Ezequiel Garcia schrieb am 13.11.2014 15:13:
> From: Phani Movva <Phani.Movva@xxxxxxxxxx>
>
> This commit adds support for Cosmic Circuits 10001 10-bit ADC device.
A few more issues - some got newly introduced, some have been overseen earlier (and some are just matter of taste ;-)
>
> Signed-off-by: Phani Movva <Phani.Movva@xxxxxxxxxx>
> Signed-off-by: Naidu Tellapati <Naidu.Tellapati@xxxxxxxxxx>
> [Ezequiel: code style cleaning]
> Signed-off-by: Ezequiel Garcia <ezequiel.garcia@xxxxxxxxxx>
> ---
> drivers/iio/adc/Kconfig | 11 ++
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/cc10001_adc.c | 425 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 437 insertions(+)
> create mode 100644 drivers/iio/adc/cc10001_adc.c
>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 88bdc8f..09e2975 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -127,6 +127,17 @@ config AT91_ADC
> help
> Say yes here to build support for Atmel AT91 ADC.
>
> +config CC10001_ADC
> + tristate "Cosmic Circuits 10001 ADC driver"
> + depends on HAS_IOMEM
> + select IIO_BUFFER
> + select IIO_TRIGGERED_BUFFER
> + help
> + Say yes here to build support for Cosmic Circuits 10001 ADC.
> +
> + This driver can also be built as a module. If so, the module will be
> + called cc10001_adc.
> +
> config EXYNOS_ADC
> tristate "Exynos ADC driver support"
> depends on ARCH_EXYNOS || ARCH_S3C24XX || ARCH_S3C64XX || (OF && COMPILE_TEST)
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index cb88a6a..9286c59 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -14,6 +14,7 @@ obj-$(CONFIG_AD7793) += ad7793.o
> obj-$(CONFIG_AD7887) += ad7887.o
> obj-$(CONFIG_AD799X) += ad799x.o
> obj-$(CONFIG_AT91_ADC) += at91_adc.o
> +obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o
> obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o
> obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
> obj-$(CONFIG_MAX1027) += max1027.o
> diff --git a/drivers/iio/adc/cc10001_adc.c b/drivers/iio/adc/cc10001_adc.c
> new file mode 100644
> index 0000000..0b74838
> --- /dev/null
> +++ b/drivers/iio/adc/cc10001_adc.c
> @@ -0,0 +1,425 @@
> +/*
> + * Copyright (c) 2014 Imagination Technologies Ltd.
> + *
> + * 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.
> + *
> + */
> +
> +#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/regulator/consumer.h>
> +#include <linux/slab.h>
> +
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
> +
> +/* Registers */
> +#define CC10001_ADC_CONFIG 0x00
> +#define CC10001_ADC_START_CONV BIT(4)
> +#define CC10001_ADC_MODE_SINGLE_CONV BIT(5)
> +
> +#define CC10001_ADC_DDATA_OUT 0x04
> +#define CC10001_ADC_EOC 0x08
> +#define CC10001_ADC_EOC_SET BIT(0)
> +
> +#define CC10001_ADC_CHSEL_SAMPLED 0x0c
> +#define CC10001_ADC_POWER_UP 0x10
> +#define CC10001_ADC_POWER_UP_SET BIT(0)
> +#define CC10001_ADC_DEBUG 0x14
> +#define CC10001_ADC_DATA_COUNT 0x20
> +
> +#define CC10001_ADC_DATA_MASK GENMASK(9, 0)
> +#define CC10001_ADC_NUM_CHANNELS 8
> +#define CC10001_ADC_CH_MASK (CC10001_ADC_NUM_CHANNELS - 1)
Don't define CC10001_ADC_CH_MASK this way, as it implies a simple relation to CC10001_ADC_NUM_CHANNELS, but it actually requires it to be base 2 (which it happens to be in this case). Preferably use GENMASK(2, 0).
> +
> +#define CC10001_INVALID_SAMPLED_OUTPUT 0xFFFF
After changing your hex values to lower case, this one is still left.
> +#define CC10001_MAX_POLL_COUNT 20
> +
> +/*
> + * As per device specification, wait six clock cycles after power-up to
> + * activate START. Since adding two more clock cycles delay does not
> + * impact the performance too much, we are adding two additional cycles delay
> + * intentionally here.
> + */
> +#define CC10001_WAIT_CYCLES 8
> +
> +struct cc10001_adc_device {
> + void __iomem *reg_base;
> + struct iio_dev *indio_dev;
This element is never used.
> + struct clk *adc_clk;
> + struct regulator *reg;
> + u16 *buf;
> +
> + struct mutex lock;
> + unsigned long channel_map;
> + unsigned int start_delay_ns;
> + unsigned int eoc_delay_ns;
> +};
> +
> +static inline void cc10001_adc_write_reg(struct cc10001_adc_device *adc_dev,
> + u32 reg, u32 val)
> +{
> + writel(val, adc_dev->reg_base + reg);
> +}
> +
> +static inline u32 cc10001_adc_read_reg(struct cc10001_adc_device *adc_dev,
> + u32 reg)
> +{
> + return readl(adc_dev->reg_base + reg);
> +}
> +
> +static void cc10001_adc_start(struct cc10001_adc_device *adc_dev,
> + unsigned int channel)
> +{
> + u32 val;
> +
> + /* Channel selection and mode of operation */
> + val = (channel & CC10001_ADC_CH_MASK) | CC10001_ADC_MODE_SINGLE_CONV;
> + cc10001_adc_write_reg(adc_dev, CC10001_ADC_CONFIG, val);
> +
> + val = cc10001_adc_read_reg(adc_dev, CC10001_ADC_CONFIG);
> + val = val | CC10001_ADC_START_CONV;
> + cc10001_adc_write_reg(adc_dev, CC10001_ADC_CONFIG, val);
> +}
> +
> +static u16 cc10001_adc_poll_done(struct iio_dev *indio_dev,
> + unsigned int channel,
> + unsigned int delay)
> +{
> + struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
> + unsigned int poll_count = 0;
> +
> + while (!(cc10001_adc_read_reg(adc_dev, CC10001_ADC_EOC) &
> + CC10001_ADC_EOC_SET)) {
Matter of taste case here, and I understand that indenting it to align with cc10001_adc_read_reg would look like the indentation of the following subroutine. Then again, you left an empty line to show a certain distinction. Up to you, I just slightly prefer to align blocks with equal hierarchy levels.
> +
> + ndelay(delay);
> + if (poll_count++ == CC10001_MAX_POLL_COUNT)
> + return CC10001_INVALID_SAMPLED_OUTPUT;
> + }
> +
> + poll_count = 0;
> + while ((cc10001_adc_read_reg(adc_dev, CC10001_ADC_CHSEL_SAMPLED) &
> + CC10001_ADC_CH_MASK) != channel) {
Same here.
> +
> + ndelay(delay);
> + if (poll_count++ == CC10001_MAX_POLL_COUNT)
> + return CC10001_INVALID_SAMPLED_OUTPUT;
> + }
> +
> + /* Read the 10 bit output register */
> + return cc10001_adc_read_reg(adc_dev, CC10001_ADC_DDATA_OUT) &
> + CC10001_ADC_DATA_MASK;
Here I feel stronger about alignment.
> +}
> +
> +static irqreturn_t cc10001_adc_trigger_h(int irq, void *p)
> +{
> + struct cc10001_adc_device *adc_dev;
> + struct iio_poll_func *pf = p;
> + struct iio_dev *indio_dev;
> + unsigned int delay_ns;
> + unsigned int channel;
> + bool sample_invalid;
> + u16 *data;
> + int i;
> +
> + indio_dev = pf->indio_dev;
> + adc_dev = iio_priv(indio_dev);
> + data = adc_dev->buf;
> +
> + mutex_lock(&adc_dev->lock);
> +
> + cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_UP,
> + CC10001_ADC_POWER_UP_SET);
> +
> + /* Wait for 8 (6+2) clock cycles before activating START */
> + ndelay(adc_dev->start_delay_ns);
> +
> + /* Calculate delay step for eoc and sampled data */
> + delay_ns = adc_dev->eoc_delay_ns / CC10001_MAX_POLL_COUNT;
> +
> + i = 0;
> + sample_invalid = false;
These definitions could be done already during declaration.
> + for_each_set_bit(channel, indio_dev->active_scan_mask,
> + indio_dev->masklength) {
Too much indentation, it should be aligned with channel.
> +
> + cc10001_adc_start(adc_dev, channel);
> +
> + data[i] = cc10001_adc_poll_done(indio_dev, channel, delay_ns);
> + if (data[i] == CC10001_INVALID_SAMPLED_OUTPUT) {
> + dev_warn(&indio_dev->dev,
> + "invalid sample on channel %d\n", channel);
> + sample_invalid = true;
> + goto done;
> + }
> + i++;
> + }
> +
> +done:
> + cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_UP, 0);
> +
> + mutex_unlock(&adc_dev->lock);
> +
> + if (!sample_invalid)
> + iio_push_to_buffers_with_timestamp(indio_dev, data,
> + iio_get_time_ns());
> + iio_trigger_notify_done(indio_dev->trig);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static u16 cc10001_adc_read_raw_voltage(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan)
> +{
> + struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
> + unsigned int delay_ns;
> + u16 val;
> +
> + cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_UP,
> + CC10001_ADC_POWER_UP_SET);
> +
> + /* Wait for 8 (6+2) clock cycles before activating START */
> + ndelay(adc_dev->start_delay_ns);
> +
> + /* Calculate delay step for eoc and sampled data */
> + delay_ns = adc_dev->eoc_delay_ns / CC10001_MAX_POLL_COUNT;
> +
> + cc10001_adc_start(adc_dev, chan->channel);
> +
> + val = cc10001_adc_poll_done(indio_dev, chan->channel, delay_ns);
> +
> + cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_UP, 0);
> +
> + return val;
> +}
> +
> +static int cc10001_adc_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
> +{
> + struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
> + int ret;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + if (iio_buffer_enabled(indio_dev))
> + return -EBUSY;
> + mutex_lock(&adc_dev->lock);
> + *val = cc10001_adc_read_raw_voltage(indio_dev, chan);
> + mutex_unlock(&adc_dev->lock);
> +
> + if (*val == CC10001_INVALID_SAMPLED_OUTPUT)
> + return -EIO;
> + return IIO_VAL_INT;
Since C offers it:
return (*val == CC10001_INVALID_SAMPLED_OUTPUT) ? -EIO : IIO_VAL_INT;
It would fit in one line if CC10001_INVALID_SAMPLED_OUTPUT was called CC10001_INVALID_SAMPLE ;-)
> +
> + case IIO_CHAN_INFO_SCALE:
> + ret = regulator_get_voltage(adc_dev->reg);
> + if (ret)
> + return ret;
> +
> + *val = ret / 1000;
> + *val2 = chan->scan_type.realbits;
> + return IIO_VAL_FRACTIONAL_LOG2;
> +
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static int cc10001_update_scan_mode(struct iio_dev *indio_dev,
> + const unsigned long *scan_mask)
Reduce indentation by one space.
> +{
> + struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
> +
> + kfree(adc_dev->buf);
> + adc_dev->buf = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
> + if (!adc_dev->buf)
> + return -ENOMEM;
> +
> + return 0;
Save some lines:
return (!adc_dev->buf) ? -ENOMEM : 0;
> +}
> +
> +static const struct iio_info cc10001_adc_info = {
> + .driver_module = THIS_MODULE,
> + .read_raw = &cc10001_adc_read_raw,
> + .update_scan_mode = &cc10001_update_scan_mode,
> +};
> +
> +static int cc10001_adc_channel_init(struct iio_dev *indio_dev)
> +{
> + struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
> + struct iio_chan_spec *chan_array, *timestamp;
> + unsigned int bit, idx = 0;
> +
> + indio_dev->num_channels = bitmap_weight(&adc_dev->channel_map,
> + CC10001_ADC_NUM_CHANNELS);
> +
> + chan_array = devm_kcalloc(&indio_dev->dev, indio_dev->num_channels + 1,
> + sizeof(struct iio_chan_spec),
> + GFP_KERNEL);
> + if (!chan_array)
> + return -ENOMEM;
> +
> + for_each_set_bit(bit, &adc_dev->channel_map,
> + CC10001_ADC_NUM_CHANNELS) {
No need to wrap, this fits exactly 80 chars.
> + struct iio_chan_spec *chan = &chan_array[idx];
> +
> + chan->type = IIO_VOLTAGE;
> + chan->indexed = 1;
> + chan->channel = bit;
> + chan->scan_index = idx;
> + chan->scan_type.sign = 'u';
> + chan->scan_type.realbits = 10;
> + chan->scan_type.storagebits = 16;
> + chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
> + chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
> + idx++;
> + }
> +
> + timestamp = &chan_array[idx];
> + timestamp->type = IIO_TIMESTAMP;
> + timestamp->channel = -1;
> + timestamp->scan_index = idx;
> + timestamp->scan_type.sign = 's';
> + timestamp->scan_type.realbits = 64;
> + timestamp->scan_type.storagebits = 64;
> +
> + indio_dev->channels = chan_array;
> +
> + return 0;
> +}
> +
> +static int cc10001_adc_probe(struct platform_device *pdev)
> +{
> + struct device_node *node = pdev->dev.of_node;
> + struct cc10001_adc_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 == NULL)
> + return -ENOMEM;
> +
> + adc_dev = iio_priv(indio_dev);
> +
> + adc_dev->channel_map = CC10001_ADC_CH_MASK;
You certainly want adc_dev->channel_map to be something like GENMASK(CC10001_ADC_NUM_CHANNELS -1, 0).
> + if (!of_property_read_u32(node, "cosmic,reserved-adc-channels", &ret))
> + adc_dev->channel_map ^= ret;
Correct way is to mask out, not to XOR.
> +
> + adc_dev->reg = devm_regulator_get(&pdev->dev, "vref");
> + if (IS_ERR_OR_NULL(adc_dev->reg))
> + return -EINVAL;
if (IS_ERR(adc_dev->reg))
return PTR_ERR(adc_dev->reg);
> +
> + ret = regulator_enable(adc_dev->reg);
> + if (ret)
> + return ret;
> +
> + indio_dev->dev.parent = &pdev->dev;
> + indio_dev->name = dev_name(&pdev->dev);
> + indio_dev->info = &cc10001_adc_info;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> +
> + 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))
Need to put error code into ret.
> + goto err_disable_reg;
> +
> + adc_dev->adc_clk = devm_clk_get(&pdev->dev, "adc");
> + if (IS_ERR(adc_dev->adc_clk)) {
> + dev_err(&pdev->dev, "Failed to get the clock\n");
Need to put error code into ret.
> + goto err_disable_reg;
> + }
> +
> + ret = clk_prepare_enable(adc_dev->adc_clk);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to enable the clock\n");
> + goto err_disable_reg;
> + }
> +
> + adc_clk_rate = clk_get_rate(adc_dev->adc_clk);
> + if (!adc_clk_rate) {
> + ret = -EINVAL;
> + dev_err(&pdev->dev, "null clock rate!\n");
Start message with upper case?
> + goto err_disable_clk;
> + }
> +
> + adc_dev->eoc_delay_ns = NSEC_PER_SEC / adc_clk_rate;
> + adc_dev->start_delay_ns = adc_dev->eoc_delay_ns * CC10001_WAIT_CYCLES;
> +
> + /* Setup the ADC channels available on the device */
> + ret = cc10001_adc_channel_init(indio_dev);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "Could not initialize the channels.\n");
> + goto err_disable_clk;
> + }
> +
> + mutex_init(&adc_dev->lock);
> +
> + ret = iio_triggered_buffer_setup(indio_dev, NULL,
> + &cc10001_adc_trigger_h, NULL);
> + if (ret < 0)
> + goto err_disable_clk;
> +
> + ret = iio_device_register(indio_dev);
> + if (ret < 0)
> + goto err_cleanup_buffer;
> +
> + platform_set_drvdata(pdev, indio_dev);
Move this above iio_device_register.
> +
> + return 0;
> +
> +err_cleanup_buffer:
> + iio_triggered_buffer_cleanup(indio_dev);
> +err_disable_clk:
> + clk_disable_unprepare(adc_dev->adc_clk);
> +err_disable_reg:
> + regulator_disable(adc_dev->reg);
> + return ret;
> +}
> +
> +static int cc10001_adc_remove(struct platform_device *pdev)
> +{
> + struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> + struct cc10001_adc_device *adc_dev = iio_priv(indio_dev);
> +
> + iio_device_unregister(indio_dev);
> + iio_triggered_buffer_cleanup(indio_dev);
> + clk_disable_unprepare(adc_dev->adc_clk);
> + regulator_disable(adc_dev->reg);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id cc10001_adc_dt_ids[] = {
> + { .compatible = "cosmic,10001-adc", },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, cc10001_adc_dt_ids);
> +
> +static struct platform_driver cc10001_adc_driver = {
> + .driver = {
> + .name = "cc10001-adc",
> + .owner = THIS_MODULE,
> + .of_match_table = cc10001_adc_dt_ids,
> + },
> + .probe = cc10001_adc_probe,
> + .remove = cc10001_adc_remove,
> +};
> +module_platform_driver(cc10001_adc_driver);
> +
> +MODULE_AUTHOR("Phani Movva <Phani.Movva@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Cosmic Circuits ADC driver");
> +MODULE_LICENSE("GPL v2");
>
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