[bug report] gpio: nuvoton: Add Nuvoton NPCM sgpio driver

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

Hello Jim Liu,

The patch c4f8457d17ce: "gpio: nuvoton: Add Nuvoton NPCM sgpio
driver" from Dec 29, 2023 (linux-next), leads to the following
(unpublishable) Smatch static checker warning:

	drivers/gpio/gpio-npcm-sgpio.c:295 npcm_sgpio_setup_clk()
	warn: why is zero skipped 'i'

drivers/gpio/gpio-npcm-sgpio.c
    283 static int npcm_sgpio_setup_clk(struct npcm_sgpio *gpio,
    284                                 const struct npcm_clk_cfg *clk_cfg)
    285 {
    286         unsigned long apb_freq;
    287         u32 val;
    288         u8 tmp;
    289         int i;
    290 
    291         apb_freq = clk_get_rate(gpio->pclk);
    292         tmp = ioread8(gpio->base + NPCM_IOXCFG1) & ~NPCM_IOXCFG1_SFT_CLK;
    293 
    294         for (i = clk_cfg->cfg_opt-1; i > 0; i--) {
                                             ^^^^^
I believe that this should be >= 0 otherwise it seems like ->sft_clk[0]
(which is 1024) would never be used anywhere.

--> 295                 val = apb_freq / clk_cfg->sft_clk[i];
    296                 if (NPCM_CLK_MHZ > val) {
    297                         iowrite8(clk_cfg->clk_sel[i] | tmp,
    298                                  gpio->base + NPCM_IOXCFG1);
    299                         return 0;
    300                 }
    301         }
    302 
    303         return -EINVAL;
    304 }

regards,
dan carpenter