SBS batteries optionally have support for PEC. This enables
PEC handling based on the implemented SBS version as suggested
by the standard. The support for PEC is re-evaluated when the
battery is hotplugged into the system, since there might be
systems supporting batteries from different SBS generations.
Signed-off-by: Sebastian Reichel <sebastian.reic...@collabora.com>
---
drivers/power/supply/sbs-battery.c | 72 ++++++++++++++++++++++++++++--
1 file changed, 69 insertions(+), 3 deletions(-)
diff --git a/drivers/power/supply/sbs-battery.c
b/drivers/power/supply/sbs-battery.c
index a9a1d28dabbe..ab774d491269 100644
--- a/drivers/power/supply/sbs-battery.c
+++ b/drivers/power/supply/sbs-battery.c
@@ -46,6 +46,14 @@ enum {
REG_MODEL_NAME,
};
+#define REG_ADDR_SPEC_INFO 0x1A
+#define SPEC_INFO_VERSION_MASK GENMASK(7, 4)
+#define SPEC_INFO_VERSION_SHIFT 4
+
+#define SBS_VERSION_1_0 1
+#define SBS_VERSION_1_1 2
+#define SBS_VERSION_1_1_WITH_PEC 3
+
/* Battery Mode defines */
#define BATTERY_MODE_OFFSET 0x03
#define BATTERY_MODE_CAPACITY_MASK BIT(15)
@@ -175,6 +183,64 @@ static char model_name[I2C_SMBUS_BLOCK_MAX + 1];
static char manufacturer[I2C_SMBUS_BLOCK_MAX + 1];
static bool force_load;
+static int sbs_update_presence(struct sbs_info *chip, bool is_present)
+{
+ struct i2c_client *client = chip->client;
+ int retries = chip->i2c_retry_count;
+ s32 ret = 0;
+ u8 version;
+
+ if (chip->is_present == is_present)
+ return 0;
+
+ if (!is_present) {
+ chip->is_present = false;
+ /* Disable PEC when no device is present */
+ client->flags &= ~I2C_CLIENT_PEC;
+ return 0;
+ }
+
+ /* Check if device supports packet error checking and use it */
+ while (retries > 0) {
+ ret = i2c_smbus_read_word_data(client, REG_ADDR_SPEC_INFO);
+ if (ret >= 0)
+ break;
+
+ /*
+ * Some batteries trigger the detection pin before the
+ * I2C bus is properly connected. This works around the
+ * issue.
+ */
+ msleep(100);
+
+ retries--;
+ }
+
+ if (ret < 0) {
+ dev_dbg(&client->dev, "failed to read spec info: %d\n", ret);
+
+ /* fallback to old behaviour */
+ client->flags &= ~I2C_CLIENT_PEC;
+ chip->is_present = true;
+
+ return ret;
+ }
+
+ version = (ret & SPEC_INFO_VERSION_MASK) >> SPEC_INFO_VERSION_SHIFT;
+
+ if (version == SBS_VERSION_1_1_WITH_PEC)
+ client->flags |= I2C_CLIENT_PEC;
+ else
+ client->flags &= ~I2C_CLIENT_PEC;
+
+ dev_dbg(&client->dev, "PEC: %s\n", (client->flags & I2C_CLIENT_PEC) ?
+ "enabled" : "disabled");
+
+ chip->is_present = true;
+
+ return 0;
+}
+
static int sbs_read_word_data(struct i2c_client *client, u8 address)
{
struct sbs_info *chip = i2c_get_clientdata(client);
@@ -579,7 +645,7 @@ static int sbs_get_property(struct power_supply *psy,
return ret;
if (psp == POWER_SUPPLY_PROP_PRESENT) {
val->intval = ret;
- chip->is_present = val->intval;
+ sbs_update_presence(chip, ret);
return 0;
}
if (ret == 0)
@@ -678,7 +744,7 @@ static int sbs_get_property(struct power_supply *psy,
if (!chip->gpio_detect &&
chip->is_present != (ret >= 0)) {
- chip->is_present = (ret >= 0);
+ sbs_update_presence(chip, (ret >= 0));
power_supply_changed(chip->power_supply);
}
@@ -709,7 +775,7 @@ static void sbs_supply_changed(struct sbs_info *chip)
ret = gpiod_get_value_cansleep(chip->gpio_detect);
if (ret < 0)
return;
- chip->is_present = ret;
+ sbs_update_presence(chip, ret);
power_supply_changed(battery);
}
--
2.26.2
