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 | 64 ++++++++++++++++++++++++++++--
1 file changed, 61 insertions(+), 3 deletions(-)
diff --git a/drivers/power/supply/sbs-battery.c
b/drivers/power/supply/sbs-battery.c
index 74221b9279a9..49c3508a6b79 100644
--- a/drivers/power/supply/sbs-battery.c
+++ b/drivers/power/supply/sbs-battery.c
@@ -51,6 +51,14 @@ enum {
REG_CHARGE_VOLTAGE,
};
+#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
+
#define REG_ADDR_MANUFACTURE_DATE 0x1B
/* Battery Mode defines */
@@ -224,14 +232,57 @@ static void sbs_disable_charger_broadcasts(struct
sbs_info *chip)
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");
+
if (!chip->is_present && is_present && !chip->charger_broadcasts)
sbs_disable_charger_broadcasts(chip);
@@ -273,7 +324,8 @@ static int sbs_read_string_data_fallback(struct i2c_client
*client, u8 address,
retries_length = chip->i2c_retry_count;
retries_block = chip->i2c_retry_count;
- dev_warn_once(&client->dev, "I2C adapter does not support
I2C_FUNC_SMBUS_READ_BLOCK_DATA.\n");
+ dev_warn_once(&client->dev, "I2C adapter does not support
I2C_FUNC_SMBUS_READ_BLOCK_DATA.\n"
+ "Fallback method does not support PEC.\n");
/* Adapter needs to support these two functions */
if (!i2c_check_functionality(client->adapter,
@@ -336,8 +388,14 @@ static int sbs_read_string_data(struct i2c_client *client,
u8 address, char *val
int retries = chip->i2c_retry_count;
int ret = 0;
- if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_READ_BLOCK_DATA))
- return sbs_read_string_data_fallback(client, address, values);
+ if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_READ_BLOCK_DATA)) {
+ bool pec = client->flags & I2C_CLIENT_PEC;
+ client->flags &= ~I2C_CLIENT_PEC;
+ ret = sbs_read_string_data_fallback(client, address, values);
+ if (pec)
+ client->flags |= I2C_CLIENT_PEC;
+ return ret;
+ }
while (retries > 0) {
ret = i2c_smbus_read_block_data(client, address, values);
--
2.26.2
