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SubjectRe: [PATCH 3/3] IIO: add Ingenic JZ47xx ADC driver.
On Mon, 28 Jan 2019 14:02:41 +0100
Artur Rojek <contact@artur-rojek.eu> wrote:

> Add an IIO driver for the ADC hardware present on Ingenic JZ47xx SoCs.
>
> Signed-off-by: Artur Rojek <contact@artur-rojek.eu>

Looks pretty good to me. A few minor things inline.

Thanks,

Jonathan
> ---
> drivers/iio/adc/Kconfig | 9 +
> drivers/iio/adc/Makefile | 1 +
> drivers/iio/adc/ingenic-adc.c | 357 ++++++++++++++++++++++++++++++++++
> 3 files changed, 367 insertions(+)
> create mode 100644 drivers/iio/adc/ingenic-adc.c
>
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 7a3ca4ec0cb7..f9f349a22b04 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -367,6 +367,15 @@ config INA2XX_ADC
> Say yes here to build support for TI INA2xx family of Power Monitors.
> This driver is mutually exclusive with the HWMON version.
>
> +config INGENIC_ADC
> + tristate "Ingenic JZ47xx SoCs ADC driver"
> + depends on MIPS || COMPILE_TEST
> + help
> + Say yes here to build support for the Ingenic JZ47xx SoCs ADC unit.
> +
> + This driver can also be built as a module. If so, the module will be
> + called ingenic_adc.
> +
> config IMX7D_ADC
> tristate "Freescale IMX7D ADC driver"
> depends on ARCH_MXC || COMPILE_TEST
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 07df37f621bd..0a7acab33b91 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -36,6 +36,7 @@ obj-$(CONFIG_HI8435) += hi8435.o
> obj-$(CONFIG_HX711) += hx711.o
> obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
> obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
> +obj-$(CONFIG_INGENIC_ADC) += ingenic-adc.o
> obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
> obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
> obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o
> diff --git a/drivers/iio/adc/ingenic-adc.c b/drivers/iio/adc/ingenic-adc.c
> new file mode 100644
> index 000000000000..4235d46a3d37
> --- /dev/null
> +++ b/drivers/iio/adc/ingenic-adc.c
> @@ -0,0 +1,357 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ADC driver for the Ingenic JZ47xx SoCs
> + * Copyright (c) 2019 Artur Rojek <contact@artur-rojek.eu>
> + *
> + * based on drivers/mfd/jz4740-adc.c
> + */
> +
> +#include <dt-bindings/iio/adc/ingenic,adc.h>
> +#include <linux/clk.h>
> +#include <linux/iio/iio.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/spinlock.h>
> +
> +#define JZ_ADC_REG_ENABLE 0x00
> +#define JZ_ADC_REG_CFG 0x04
> +#define JZ_ADC_REG_CTRL 0x08
> +#define JZ_ADC_REG_STATUS 0x0c
> +#define JZ_ADC_REG_ADTCH 0x18
> +#define JZ_ADC_REG_ADBDAT 0x1c
> +#define JZ_ADC_REG_ADSDAT 0x20
> +
> +#define REG_CFG_BAT_MD BIT(4)

Please prefix all these as well to avoid a potential name clash with a header
in the future. Better to avoid it now!

> +
> +#define AUX_VREF 3300
> +#define AUX_VREF_BITS 12
> +#define BATTERY_LOW_VREF 2500
> +#define BATTERY_LOW_VREF_BITS 12
> +#define JZ4725B_BATTERY_HIGH_VREF 7500
> +#define JZ4725B_BATTERY_HIGH_VREF_BITS 10
> +#define JZ4740_BATTERY_HIGH_VREF (7500 * 0.986)
> +#define JZ4740_BATTERY_HIGH_VREF_BITS 12
> +
> +struct ingenic_adc_soc_data {
> + unsigned int battery_high_vref;
> + unsigned int battery_high_vref_bits;
> + const int *battery_raw_avail;
> + size_t battery_raw_avail_size;
> + const int *battery_scale_avail;
> + size_t battery_scale_avail_size;
> +};
> +
> +struct ingenic_adc {
> + void __iomem *base;
> + struct clk *clk;

> + spinlock_t lock;
This isn't taken anywhere that can't sleep, so mutex preferred to play
nice with realtime kernels etc.

> + const struct ingenic_adc_soc_data *soc_data;
> + bool low_vref_mode;
> +};
> +
> +static void ingenic_adc_set_config(struct ingenic_adc *adc,
> + uint32_t mask,
> + uint32_t val)
> +{
> + unsigned long flags;
> + uint32_t cfg;
> +
> + clk_enable(adc->clk);
> + spin_lock_irqsave(&adc->lock, flags);
> +
> + cfg = readl(adc->base + JZ_ADC_REG_CFG) & ~mask;
> + cfg |= val;
> + writel(cfg, adc->base + JZ_ADC_REG_CFG);
> +
> + spin_unlock_irqrestore(&adc->lock, flags);
> + clk_disable(adc->clk);
> +}
> +
> +static void ingenic_adc_enable(struct ingenic_adc *adc,
> + int engine,
> + bool enabled)
> +{
> + unsigned long flags;
> + u8 val;
> +
> + spin_lock_irqsave(&adc->lock, flags);
> + val = readb(adc->base + JZ_ADC_REG_ENABLE);
> +
> + if (enabled)
> + val |= BIT(engine);
> + else
> + val &= ~BIT(engine);
> +
> + writeb(val, adc->base + JZ_ADC_REG_ENABLE);
> + spin_unlock_irqrestore(&adc->lock, flags);
> +}
> +
> +static int ingenic_adc_capture(struct ingenic_adc *adc,
> + int engine)
> +{
> + u8 val;
> + int ret;
> +
> + ingenic_adc_enable(adc, engine, true);
> + ret = readb_poll_timeout(adc->base + JZ_ADC_REG_ENABLE, val,
> + !(val & BIT(engine)), 250, 1000);
> + if (ret)
> + ingenic_adc_enable(adc, engine, false);
> +
> + return ret;
> +}
> +
> +static int ingenic_adc_write_raw(struct iio_dev *iio_dev,
> + struct iio_chan_spec const *chan,
> + int val,
> + int val2,
> + long m)
> +{
> + struct ingenic_adc *adc = iio_priv(iio_dev);
> +
> + switch (m) {
> + case IIO_CHAN_INFO_SCALE:
> + switch (chan->channel) {
> + case INGENIC_ADC_BATTERY:
> + if (val > BATTERY_LOW_VREF) {
> + ingenic_adc_set_config(adc,
> + REG_CFG_BAT_MD,
> + 0);
> + adc->low_vref_mode = false;
> + } else {
> + ingenic_adc_set_config(adc,
> + REG_CFG_BAT_MD,
> + REG_CFG_BAT_MD);
> + adc->low_vref_mode = true;
> + }
> + return 0;
> + default:
> + return -EINVAL;
> + }
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static const int jz4725b_adc_battery_raw_avail[] = {
> + 0, 1, (1 << BATTERY_LOW_VREF_BITS) - 1,
> +};
> +
> +static const int jz4725b_adc_battery_scale_avail[] = {
> + JZ4725B_BATTERY_HIGH_VREF, JZ4725B_BATTERY_HIGH_VREF_BITS,
> + BATTERY_LOW_VREF, BATTERY_LOW_VREF_BITS,
> +};
> +
> +static const int jz4740_adc_battery_raw_avail[] = {
> + 0, 1, (1 << BATTERY_LOW_VREF_BITS) - 1,
> +};
> +
> +static const int jz4740_adc_battery_scale_avail[] = {
> + JZ4740_BATTERY_HIGH_VREF, JZ4740_BATTERY_HIGH_VREF_BITS,
> + BATTERY_LOW_VREF, BATTERY_LOW_VREF_BITS,
> +};
> +
> +static const struct ingenic_adc_soc_data jz4725b_adc_soc_data = {
> + .battery_high_vref = JZ4725B_BATTERY_HIGH_VREF,
> + .battery_high_vref_bits = JZ4725B_BATTERY_HIGH_VREF_BITS,
> + .battery_raw_avail = jz4725b_adc_battery_raw_avail,
> + .battery_raw_avail_size = ARRAY_SIZE(jz4725b_adc_battery_raw_avail),
> + .battery_scale_avail = jz4725b_adc_battery_scale_avail,
> + .battery_scale_avail_size = ARRAY_SIZE(jz4725b_adc_battery_scale_avail),
> +};
> +
> +static const struct ingenic_adc_soc_data jz4740_adc_soc_data = {
> + .battery_high_vref = JZ4740_BATTERY_HIGH_VREF,
> + .battery_high_vref_bits = JZ4740_BATTERY_HIGH_VREF_BITS,
> + .battery_raw_avail = jz4740_adc_battery_raw_avail,
> + .battery_raw_avail_size = ARRAY_SIZE(jz4740_adc_battery_raw_avail),
> + .battery_scale_avail = jz4740_adc_battery_scale_avail,
> + .battery_scale_avail_size = ARRAY_SIZE(jz4740_adc_battery_scale_avail),
> +};
> +
> +static int ingenic_adc_read_avail(struct iio_dev *iio_dev,
> + struct iio_chan_spec const *chan,
> + const int **vals,
> + int *type,
> + int *length,
> + long m)
> +{
> + struct ingenic_adc *adc = iio_priv(iio_dev);
> +
> + switch (m) {
> + case IIO_CHAN_INFO_RAW:
> + *type = IIO_VAL_INT;
> + *length = adc->soc_data->battery_raw_avail_size;
> + *vals = adc->soc_data->battery_raw_avail;
> + return IIO_AVAIL_RANGE;
> + case IIO_CHAN_INFO_SCALE:
> + *type = IIO_VAL_FRACTIONAL_LOG2;
> + *length = adc->soc_data->battery_scale_avail_size;
> + *vals = adc->soc_data->battery_scale_avail;
> + return IIO_AVAIL_LIST;
> + default:
> + return -EINVAL;
> + };
> +}
> +
> +static int ingenic_adc_read_raw(struct iio_dev *iio_dev,
> + struct iio_chan_spec const *chan,
> + int *val,
> + int *val2,
> + long m)
> +{
> + struct ingenic_adc *adc = iio_priv(iio_dev);
> + int ret;
> +
> + switch (m) {
> + case IIO_CHAN_INFO_RAW:
> + clk_enable(adc->clk);
> + ret = ingenic_adc_capture(adc, chan->channel);
> + if (ret) {
> + clk_disable(adc->clk);
> + return ret;
> + }
> +
> + switch (chan->channel) {
> + case INGENIC_ADC_AUX:
> + *val = readw(adc->base + JZ_ADC_REG_ADSDAT);
> + break;
> + case INGENIC_ADC_BATTERY:
> + *val = readw(adc->base + JZ_ADC_REG_ADBDAT);
> + break;
> + }
> +
> + clk_disable(adc->clk);
> +
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SCALE:
> + switch (chan->channel) {
> + case INGENIC_ADC_AUX:
> + *val = AUX_VREF;
> + *val2 = AUX_VREF_BITS;
> + break;
> + case INGENIC_ADC_BATTERY:
> + if (adc->low_vref_mode) {
> + *val = BATTERY_LOW_VREF;
> + *val2 = BATTERY_LOW_VREF_BITS;
> + } else {
> + *val = adc->soc_data->battery_high_vref;
> + *val2 = adc->soc_data->battery_high_vref_bits;
> + }
> + break;
> + }
> +
> + return IIO_VAL_FRACTIONAL_LOG2;
> + default:
> + return -EINVAL;
> + }
> +}
> +
> +static const struct iio_info ingenic_adc_info = {
> + .write_raw = ingenic_adc_write_raw,
> + .read_raw = ingenic_adc_read_raw,
> + .read_avail = ingenic_adc_read_avail,
> +};
> +
> +static const struct iio_chan_spec ingenic_channels[] = {
> + {
> + .extend_name = "aux",
> + .type = IIO_VOLTAGE,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> + BIT(IIO_CHAN_INFO_SCALE),
> + .indexed = 1,
> + .channel = INGENIC_ADC_AUX,
> + },
> + {
> + .extend_name = "battery",
> + .type = IIO_VOLTAGE,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> + BIT(IIO_CHAN_INFO_SCALE),
> + .info_mask_separate_available = BIT(IIO_CHAN_INFO_RAW) |
> + BIT(IIO_CHAN_INFO_SCALE),
> + .indexed = 1,
> + .channel = INGENIC_ADC_BATTERY,
> + },
> +};
> +
> +static int ingenic_adc_probe(struct platform_device *pdev)
> +{
> + struct iio_dev *iio_dev;
> + struct ingenic_adc *adc;
> + struct resource *mem_base;
> + const struct ingenic_adc_soc_data *soc_data;
> + int ret;
> +
> + soc_data = device_get_match_data(&pdev->dev);
> + if (!soc_data)
> + return -EINVAL;
> +
> + iio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc));
> + if (!iio_dev)
> + return -ENOMEM;
> +
> + adc = iio_priv(iio_dev);
> + spin_lock_init(&adc->lock);
> + adc->soc_data = soc_data;
> +
> + mem_base = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + adc->base = devm_ioremap_resource(&pdev->dev, mem_base);
> + if (IS_ERR(adc->base)) {
> + dev_err(&pdev->dev, "Unable to ioremap mmio resource\n");
> + return PTR_ERR(adc->base);
> + }
> +
> + adc->clk = devm_clk_get(&pdev->dev, "adc");
> + if (IS_ERR(adc->clk)) {
> + dev_err(&pdev->dev, "Unable to get clock\n");
> + return PTR_ERR(adc->clk);
> + }
> +
> + ret = clk_prepare_enable(adc->clk);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to enable clock\n");
> + return ret;
> + }
> +
> + /* Put hardware in a known passive state. */
> + writeb(0x00, adc->base + JZ_ADC_REG_ENABLE);
> + writeb(0xff, adc->base + JZ_ADC_REG_CTRL);
> + clk_disable(adc->clk);
> +
> + devm_add_action(&pdev->dev, (void (*)(void *))clk_unprepare, adc->clk);
Don't cast the function, just have a little wrapper with the right signature.

This can fail. Call devm_add_action_or_reset instead and handle the return value.

> +
> + iio_dev->dev.parent = &pdev->dev;
> + iio_dev->name = "adc";

The name needs to identify this part as opposed to any other ADCs plugged into the
board. I would suggest using jz4725b of jz4740 as appropriate.

> + iio_dev->modes = INDIO_DIRECT_MODE;
> + iio_dev->channels = ingenic_channels;
> + iio_dev->num_channels = ARRAY_SIZE(ingenic_channels);
> + iio_dev->info = &ingenic_adc_info;
> +
> + ret = devm_iio_device_register(&pdev->dev, iio_dev);
> + if (ret) {
> + dev_err(&pdev->dev, "Unable to register IIO device\n");
> + return ret;
> + }
> +
> + return 0;

Drop the return ret out of the brackets above and this isn't needed.

> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id ingenic_adc_of_match[] = {
> + { .compatible = "ingenic,jz4725b-adc", .data = &jz4725b_adc_soc_data, },
> + { .compatible = "ingenic,jz4740-adc", .data = &jz4740_adc_soc_data, },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, ingenic_adc_of_match);
> +#endif
> +
> +static struct platform_driver ingenic_adc_driver = {
> + .driver = {
> + .name = "ingenic-adc",
> + .of_match_table = of_match_ptr(ingenic_adc_of_match),
> + },
> + .probe = ingenic_adc_probe,
> +};
> +module_platform_driver(ingenic_adc_driver);


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