[PATCH] leds: qcom-lpg: allocate channels with main struct

Rosen Penev
2026-03-30T21:19:03Z

Use a flexible array member to combine kzalloc and kcalloc. This
required moving the struct lpg_channel definition up as flexible array
members require a full definition.

Add __counted_by for extra runtime analysis.

Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
drivers/leds/rgb/leds-qcom-lpg.c | 117 +++++++++++++++----------------
1 file changed, 56 insertions(+), 61 deletions(-)

diff --git a/drivers/leds/rgb/leds-qcom-lpg.c b/drivers/leds/rgb/leds-qcom-lpg.c
index f6061c47f863..83cedf4a0cbf 100644
--- a/drivers/leds/rgb/leds-qcom-lpg.c
+++ b/drivers/leds/rgb/leds-qcom-lpg.c
@@ -80,58 +80,8 @@
#define SDAM_PAUSE_HI_MULTIPLIER_OFFSET 0x8
#define SDAM_PAUSE_LO_MULTIPLIER_OFFSET 0x9

-struct lpg_channel;
struct lpg_data;

-/**
- * struct lpg - LPG device context
- * @dev: pointer to LPG device
- * @map: regmap for register access
- * @lock: used to synchronize LED and pwm callback requests
- * @pwm: PWM-chip object, if operating in PWM mode
- * @data: reference to version specific data
- * @lut_base: base address of the LUT block (optional)
- * @lut_size: number of entries in the LUT block
- * @lut_bitmap: allocation bitmap for LUT entries
- * @pbs_dev: PBS device
- * @lpg_chan_sdam: LPG SDAM peripheral device
- * @lut_sdam: LUT SDAM peripheral device
- * @pbs_en_bitmap: bitmap for tracking PBS triggers
- * @triled_base: base address of the TRILED block (optional)
- * @triled_src: power-source for the TRILED
- * @triled_has_atc_ctl: true if there is TRI_LED_ATC_CTL register
- * @triled_has_src_sel: true if there is TRI_LED_SRC_SEL register
- * @channels: list of PWM channels
- * @num_channels: number of @channels
- */
-struct lpg {
- struct device *dev;
- struct regmap *map;
-
- struct mutex lock;
-
- struct pwm_chip *pwm;
-
- const struct lpg_data *data;
-
- u32 lut_base;
- u32 lut_size;
- unsigned long *lut_bitmap;
-
- struct pbs_dev *pbs_dev;
- struct nvmem_device *lpg_chan_sdam;
- struct nvmem_device *lut_sdam;
- unsigned long pbs_en_bitmap;
-
- u32 triled_base;
- u32 triled_src;
- bool triled_has_atc_ctl;
- bool triled_has_src_sel;
-
- struct lpg_channel *channels;
- unsigned int num_channels;
-};
-
/**
* struct lpg_channel - per channel data
* @lpg: reference to parent lpg
@@ -216,6 +166,55 @@ struct lpg_led {
struct lpg_channel *channels[] __counted_by(num_channels);
};

+/**
+ * struct lpg - LPG device context
+ * @dev: pointer to LPG device
+ * @map: regmap for register access
+ * @lock: used to synchronize LED and pwm callback requests
+ * @pwm: PWM-chip object, if operating in PWM mode
+ * @data: reference to version specific data
+ * @lut_base: base address of the LUT block (optional)
+ * @lut_size: number of entries in the LUT block
+ * @lut_bitmap: allocation bitmap for LUT entries
+ * @pbs_dev: PBS device
+ * @lpg_chan_sdam: LPG SDAM peripheral device
+ * @lut_sdam: LUT SDAM peripheral device
+ * @pbs_en_bitmap: bitmap for tracking PBS triggers
+ * @triled_base: base address of the TRILED block (optional)
+ * @triled_src: power-source for the TRILED
+ * @triled_has_atc_ctl: true if there is TRI_LED_ATC_CTL register
+ * @triled_has_src_sel: true if there is TRI_LED_SRC_SEL register
+ * @channels: list of PWM channels
+ * @num_channels: number of @channels
+ */
+struct lpg {
+ struct device *dev;
+ struct regmap *map;
+
+ struct mutex lock;
+
+ struct pwm_chip *pwm;
+
+ const struct lpg_data *data;
+
+ u32 lut_base;
+ u32 lut_size;
+ unsigned long *lut_bitmap;
+
+ struct pbs_dev *pbs_dev;
+ struct nvmem_device *lpg_chan_sdam;
+ struct nvmem_device *lut_sdam;
+ unsigned long pbs_en_bitmap;
+
+ u32 triled_base;
+ u32 triled_src;
+ bool triled_has_atc_ctl;
+ bool triled_has_src_sel;
+
+ unsigned int num_channels;
+ struct lpg_channel channels[] __counted_by(num_channels);
+};
+
/**
* struct lpg_channel_data - per channel initialization data
* @sdam_offset: Channel offset in LPG SDAM
@@ -1475,12 +1474,6 @@ static int lpg_init_channels(struct lpg *lpg)
struct lpg_channel *chan;
int i;

- lpg->num_channels = data->num_channels;
- lpg->channels = devm_kcalloc(lpg->dev, data->num_channels,
- sizeof(struct lpg_channel), GFP_KERNEL);
- if (!lpg->channels)
- return -ENOMEM;
-
for (i = 0; i < data->num_channels; i++) {
chan = &lpg->channels[i];

@@ -1603,18 +1596,20 @@ static int lpg_init_sdam(struct lpg *lpg)

static int lpg_probe(struct platform_device *pdev)
{
+ const struct lpg_data *data;
struct lpg *lpg;
int ret;
int i;

- lpg = devm_kzalloc(&pdev->dev, sizeof(*lpg), GFP_KERNEL);
+ data = of_device_get_match_data(&pdev->dev);
+ if (!data)
+ return -EINVAL;
+
+ lpg = devm_kzalloc(&pdev->dev, struct_size(lpg, channels, data->num_channels), GFP_KERNEL);
if (!lpg)
return -ENOMEM;

- lpg->data = of_device_get_match_data(&pdev->dev);
- if (!lpg->data)
- return -EINVAL;
-
+ lpg->num_channels = data->num_channels;
lpg->dev = &pdev->dev;
mutex_init(&lpg->lock);

--
2.53.0