回复: [bug report] ASoC: tas2781: Add tas2781 driver

23 Jun 2023


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-----邮件原件-----
发件人: Dan Carpenter dan.carpenter@linaro.org
发送时间: 2023年6月22日 23:07
收件人: 13916275206@139.com
抄送: alsa-devel@alsa-project.org
主题: [bug report] ASoC: tas2781: Add tas2781 driver
Hello Shenghao Ding,
The patch ef3bcde75d06: "ASoC: tas2781: Add tas2781 driver" from Jun 18,
2023, leads to the following Smatch static checker warning:
sound/soc/codecs/tas2781-i2c.c:651 tasdevice_parse_dt()
   warn: assigning signed to unsigned: 'tas_priv->ndev = ndev'
's32min-s32max'
sound/soc/codecs/tas2781-i2c.c
    602 static void tasdevice_parse_dt(struct tasdevice_priv *tas_priv)
    603 {
    604         struct i2c_client *client = (struct i2c_client
*)tas_priv->client;
    605         unsigned int dev_addrs[TASDEVICE_MAX_CHANNELS];
    606         int rc, i, ndev = 0;
    607
    608         if (tas_priv->isacpi) {
    609                 ndev =
device_property_read_u32_array(&client->dev,
    610                         "ti,audio-slots", NULL, 0);
When we pass NULL to device_property_read_u32_array() then it returns then
number of items.
611                 if (ndev <= 0) {
612                         ndev = 1;
613                         dev_addrs[0] = client->addr;
614                 } else {
615                         ndev = (ndev <

ARRAY_SIZE(dev_addrs))
    616                                 ? ndev :
ARRAY_SIZE(dev_addrs);
    617                         ndev =
device_property_read_u32_array(&client->dev,
                                ^^^^^^^
Smatch is concerned that this value can be negative.  But actually this
sets it
...
to zero, doesn't it?  Is that intentional?  It feels like we should leave
ndev as
...
the number of items.  Or if we want ndev to be zero do "ndev = 0;" on the
next line.
618                                 "ti,audio-slots", dev_addrs,

ndev);
Thanks for your report, correct and add as following:
    		if (ndev <= 0) {
    			ndev = 1;
    			dev_addrs[0] = client->addr;
    		}
One more thing, how to smatch the code in kernel. Where can I find the
guideline?
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619                 }
620
621                 tas_priv->irq_info.irq_gpio =
622

acpi_dev_gpio_irq_get(ACPI_COMPANION(&client->dev), 0);
    623         } else {
    624                 struct device_node *np =
tas_priv->dev->of_node;
    625 #ifdef CONFIG_OF
    626                 const __be32 *reg, *reg_end;
    627                 int len, sw, aw;
    628
    629                 aw = of_n_addr_cells(np);
    630                 sw = of_n_size_cells(np);
    631                 if (sw == 0) {
    632                         reg = (const __be32
*)of_get_property(np,
    633                                 "reg", &len);
    634                         reg_end = reg + len/sizeof(*reg);
    635                         ndev = 0;
    636                         do {
    637                                 dev_addrs[ndev] =
of_read_number(reg, aw);
    638                                 reg += aw;
    639                                 ndev++;
    640                         } while (reg < reg_end);
    641                 } else {
    642                         ndev = 1;
    643                         dev_addrs[0] = client->addr;
    644                 }
    645 #else
    646                 ndev = 1;
    647                 dev_addrs[0] = client->addr;
    648 #endif
    649                 tas_priv->irq_info.irq_gpio = of_irq_get(np, 0);
    650         }
--> 651         tas_priv->ndev = ndev;
                ^^^^^^^^^^^^^^^^^^^^^
Warning
Do I need the casting? ndev is sure to less than or equal to 8 and more than
1, is won't be overflow in unsigned char.
...
652         for (i = 0; i < ndev; i++)
653                 tas_priv->tasdevice[i].dev_addr = dev_addrs[i];
654
655         tas_priv->reset = devm_gpiod_get_optional(&client->dev,
656                         "reset-gpios", GPIOD_OUT_HIGH);


regards,
dan carpenter

回复: [bug report] ASoC: tas2781: Add tas2781 driver

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