From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:19182 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752128AbcAELpA (ORCPT ); Tue, 5 Jan 2016 06:45:00 -0500 Date: Tue, 5 Jan 2016 14:44:52 +0300 From: Dan Carpenter To: vz@mleia.com Cc: linux-clk@vger.kernel.org Subject: re: clk: lpc32xx: add common clock framework driver Message-ID: <20160105114452.GA31494@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-clk-owner@vger.kernel.org List-ID: Hello Vladimir Zapolskiy (and other clk devs as well), The patch f7c82a60ba26: "clk: lpc32xx: add common clock framework driver" from Dec 6, 2015, leads to the following static checker warning: drivers/clk/nxp/clk-lpc32xx.c:1019 clk_mux_get_parent() warn: signedness bug returning '(-22)' drivers/clk/nxp/clk-lpc32xx.c 1003 static u8 clk_mux_get_parent(struct clk_hw *hw) ^^ 1004 { 1005 struct lpc32xx_clk_mux *mux = to_lpc32xx_mux(hw); 1006 u32 num_parents = clk_hw_get_num_parents(hw); 1007 u32 val; 1008 1009 regmap_read(clk_regmap, mux->reg, &val); 1010 val >>= mux->shift; 1011 val &= mux->mask; 1012 1013 if (mux->table) { 1014 u32 i; 1015 1016 for (i = 0; i < num_parents; i++) 1017 if (mux->table[i] == val) 1018 return i; 1019 return -EINVAL; ^^^^^^^^^^^^^^ 1020 } 1021 1022 if (val >= num_parents) 1023 return -EINVAL; ^^^^^^^^^^^^^^ This obviously doesn't work since this is a u8 function. I looked at how this was called to see what we should return on error. This is called from __clk_init(). It tests for negative error codes. Ooops. Also there is no static checker warning for that but I will create one. I'm not sure what to do here. I bet the correct thing is to convert all the get_parent() function to return int. Another option might be to add documentation, but I feel like in the kernel int returns are self documenting and that's the best option. 1024 1025 return val; 1026 } regards, dan carpenter