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From: Petre Rodan <petre.rodan@subdimension.ro>
To: linux-iio@vger.kernel.org,
	linux-kernel@vger.kernel.org
Cc: Petre Rodan <petre.rodan@subdimension.ro>,
	Andreas Klinger <ak@it-klinger.de>,
	Jonathan Cameron <jic23@kernel.org>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Angel Iglesias <ang.iglesiasg@gmail.com>,
	Matti Vaittinen <mazziesaccount@gmail.com>
Subject: [PATCH v3 05/10] iio: pressure: mprls0025pa improve driver error resilience
Date: Fri, 29 Dec 2023 11:24:33 +0200
Message-ID: <20231229092445.30180-6-petre.rodan@subdimension.ro>
In-Reply-To: <20231229092445.30180-1-petre.rodan@subdimension.ro>
References: <20231229092445.30180-1-petre.rodan@subdimension.ro>
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Improve driver error resilience by ignoring the measurement if any of
the 3 error flags gets set while interacting with the sensor.
Based on the datasheet, in table 14 on page 14, the status byte
contains:
    bit 5 busy flag - 1 if device is busy
    bit 2 memory integrity/error flag - 1 if integrity test failed
    bit 0 math saturation - 1 if internal math saturation has occurred

Co-developed-by: Andreas Klinger <ak@it-klinger.de>
Signed-off-by: Andreas Klinger <ak@it-klinger.de>
Signed-off-by: Petre Rodan <petre.rodan@subdimension.ro>
---
v2 -> v3 no changes

 drivers/iio/pressure/mprls0025pa.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/pressure/mprls0025pa.c b/drivers/iio/pressure/mprls0025pa.c
index e3f0de020a40..233cc1dc38ad 100644
--- a/drivers/iio/pressure/mprls0025pa.c
+++ b/drivers/iio/pressure/mprls0025pa.c
@@ -39,6 +39,8 @@
 #define MPR_I2C_MEMORY	BIT(2)	/* integrity test passed */
 #define MPR_I2C_MATH	BIT(0)	/* internal math saturation */

+#define MPR_I2C_ERR_FLAG  (MPR_I2C_BUSY | MPR_I2C_MEMORY | MPR_I2C_MATH)
+
 /*
  * support _RAW sysfs interface:
  *
@@ -213,7 +215,7 @@ static int mpr_read_pressure(struct mpr_data *data, s32 *press)
 					status);
 				return status;
 			}
-			if (!(status & MPR_I2C_BUSY))
+			if (!(status & MPR_I2C_ERR_FLAG))
 				break;
 		}
 		if (i == nloops) {
@@ -233,7 +235,7 @@ static int mpr_read_pressure(struct mpr_data *data, s32 *press)
 		return -EIO;
 	}

-	if (buf[0] & MPR_I2C_BUSY) {
+	if (buf[0] & MPR_I2C_ERR_FLAG) {
 		/*
 		 * it should never be the case that status still indicates
 		 * business
--
2.41.0