From: Eddie James <eajames@linux.ibm.com>
To: linux-iio@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, joel@jms.id.au, pmeerw@pmeerw.net,
lars@metafoo.de, knaack.h@gmx.de, jic23@kernel.org,
Christopher Bostic <cbostic@linux.vnet.ibm.com>,
Eddie James <eajames@linux.ibm.com>
Subject: [PATCH v2 2/3] iio: dps310: Temperature measurement errata
Date: Wed, 8 May 2019 14:35:27 -0500 [thread overview]
Message-ID: <1557344128-690-3-git-send-email-eajames@linux.ibm.com> (raw)
In-Reply-To: <1557344128-690-1-git-send-email-eajames@linux.ibm.com>
From: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Add a manufacturer's suggested workaround to deal with early revisions
of chip that don't indicate correct temperature. Readings can be in the
~60C range when they should be in the ~20's.
Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
drivers/iio/pressure/dps310.c | 51 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 50 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/pressure/dps310.c b/drivers/iio/pressure/dps310.c
index 7afaa88..c42808e 100644
--- a/drivers/iio/pressure/dps310.c
+++ b/drivers/iio/pressure/dps310.c
@@ -221,6 +221,9 @@ static bool dps310_is_writeable_reg(struct device *dev, unsigned int reg)
case DPS310_MEAS_CFG:
case DPS310_CFG_REG:
case DPS310_RESET:
+ case 0x0e:
+ case 0x0f:
+ case 0x62:
return true;
default:
return false;
@@ -237,6 +240,7 @@ static bool dps310_is_volatile_reg(struct device *dev, unsigned int reg)
case DPS310_TMP_B1:
case DPS310_TMP_B2:
case DPS310_MEAS_CFG:
+ case 0x32:
return true;
default:
return false;
@@ -314,7 +318,7 @@ static int dps310_read_raw(struct iio_dev *iio,
.writeable_reg = dps310_is_writeable_reg,
.volatile_reg = dps310_is_volatile_reg,
.cache_type = REGCACHE_RBTREE,
- .max_register = 0x29,
+ .max_register = 0x62,
};
static const struct iio_info dps310_info = {
@@ -322,6 +326,47 @@ static int dps310_read_raw(struct iio_dev *iio,
.write_raw = dps310_write_raw,
};
+/*
+ * Some verions of chip will read temperatures in the ~60C range when
+ * its actually ~20C. This is the manufacturer recommended workaround
+ * to correct the issue.
+ */
+static int dps310_temp_workaround(struct dps310_data *data)
+{
+ int r, reg;
+
+ r = regmap_read(data->regmap, 0x32, ®);
+ if (r < 0)
+ return r;
+
+ /*
+ * If bit 1 is set then the device is okay, and the workaround does not
+ * need to be applied
+ */
+ if (reg & BIT(1))
+ return 0;
+
+ r = regmap_write(data->regmap, 0x0e, 0xA5);
+ if (r < 0)
+ return r;
+
+ r = regmap_write(data->regmap, 0x0f, 0x96);
+ if (r < 0)
+ return r;
+
+ r = regmap_write(data->regmap, 0x62, 0x02);
+ if (r < 0)
+ return r;
+
+ r = regmap_write(data->regmap, 0x0e, 0x00);
+ if (r < 0)
+ return r;
+
+ r = regmap_write(data->regmap, 0x0f, 0x00);
+
+ return r;
+}
+
static int dps310_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -383,6 +428,10 @@ static int dps310_probe(struct i2c_client *client,
if (r < 0)
goto err;
+ r = dps310_temp_workaround(data);
+ if (r < 0)
+ return r;
+
r = devm_iio_device_register(&client->dev, iio);
if (r)
goto err;
--
1.8.3.1
next prev parent reply other threads:[~2019-05-08 19:36 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-08 19:35 [PATCH v2 0/3] iio: Add driver for Infineon DPS310 Eddie James
2019-05-08 19:35 ` [PATCH v2 1/3] " Eddie James
2019-05-11 9:22 ` Jonathan Cameron
2019-05-15 18:46 ` Eddie James
2019-05-18 8:46 ` Jonathan Cameron
2019-05-08 19:35 ` Eddie James [this message]
2019-05-09 3:09 ` [PATCH v2 2/3] iio: dps310: Temperature measurement errata Matt Ranostay
2019-05-09 15:17 ` Eddie James
2019-05-10 2:21 ` Matt Ranostay
2019-05-08 19:35 ` [PATCH v2 3/3] iio: dps310: Add pressure sensing capability Eddie James
2019-05-11 9:48 ` Jonathan Cameron
2019-05-14 20:25 ` Eddie James
2019-05-18 8:47 ` Jonathan Cameron
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