leds: renesas-tpu: Improve the readability to pick the lowest acceptable rate

I spent a few minutes to understand why the code catching the mismatch case
by checking if k is 0 or not. And the code using "k - 1" as array index is
unusual.

This patch checks acceptable rate from the lowest rate, and then we don't need
to subtract k by 1. This change improves the readability.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

diff --git a/drivers/leds/leds-renesas-tpu.c b/drivers/leds/leds-renesas-tpu.c
index e0fff1ca59238063f088bfd8792da85f7bde9d84..d3c2b7e68fbcf0c9ac5b293dd311e37debc64029 100644 (file)
--- a/drivers/leds/leds-renesas-tpu.c
+++ b/drivers/leds/leds-renesas-tpu.c
@@ -133,24 +133,24 @@ static int r_tpu_enable(struct r_tpu_priv *p, enum led_brightness brightness)
        rate = clk_get_rate(p->clk);
 
        /* pick the lowest acceptable rate */
-       for (k = 0; k < ARRAY_SIZE(prescaler); k++)
-               if ((rate / prescaler[k]) < p->min_rate)
+       for (k = ARRAY_SIZE(prescaler) - 1; k >= 0; k--)
+               if ((rate / prescaler[k]) >= p->min_rate)
                        break;
 
-       if (!k) {
+       if (k < 0) {
                dev_err(&p->pdev->dev, "clock rate mismatch\n");
                goto err0;
        }
        dev_dbg(&p->pdev->dev, "rate = %lu, prescaler %u\n",
-               rate, prescaler[k - 1]);
+               rate, prescaler[k]);
 
        /* clear TCNT on TGRB match, count on rising edge, set prescaler */
-       r_tpu_write(p, TCR, 0x0040 | (k - 1));
+       r_tpu_write(p, TCR, 0x0040 | k);
 
        /* output 0 until TGRA, output 1 until TGRB */
        r_tpu_write(p, TIOR, 0x0002);
 
-       rate /= prescaler[k - 1] * p->refresh_rate;
+       rate /= prescaler[k] * p->refresh_rate;
        r_tpu_write(p, TGRB, rate);
        dev_dbg(&p->pdev->dev, "TRGB = 0x%04lx\n", rate);