kernel/linux.git/include/linux/iio/adc, branch v6.19.11

iio: adc: qcom-vadc-common: fix vadc_scale_fn_type kernel-doc

2025-10-20T17:51:04+00:00

Fix multiple warnings in enum vadc_scale_fn_type by adding a leading '@' to the kernel-doc descriptions. Fixed 14 warnings in this one enum, such as: Warning: include/linux/iio/adc/qcom-vadc-common.h:123 Enum value 'SCALE_DEFAULT' not described in enum 'vadc_scale_fn_type' Warning: ../include/linux/iio/adc/qcom-vadc-common.h:123 Enum value 'SCALE_THERM_100K_PULLUP' not described in enum 'vadc_scale_fn_type' Warning: ../include/linux/iio/adc/qcom-vadc-common.h:123 Enum value 'SCALE_PMIC_THERM' not described in enum 'vadc_scale_fn_type' Also prevent the warning on SCALE_HW_CALIB_INVALID by marking it "private:" so that kernel-doc notation is not needed for it. This leaves only one warning here, which I don't know the appropriate description of: qcom-vadc-common.h:125: warning: Enum value 'SCALE_HW_CALIB_PMIC_THERM_PM7' not described in enum 'vadc_scale_fn_type' Signed-off-by: Randy Dunlap Signed-off-by: Jonathan Cameron

iio: adc: ad_sigma_delta: add SPI offload support

2025-07-13T14:36:25+00:00

Add SPI offload support to the ad_sigma_delta module. When the SPI controller has SPI offload capabilities, the module will now use that for buffered reads instead of the RDY interrupt trigger. Drivers that use the ad_sigma_delta module will have to opt into this by setting supports_spi_offload since each driver will likely need additional changes before SPI offload can be used. This will allow us to gradually enable SPI offload support for each driver. Signed-off-by: David Lechner Reviewed-by: Andy Shevchenko Reviewed-by: Nuno Sá Link: https://patch.msgid.link/20250701-iio-adc-ad7173-add-spi-offload-support-v3-11-42abb83e3dac@baylibre.com Signed-off-by: Jonathan Cameron

iio: adc: ad_sigma_delta: use spi_optimize_message()

2025-07-13T14:36:25+00:00

Use spi_optimize_message() to improve the performance of buffered reads. By setting up the SPI message and pre-optimizing it in the buffer postenable callback, we can reduce overhead during each sample read. A rough estimate shows that this reduced the CPU usage of the interrupt handler thread from 22% to 16% using an EVAL-AD4112ARDZ board on a DE10-Nano (measuring a single channel at the default 6.2 kHz sample rate). Signed-off-by: David Lechner Reviewed-by: Andy Shevchenko Reviewed-by: Nuno Sá Link: https://patch.msgid.link/20250701-iio-adc-ad7173-add-spi-offload-support-v3-8-42abb83e3dac@baylibre.com Signed-off-by: Jonathan Cameron

iio: adc: ad_sigma_delta: use u8 instead of uint8_t

2025-07-13T14:36:25+00:00

Replace uint8_t with u8 in the ad_sigma_delta driver. Technically, uint8_t comes from the C standard library, while u8 is a Linux kernel type. Since we don't use the C standard library in the kernel, we should use the kernel types instead. There is also one instance where int64_t is replaced with s64. Signed-off-by: David Lechner Reviewed-by: Andy Shevchenko Reviewed-by: Nuno Sá Link: https://patch.msgid.link/20250701-iio-adc-ad7173-add-spi-offload-support-v3-3-42abb83e3dac@baylibre.com Signed-off-by: Jonathan Cameron

iio: adc: ad7173: move fwnode_irq_get_byname() call site

2025-02-03T19:15:37+00:00

Move the call to fwnode_irq_get_byname() from the driver-specific ad7173_fw_parse_device_config() to the shared ad_sd_init() function. The main reason for this is that we want struct ad_sigma_delta_info to be static const data that describes the actual ADC chip, not the application-specific configuration or any runtime state. Previously, this struct was being used to pass the IRQ number to the shared ad_sd_init() function. Now, this is replaced by a boolean flag that is set at compile time and the ad_sd_init() function handles looking up the IRQ number instead. This also has the added benefit that if any other drivers need to make use of this in the future, they just have to set the flag and the shared code will take care of the rest rather than duplicating the code in each driver. Signed-off-by: David Lechner Link: https://patch.msgid.link/20250113-iio-adc-ad7313-fix-non-const-info-struct-v4-1-b63be3ecac4a@baylibre.com Signed-off-by: Jonathan Cameron

iio: adc: ad_sigma_delta: Store information about reset sequence length

2024-12-11T19:20:48+00:00

The various chips can be reset using a sequence of SPI transfers with MOSI = 1. The length of such a sequence varies from chip to chip. Store that length in struct ad_sigma_delta_info and replace the respective parameter to ad_sd_reset() with it. Note the ad7192 used to pass 48 as length but the documentation specifies 40 as the required length. Assuming the latter is right. (Using a too long sequence doesn't hurt apart from using a longer spi transfer than necessary, so this is no relevant fix.) The motivation for storing this information is that this is useful to clear a pending R̅D̅Y̅ signal in the next change. Signed-off-by: Uwe Kleine-König Link: https://patch.msgid.link/9750db62fce638bf140ff48172c23bff7f785e5b.1733504533.git.u.kleine-koenig@baylibre.com Signed-off-by: Jonathan Cameron

iio: adc: ad_sigma_delta: Fix a race condition

2024-12-11T19:20:48+00:00

The ad_sigma_delta driver helper uses irq_disable_nosync(). With that one it is possible that the irq handler still runs after the irq_disable_nosync() function call returns. Also to properly synchronize irq disabling in the different threads proper locking is needed and because it's unclear if the irq handler's irq_disable_nosync() call comes first or the one in the enabler's error path, all code locations that disable the irq must check for .irq_dis first to ensure there is exactly one disable call per enable call. So add a spinlock to the struct ad_sigma_delta and use it to synchronize irq enabling and disabling. Also only act in the irq handler if the irq is still enabled. Fixes: af3008485ea0 ("iio:adc: Add common code for ADI Sigma Delta devices") Signed-off-by: Uwe Kleine-König Link: https://patch.msgid.link/9e6def47e2e773e0e15b7a2c29d22629b53d91b1.1733504533.git.u.kleine-koenig@baylibre.com Signed-off-by: Jonathan Cameron

iio: adc: ad_sigma_delta: Add support for reading irq status using a GPIO

2024-12-11T19:20:48+00:00

Some of the ADCs by Analog signal their irq condition on the MISO line. So typically that line is connected to an SPI controller and a GPIO. The GPIO is used as input and the respective interrupt is enabled when the last SPI transfer is completed. Depending on the GPIO controller the toggling MISO line might make the interrupt pending even while it's masked. In that case the irq handler is called immediately after irq_enable() and so before the device actually pulls that line low which results in non-sense values being reported to the upper layers. The only way to find out if the line was actually pulled low is to read the GPIO. (There is a flag in AD7124's status register that also signals if an interrupt was asserted, but reading that register toggles the MISO line and so might trigger another spurious interrupt.) Add the possibility to specify an interrupt GPIO in the machine description in addition to the plain interrupt. This GPIO is used then to check if the irq line is actually active in the irq handler. Signed-off-by: Uwe Kleine-König Link: https://patch.msgid.link/5be9a4cc4dc600ec384c88db01dd661a21506b9c.1733504533.git.u.kleine-koenig@baylibre.com Signed-off-by: Jonathan Cameron

iio: adc: ad_sigma_delta: add tab to align irq_line

2024-12-07T17:47:58+00:00

Align the irq_line field in struct ad_sigma_delta with the other fields. Signed-off-by: David Lechner Link: https://patch.msgid.link/20241122-iio-adc-ad_signal_delta-fix-align-v1-1-d0a071d2dc83@baylibre.com Signed-off-by: Jonathan Cameron

iio: adc: ad_sigma_delta: add disable_one callback

2024-06-25T20:04:32+00:00

Sigma delta ADCs with a sequencer need to disable the previously enabled channel when reading using ad_sigma_delta_single_conversion(). This was done manually in drivers for devices with sequencers. This patch implements handling of single channel disabling after a single conversion. Reviewed-by: Nuno Sa Signed-off-by: Dumitru Ceclan Reviewed-by: David Lechner Link: https://patch.msgid.link/20240607-ad4111-v7-3-97e3855900a0@analog.com Signed-off-by: Jonathan Cameron