clk-nspire.c
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/*
*
* Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au>
*
* 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-provider.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#define MHZ (1000 * 1000)
#define BASE_CPU_SHIFT 1
#define BASE_CPU_MASK 0x7F
#define CPU_AHB_SHIFT 12
#define CPU_AHB_MASK 0x07
#define FIXED_BASE_SHIFT 8
#define FIXED_BASE_MASK 0x01
#define CLASSIC_BASE_SHIFT 16
#define CLASSIC_BASE_MASK 0x1F
#define CX_BASE_SHIFT 15
#define CX_BASE_MASK 0x3F
#define CX_UNKNOWN_SHIFT 21
#define CX_UNKNOWN_MASK 0x03
struct nspire_clk_info {
u32 base_clock;
u16 base_cpu_ratio;
u16 base_ahb_ratio;
};
#define EXTRACT(var, prop) (((var)>>prop##_SHIFT) & prop##_MASK)
static void nspire_clkinfo_cx(u32 val, struct nspire_clk_info *clk)
{
if (EXTRACT(val, FIXED_BASE))
clk->base_clock = 48 * MHZ;
else
clk->base_clock = 6 * EXTRACT(val, CX_BASE) * MHZ;
clk->base_cpu_ratio = EXTRACT(val, BASE_CPU) * EXTRACT(val, CX_UNKNOWN);
clk->base_ahb_ratio = clk->base_cpu_ratio * (EXTRACT(val, CPU_AHB) + 1);
}
static void nspire_clkinfo_classic(u32 val, struct nspire_clk_info *clk)
{
if (EXTRACT(val, FIXED_BASE))
clk->base_clock = 27 * MHZ;
else
clk->base_clock = (300 - 6 * EXTRACT(val, CLASSIC_BASE)) * MHZ;
clk->base_cpu_ratio = EXTRACT(val, BASE_CPU) * 2;
clk->base_ahb_ratio = clk->base_cpu_ratio * (EXTRACT(val, CPU_AHB) + 1);
}
static void __init nspire_ahbdiv_setup(struct device_node *node,
void (*get_clkinfo)(u32, struct nspire_clk_info *))
{
u32 val;
void __iomem *io;
struct clk *clk;
const char *clk_name = node->name;
const char *parent_name;
struct nspire_clk_info info;
io = of_iomap(node, 0);
if (!io)
return;
val = readl(io);
iounmap(io);
get_clkinfo(val, &info);
of_property_read_string(node, "clock-output-names", &clk_name);
parent_name = of_clk_get_parent_name(node, 0);
clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,
1, info.base_ahb_ratio);
if (!IS_ERR(clk))
of_clk_add_provider(node, of_clk_src_simple_get, clk);
}
static void __init nspire_ahbdiv_setup_cx(struct device_node *node)
{
nspire_ahbdiv_setup(node, nspire_clkinfo_cx);
}
static void __init nspire_ahbdiv_setup_classic(struct device_node *node)
{
nspire_ahbdiv_setup(node, nspire_clkinfo_classic);
}
CLK_OF_DECLARE(nspire_ahbdiv_cx, "lsi,nspire-cx-ahb-divider",
nspire_ahbdiv_setup_cx);
CLK_OF_DECLARE(nspire_ahbdiv_classic, "lsi,nspire-classic-ahb-divider",
nspire_ahbdiv_setup_classic);
static void __init nspire_clk_setup(struct device_node *node,
void (*get_clkinfo)(u32, struct nspire_clk_info *))
{
u32 val;
void __iomem *io;
struct clk *clk;
const char *clk_name = node->name;
struct nspire_clk_info info;
io = of_iomap(node, 0);
if (!io)
return;
val = readl(io);
iounmap(io);
get_clkinfo(val, &info);
of_property_read_string(node, "clock-output-names", &clk_name);
clk = clk_register_fixed_rate(NULL, clk_name, NULL, CLK_IS_ROOT,
info.base_clock);
if (!IS_ERR(clk))
of_clk_add_provider(node, of_clk_src_simple_get, clk);
else
return;
pr_info("TI-NSPIRE Base: %uMHz CPU: %uMHz AHB: %uMHz\n",
info.base_clock / MHZ,
info.base_clock / info.base_cpu_ratio / MHZ,
info.base_clock / info.base_ahb_ratio / MHZ);
}
static void __init nspire_clk_setup_cx(struct device_node *node)
{
nspire_clk_setup(node, nspire_clkinfo_cx);
}
static void __init nspire_clk_setup_classic(struct device_node *node)
{
nspire_clk_setup(node, nspire_clkinfo_classic);
}
CLK_OF_DECLARE(nspire_clk_cx, "lsi,nspire-cx-clock", nspire_clk_setup_cx);
CLK_OF_DECLARE(nspire_clk_classic, "lsi,nspire-classic-clock",
nspire_clk_setup_classic);