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authorPatrick Rudolph <patrick.rudolph@9elements.com>2023-08-17 12:25:26 +0300
committerGuenter Roeck <linux@roeck-us.net>2023-08-21 16:04:31 +0300
commite7593bda6a2e2e46521567f0ddea940f4acda0db (patch)
tree2ca4353050fd66d2c7792c83e60ddabc6fc452d4 /drivers/hwmon
parent3fd2188e588ffd8d45df5ac92ab1089328211a86 (diff)
downloadlinux-e7593bda6a2e2e46521567f0ddea940f4acda0db.tar.xz
hwmon: pmbus: Fix -EIO seen on pli1209
After doing performance optimizations the pli1209 driver failed to probe with a probabilty of 2%. It wasn't able to read the PMBUS_OPERATION register due to an -EIO error. An investigation showed that the PLI1209 takes 230 usec to execute the CLEAR_FAULTS command. During that time it's busy and NACKs all requests on the SMBUS interface. It also NACKs reads on PMBUS_STATUS_BYTE making it impossible to poll the BUSY flag. Add a custom write_data function to just wait for not BUSY unconditionally after sending a CLEAR_FAULTS command. TEST: Verified using an I2C bus analyser that no more NACKs are seen after sending a CLEAR_FAULTS command. Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com> Link: https://lore.kernel.org/r/20230817092527.808631-3-Naresh.Solanki@9elements.com Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon')
-rw-r--r--drivers/hwmon/pmbus/pli1209bc.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/hwmon/pmbus/pli1209bc.c b/drivers/hwmon/pmbus/pli1209bc.c
index 7d8bd3167b21..c95433790b11 100644
--- a/drivers/hwmon/pmbus/pli1209bc.c
+++ b/drivers/hwmon/pmbus/pli1209bc.c
@@ -5,6 +5,7 @@
* Copyright (c) 2022 9elements GmbH
*/
+#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/pmbus.h>
@@ -53,6 +54,30 @@ static int pli1209bc_read_word_data(struct i2c_client *client, int page,
}
}
+static int pli1209bc_write_byte(struct i2c_client *client, int page, u8 reg)
+{
+ int ret;
+
+ switch (reg) {
+ case PMBUS_CLEAR_FAULTS:
+ ret = pmbus_write_byte(client, page, reg);
+ /*
+ * PLI1209 takes 230 usec to execute the CLEAR_FAULTS command.
+ * During that time it's busy and NACKs all requests on the
+ * SMBUS interface. It also NACKs reads on PMBUS_STATUS_BYTE
+ * making it impossible to poll the BUSY flag.
+ *
+ * Just wait for not BUSY unconditionally.
+ */
+ usleep_range(250, 300);
+ break;
+ default:
+ ret = -ENODATA;
+ break;
+ }
+ return ret;
+}
+
#if IS_ENABLED(CONFIG_SENSORS_PLI1209BC_REGULATOR)
static const struct regulator_desc pli1209bc_reg_desc = {
.name = "vout2",
@@ -102,6 +127,7 @@ static struct pmbus_driver_info pli1209bc_info = {
| PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
| PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_INPUT,
.read_word_data = pli1209bc_read_word_data,
+ .write_byte = pli1209bc_write_byte,
#if IS_ENABLED(CONFIG_SENSORS_PLI1209BC_REGULATOR)
.num_regulators = 1,
.reg_desc = &pli1209bc_reg_desc,