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225 lines
6.4 KiB
Diff
225 lines
6.4 KiB
Diff
From bd8dd593f7d2211f2273e05741d157b0c8d020ae Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
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Date: Tue, 13 Sep 2016 09:06:04 +0200
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Subject: [PATCH] clk: bcm: Add driver for BCM53573 ILP clock
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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This clock is present on BCM53573 devices (including BCM47189) that use
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Cortex-A7. ILP is a part of PMU (Power Management Unit) multi-function
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device so we use syscon (and regmap) for it.
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Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
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Acked-by: Rob Herring <robh@kernel.org>
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[sboyd@codeaurora.org: Remove 0 from clk_init_data to silence sparse]
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Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
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---
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.../bindings/clock/brcm,bcm53573-ilp.txt | 36 +++++
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drivers/clk/bcm/Makefile | 1 +
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drivers/clk/bcm/clk-bcm53573-ilp.c | 148 +++++++++++++++++++++
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3 files changed, 185 insertions(+)
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create mode 100644 Documentation/devicetree/bindings/clock/brcm,bcm53573-ilp.txt
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create mode 100644 drivers/clk/bcm/clk-bcm53573-ilp.c
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--- /dev/null
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+++ b/Documentation/devicetree/bindings/clock/brcm,bcm53573-ilp.txt
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@@ -0,0 +1,36 @@
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+Broadcom BCM53573 ILP clock
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+===========================
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+
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+This binding uses the common clock binding:
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+ Documentation/devicetree/bindings/clock/clock-bindings.txt
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+
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+This binding is used for ILP clock (sometimes referred as "slow clock")
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+on Broadcom BCM53573 devices using Cortex-A7 CPU.
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+
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+ILP's rate has to be calculated on runtime and it depends on ALP clock
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+which has to be referenced.
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+
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+This clock is part of PMU (Power Management Unit), a Broadcom's device
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+handing power-related aspects. Its node must be sub-node of the PMU
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+device.
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+
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+Required properties:
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+- compatible: "brcm,bcm53573-ilp"
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+- clocks: has to reference an ALP clock
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+- #clock-cells: should be <0>
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+- clock-output-names: from common clock bindings, should contain clock
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+ name
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+
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+Example:
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+
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+pmu@18012000 {
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+ compatible = "simple-mfd", "syscon";
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+ reg = <0x18012000 0x00001000>;
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+
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+ ilp {
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+ compatible = "brcm,bcm53573-ilp";
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+ clocks = <&alp>;
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+ #clock-cells = <0>;
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+ clock-output-names = "ilp";
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+ };
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+};
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--- a/drivers/clk/bcm/Makefile
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+++ b/drivers/clk/bcm/Makefile
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@@ -4,6 +4,7 @@ obj-$(CONFIG_CLK_BCM_KONA) += clk-bcm281
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obj-$(CONFIG_CLK_BCM_KONA) += clk-bcm21664.o
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obj-$(CONFIG_COMMON_CLK_IPROC) += clk-iproc-armpll.o clk-iproc-pll.o clk-iproc-asiu.o
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obj-$(CONFIG_ARCH_BCM2835) += clk-bcm2835.o
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+obj-$(CONFIG_ARCH_BCM_53573) += clk-bcm53573-ilp.o
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obj-$(CONFIG_COMMON_CLK_IPROC) += clk-ns2.o
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obj-$(CONFIG_ARCH_BCM_CYGNUS) += clk-cygnus.o
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obj-$(CONFIG_ARCH_BCM_NSP) += clk-nsp.o
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--- /dev/null
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+++ b/drivers/clk/bcm/clk-bcm53573-ilp.c
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@@ -0,0 +1,148 @@
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+/*
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+ * Copyright (C) 2016 Rafał Miłecki <rafal@milecki.pl>
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License version 2 as
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+ * published by the Free Software Foundation.
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+ */
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+
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+#include <linux/clk-provider.h>
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+#include <linux/err.h>
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+#include <linux/io.h>
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+#include <linux/mfd/syscon.h>
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+#include <linux/of.h>
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+#include <linux/of_address.h>
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+#include <linux/regmap.h>
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+#include <linux/slab.h>
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+
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+#define PMU_XTAL_FREQ_RATIO 0x66c
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+#define XTAL_ALP_PER_4ILP 0x00001fff
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+#define XTAL_CTL_EN 0x80000000
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+#define PMU_SLOW_CLK_PERIOD 0x6dc
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+
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+struct bcm53573_ilp {
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+ struct clk_hw hw;
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+ struct regmap *regmap;
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+};
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+
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+static int bcm53573_ilp_enable(struct clk_hw *hw)
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+{
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+ struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);
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+
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+ regmap_write(ilp->regmap, PMU_SLOW_CLK_PERIOD, 0x10199);
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+ regmap_write(ilp->regmap, 0x674, 0x10000);
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+
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+ return 0;
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+}
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+
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+static void bcm53573_ilp_disable(struct clk_hw *hw)
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+{
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+ struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);
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+
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+ regmap_write(ilp->regmap, PMU_SLOW_CLK_PERIOD, 0);
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+ regmap_write(ilp->regmap, 0x674, 0);
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+}
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+
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+static unsigned long bcm53573_ilp_recalc_rate(struct clk_hw *hw,
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+ unsigned long parent_rate)
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+{
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+ struct bcm53573_ilp *ilp = container_of(hw, struct bcm53573_ilp, hw);
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+ struct regmap *regmap = ilp->regmap;
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+ u32 last_val, cur_val;
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+ int sum = 0, num = 0, loop_num = 0;
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+ int avg;
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+
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+ /* Enable measurement */
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+ regmap_write(regmap, PMU_XTAL_FREQ_RATIO, XTAL_CTL_EN);
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+
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+ /* Read initial value */
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+ regmap_read(regmap, PMU_XTAL_FREQ_RATIO, &last_val);
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+ last_val &= XTAL_ALP_PER_4ILP;
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+
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+ /*
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+ * At minimum we should loop for a bit to let hardware do the
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+ * measurement. This isn't very accurate however, so for a better
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+ * precision lets try getting 20 different values for and use average.
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+ */
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+ while (num < 20) {
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+ regmap_read(regmap, PMU_XTAL_FREQ_RATIO, &cur_val);
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+ cur_val &= XTAL_ALP_PER_4ILP;
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+
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+ if (cur_val != last_val) {
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+ /* Got different value, use it */
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+ sum += cur_val;
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+ num++;
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+ loop_num = 0;
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+ last_val = cur_val;
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+ } else if (++loop_num > 5000) {
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+ /* Same value over and over, give up */
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+ sum += cur_val;
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+ num++;
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+ break;
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+ }
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+
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+ cpu_relax();
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+ }
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+
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+ /* Disable measurement to save power */
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+ regmap_write(regmap, PMU_XTAL_FREQ_RATIO, 0x0);
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+
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+ avg = sum / num;
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+
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+ return parent_rate * 4 / avg;
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+}
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+
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+static const struct clk_ops bcm53573_ilp_clk_ops = {
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+ .enable = bcm53573_ilp_enable,
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+ .disable = bcm53573_ilp_disable,
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+ .recalc_rate = bcm53573_ilp_recalc_rate,
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+};
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+
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+static void bcm53573_ilp_init(struct device_node *np)
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+{
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+ struct bcm53573_ilp *ilp;
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+ struct clk_init_data init = { };
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+ const char *parent_name;
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+ int err;
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+
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+ ilp = kzalloc(sizeof(*ilp), GFP_KERNEL);
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+ if (!ilp)
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+ return;
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+
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+ parent_name = of_clk_get_parent_name(np, 0);
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+ if (!parent_name) {
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+ err = -ENOENT;
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+ goto err_free_ilp;
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+ }
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+
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+ ilp->regmap = syscon_node_to_regmap(of_get_parent(np));
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+ if (IS_ERR(ilp->regmap)) {
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+ err = PTR_ERR(ilp->regmap);
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+ goto err_free_ilp;
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+ }
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+
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+ init.name = np->name;
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+ init.ops = &bcm53573_ilp_clk_ops;
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+ init.parent_names = &parent_name;
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+ init.num_parents = 1;
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+
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+ ilp->hw.init = &init;
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+ err = clk_hw_register(NULL, &ilp->hw);
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+ if (err)
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+ goto err_free_ilp;
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+
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+ err = of_clk_add_hw_provider(np, of_clk_hw_simple_get, &ilp->hw);
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+ if (err)
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+ goto err_clk_hw_unregister;
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+
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+ return;
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+
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+err_clk_hw_unregister:
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+ clk_hw_unregister(&ilp->hw);
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+err_free_ilp:
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+ kfree(ilp);
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+ pr_err("Failed to init ILP clock: %d\n", err);
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+}
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+
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+/* We need it very early for arch code, before device model gets ready */
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+CLK_OF_DECLARE(bcm53573_ilp_clk, "brcm,bcm53573-ilp", bcm53573_ilp_init);
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