Hi Dan,
Thanks for the report, I'll fix the bug as soon as possible.
Regards,
Flavio
> -----Original Message-----
> From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Sent: Tuesday, November 28, 2023 8:20 AM
> To: Flavio Suligoi <f.suligoi@xxxxxxx>
> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
> Subject: [bug report] backlight: mp3309c: Add support for MPS MP3309C
>
> Hello Flavio Suligoi,
>
> The patch 2e914516a58c: "backlight: mp3309c: Add support for MPS
> MP3309C" from Nov 16, 2023 (linux-next), leads to the following
> Smatch static checker warning:
>
> drivers/video/backlight/mp3309c.c:277 pm3309c_parse_dt_node()
> error: uninitialized symbol 'prop_levels'.
>
> drivers/video/backlight/mp3309c.c
> 202 static int pm3309c_parse_dt_node(struct mp3309c_chip *chip,
> 203 struct mp3309c_platform_data
> *pdata)
> 204 {
> 205 struct device_node *node = chip->dev->of_node;
> 206 struct property *prop_pwms, *prop_levels;
> 207 int length = 0;
> 208 int ret, i;
> 209 unsigned int num_levels, tmp_value;
> 210
> 211 if (!node) {
> 212 dev_err(chip->dev, "failed to get DT node\n");
> 213 return -ENODEV;
> 214 }
> 215
> 216 /*
> 217 * Dimming mode: the MP3309C provides two dimming
> control mode:
> 218 *
> 219 * - PWM mode
> 220 * - Analog by I2C control mode (default)
> 221 *
> 222 * I2C control mode is assumed as default but, if the
> pwms property is
> 223 * found in the backlight node, the mode switches to PWM
> mode.
> 224 */
> 225 pdata->dimming_mode = DIMMING_ANALOG_I2C;
> 226 prop_pwms = of_find_property(node, "pwms", &length);
> 227 if (prop_pwms) {
> 228 chip->pwmd = devm_pwm_get(chip->dev, NULL);
> 229 if (IS_ERR(chip->pwmd))
> 230 return dev_err_probe(chip->dev,
> PTR_ERR(chip->pwmd),
> 231 "error getting pwm
> data\n");
> 232 pdata->dimming_mode = DIMMING_PWM;
> 233 pwm_apply_args(chip->pwmd);
> 234 }
> 235
> 236 /*
> 237 * In I2C control mode the dimming levels (0..31) are
> fixed by the
> 238 * hardware, while in PWM control mode they can be
> chosen by the user,
> 239 * to allow nonlinear mappings.
> 240 */
> 241 if (pdata->dimming_mode == DIMMING_ANALOG_I2C) {
> 242 /*
> 243 * Analog (by I2C commands) control mode: fixed
> 0..31 brightness
> 244 * levels
> 245 */
> 246 num_levels = ANALOG_I2C_NUM_LEVELS;
> 247
> 248 /* Enable GPIO used in I2C dimming mode only */
> 249 chip->enable_gpio = devm_gpiod_get(chip->dev,
> "enable",
> 250
> GPIOD_OUT_HIGH);
> 251 if (IS_ERR(chip->enable_gpio))
> 252 return dev_err_probe(chip->dev,
> 253 PTR_ERR(chip-
> >enable_gpio),
> 254 "error getting
> enable gpio\n");
>
> prop_levels not initialized on this path.
>
> 255 } else {
> 256 /*
> 257 * PWM control mode: check for brightness level
> in DT
> 258 */
> 259 prop_levels = of_find_property(node,
> "brightness-levels",
> 260 &length);
> 261 if (prop_levels) {
> 262 /* Read brightness levels from DT */
> 263 num_levels = length / sizeof(u32);
> 264 if (num_levels < 2)
> 265 return -EINVAL;
> 266 } else {
> 267 /* Use default brightness levels */
> 268 num_levels =
> MP3309C_PWM_DEFAULT_NUM_LEVELS;
> 269 }
> 270 }
> 271
> 272 /* Fill brightness levels array */
> 273 pdata->levels = devm_kcalloc(chip->dev, num_levels,
> 274 sizeof(*pdata->levels),
> GFP_KERNEL);
> 275 if (!pdata->levels)
> 276 return -ENOMEM;
> --> 277 if (prop_levels) {
> ^^^^^^^^^^^
> Uninitialized
>
> 278 ret = of_property_read_u32_array(node,
> "brightness-levels",
> 279 pdata->levels,
> 280 num_levels);
> 281 if (ret < 0)
> 282 return ret;
> 283 } else {
> 284 for (i = 0; i < num_levels; i++)
> 285 pdata->levels[i] = i;
> 286 }
> 287
> 288 pdata->max_brightness = num_levels - 1;
> 289
> 290 ret = of_property_read_u32(node, "default-brightness",
> 291 &pdata->default_brightness);
> 292 if (ret)
> 293 pdata->default_brightness = pdata-
> >max_brightness;
> 294 if (pdata->default_brightness > pdata->max_brightness) {
> 295 dev_err(chip->dev,
> 296 "default brightness exceeds max
> brightness\n");
> 297 pdata->default_brightness = pdata-
> >max_brightness;
> 298 }
> 299
> 300 /*
>
> regards,
> dan carpenter
