[PATCH 5/5] leds: lp8860: Do not always program EEPROM on probe

[Andrew Davis]

The EEPROM has limited writes and the contents might have factory set
values that should not be changed. The values currently written by this
driver are just one example of values, but might not be correct for many
use-cases. Do not overwrite the EEPROM with these example values every
probe.

At some point it would be better to populate the content of the EEPROM
based on a configuration provided by the user and check that the values
in EEPROM are not already the same to avoid unneeded write cycles.

That configuration would depend on how the device is used on the board to
which it is attached, for that Device Tree might be the right way. Until a
method can be devised, gate the EEPROM writing behind a module param.

Reported-by: David Owens <daowens01@xxxxxxxxx>
Signed-off-by: Andrew Davis <afd@xxxxxx>
---
 drivers/leds/leds-lp8860.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/leds/leds-lp8860.c b/drivers/leds/leds-lp8860.c
index 6d1c9434e6d17..7a436861c4b71 100644
--- a/drivers/leds/leds-lp8860.c
+++ b/drivers/leds/leds-lp8860.c
@@ -97,6 +97,16 @@ struct lp8860_led {
 	struct regmap *regmap;
 };
 
+static bool program_eeprom;
+module_param(program_eeprom, bool, 0644);
+MODULE_PARM_DESC(program_eeprom, "Program the configuration EEPROM on device startup");
+
+/*
+ * EEPROM bits are intended to be set/programmed before normal operation only
+ * once during silicon production, but can be reprogrammed for evaluation purposes
+ * up to 1000 cycles. To program this EEPROM using this driver, update the below
+ * table and set the module param "program_eeprom" to 1
+ */
 static const struct reg_sequence lp8860_eeprom_disp_regs[] = {
 	{ LP8860_EEPROM_REG_0, 0xed },
 	{ LP8860_EEPROM_REG_1, 0xdf },
@@ -302,9 +312,11 @@ static int lp8860_probe(struct i2c_client *client)
 		return ret;
 	}
 
-	ret = lp8860_program_eeprom(led);
-	if (ret)
-		return ret;
+	if (program_eeprom) {
+		ret = lp8860_program_eeprom(led);
+		if (ret)
+			return ret;
+	}
 
 	init_data.fwnode = of_fwnode_handle(child_node);
 	init_data.devicename = LP8860_NAME;
-- 
2.39.2