diff options
Diffstat (limited to 'drivers/clk/shmobile/clk-rcar-gen2.c')
| -rw-r--r-- | drivers/clk/shmobile/clk-rcar-gen2.c | 48 |
1 files changed, 44 insertions, 4 deletions
diff --git a/drivers/clk/shmobile/clk-rcar-gen2.c b/drivers/clk/shmobile/clk-rcar-gen2.c index a59ec217a124..dff7f79a19b9 100644 --- a/drivers/clk/shmobile/clk-rcar-gen2.c +++ b/drivers/clk/shmobile/clk-rcar-gen2.c @@ -26,6 +26,8 @@ struct rcar_gen2_cpg { void __iomem *reg; }; +#define CPG_FRQCRB 0x00000004 +#define CPG_FRQCRB_KICK BIT(31) #define CPG_SDCKCR 0x00000074 #define CPG_PLL0CR 0x000000d8 #define CPG_FRQCRC 0x000000e0 @@ -45,6 +47,7 @@ struct rcar_gen2_cpg { struct cpg_z_clk { struct clk_hw hw; void __iomem *reg; + void __iomem *kick_reg; }; #define to_z_clk(_hw) container_of(_hw, struct cpg_z_clk, hw) @@ -83,17 +86,45 @@ static int cpg_z_clk_set_rate(struct clk_hw *hw, unsigned long rate, { struct cpg_z_clk *zclk = to_z_clk(hw); unsigned int mult; - u32 val; + u32 val, kick; + unsigned int i; mult = div_u64((u64)rate * 32, parent_rate); mult = clamp(mult, 1U, 32U); + if (clk_readl(zclk->kick_reg) & CPG_FRQCRB_KICK) + return -EBUSY; + val = clk_readl(zclk->reg); val &= ~CPG_FRQCRC_ZFC_MASK; val |= (32 - mult) << CPG_FRQCRC_ZFC_SHIFT; clk_writel(val, zclk->reg); - return 0; + /* + * Set KICK bit in FRQCRB to update hardware setting and wait for + * clock change completion. + */ + kick = clk_readl(zclk->kick_reg); + kick |= CPG_FRQCRB_KICK; + clk_writel(kick, zclk->kick_reg); + + /* + * Note: There is no HW information about the worst case latency. + * + * Using experimental measurements, it seems that no more than + * ~10 iterations are needed, independently of the CPU rate. + * Since this value might be dependant of external xtal rate, pll1 + * rate or even the other emulation clocks rate, use 1000 as a + * "super" safe value. + */ + for (i = 1000; i; i--) { + if (!(clk_readl(zclk->kick_reg) & CPG_FRQCRB_KICK)) + return 0; + + cpu_relax(); + } + + return -ETIMEDOUT; } static const struct clk_ops cpg_z_clk_ops = { @@ -120,6 +151,7 @@ static struct clk * __init cpg_z_clk_register(struct rcar_gen2_cpg *cpg) init.num_parents = 1; zclk->reg = cpg->reg + CPG_FRQCRC; + zclk->kick_reg = cpg->reg + CPG_FRQCRB; zclk->hw.init = &init; clk = clk_register(NULL, &zclk->hw); @@ -186,7 +218,7 @@ rcar_gen2_cpg_register_clock(struct device_node *np, struct rcar_gen2_cpg *cpg, const char *name) { const struct clk_div_table *table = NULL; - const char *parent_name = "main"; + const char *parent_name; unsigned int shift; unsigned int mult = 1; unsigned int div = 1; @@ -201,23 +233,31 @@ rcar_gen2_cpg_register_clock(struct device_node *np, struct rcar_gen2_cpg *cpg, * the multiplier value. */ u32 value = clk_readl(cpg->reg + CPG_PLL0CR); + parent_name = "main"; mult = ((value >> 24) & ((1 << 7) - 1)) + 1; } else if (!strcmp(name, "pll1")) { + parent_name = "main"; mult = config->pll1_mult / 2; } else if (!strcmp(name, "pll3")) { + parent_name = "main"; mult = config->pll3_mult; } else if (!strcmp(name, "lb")) { + parent_name = "pll1"; div = cpg_mode & BIT(18) ? 36 : 24; } else if (!strcmp(name, "qspi")) { + parent_name = "pll1_div2"; div = (cpg_mode & (BIT(3) | BIT(2) | BIT(1))) == BIT(2) - ? 16 : 20; + ? 8 : 10; } else if (!strcmp(name, "sdh")) { + parent_name = "pll1"; table = cpg_sdh_div_table; shift = 8; } else if (!strcmp(name, "sd0")) { + parent_name = "pll1"; table = cpg_sd01_div_table; shift = 4; } else if (!strcmp(name, "sd1")) { + parent_name = "pll1"; table = cpg_sd01_div_table; shift = 0; } else if (!strcmp(name, "z")) { |