From: Rafał Miłecki <[email protected]> This clock is present on cheaper Northstar devices like BCM53573 or BCM47189 using Corex-A7. This driver uses PMU (Power Management Unit) to calculate clock rate and allows using it in a generic (clk_*) way.
Signed-off-by: Rafał Miłecki <[email protected]> --- .../devicetree/bindings/clock/brcm,ns-ilp.txt | 28 ++++ drivers/clk/bcm/Makefile | 1 + drivers/clk/bcm/clk-ns-ilp.c | 146 +++++++++++++++++++++ 3 files changed, 175 insertions(+) create mode 100644 Documentation/devicetree/bindings/clock/brcm,ns-ilp.txt create mode 100644 drivers/clk/bcm/clk-ns-ilp.c diff --git a/Documentation/devicetree/bindings/clock/brcm,ns-ilp.txt b/Documentation/devicetree/bindings/clock/brcm,ns-ilp.txt new file mode 100644 index 0000000..c4df38e --- /dev/null +++ b/Documentation/devicetree/bindings/clock/brcm,ns-ilp.txt @@ -0,0 +1,28 @@ +Broadcom Northstar ILP clock +============================ + +This binding uses the common clock binding: + Documentation/devicetree/bindings/clock/clock-bindings.txt + +This binding is used for ILP clock on Broadcom Northstar devices using +Corex-A7 CPU. ILP clock depends on ALP one and has to be calculated on +runtime. + +Required properties: +- compatible: "brcm,ns-ilp" +- reg: iomem address range of PMU (Power Management Unit) +- reg-names: "pmu", the only needed & supported reg right now +- clocks: should reference an ALP clock +- clock-names: "alp", the only needed & supported clock right now +- #clock-cells: should be <0> + +Example: + +ilp: ilp { + compatible = "brcm,ns-ilp"; + reg = <0x18012000 0x1000>; + reg-names = "pmu"; + clocks = <&alp>; + clock-names = "alp-clk"; + #clock-cells = <0>; +}; diff --git a/drivers/clk/bcm/Makefile b/drivers/clk/bcm/Makefile index 1d79bd2..1389379 100644 --- a/drivers/clk/bcm/Makefile +++ b/drivers/clk/bcm/Makefile @@ -10,3 +10,4 @@ obj-$(CONFIG_COMMON_CLK_IPROC) += clk-ns2.o obj-$(CONFIG_ARCH_BCM_CYGNUS) += clk-cygnus.o obj-$(CONFIG_ARCH_BCM_NSP) += clk-nsp.o obj-$(CONFIG_ARCH_BCM_5301X) += clk-nsp.o +obj-$(CONFIG_ARCH_BCM_5301X) += clk-ns-ilp.o diff --git a/drivers/clk/bcm/clk-ns-ilp.c b/drivers/clk/bcm/clk-ns-ilp.c new file mode 100644 index 0000000..230458e8 --- /dev/null +++ b/drivers/clk/bcm/clk-ns-ilp.c @@ -0,0 +1,146 @@ +/* + * Copyright (C) 2016 Rafał Miłecki <[email protected]> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/clk.h> +#include <linux/clk-provider.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/slab.h> + +#define PMU_XTAL_FREQ_RATIO 0x66c +#define XTAL_ALP_PER_4ILP 0x00001fff +#define XTAL_CTL_EN 0x80000000 +#define PMU_SLOW_CLK_PERIOD 0x6dc + +struct ns_ilp { + struct clk *clk; + struct clk_hw hw; + struct clk *alp_clk; + void __iomem *pmu; +}; + +static int ns_ilp_enable(struct clk_hw *hw) +{ + struct ns_ilp *ilp = container_of(hw, struct ns_ilp, hw); + + writel(0x10199, ilp->pmu + PMU_SLOW_CLK_PERIOD); + writel(0x10000, ilp->pmu + 0x674); + + return 0; +} + +static unsigned long ns_ilp_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct ns_ilp *ilp = container_of(hw, struct ns_ilp, hw); + void __iomem *pmu = ilp->pmu; + u32 last_val, cur_val; + u32 sum = 0, num = 0, loop_num = 0; + u32 avg; + int err; + + err = clk_prepare_enable(ilp->alp_clk); + if (err) + return 0; + + /* Enable */ + writel(XTAL_CTL_EN, pmu + PMU_XTAL_FREQ_RATIO); + + /* Read initial value */ + last_val = readl(pmu + PMU_XTAL_FREQ_RATIO) & XTAL_ALP_PER_4ILP; + + /* Try getting 20 different values for calculating average */ + while (num < 20) { + cur_val = readl(pmu + PMU_XTAL_FREQ_RATIO) & XTAL_ALP_PER_4ILP; + + if (cur_val != last_val) { + /* Got different value, use it */ + sum += cur_val; + num++; + loop_num = 0; + last_val = cur_val; + } else if (++loop_num > 5000) { + /* Same value over and over, give up */ + sum += cur_val; + num++; + break; + } + } + + /* Disable */ + writel(0x0, pmu + PMU_XTAL_FREQ_RATIO); + + avg = sum / num; + + return clk_get_rate(ilp->alp_clk) * 4 / avg; +} + +const struct clk_ops ns_ilp_clk_ops = { + .enable = ns_ilp_enable, + .recalc_rate = ns_ilp_recalc_rate, +}; + +static void ns_ilp_init(struct device_node *np) +{ + struct ns_ilp *ilp; + struct resource res; + struct clk_init_data init = { 0 }; + int index; + int err; + + ilp = kzalloc(sizeof(*ilp), GFP_KERNEL); + if (!ilp) + return; + + index = of_property_match_string(np, "reg-names", "pmu"); + if (index < 0) { + err = index; + goto err_free_ilp; + } + err = of_address_to_resource(np, index, &res); + if (err) { + err = index; + goto err_free_ilp; + } + ilp->pmu = ioremap_nocache(res.start, resource_size(&res)); + if (IS_ERR(ilp->pmu)) { + err = PTR_ERR(ilp->pmu); + goto err_free_ilp; + } + + ilp->alp_clk = of_clk_get_by_name(np, "alp-clk"); + if (IS_ERR(ilp->alp_clk)) { + err = PTR_ERR(ilp->alp_clk); + goto err_unmap_pmu; + } + + init.name = np->name; + init.ops = &ns_ilp_clk_ops; + init.flags = CLK_IS_ROOT; + + ilp->hw.init = &init; + ilp->clk = clk_register(NULL, &ilp->hw); + if (WARN_ON(IS_ERR(ilp->clk))) + goto err_put_alp_clk; + + of_clk_add_provider(np, of_clk_src_simple_get, ilp->clk); + + return; + +err_put_alp_clk: + clk_put(ilp->alp_clk); +err_unmap_pmu: + iounmap(ilp->pmu); +err_free_ilp: + kfree(ilp); + pr_err("Failed to init ILP clock: %d\n", err); +} +CLK_OF_DECLARE(ns_ilp_clk, "brcm,ns-ilp", ns_ilp_init); -- 1.8.4.5
