Currently, if the DT does not define num-interpolated-steps then
num_steps is undefined and the interpolation code will deploy randomly.
Fix with a simple initialize to zero.

Fixes: 573fe6d1c25c ("backlight: pwm_bl: Linear interpolation between brightness-levels")
Reported-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

When you want to change the brightness using a PWM signal, one thing you
need to consider is how human perceive the brightness. Human perceive
the brightness change non-linearly, we have better sensitivity at low
luminance than high luminance, so to achieve perceived linear dimming,
the brightness must be matches to the way our eyes behave. The CIE 1931
lightness formula is what actually describes how we perceive light.

This patch computes a default table with the brightness levels filled
with the numbers provided by the CIE 1931 algorithm, the number of the
brightness levels is calculated based on the PWM resolution.

The calculation of the table using the CIE 1931 algorithm is enabled by
default when you do not define the 'brightness-levels' propriety in your
device tree.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Setting num-interpolated-steps in the dts will allow you to have linear
interpolation between values of brightness-levels. This way a high
resolution pwm duty cycle can be used without having to list out every
possible value in the dts. This system also allows for gamma corrected
values.

The most simple example is interpolate between two brightness values a
number of steps, this can be done setting the following in the dts:

  brightness-levels = <0 65535>;
  num-interpolated-steps = <1024>;
  default-brightness-level = <512>;

This will create a brightness-level table with the following values:

  <0 63 126 189 252 315 378 441 ... 64260 64323 64386 64449 65535>

Another use case can be describe a gamma corrected curve, as we have
better sensitivity at low luminance than high luminance we probably
want have smaller steps for low brightness levels values and bigger
steps for high brightness levels values. This can be achieved with
the following in the dts:

  brightness-levels = <0 4096 65535>;
  num-interpolated-steps = <1024>;
  default-brightness-level = <512>;

This will create a brightness-levels table with the following values:

  <0 4 8 12 16 20 ... 4096 4156 4216 4276 ... 65535>

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

The devm_kzalloc() function has a 2-factor argument form, devm_kcalloc().
This patch replaces cases of:

        devm_kzalloc(handle, a * b, gfp)

with:
        devm_kcalloc(handle, a * b, gfp)

as well as handling cases of:

        devm_kzalloc(handle, a * b * c, gfp)

with:

        devm_kzalloc(handle, array3_size(a, b, c), gfp)

as it's slightly less ugly than:

        devm_kcalloc(handle, array_size(a, b), c, gfp)

This does, however, attempt to ignore constant size factors like:

        devm_kzalloc(handle, 4 * 1024, gfp)

though any constants defined via macros get caught up in the conversion.

Any factors with a sizeof() of "unsigned char", "char", and "u8" were
dropped, since they're redundant.

Some manual whitespace fixes were needed in this patch, as Coccinelle
really liked to write "=devm_kcalloc..." instead of "= devm_kcalloc...".

The Coccinelle script used for this was:

// Fix redundant parens around sizeof().
@@
expression HANDLE;
type TYPE;
expression THING, E;
@@

(
  devm_kzalloc(HANDLE,
-	(sizeof(TYPE)) * E
+	sizeof(TYPE) * E
  , ...)
|
  devm_kzalloc(HANDLE,
-	(sizeof(THING)) * E
+	sizeof(THING) * E
  , ...)
)

// Drop single-byte sizes and redundant parens.
@@
expression HANDLE;
expression COUNT;
typedef u8;
typedef __u8;
@@

(
  devm_kzalloc(HANDLE,
-	sizeof(u8) * (COUNT)
+	COUNT
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(__u8) * (COUNT)
+	COUNT
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(char) * (COUNT)
+	COUNT
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(unsigned char) * (COUNT)
+	COUNT
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(u8) * COUNT
+	COUNT
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(__u8) * COUNT
+	COUNT
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(char) * COUNT
+	COUNT
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(unsigned char) * COUNT
+	COUNT
  , ...)
)

// 2-factor product with sizeof(type/expression) and identifier or constant.
@@
expression HANDLE;
type TYPE;
expression THING;
identifier COUNT_ID;
constant COUNT_CONST;
@@

(
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(TYPE) * (COUNT_ID)
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(TYPE) * COUNT_ID
+	COUNT_ID, sizeof(TYPE)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(TYPE) * (COUNT_CONST)
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(TYPE) * COUNT_CONST
+	COUNT_CONST, sizeof(TYPE)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(THING) * (COUNT_ID)
+	COUNT_ID, sizeof(THING)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(THING) * COUNT_ID
+	COUNT_ID, sizeof(THING)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(THING) * (COUNT_CONST)
+	COUNT_CONST, sizeof(THING)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(THING) * COUNT_CONST
+	COUNT_CONST, sizeof(THING)
  , ...)
)

// 2-factor product, only identifiers.
@@
expression HANDLE;
identifier SIZE, COUNT;
@@

- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	SIZE * COUNT
+	COUNT, SIZE
  , ...)

// 3-factor product with 1 sizeof(type) or sizeof(expression), with
// redundant parens removed.
@@
expression HANDLE;
expression THING;
identifier STRIDE, COUNT;
type TYPE;
@@

(
  devm_kzalloc(HANDLE,
-	sizeof(TYPE) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(TYPE) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(TYPE) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(TYPE) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(TYPE))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(THING) * (COUNT) * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(THING) * (COUNT) * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(THING) * COUNT * (STRIDE)
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(THING) * COUNT * STRIDE
+	array3_size(COUNT, STRIDE, sizeof(THING))
  , ...)
)

// 3-factor product with 2 sizeof(variable), with redundant parens removed.
@@
expression HANDLE;
expression THING1, THING2;
identifier COUNT;
type TYPE1, TYPE2;
@@

(
  devm_kzalloc(HANDLE,
-	sizeof(TYPE1) * sizeof(TYPE2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(THING1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(THING1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(THING1), sizeof(THING2))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(TYPE1) * sizeof(THING2) * COUNT
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
|
  devm_kzalloc(HANDLE,
-	sizeof(TYPE1) * sizeof(THING2) * (COUNT)
+	array3_size(COUNT, sizeof(TYPE1), sizeof(THING2))
  , ...)
)

// 3-factor product, only identifiers, with redundant parens removed.
@@
expression HANDLE;
identifier STRIDE, SIZE, COUNT;
@@

(
  devm_kzalloc(HANDLE,
-	(COUNT) * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  devm_kzalloc(HANDLE,
-	COUNT * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  devm_kzalloc(HANDLE,
-	COUNT * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  devm_kzalloc(HANDLE,
-	(COUNT) * (STRIDE) * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  devm_kzalloc(HANDLE,
-	COUNT * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  devm_kzalloc(HANDLE,
-	(COUNT) * STRIDE * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  devm_kzalloc(HANDLE,
-	(COUNT) * (STRIDE) * (SIZE)
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
|
  devm_kzalloc(HANDLE,
-	COUNT * STRIDE * SIZE
+	array3_size(COUNT, STRIDE, SIZE)
  , ...)
)

// Any remaining multi-factor products, first at least 3-factor products,
// when they're not all constants...
@@
expression HANDLE;
expression E1, E2, E3;
constant C1, C2, C3;
@@

(
  devm_kzalloc(HANDLE, C1 * C2 * C3, ...)
|
  devm_kzalloc(HANDLE,
-	(E1) * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  devm_kzalloc(HANDLE,
-	(E1) * (E2) * E3
+	array3_size(E1, E2, E3)
  , ...)
|
  devm_kzalloc(HANDLE,
-	(E1) * (E2) * (E3)
+	array3_size(E1, E2, E3)
  , ...)
|
  devm_kzalloc(HANDLE,
-	E1 * E2 * E3
+	array3_size(E1, E2, E3)
  , ...)
)

// And then all remaining 2 factors products when they're not all constants,
// keeping sizeof() as the second factor argument.
@@
expression HANDLE;
expression THING, E1, E2;
type TYPE;
constant C1, C2, C3;
@@

(
  devm_kzalloc(HANDLE, sizeof(THING) * C2, ...)
|
  devm_kzalloc(HANDLE, sizeof(TYPE) * C2, ...)
|
  devm_kzalloc(HANDLE, C1 * C2 * C3, ...)
|
  devm_kzalloc(HANDLE, C1 * C2, ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(TYPE) * (E2)
+	E2, sizeof(TYPE)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(TYPE) * E2
+	E2, sizeof(TYPE)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(THING) * (E2)
+	E2, sizeof(THING)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	sizeof(THING) * E2
+	E2, sizeof(THING)
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	(E1) * E2
+	E1, E2
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	(E1) * (E2)
+	E1, E2
  , ...)
|
- devm_kzalloc
+ devm_kcalloc
  (HANDLE,
-	E1 * E2
+	E1, E2
  , ...)
)

Signed-off-by: Kees Cook <keescook@chromium.org>

Two framebuffer device-node names were looked up during probe, but were
only used as flags to indicate the presence of two framebuffer device.

Drop the unused framebuffer name along with a likewise unused device
pointer from the driver data, and update the platform data to pass in
booleans instead of the framebuffer strings. This allows us do drop the
node references acquired during probe, which would otherwise leak.

Note that there are no other in-kernel users of the modified
platform-data fields.

Fixes: 59eb2b5e57ea ("drivers/video/backlight/as3711_bl.c: add OF support")
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Fix child-node lookup during probe, which ended up searching the whole
device tree depth-first starting at the parent rather than just matching
on its children.

This would only cause trouble if the child node is missing while there
is an unrelated node named "backlight" elsewhere in the tree.

Cc: stable <stable@vger.kernel.org>     # 3.7
Fixes: eebfdc17cc6c ("backlight: Add TPS65217 WLED driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Fix child-node lookup during probe, which ended up searching the whole
device tree depth-first starting at the parent rather than just matching
on its children.

To make things worse, the parent mfd node was also prematurely freed,
while the child backlight node was leaked.

Cc: stable <stable@vger.kernel.org>     # 3.9
Fixes: 47ec340cb8e2 ("mfd: max8925: Support dt for backlight")
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Fix child-node lookup during probe, which ended up searching the whole
device tree depth-first starting at the parent rather than just matching
on its children.

To make things worse, the parent mfd node was also prematurely freed.

Cc: stable <stable@vger.kernel.org>     # 3.10
Fixes: 59eb2b5e57ea ("drivers/video/backlight/as3711_bl.c: add OF support")
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Leaking driver internal tracking into the already massively confusing
backlight power tracking is really confusing.

Stop that by allocating a tiny driver private data structure instead.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>