From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BDEEFEC5; Mon, 10 Mar 2025 20:26:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741638411; cv=none; b=nkFj/nHxp0Vftvmu4bOEItUTgPuWhMKzp6tagm2WZFm8bVXffxf9HVpiSZi/tOu13CDZ74tc04fc0Ff9Y74i+WtOEtzaMHERvKZSWAsYFlmpN5uN4zuPp+pUktGzTdzaCb9ZaIWZl/5oZE6nm2ZjVSBYMI6U6EIRmQiSbsix+mI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741638411; c=relaxed/simple; bh=6TBv8eUZABNkITVZTddPYa48Ozritmys3dSTxrbdGck=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=CBKpMLi8OoFYUItUepNrLt3uVq0nrm1sBdv1IU6PQT1X3cpz1MaQORcrJm8vji26QdWsQRlPzwl9EYnS1XT2wMErSWNEfCZ5q4LHHDaRe+OAf5ybhS4jIFK7NIQKPvGh8gVFzBss2VLjkzEALXBq9/rAJW5vN4ajANMv5OUiFJE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bSvdsQlG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bSvdsQlG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D6720C4CEE5; Mon, 10 Mar 2025 20:26:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741638411; bh=6TBv8eUZABNkITVZTddPYa48Ozritmys3dSTxrbdGck=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=bSvdsQlGcmGFCLbPdeAK4oIeozGaZPIq9L9QmMQSzy82NsHQ0sQuHiTHqr4WkvJgJ pH6m4rJI6jR7mquxwVkvHRUtImzSwcmlMfrwudfAWhDguJ0adjuyzByHNI8A/FKVxf TpGCdKpVyVCwRc0vNoG6fZsnNkzQUYODo/IWiBaxfYppGE/Q2qEOqW3G13VVC6G4sH mQT4OiMQBQ2YrpHcsStxquf8x/mI7Siy575F0VRl2pmDhAvHVNqBpStQGM2wTpU2CU XCaYxIqHoR4mroxZ3uaCayFmbfYDJO729td5Y2g7bxDevTtf0b4nklugA4frdKNMnq IZ+JcSoHnFGAQ== Date: Mon, 10 Mar 2025 20:26:40 +0000 From: Jonathan Cameron To: Matti Vaittinen Cc: Matti Vaittinen , Lars-Peter Clausen , Nuno Sa , David Lechner , Javier Carrasco , Olivier Moysan , Guillaume Stols , Dumitru Ceclan , Trevor Gamblin , Matteo Martelli , Alisa-Dariana Roman , Andy Shevchenko , =?UTF-8?B?Sm/Do28=?= Paulo =?UTF-8?B?R29uw6dhbHZlcw==?= , AngeloGioacchino Del Regno , linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org Subject: Re: [PATCH v6 06/10] iio: adc: Support ROHM BD79124 ADC Message-ID: <20250310202640.71f7ec1f@jic23-huawei> In-Reply-To: <448f1f3cd05a9798e79a3948f95ada3e4c3483f7.1741610847.git.mazziesaccount@gmail.com> References: <448f1f3cd05a9798e79a3948f95ada3e4c3483f7.1741610847.git.mazziesaccount@gmail.com> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.48; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-iio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 10 Mar 2025 14:56:47 +0200 Matti Vaittinen wrote: > The ROHM BD79124 is a 12-bit, 8-channel, SAR ADC. The ADC supports > an automatic measurement mode, with an alarm interrupt for out-of-window > measurements. The window is configurable for each channel. > > The I2C protocol for manual start of the measurement and data reading is > somewhat peculiar. It requires the master to do clock stretching after > sending the I2C slave-address until the slave has captured the data. > Needless to say this is not well suopported by the I2C controllers. > > Thus the driver does not support the BD79124's manual measurement mode > but implements the measurements using automatic measurement mode relying > on the BD79124's ability of storing latest measurements into register. > > The driver does also support configuring the threshold events for > detecting the out-of-window events. > > The BD79124 keeps asserting IRQ for as long as the measured voltage is > out of the configured window. Thus the driver masks the received event > for a fixed duration (1 second) when an event is handled. This prevents > the user-space from choking on the events > > The ADC input pins can be also configured as general purpose outputs. > Those pins which don't have corresponding ADC channel node in the > device-tree will be controllable as GPO. > > Signed-off-by: Matti Vaittinen The comment below wins the Monday award for the trivial :) > diff --git a/drivers/iio/adc/rohm-bd79124.c b/drivers/iio/adc/rohm-bd79124.c > new file mode 100644 > index 000000000000..f63141daf5e2 > --- /dev/null > +++ b/drivers/iio/adc/rohm-bd79124.c > +static int bd79124_enable_event(struct bd79124_data *data, > + enum iio_event_direction dir, unsigned int channel) > +{ > + int dir_bit = BIT(dir); > + int reg, ret; > + u16 *limit; > + > + guard(mutex)(&data->mutex); > + /* Set channel to be measured */ > + ret = bd79124_start_measurement(data, channel); > + if (ret) > + return ret; > + > + data->alarm_monitored[channel] |= dir_bit; > + > + /* Add the channel to the list of monitored channels */ > + ret = regmap_set_bits(data->map, BD79124_REG_ALERT_CH_SEL, > + BIT(channel)); > + if (ret) > + return ret; > + > + if (dir == IIO_EV_DIR_RISING) { > + limit = &data->alarm_f_limit[channel]; > + reg = BD79124_GET_HIGH_LIMIT_REG(channel); > + } else { > + limit = &data->alarm_f_limit[channel]; > + reg = BD79124_GET_LOW_LIMIT_REG(channel); > + } > + /* > + * Don't write the new limit to the hardware if we are in the > + * rate-limit period. The timer which re-enables the event will set > + * the limit. > + */ > + if (!(data->alarm_suppressed[channel] & dir_bit)) { > + ret = bd79124_write_int_to_reg(data, reg, *limit); > + if (ret) > + return ret; > + } > + > + /* > + * Enable comparator. Trust the regmap cache, no need to check > + * if it was already enabled. > + * > + * We could do this in the hw-init, but there may be users who > + * never enable alarms and for them it makes sense to not > + * enable the comparator at probe. > + */ > + return regmap_set_bits(data->map, BD79124_REG_GEN_CFG, > + BD79124_MASK_DWC_EN); > + Stray blank line. > +} >