescale | ADC_PRSCEN;
I guess you need to enable the prescaler here ;) (or removed the TODO comment)
> + writel(con | ADC_RES, EXYNOS_ADC_CON(info->regs));
> +
> + return 0;
> +}
> +
> +#else
> +#define s3c_adc_suspend NULL
> +#define s3c_adc_resume NULL
> +#endif
> +
> +static const struct dev_pm_ops adc_pm_ops = {
> + .suspend = exynos5_adc_suspend,
> + .resume = exynos5_adc_resume,
> +};
static SIMPLE_DEV_PM_OPS(exynos5_adc_pm_ops, exynos5_adc_suspend,
exynos5_adc_resume);
> +
> +static struct platform_driver exynos5_adc_driver = {
> + .probe = exynos5_adc_probe,
> + .remove = exynos5_adc_remove,
> + .driver = {
> + .name = "exynos5-adc",
> + .owner = THIS_MODULE,
> + .of_match_table = of_match_ptr(exynos5_adc_match),
> + .pm = &adc_pm_ops,
> + },
> +};
> +
> +module_platform_driver(exynos5_adc_driver);
> +
> +MODULE_AUTHOR("Naveen Krishna Chatradhi <ch.naveen@xxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Samsung EXYNOS5 ADC driver");
> +MODULE_LICENSE("GPL");
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