On Fri, 05 Jul 2024 15:42:24 +0200 Thomas Bonnefille <thomas.bonnefille@xxxxxxxxxxx> wrote: > This adds a driver for the common Sophgo SARADC. > > Signed-off-by: Thomas Bonnefille <thomas.bonnefille@xxxxxxxxxxx> Some more minor feedback inline. Thanks, Jonathan > diff --git a/drivers/iio/adc/sophgo-cv18xx-adc.c b/drivers/iio/adc/sophgo-cv18xx-adc.c > new file mode 100644 > index 000000000000..dd1188b1923e > --- /dev/null > +++ b/drivers/iio/adc/sophgo-cv18xx-adc.c > @@ -0,0 +1,195 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > +/* > + * Sophgo CV18XX series SARADC Driver > + * > + * Copyright (C) Bootlin 2024 > + * Author: Thomas Bonnefille <thomas.bonnefille@xxxxxxxxxxx> > + */ > + > +#include <linux/clk.h> > +#include <linux/completion.h> > +#include <linux/dev_printk.h> > +#include <linux/interrupt.h> > +#include <linux/iio/iio.h> > +#include <linux/iopoll.h> > +#include <linux/mod_devicetable.h> > +#include <linux/module.h> > +#include <linux/mutex.h> > +#include <linux/platform_device.h> > + > +#define CV18XX_ADC_CTRL_REG 0x04 > +#define CV18XX_ADC_EN BIT(0) > +#define CV18XX_ADC_SEL(x) BIT((x)+4) BIT((x) + 4) > +#define CV18XX_ADC_STATUS_REG 0x08 > +#define CV18XX_ADC_BUSY BIT(0) > +#define CV18XX_ADC_CYC_SET_REG 0x0C > +#define CV18XX_ADC_DEF_CYC_SETTINGS 0xF1F0F I'd prefer to see that broken up into fields if we have any info on what they are. > +#define CV18XX_ADC_CH_RESULT_REG(x) (0x10+4*(x)) (0x10 + 4 * (x)) code style also applies in macros. > +#define CV18XX_ADC_CH_RESULT 0xfff GENMASK(11, 0) > +#define CV18XX_ADC_CH_VALID BIT(15) > +#define CV18XX_ADC_INTR_EN_REG 0x20 > +#define CV18XX_ADC_INTR_CLR_REG 0x24 > +#define CV18XX_ADC_INTR_STA_REG 0x28 > > + > +static int cv18xx_adc_read_raw(struct iio_dev *indio_dev, > + struct iio_chan_spec const *chan, > + int *val, int *val2, long mask) > +{ > + switch (mask) { > + case IIO_CHAN_INFO_RAW: { > + struct cv18xx_adc *saradc = iio_priv(indio_dev); > + u32 sample; > + int ret; > + > + scoped_guard(mutex, &saradc->lock) { > + cv18xx_adc_start_measurement(saradc, chan->scan_index); > + ret = cv18xx_adc_wait(saradc); > + if (ret < 0) > + return ret; > + > + sample = readl(saradc->regs + CV18XX_ADC_CH_RESULT_REG(chan->scan_index)); > + } > + if (!(sample & CV18XX_ADC_CH_VALID)) > + return -ENODATA; > + > + *val = sample & CV18XX_ADC_CH_RESULT; > + return IIO_VAL_INT; } > + case IIO_CHAN_INFO_SCALE: > + *val = 3300; > + *val2 = 12; > + return IIO_VAL_FRACTIONAL_LOG2; > + default: > + return -EINVAL; > + } > +} > + > +static irqreturn_t cv18xx_adc_interrupt_handler(int irq, void *private) > +{ > + struct cv18xx_adc *saradc = private; > + > + if (!(readl(saradc->regs + CV18XX_ADC_INTR_STA_REG) & BIT(0))) Add a define for that BIT(0) and use FIELD_GET() to extract it. > + return IRQ_NONE; > + > + writel(1, saradc->regs + CV18XX_ADC_INTR_CLR_REG); Add a define for the 1 here (I guess it's BIT(0)?) as well to show what is logically being cleared rather than simply the register value. > + complete(&saradc->completion); > + return IRQ_HANDLED; > +} > + > +static const struct iio_info cv18xx_adc_info = { > + .read_raw = &cv18xx_adc_read_raw, > +}; > + > +static int cv18xx_adc_probe(struct platform_device *pdev) > +{ > + struct cv18xx_adc *saradc; > + struct iio_dev *indio_dev; > + int ret; > + > + indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*saradc)); > + if (!indio_dev) > + return -ENOMEM; > + > + saradc = iio_priv(indio_dev); > + indio_dev->name = "sophgo-cv18xx-adc"; > + indio_dev->modes = INDIO_DIRECT_MODE; > + indio_dev->info = &cv18xx_adc_info; > + indio_dev->num_channels = ARRAY_SIZE(sophgo_channels); > + indio_dev->channels = sophgo_channels; > + One blank line is almost always enough for readability and if you use too many we get less code on the screen and hence it hurts readability a little. > + > + if (IS_ERR(devm_clk_get_optional_enabled(&pdev->dev, NULL))) > + dev_dbg(&pdev->dev, "Can't get clock from device tree, using No-Die domain"); Failure to get a clock is an error and you should exit with a suitable dev_err_probe(). Getting a NULL answer from this call reflects that one wasn't provided and your handling here would be appropriate for that. > + > + saradc->regs = devm_platform_ioremap_resource(pdev, 0); > + if (IS_ERR(saradc->regs)) { > + ret = PTR_ERR(saradc->regs); > + return ret; return PTR_ERR(saradc->regs); and drop the brackets. > + } > + > + saradc->irq = platform_get_irq_optional(pdev, 0); > + if (saradc->irq >= 0) { > + init_completion(&saradc->completion); > + ret = devm_request_irq(&pdev->dev, saradc->irq, > + cv18xx_adc_interrupt_handler, 0, > + dev_name(&pdev->dev), saradc); Where it isn't limited by line length, preferred style is to align to just after the opening bracket. e.g. ret = devm_request_irq(&pdev->dev, saradc->irq, cv18xx_adc_interrupt_handler, 0, dev_name(&pdev->dev), saradc); > + if (ret) > + return ret; > + > + writel(1, saradc->regs + CV18XX_ADC_INTR_EN_REG); > + Drop this blank line. > + } One blank here is plenty. > + > + > + mutex_init(&saradc->lock); Whilst mutex cleanup is of dubious benefit as only helpful if doing particularly forms of mutex debugging and looking for use after free etc, we do finally have devm_mutex_init() to make it easy so for new code I'm going to encourage it's use but not insist on it yet... ret = devm_mutex_init(&saradc->lock); if (ret) return; > + platform_set_drvdata(pdev, indio_dev); > + writel(CV18XX_ADC_DEF_CYC_SETTINGS, saradc->regs + CV18XX_ADC_CYC_SET_REG); > + ret = devm_iio_device_register(&pdev->dev, indio_dev); > + if (ret) > + return ret; > + > + return 0; return devm_iio_device_register(). > +}