[PATCH 5.10 192/563] backlight: qcom-wled: Override default length with qcom,enabled-strings

From: Greg Kroah-Hartman
Date: Mon Jan 24 2022 - 15:09:04 EST


From: Marijn Suijten <marijn.suijten@xxxxxxxxxxxxxx>

[ Upstream commit 2b4b49602f9feca7b7a84eaa33ad9e666c8aa695 ]

The length of qcom,enabled-strings as property array is enough to
determine the number of strings to be enabled, without needing to set
qcom,num-strings to override the default number of strings when less
than the default (which is also the maximum) is provided in DT.

This also introduces an extra warning when qcom,num-strings is set,
denoting that it is not necessary to set both anymore. It is usually
more concise to set just qcom,num-length when a zero-based, contiguous
range of strings is needed (the majority of the cases), or to only set
qcom,enabled-strings when a specific set of indices is desired.

Fixes: 775d2ffb4af6 ("backlight: qcom-wled: Restructure the driver for WLED3")
Signed-off-by: Marijn Suijten <marijn.suijten@xxxxxxxxxxxxxx>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxxx>
Reviewed-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20211115203459.1634079-6-marijn.suijten@xxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/video/backlight/qcom-wled.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c
index 9e09165984b48..70fcee74866a5 100644
--- a/drivers/video/backlight/qcom-wled.c
+++ b/drivers/video/backlight/qcom-wled.c
@@ -1521,6 +1521,8 @@ static int wled_configure(struct wled *wled)
return -EINVAL;
}
}
+
+ cfg->num_strings = string_len;
}

rc = of_property_read_u32(dev->of_node, "qcom,num-strings", &val);
@@ -1531,9 +1533,13 @@ static int wled_configure(struct wled *wled)
return -EINVAL;
}

- if (string_len > 0 && val > string_len) {
- dev_err(dev, "qcom,num-strings exceeds qcom,enabled-strings\n");
- return -EINVAL;
+ if (string_len > 0) {
+ dev_warn(dev, "Only one of qcom,num-strings or qcom,enabled-strings"
+ " should be set\n");
+ if (val > string_len) {
+ dev_err(dev, "qcom,num-strings exceeds qcom,enabled-strings\n");
+ return -EINVAL;
+ }
}

cfg->num_strings = val;
--
2.34.1