[bug report] clk: visconti: Add support common clock driver and reset driver

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Nobuhiro Iwamatsu,

The patch b4cbe606dc36: "clk: visconti: Add support common clock
driver and reset driver" from Oct 25, 2021, leads to the following
Smatch static checker warning:

	drivers/clk/visconti/clkc.c:150 visconti_clk_register_gates()
	warn: always true condition '(clks[i]->rs_id >= 0) => (0-255 >= 0)'

drivers/clk/visconti/clkc.c
    124 int visconti_clk_register_gates(struct visconti_clk_provider *ctx,
    125                                 const struct visconti_clk_gate_table *clks,
    126                                 int num_gate,
    127                                 const struct visconti_reset_data *reset,
    128                                 spinlock_t *lock)
    129 {
    130         struct device *dev = ctx->dev;
    131         int i;
    132 
    133         for (i = 0; i < num_gate; i++) {
    134                 const char *parent_div_name = clks[i].parent_data[0].name;
    135                 struct clk_parent_data *pdata;
    136                 u32 rson_offset, rsoff_offset;
    137                 struct clk_hw *gate_clk;
    138                 struct clk_hw *div_clk;
    139                 char *dev_name;
    140                 u8 rs_idx;
    141 
    142                 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
    143                 if (!pdata)
    144                         return -ENOMEM;
    145 
    146                 dev_name = devm_kasprintf(dev, GFP_KERNEL, "%s_div", clks[i].name);
    147                 if (!dev_name)
    148                         return -ENOMEM;
    149 
--> 150                 if (clks[i].rs_id >= 0) {

This is a u8.  But it does get set to -1 for PISYSTEM in clkc-tmpv770x.c

> drivers/clk/visconti/clkc-tmpv770x.c
>   175                /* PISYSTEM */
>   176                { TMPV770X_CLK_WRCK, "wrck",
>   177                        clks_parent_data, ARRAY_SIZE(clks_parent_data),
>   178                        0, 0x68, 0x168, 9, 32,
>   179                        -1, }, /* No reset */

    151                         rson_offset = reset[clks[i].rs_id].rson_offset;
    152                         rsoff_offset = reset[clks[i].rs_id].rsoff_offset;
    153                         rs_idx = reset[clks[i].rs_id].rs_idx;
    154                 } else {
    155                         rson_offset = rsoff_offset = rs_idx = -1;

All these variables are unsigned but they're set to -1.  clks[i].rs_idx
is also unsigned.

    156                 }
    157 
    158                 div_clk = devm_clk_hw_register_fixed_factor(dev,
    159                                                             dev_name,
    160                                                             parent_div_name,
    161                                                             0, 1,
    162                                                             clks[i].div);
    163                 if (IS_ERR(div_clk))
    164                         return PTR_ERR(div_clk);
    165 
    166                 gate_clk = visconti_clk_register_gate(dev,
    167                                                       clks[i].name,
    168                                                       dev_name,
    169                                                       ctx->regmap,
    170                                                       &clks[i],
    171                                                       rson_offset,
    172                                                       rsoff_offset,
    173                                                       rs_idx,
    174                                                       lock);
    175                 if (IS_ERR(gate_clk)) {
    176                         dev_err(dev, "%s: failed to register clock %s\n",
    177                                 __func__, clks[i].name);
    178                         return PTR_ERR(gate_clk);
    179                 }
    180 
    181                 ctx->clk_data.hws[clks[i].id] = gate_clk;
    182         }
    183 
    184         return 0;
    185 }

regards,
dan carpenter