From: David Lechner <dlechner@baylibre.com>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
Jonathan Cameron <jic23@kernel.org>
Cc: "Nuno Sá" <nuno.sa@analog.com>,
"Andy Shevchenko" <andy@kernel.org>,
"Linus Walleij" <linusw@kernel.org>,
"Bartosz Golaszewski" <brgl@kernel.org>,
linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-gpio@vger.kernel.org
Subject: Re: [PATCH v2 3/4] iio: adc: ti-ads7950: switch to using guard() notation
Date: Sat, 21 Feb 2026 11:34:33 -0600 [thread overview]
Message-ID: <0b9e1c9d-9bee-4fc3-ac19-28d969f65ef2@baylibre.com> (raw)
In-Reply-To: <20260219022929.3558081-4-dmitry.torokhov@gmail.com>
On 2/18/26 8:29 PM, Dmitry Torokhov wrote:
> guard() notation allows early returns when encountering errors, making
> control flow more obvious. Use it.
>
> Also variables that now only hold error codes (or 0) are renamed to
> "error" to make their purpose clearer.
>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> ---
> drivers/iio/adc/ti-ads7950.c | 105 ++++++++++++++++-------------------
> 1 file changed, 48 insertions(+), 57 deletions(-)
>
> diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c
> index 2a7d4a1d9fa9..d31397f37ec4 100644
> --- a/drivers/iio/adc/ti-ads7950.c
> +++ b/drivers/iio/adc/ti-ads7950.c
> @@ -306,18 +306,17 @@ static irqreturn_t ti_ads7950_trigger_handler(int irq, void *p)
> struct iio_poll_func *pf = p;
> struct iio_dev *indio_dev = pf->indio_dev;
> struct ti_ads7950_state *st = iio_priv(indio_dev);
> - int ret;
> + int error;
>
> - mutex_lock(&st->slock);
> - ret = spi_sync(st->spi, &st->ring_msg);
> - if (ret < 0)
> - goto out;
> + scoped_guard(mutex, &st->slock) {
> + error = spi_sync(st->spi, &st->ring_msg);
> + if (error)
> + break;
I'm not a fan of scoped_guard() because of the hidden for loop in it.
It hides the fact that the break; is breaking out of that for loop.
It would be more clear/obvious written as:
do {
guard(mutex)(&st->slock);
ret = spi_sync(st->spi, &st->ring_msg);
if (ret)
break;
iio_push_to_buffers_with_timestamp(indio_dev, &st->rx_buf[2],
iio_get_time_ns(indio_dev));
} while (0);
>
> - iio_push_to_buffers_with_timestamp(indio_dev, &st->rx_buf[2],
> - iio_get_time_ns(indio_dev));
> + iio_push_to_buffers_with_timestamp(indio_dev, &st->rx_buf[2],
> + iio_get_time_ns(indio_dev));
> + }
>
> -out:
> - mutex_unlock(&st->slock);
> iio_trigger_notify_done(indio_dev->trig);
>
> return IRQ_HANDLED;
> @@ -326,22 +325,19 @@ static irqreturn_t ti_ads7950_trigger_handler(int irq, void *p)
> static int ti_ads7950_scan_direct(struct iio_dev *indio_dev, unsigned int ch)
> {
> struct ti_ads7950_state *st = iio_priv(indio_dev);
> - int ret, cmd;
> + int error;
> + int cmd;
> +
> + guard(mutex)(&st->slock);
>
> - mutex_lock(&st->slock);
> cmd = TI_ADS7950_MAN_CMD(TI_ADS7950_CR_CHAN(ch));
> st->single_tx = cmd;
>
> - ret = spi_sync(st->spi, &st->scan_single_msg);
> - if (ret)
> - goto out;
> -
> - ret = st->single_rx;
> -
> -out:
> - mutex_unlock(&st->slock);
> + error = spi_sync(st->spi, &st->scan_single_msg);
> + if (error)
> + return error;
>
> - return ret;
> + return st->single_rx;
> }
>
> static int ti_ads7950_get_range(struct ti_ads7950_state *st)
> @@ -407,9 +403,9 @@ static int ti_ads7950_set(struct gpio_chip *chip, unsigned int offset,
> int value)
> {
> struct ti_ads7950_state *st = gpiochip_get_data(chip);
> - int ret;
> + int error;
>
> - mutex_lock(&st->slock);
> + guard(mutex)(&st->slock);
>
> if (value)
> st->cmd_settings_bitmask |= BIT(offset);
> @@ -417,47 +413,44 @@ static int ti_ads7950_set(struct gpio_chip *chip, unsigned int offset,
> st->cmd_settings_bitmask &= ~BIT(offset);
>
> st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);
> - ret = spi_sync(st->spi, &st->scan_single_msg);
> -
> - mutex_unlock(&st->slock);
> + error = spi_sync(st->spi, &st->scan_single_msg);
> + if (error)
> + return error;
>
> - return ret;
> + return 0;
> }
>
> static int ti_ads7950_get(struct gpio_chip *chip, unsigned int offset)
> {
> struct ti_ads7950_state *st = gpiochip_get_data(chip);
> - int ret = 0;
> bool state;
> + int error;
>
> - mutex_lock(&st->slock);
> + guard(mutex)(&st->slock);
>
> /* If set as output, return the output */
> if (st->gpio_cmd_settings_bitmask & BIT(offset)) {
> state = st->cmd_settings_bitmask & BIT(offset);
> - goto out;
> + return state;
This can return directly instead of using local variable.
> }
>
> /* GPIO data bit sets SDO bits 12-15 to GPIO input */
> st->cmd_settings_bitmask |= TI_ADS7950_CR_GPIO_DATA;
> st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);
> - ret = spi_sync(st->spi, &st->scan_single_msg);
> - if (ret)
> - goto out;
> + error = spi_sync(st->spi, &st->scan_single_msg);
> + if (error)
> + return error;
>
> state = (st->single_rx >> 12) & BIT(offset);
>
> /* Revert back to original settings */
> st->cmd_settings_bitmask &= ~TI_ADS7950_CR_GPIO_DATA;
> st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);
> - ret = spi_sync(st->spi, &st->scan_single_msg);
> - if (ret)
> - goto out;
> -
> -out:
> - mutex_unlock(&st->slock);
> + error = spi_sync(st->spi, &st->scan_single_msg);
> + if (error)
> + return error;
>
> - return ret ?: state;
> + return state;
> }
>
> static int ti_ads7950_get_direction(struct gpio_chip *chip,
> @@ -473,9 +466,9 @@ static int _ti_ads7950_set_direction(struct gpio_chip *chip, int offset,
> int input)
> {
> struct ti_ads7950_state *st = gpiochip_get_data(chip);
> - int ret = 0;
> + int error;
>
> - mutex_lock(&st->slock);
> + guard(mutex)(&st->slock);
>
> /* Only change direction if needed */
> if (input && (st->gpio_cmd_settings_bitmask & BIT(offset)))
> @@ -483,15 +476,14 @@ static int _ti_ads7950_set_direction(struct gpio_chip *chip, int offset,
> else if (!input && !(st->gpio_cmd_settings_bitmask & BIT(offset)))
> st->gpio_cmd_settings_bitmask |= BIT(offset);
> else
> - goto out;
> + return 0;
>
> st->single_tx = TI_ADS7950_GPIO_CMD_SETTINGS(st);
> - ret = spi_sync(st->spi, &st->scan_single_msg);
> + error = spi_sync(st->spi, &st->scan_single_msg);
Can just return directly here now.
> + if (error)
> + return error;
>
> -out:
> - mutex_unlock(&st->slock);
> -
> - return ret;
> + return 0;
> }
>
> static int ti_ads7950_direction_input(struct gpio_chip *chip,
> @@ -514,27 +506,26 @@ static int ti_ads7950_direction_output(struct gpio_chip *chip,
>
> static int ti_ads7950_init_hw(struct ti_ads7950_state *st)
> {
> - int ret = 0;
> + int error;
>
> - mutex_lock(&st->slock);
> + guard(mutex)(&st->slock);
>
> /* Settings for Manual/Auto1/Auto2 commands */
> /* Default to 5v ref */
> st->cmd_settings_bitmask = TI_ADS7950_CR_RANGE_5V;
> st->single_tx = TI_ADS7950_MAN_CMD_SETTINGS(st);
> - ret = spi_sync(st->spi, &st->scan_single_msg);
> - if (ret)
> - goto out;
> + error = spi_sync(st->spi, &st->scan_single_msg);
> + if (error)
> + return error;
>
> /* Settings for GPIO command */
> st->gpio_cmd_settings_bitmask = 0x0;
> st->single_tx = TI_ADS7950_GPIO_CMD_SETTINGS(st);
> - ret = spi_sync(st->spi, &st->scan_single_msg);
> -
> -out:
> - mutex_unlock(&st->slock);
> + error = spi_sync(st->spi, &st->scan_single_msg);
And can return directly here.
> + if (error)
> + return error;
>
> - return ret;
> + return 0;
> }
>
> static int ti_ads7950_probe(struct spi_device *spi)
next prev parent reply other threads:[~2026-02-21 17:34 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-19 2:29 [PATCH v2 0/4] ti-ads7950: fix gpio handling and facelift Dmitry Torokhov
2026-02-19 2:29 ` [PATCH v2 1/4] iio: adc: ti-ads7950: normalize return value of gpio_get Dmitry Torokhov
2026-02-19 7:52 ` Andy Shevchenko
2026-02-19 9:17 ` Bartosz Golaszewski
2026-02-19 18:25 ` Linus Walleij
2026-02-22 14:03 ` Jonathan Cameron
2026-02-22 21:22 ` Dmitry Torokhov
2026-02-19 2:29 ` [PATCH v2 2/4] iio: adc: ti-ads7950: do not clobber gpio state in ti_ads7950_get() Dmitry Torokhov
2026-02-19 7:55 ` Andy Shevchenko
2026-02-21 17:21 ` David Lechner
2026-02-19 2:29 ` [PATCH v2 3/4] iio: adc: ti-ads7950: switch to using guard() notation Dmitry Torokhov
2026-02-19 7:51 ` Andy Shevchenko
2026-02-21 17:20 ` David Lechner
2026-02-22 21:31 ` Dmitry Torokhov
2026-02-23 16:35 ` David Lechner
2026-02-21 17:34 ` David Lechner [this message]
2026-02-22 21:37 ` Dmitry Torokhov
2026-02-23 16:31 ` David Lechner
2026-02-19 2:29 ` [PATCH v2 4/4] iio: adc: ti-ads7950: complete conversion to using managed resources Dmitry Torokhov
2026-02-19 7:59 ` Andy Shevchenko
2026-02-21 0:09 ` Dmitry Torokhov
2026-02-22 19:12 ` Andy Shevchenko
2026-02-23 20:52 ` Jonathan Cameron
2026-02-21 17:43 ` David Lechner
2026-02-22 14:09 ` Jonathan Cameron
2026-02-22 21:39 ` Dmitry Torokhov
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