diff options
| -rw-r--r-- | drivers/clk/renesas/rcar-gen3-cpg.c | 133 | ||||
| -rw-r--r-- | drivers/clk/renesas/rcar-gen3-cpg.h | 1 |
2 files changed, 134 insertions, 0 deletions
diff --git a/drivers/clk/renesas/rcar-gen3-cpg.c b/drivers/clk/renesas/rcar-gen3-cpg.c index 0904886f5501..b85918fa62c6 100644 --- a/drivers/clk/renesas/rcar-gen3-cpg.c +++ b/drivers/clk/renesas/rcar-gen3-cpg.c @@ -13,6 +13,7 @@ */ #include <linux/bug.h> +#include <linux/bitfield.h> #include <linux/clk.h> #include <linux/clk-provider.h> #include <linux/device.h> @@ -62,6 +63,134 @@ static void cpg_simple_notifier_register(struct raw_notifier_head *notifiers, } /* + * Z Clock + * + * Traits of this clock: + * prepare - clk_prepare only ensures that parents are prepared + * enable - clk_enable only ensures that parents are enabled + * rate - rate is adjustable. clk->rate = (parent->rate * mult / 32 ) / 2 + * parent - fixed parent. No clk_set_parent support + */ +#define CPG_FRQCRB 0x00000004 +#define CPG_FRQCRB_KICK BIT(31) +#define CPG_FRQCRC 0x000000e0 +#define CPG_FRQCRC_ZFC_MASK GENMASK(12, 8) + +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) + +static unsigned long cpg_z_clk_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct cpg_z_clk *zclk = to_z_clk(hw); + unsigned int mult; + + mult = 32 - FIELD_GET(CPG_FRQCRC_ZFC_MASK, clk_readl(zclk->reg)); + + /* Factor of 2 is for fixed divider */ + return DIV_ROUND_CLOSEST_ULL((u64)parent_rate * mult, 32 * 2); +} + +static long cpg_z_clk_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + /* Factor of 2 is for fixed divider */ + unsigned long prate = *parent_rate / 2; + unsigned int mult; + + mult = div_u64(rate * 32ULL, prate); + mult = clamp(mult, 1U, 32U); + + return (u64)prate * mult / 32; +} + +static int cpg_z_clk_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct cpg_z_clk *zclk = to_z_clk(hw); + unsigned int mult; + unsigned int i; + u32 val, kick; + + /* Factor of 2 is for fixed divider */ + mult = DIV_ROUND_CLOSEST_ULL(rate * 32ULL * 2, parent_rate); + mult = clamp(mult, 1U, 32U); + + if (clk_readl(zclk->kick_reg) & CPG_FRQCRB_KICK) + return -EBUSY; + + val = clk_readl(zclk->reg) & ~CPG_FRQCRC_ZFC_MASK; + val |= FIELD_PREP(CPG_FRQCRC_ZFC_MASK, 32 - mult); + clk_writel(val, zclk->reg); + + /* + * 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 dependent 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 = { + .recalc_rate = cpg_z_clk_recalc_rate, + .round_rate = cpg_z_clk_round_rate, + .set_rate = cpg_z_clk_set_rate, +}; + +static struct clk * __init cpg_z_clk_register(const char *name, + const char *parent_name, + void __iomem *reg) +{ + struct clk_init_data init; + struct cpg_z_clk *zclk; + struct clk *clk; + + zclk = kzalloc(sizeof(*zclk), GFP_KERNEL); + if (!zclk) + return ERR_PTR(-ENOMEM); + + init.name = name; + init.ops = &cpg_z_clk_ops; + init.flags = 0; + init.parent_names = &parent_name; + init.num_parents = 1; + + zclk->reg = reg + CPG_FRQCRC; + zclk->kick_reg = reg + CPG_FRQCRB; + zclk->hw.init = &init; + + clk = clk_register(NULL, &zclk->hw); + if (IS_ERR(clk)) + kfree(zclk); + + return clk; +} + +/* * SDn Clock */ #define CPG_SD_STP_HCK BIT(9) @@ -420,6 +549,10 @@ struct clk * __init rcar_gen3_cpg_clk_register(struct device *dev, mult = 1; break; + case CLK_TYPE_GEN3_Z: + return cpg_z_clk_register(core->name, __clk_get_name(parent), + base); + default: return ERR_PTR(-EINVAL); } diff --git a/drivers/clk/renesas/rcar-gen3-cpg.h b/drivers/clk/renesas/rcar-gen3-cpg.h index 2e4284399f53..c73d4d6fdc85 100644 --- a/drivers/clk/renesas/rcar-gen3-cpg.h +++ b/drivers/clk/renesas/rcar-gen3-cpg.h @@ -21,6 +21,7 @@ enum rcar_gen3_clk_types { CLK_TYPE_GEN3_SD, CLK_TYPE_GEN3_R, CLK_TYPE_GEN3_PE, + CLK_TYPE_GEN3_Z, }; #define DEF_GEN3_SD(_name, _id, _parent, _offset) \ |