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clocksource/drivers/fttmr010: Refactor to handle clock 

The plain Faraday FTTMR010 timer needs a clock to figure out its
tick rate, and the gemini reads it directly from the system
controller set-up. Split the init function and add two paths for
the two compatible-strings. We only support clocking using PCLK
because of lack of documentation on how EXTCLK works.

The Gemini still works like before, but we can also support a
generic, clock-based version.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
This commit is contained in:
Linus Walleij 2017-03-24 22:32:35 +01:00 committed by Daniel Lezcano
parent f5bf0ee4eb
commit 28e71e2fe8
1 changed files with 73 additions and 46 deletions
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119
drivers/clocksource/timer-fttmr010.c
View File

@ -16,17 +16,7 @@
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/sched_clock.h>
/*
* Relevant registers in the global syscon
*/
#define GLOBAL_STATUS 0x04
#define CPU_AHB_RATIO_MASK (0x3 << 18)
#define CPU_AHB_1_1 (0x0 << 18)
#define CPU_AHB_3_2 (0x1 << 18)
#define CPU_AHB_24_13 (0x2 << 18)
#define CPU_AHB_2_1 (0x3 << 18)
#define REG_TO_AHB_SPEED(reg) ((((reg) >> 15) & 0x7) * 10 + 130)
#include <linux/clk.h>
/*
* Register definitions for the timers
@ -189,23 +179,9 @@ static struct irqaction fttmr010_timer_irq = {
.handler = fttmr010_timer_interrupt,
};
static int __init gemini_timer_of_init(struct device_node *np)
static int __init fttmr010_timer_common_init(struct device_node *np)
{
static struct regmap *map;
int irq;
int ret;
u32 val;
map = syscon_regmap_lookup_by_phandle(np, "syscon");
if (IS_ERR(map)) {
pr_err("Can't get regmap for syscon handle");
return -ENODEV;
}
ret = regmap_read(map, GLOBAL_STATUS, &val);
if (ret) {
pr_err("Can't read syscon status register");
return -ENXIO;
}
base = of_iomap(np, 0);
if (!base) {
@ -219,26 +195,6 @@ static int __init gemini_timer_of_init(struct device_node *np)
return -EINVAL;
}
tick_rate = REG_TO_AHB_SPEED(val) * 1000000;
printk(KERN_INFO "Bus: %dMHz", tick_rate / 1000000);
tick_rate /= 6; /* APB bus run AHB*(1/6) */
switch (val & CPU_AHB_RATIO_MASK) {
case CPU_AHB_1_1:
printk(KERN_CONT "(1/1)\n");
break;
case CPU_AHB_3_2:
printk(KERN_CONT "(3/2)\n");
break;
case CPU_AHB_24_13:
printk(KERN_CONT "(24/13)\n");
break;
case CPU_AHB_2_1:
printk(KERN_CONT "(2/1)\n");
break;
}
/*
* Reset the interrupt mask and status
*/
@ -273,4 +229,75 @@ static int __init gemini_timer_of_init(struct device_node *np)
return 0;
}
static int __init fttmr010_timer_of_init(struct device_node *np)
{
/*
* These implementations require a clock reference.
* FIXME: we currently only support clocking using PCLK
* and using EXTCLK is not supported in the driver.
*/
struct clk *clk;
clk = of_clk_get_by_name(np, "PCLK");
if (IS_ERR(clk)) {
pr_err("could not get PCLK");
return PTR_ERR(clk);
}
tick_rate = clk_get_rate(clk);
return fttmr010_timer_common_init(np);
}
CLOCKSOURCE_OF_DECLARE(fttmr010, "faraday,fttmr010", fttmr010_timer_of_init);
/*
* Gemini-specific: relevant registers in the global syscon
*/
#define GLOBAL_STATUS 0x04
#define CPU_AHB_RATIO_MASK (0x3 << 18)
#define CPU_AHB_1_1 (0x0 << 18)
#define CPU_AHB_3_2 (0x1 << 18)
#define CPU_AHB_24_13 (0x2 << 18)
#define CPU_AHB_2_1 (0x3 << 18)
#define REG_TO_AHB_SPEED(reg) ((((reg) >> 15) & 0x7) * 10 + 130)
static int __init gemini_timer_of_init(struct device_node *np)
{
static struct regmap *map;
int ret;
u32 val;
map = syscon_regmap_lookup_by_phandle(np, "syscon");
if (IS_ERR(map)) {
pr_err("Can't get regmap for syscon handle\n");
return -ENODEV;
}
ret = regmap_read(map, GLOBAL_STATUS, &val);
if (ret) {
pr_err("Can't read syscon status register\n");
return -ENXIO;
}
tick_rate = REG_TO_AHB_SPEED(val) * 1000000;
pr_info("Bus: %dMHz ", tick_rate / 1000000);
tick_rate /= 6; /* APB bus run AHB*(1/6) */
switch (val & CPU_AHB_RATIO_MASK) {
case CPU_AHB_1_1:
pr_cont("(1/1)\n");
break;
case CPU_AHB_3_2:
pr_cont("(3/2)\n");
break;
case CPU_AHB_24_13:
pr_cont("(24/13)\n");
break;
case CPU_AHB_2_1:
pr_cont("(2/1)\n");
break;
}
return fttmr010_timer_common_init(np);
}
CLOCKSOURCE_OF_DECLARE(gemini, "cortina,gemini-timer", gemini_timer_of_init);