Re: [PATCH v4 2/3] platform: arm64: add Huawei Matebook E Go EC driver

[kernel test robot <lkp@xxxxxxxxx>]

Hi Pengyu,

kernel test robot noticed the following build warnings:

[auto build test WARNING on b323d8e7bc03d27dec646bfdccb7d1a92411f189]

url:    https://github.com/intel-lab-lkp/linux/commits/Pengyu-Luo/dt-bindings-platform-Add-Huawei-Matebook-E-Go-EC/20250116-192206
base:   b323d8e7bc03d27dec646bfdccb7d1a92411f189
patch link:    https://lore.kernel.org/r/20250116111559.83641-3-mitltlatltl%40gmail.com
patch subject: [PATCH v4 2/3] platform: arm64: add Huawei Matebook E Go EC driver
config: sh-allmodconfig (https://download.01.org/0day-ci/archive/20250117/202501171826.NGZwFrgW-lkp@xxxxxxxxx/config)
compiler: sh4-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250117/202501171826.NGZwFrgW-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202501171826.NGZwFrgW-lkp@xxxxxxxxx/

All warnings (new ones prefixed by >>):

   drivers/platform/arm64/huawei-gaokun-ec.c: In function 'extr_resp_shallow':
>> drivers/platform/arm64/huawei-gaokun-ec.c:91:20: warning: return discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
      91 |         return src + RESP_HDR_SIZE;
         |                    ^
   drivers/platform/arm64/huawei-gaokun-ec.c: In function 'gaokun_ec_request':
>> drivers/platform/arm64/huawei-gaokun-ec.c:112:32: warning: initialization discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
     112 |                         .buf = req,
         |                                ^~~


vim +/const +91 drivers/platform/arm64/huawei-gaokun-ec.c

    88	
    89	static inline void *extr_resp_shallow(const u8 *src)
    90	{
  > 91		return src + RESP_HDR_SIZE;
    92	}
    93	
    94	struct gaokun_ec {
    95		struct i2c_client *client;
    96		struct mutex lock; /* EC transaction lock */
    97		struct blocking_notifier_head notifier_list;
    98		struct device *hwmon_dev;
    99		struct input_dev *idev;
   100		bool suspended;
   101	};
   102	
   103	static int gaokun_ec_request(struct gaokun_ec *ec, const u8 *req,
   104				     size_t resp_len, u8 *resp)
   105	{
   106		struct i2c_client *client = ec->client;
   107		struct i2c_msg msgs[2] = {
   108			{
   109				.addr = client->addr,
   110				.flags = client->flags,
   111				.len = REQ_LEN(req),
 > 112				.buf = req,
   113			}, {
   114				.addr = client->addr,
   115				.flags = client->flags | I2C_M_RD,
   116				.len = resp_len,
   117				.buf = resp,
   118			},
   119		};
   120	
   121		guard(mutex)(&ec->lock);
   122		i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
   123		usleep_range(2000, 2500); /* have a break, ACPI did this */
   124	
   125		return *resp ? -EIO : 0;
   126	}
   127	

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