Author: Julia Lawall <julia@diku.dk> If it is reasonable to apply PTR_ERR to the result of calling clk_get, then that result should first be tested with IS_ERR, not with !. The semantic patch that makes this change is as follows: (http://www.emn.fr/x-info/coccinelle/) // @@ expression E,E1; @@ if ( – E == NULL + IS_ERR(E) ) { …