[RFC PATCH 2/2] clk: renesas: rcar-gen3-cpg.c: refactor checks for accessing the div table

[Wolfram Sang]

Do the checks for accessing the SD divider table only when the rate gets
updated, namely on init and set_rate. In all other cases, reuse the last
value. This simplifies code, runtime load, and error reporting.

Signed-off-by: Wolfram Sang <wsa+rene...@sang-engineering.com>
---
 drivers/clk/renesas/rcar-gen3-cpg.c | 46 ++++++++++++++++---------------------
 1 file changed, 20 insertions(+), 26 deletions(-)

diff --git a/drivers/clk/renesas/rcar-gen3-cpg.c 
b/drivers/clk/renesas/rcar-gen3-cpg.c
index 71b8a986bd4889..d4d27cf6110d38 100644
--- a/drivers/clk/renesas/rcar-gen3-cpg.c
+++ b/drivers/clk/renesas/rcar-gen3-cpg.c
@@ -60,6 +60,7 @@ struct sd_clock {
        unsigned int div_num;
        unsigned int div_min;
        unsigned int div_max;
+       unsigned int cur_div_idx;
 };
 
 /* SDn divider
@@ -96,21 +97,10 @@ static const struct sd_div_table cpg_sd_div_table[] = {
 static int cpg_sd_clock_enable(struct clk_hw *hw)
 {
        struct sd_clock *clock = to_sd_clock(hw);
-       u32 val, sd_fc;
-       unsigned int i;
-
-       val = readl(clock->reg);
-
-       sd_fc = val & CPG_SD_FC_MASK;
-       for (i = 0; i < clock->div_num; i++)
-               if (sd_fc == (clock->div_table[i].val & CPG_SD_FC_MASK))
-                       break;
-
-       if (i >= clock->div_num)
-               return -EINVAL;
+       u32 val = readl(clock->reg);
 
        val &= ~(CPG_SD_STP_MASK);
-       val |= clock->div_table[i].val & CPG_SD_STP_MASK;
+       val |= clock->div_table[clock->cur_div_idx].val & CPG_SD_STP_MASK;
 
        writel(val, clock->reg);
 
@@ -135,20 +125,9 @@ static unsigned long cpg_sd_clock_recalc_rate(struct 
clk_hw *hw,
                                                unsigned long parent_rate)
 {
        struct sd_clock *clock = to_sd_clock(hw);
-       u32 val, sd_fc;
-       unsigned int i;
-
-       val = readl(clock->reg);
-
-       sd_fc = val & CPG_SD_FC_MASK;
-       for (i = 0; i < clock->div_num; i++)
-               if (sd_fc == (clock->div_table[i].val & CPG_SD_FC_MASK))
-                       break;
-
-       if (i >= clock->div_num)
-               return -EINVAL;
 
-       return DIV_ROUND_CLOSEST(parent_rate, clock->div_table[i].div);
+       return DIV_ROUND_CLOSEST(parent_rate,
+                                clock->div_table[clock->cur_div_idx].div);
 }
 
 static unsigned int cpg_sd_clock_calc_div(struct sd_clock *clock,
@@ -189,6 +168,8 @@ static int cpg_sd_clock_set_rate(struct clk_hw *hw, 
unsigned long rate,
        if (i >= clock->div_num)
                return -EINVAL;
 
+       clock->cur_div_idx = i;
+
        val = readl(clock->reg);
        val &= ~(CPG_SD_STP_MASK | CPG_SD_FC_MASK);
        val |= clock->div_table[i].val & (CPG_SD_STP_MASK | CPG_SD_FC_MASK);
@@ -214,6 +195,7 @@ static struct clk * __init cpg_sd_clk_register(const struct 
cpg_core_clk *core,
        struct sd_clock *clock;
        struct clk *clk;
        unsigned int i;
+       u32 sd_fc;
 
        clock = kzalloc(sizeof(*clock), GFP_KERNEL);
        if (!clock)
@@ -230,6 +212,18 @@ static struct clk * __init cpg_sd_clk_register(const 
struct cpg_core_clk *core,
        clock->div_table = cpg_sd_div_table;
        clock->div_num = ARRAY_SIZE(cpg_sd_div_table);
 
+       sd_fc = readl(clock->reg) & CPG_SD_FC_MASK;
+       for (i = 0; i < clock->div_num; i++)
+               if (sd_fc == (clock->div_table[i].val & CPG_SD_FC_MASK))
+                       break;
+
+       if (WARN_ON(i >= clock->div_num)) {
+               kfree(clock);
+               return ERR_PTR(-EINVAL);
+       }
+
+       clock->cur_div_idx = i;
+
        clock->div_max = clock->div_table[0].div;
        clock->div_min = clock->div_max;
        for (i = 1; i < clock->div_num; i++) {
-- 
2.11.0