From c03235485c88707bfbdb364061b14bc5e3b989c8 Mon Sep 17 00:00:00 2001 From: Carlo Caione Date: Thu, 18 Oct 2012 21:42:39 +0200 Subject: BCM2835: add clocksource driver Signed-off-by: Carlo Caione Signed-off-by: Sascha Hauer --- drivers/clocksource/Kconfig | 4 ++ drivers/clocksource/Makefile | 1 + drivers/clocksource/bcm2835.c | 90 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 95 insertions(+) create mode 100644 drivers/clocksource/bcm2835.c (limited to 'drivers') diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index 9d6d293ee3..09acdd74c5 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -2,6 +2,10 @@ config ARM_SMP_TWD bool depends on ARM && CPU_V7 +config CLOCKSOURCE_BCM2835 + bool + depends on ARCH_BCM2835 + config CLOCKSOURCE_NOMADIK bool depends on ARM diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index bef465cea7..92d7c1344a 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -1,2 +1,3 @@ obj-$(CONFIG_ARM_SMP_TWD) += arm_smp_twd.o +obj-$(CONFIG_CLOCKSOURCE_BCM2835) += bcm2835.o obj-$(CONFIG_CLOCKSOURCE_NOMADIK) += nomadik.o diff --git a/drivers/clocksource/bcm2835.c b/drivers/clocksource/bcm2835.c new file mode 100644 index 0000000000..d5fe0f03a2 --- /dev/null +++ b/drivers/clocksource/bcm2835.c @@ -0,0 +1,90 @@ +/* + * Author: Carlo Caione + * + * Based on clocksource for nomadik + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + + +#include +#include +#include +#include +#include +#include +#include +#include + +/* Registers */ +#define ST_CLO 0x04 + +static __iomem void *stc_base; + +static uint64_t stc_read_cycles(void) +{ + return readl(stc_base + ST_CLO); +} + +static struct clocksource bcm2835_stc = { + .read = stc_read_cycles, + .mask = CLOCKSOURCE_MASK(32), +}; + +static int bcm2835_cs_probe(struct device_d *dev) +{ + static struct clk *stc_clk; + u32 rate; + int ret; + + stc_clk = clk_get(dev, NULL); + if (IS_ERR(stc_clk)) { + ret = PTR_ERR(stc_clk); + dev_err(dev, "clock not found: %d\n", ret); + return ret; + } + + ret = clk_enable(stc_clk); + if (ret) { + dev_err(dev, "clock failed to enable: %d\n", ret); + clk_put(stc_clk); + return ret; + } + + rate = clk_get_rate(stc_clk); + stc_base = dev_request_mem_region(dev, 0); + + clocks_calc_mult_shift(&bcm2835_stc.mult, &bcm2835_stc.shift, rate, NSEC_PER_SEC, 60); + init_clock(&bcm2835_stc); + + return 0; +} + +static __maybe_unused struct of_device_id bcm2835_cs_dt_ids[] = { + { + .compatible = "brcm,bcm2835-system-timer", + }, { + /* sentinel */ + } +}; + +static struct driver_d bcm2835_cs_driver = { + .name = "bcm2835-cs", + .probe = bcm2835_cs_probe, + .of_compatible = DRV_OF_COMPAT(bcm2835_cs_dt_ids), +}; + +static int bcm2835_cs_init(void) +{ + return platform_driver_register(&bcm2835_cs_driver); +} +coredevice_initcall(bcm2835_cs_init); -- cgit v1.2.3