On Sun, Nov 29, 2015 at 11:03:08AM +0800, Chen-Yu Tsai wrote: > The "cpus" clock is the clock for the embedded processor in the A80. > It is also part of the PRCM clock tree. This clock includes a pre- > divider on one of its inputs. For now we are using a custom clock > driver for it. In the future we may want to develop a generalized > driver for these types of clocks, which also includes the AHB clock > driver on sun[5678]i. > > Signed-off-by: Chen-Yu Tsai <[email protected]> > --- > Documentation/devicetree/bindings/clock/sunxi.txt | 1 +
For the binding: Acked-by: Rob Herring <[email protected]> > drivers/clk/sunxi/Makefile | 1 + > drivers/clk/sunxi/clk-sun9i-cpus.c | 240 > ++++++++++++++++++++++ > 3 files changed, 242 insertions(+) > create mode 100644 drivers/clk/sunxi/clk-sun9i-cpus.c > > diff --git a/Documentation/devicetree/bindings/clock/sunxi.txt > b/Documentation/devicetree/bindings/clock/sunxi.txt > index b6859ed6913f..153ac72869e8 100644 > --- a/Documentation/devicetree/bindings/clock/sunxi.txt > +++ b/Documentation/devicetree/bindings/clock/sunxi.txt > @@ -27,6 +27,7 @@ Required properties: > "allwinner,sun5i-a10s-ahb-gates-clk" - for the AHB gates on A10s > "allwinner,sun7i-a20-ahb-gates-clk" - for the AHB gates on A20 > "allwinner,sun6i-a31-ar100-clk" - for the AR100 on A31 > + "allwinner,sun9i-a80-cpus-clk" - for the CPUS on A80 > "allwinner,sun6i-a31-ahb1-clk" - for the AHB1 clock on A31 > "allwinner,sun6i-a31-ahb1-gates-clk" - for the AHB1 gates on A31 > "allwinner,sun8i-a23-ahb1-gates-clk" - for the AHB1 gates on A23 > diff --git a/drivers/clk/sunxi/Makefile b/drivers/clk/sunxi/Makefile > index c55d5cd1c0e5..f7d439fa9980 100644 > --- a/drivers/clk/sunxi/Makefile > +++ b/drivers/clk/sunxi/Makefile > @@ -16,6 +16,7 @@ obj-y += clk-sun9i-mmc.o > obj-y += clk-usb.o > > obj-$(CONFIG_MACH_SUN9I) += clk-sun8i-apb0.o > +obj-$(CONFIG_MACH_SUN9I) += clk-sun9i-cpus.o > > obj-$(CONFIG_MFD_SUN6I_PRCM) += \ > clk-sun6i-ar100.o clk-sun6i-apb0.o clk-sun6i-apb0-gates.o > diff --git a/drivers/clk/sunxi/clk-sun9i-cpus.c > b/drivers/clk/sunxi/clk-sun9i-cpus.c > new file mode 100644 > index 000000000000..7626d2194b96 > --- /dev/null > +++ b/drivers/clk/sunxi/clk-sun9i-cpus.c > @@ -0,0 +1,240 @@ > +/* > + * Copyright (C) 2015 Chen-Yu Tsai > + * > + * Chen-Yu Tsai <[email protected]> > + * > + * Allwinner A80 CPUS clock driver > + * > + */ > + > +#include <linux/clk.h> > +#include <linux/clk-provider.h> > +#include <linux/slab.h> > +#include <linux/spinlock.h> > +#include <linux/of.h> > +#include <linux/of_address.h> > + > +static DEFINE_SPINLOCK(sun9i_a80_cpus_lock); > + > +/** > + * sun9i_a80_cpus_clk_setup() - Setup function for a80 cpus composite clk > + */ > + > +#define SUN9I_CPUS_MAX_PARENTS 4 > +#define SUN9I_CPUS_MUX_PARENT_PLL4 3 > +#define SUN9I_CPUS_MUX_SHIFT 16 > +#define SUN9I_CPUS_MUX_MASK GENMASK(17, 16) > +#define SUN9I_CPUS_MUX_GET_PARENT(reg) ((reg & SUN9I_CPUS_MUX_MASK) >> > \ > + SUN9I_CPUS_MUX_SHIFT) > + > +#define SUN9I_CPUS_DIV_SHIFT 4 > +#define SUN9I_CPUS_DIV_MASK GENMASK(5, 4) > +#define SUN9I_CPUS_DIV_GET(reg) ((reg & SUN9I_CPUS_DIV_MASK) >> > \ > + SUN9I_CPUS_DIV_SHIFT) > +#define SUN9I_CPUS_DIV_SET(reg, div) ((reg & ~SUN9I_CPUS_DIV_MASK) | \ > + (div << SUN9I_CPUS_DIV_SHIFT)) > +#define SUN9I_CPUS_PLL4_DIV_SHIFT 8 > +#define SUN9I_CPUS_PLL4_DIV_MASK GENMASK(12, 8) > +#define SUN9I_CPUS_PLL4_DIV_GET(reg) ((reg & SUN9I_CPUS_PLL4_DIV_MASK) >> \ > + SUN9I_CPUS_PLL4_DIV_SHIFT) > +#define SUN9I_CPUS_PLL4_DIV_SET(reg, div) ((reg & ~SUN9I_CPUS_PLL4_DIV_MASK) > | \ > + (div << > SUN9I_CPUS_PLL4_DIV_SHIFT)) > + > +struct sun9i_a80_cpus_clk { > + struct clk_hw hw; > + void __iomem *reg; > +}; > + > +#define to_sun9i_a80_cpus_clk(_hw) container_of(_hw, struct > sun9i_a80_cpus_clk, hw) > + > +static unsigned long sun9i_a80_cpus_clk_recalc_rate(struct clk_hw *hw, > + unsigned long parent_rate) > +{ > + struct sun9i_a80_cpus_clk *cpus = to_sun9i_a80_cpus_clk(hw); > + unsigned long rate; > + u32 reg; > + > + /* Fetch the register value */ > + reg = readl(cpus->reg); > + > + /* apply pre-divider first if parent is pll4 */ > + if (SUN9I_CPUS_MUX_GET_PARENT(reg) == SUN9I_CPUS_MUX_PARENT_PLL4) > + parent_rate /= SUN9I_CPUS_PLL4_DIV_GET(reg) + 1; > + > + /* clk divider */ > + rate = parent_rate / (SUN9I_CPUS_DIV_GET(reg) + 1); > + > + return rate; > +} > + > +static long sun9i_a80_cpus_clk_round(unsigned long rate, u8 *divp, u8 > *pre_divp, > + u8 parent, unsigned long parent_rate) > +{ > + u8 div, pre_div = 1; > + > + /* > + * clock can only divide, so we will never be able to achieve > + * frequencies higher than the parent frequency > + */ > + if (parent_rate && rate > parent_rate) > + rate = parent_rate; > + > + div = DIV_ROUND_UP(parent_rate, rate); > + > + /* calculate pre-divider if parent is pll4 */ > + if (parent == SUN9I_CPUS_MUX_PARENT_PLL4 && div > 4) { > + /* pre-divider is 1 ~ 32 */ > + if (div < 32) { > + pre_div = div; > + div = 1; > + } else if (div < 64) { > + pre_div = DIV_ROUND_UP(div, 2); > + div = 2; > + } else if (div < 96) { > + pre_div = DIV_ROUND_UP(div, 3); > + div = 3; > + } else { > + pre_div = DIV_ROUND_UP(div, 4); > + div = 4; > + } > + } > + > + /* we were asked to pass back divider values */ > + if (divp) { > + *divp = div - 1; > + *pre_divp = pre_div - 1; > + } > + > + return parent_rate / pre_div / div; > +} > + > +static int sun9i_a80_cpus_clk_determine_rate(struct clk_hw *clk, > + struct clk_rate_request *req) > +{ > + struct clk_hw *parent, *best_parent = NULL; > + int i, num_parents; > + unsigned long parent_rate, best = 0, child_rate, best_child_rate = 0; > + unsigned long rate = req->rate; > + > + /* find the parent that can help provide the fastest rate <= rate */ > + num_parents = clk_hw_get_num_parents(clk); > + for (i = 0; i < num_parents; i++) { > + parent = clk_hw_get_parent_by_index(clk, i); > + if (!parent) > + continue; > + if (clk_hw_get_flags(clk) & CLK_SET_RATE_PARENT) > + parent_rate = clk_hw_round_rate(parent, rate); > + else > + parent_rate = clk_hw_get_rate(parent); > + > + child_rate = sun9i_a80_cpus_clk_round(rate, NULL, NULL, i, > + parent_rate); > + > + if (child_rate <= rate && child_rate > best_child_rate) { > + best_parent = parent; > + best = parent_rate; > + best_child_rate = child_rate; > + } > + } > + > + if (!best_parent) > + return -EINVAL; > + > + req->best_parent_hw = best_parent; > + req->best_parent_rate = best; > + req->rate = best_child_rate; > + > + return 0; > +} > + > +static int sun9i_a80_cpus_clk_set_rate(struct clk_hw *hw, unsigned long rate, > + unsigned long parent_rate) > +{ > + struct sun9i_a80_cpus_clk *cpus = to_sun9i_a80_cpus_clk(hw); > + unsigned long flags; > + u8 div, pre_div, parent; > + u32 reg; > + > + spin_lock_irqsave(&sun9i_a80_cpus_lock, flags); > + > + reg = readl(cpus->reg); > + > + /* need to know which parent is used to apply pre-divider */ > + parent = SUN9I_CPUS_MUX_GET_PARENT(reg); > + sun9i_a80_cpus_clk_round(rate, &div, &pre_div, parent, parent_rate); > + > + reg = SUN9I_CPUS_DIV_SET(reg, div); > + reg = SUN9I_CPUS_PLL4_DIV_SET(reg, pre_div); > + writel(reg, cpus->reg); > + > + spin_unlock_irqrestore(&sun9i_a80_cpus_lock, flags); > + > + return 0; > +} > + > +static const struct clk_ops sun9i_a80_cpus_clk_ops = { > + .determine_rate = sun9i_a80_cpus_clk_determine_rate, > + .recalc_rate = sun9i_a80_cpus_clk_recalc_rate, > + .set_rate = sun9i_a80_cpus_clk_set_rate, > +}; > + > +static void sun9i_a80_cpus_setup(struct device_node *node) > +{ > + const char *clk_name = node->name; > + const char *parents[SUN9I_CPUS_MAX_PARENTS]; > + struct resource res; > + struct sun9i_a80_cpus_clk *cpus; > + struct clk_mux *mux; > + struct clk *clk; > + int ret; > + > + cpus = kzalloc(sizeof(*cpus), GFP_KERNEL); > + if (!cpus) > + return; > + > + cpus->reg = of_io_request_and_map(node, 0, of_node_full_name(node)); > + if (IS_ERR(cpus->reg)) > + goto err_free_cpus; > + > + of_property_read_string(node, "clock-output-names", &clk_name); > + > + /* we have a mux, we will have >1 parents */ > + ret = of_clk_parent_fill(node, parents, SUN9I_CPUS_MAX_PARENTS); > + > + mux = kzalloc(sizeof(*mux), GFP_KERNEL); > + if (!mux) > + goto err_unmap; > + > + /* set up clock properties */ > + mux->reg = cpus->reg; > + mux->shift = SUN9I_CPUS_MUX_SHIFT; > + /* un-shifted mask is what mux_clk expects */ > + mux->mask = SUN9I_CPUS_MUX_MASK >> SUN9I_CPUS_MUX_SHIFT; > + mux->lock = &sun9i_a80_cpus_lock; > + > + clk = clk_register_composite(NULL, clk_name, parents, ret, > + &mux->hw, &clk_mux_ops, > + &cpus->hw, &sun9i_a80_cpus_clk_ops, > + NULL, NULL, 0); > + if (IS_ERR(clk)) > + goto err_free_mux; > + > + ret = of_clk_add_provider(node, of_clk_src_simple_get, clk); > + if (ret) > + goto err_unregister; > + > + return; > + > +err_unregister: > + clk_unregister(clk); > +err_free_mux: > + kfree(mux); > +err_unmap: > + iounmap(cpus->reg); > + of_address_to_resource(node, 0, &res); > + release_mem_region(res.start, resource_size(&res)); > +err_free_cpus: > + kfree(cpus); > +} > +CLK_OF_DECLARE(sun9i_a80_cpus, "allwinner,sun9i-a80-cpus-clk", > + sun9i_a80_cpus_setup); > -- > 2.6.2 > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
