diff options
Diffstat (limited to 'arch/sh/drivers/heartbeat.c')
| -rw-r--r-- | arch/sh/drivers/heartbeat.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/arch/sh/drivers/heartbeat.c b/arch/sh/drivers/heartbeat.c new file mode 100644 index 000000000..24391b444 --- /dev/null +++ b/arch/sh/drivers/heartbeat.c @@ -0,0 +1,152 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Generic heartbeat driver for regular LED banks + * + * Copyright (C) 2007 - 2010 Paul Mundt + * + * Most SH reference boards include a number of individual LEDs that can + * be independently controlled (either via a pre-defined hardware + * function or via the LED class, if desired -- the hardware tends to + * encapsulate some of the same "triggers" that the LED class supports, + * so there's not too much value in it). + * + * Additionally, most of these boards also have a LED bank that we've + * traditionally used for strobing the load average. This use case is + * handled by this driver, rather than giving each LED bit position its + * own struct device. + */ +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/sched.h> +#include <linux/sched/loadavg.h> +#include <linux/timer.h> +#include <linux/io.h> +#include <linux/slab.h> +#include <asm/heartbeat.h> + +#define DRV_NAME "heartbeat" +#define DRV_VERSION "0.1.2" + +static unsigned char default_bit_pos[] = { 0, 1, 2, 3, 4, 5, 6, 7 }; + +static inline void heartbeat_toggle_bit(struct heartbeat_data *hd, + unsigned bit, unsigned int inverted) +{ + unsigned int new; + + new = (1 << hd->bit_pos[bit]); + if (inverted) + new = ~new; + + new &= hd->mask; + + switch (hd->regsize) { + case 32: + new |= ioread32(hd->base) & ~hd->mask; + iowrite32(new, hd->base); + break; + case 16: + new |= ioread16(hd->base) & ~hd->mask; + iowrite16(new, hd->base); + break; + default: + new |= ioread8(hd->base) & ~hd->mask; + iowrite8(new, hd->base); + break; + } +} + +static void heartbeat_timer(struct timer_list *t) +{ + struct heartbeat_data *hd = from_timer(hd, t, timer); + static unsigned bit = 0, up = 1; + + heartbeat_toggle_bit(hd, bit, hd->flags & HEARTBEAT_INVERTED); + + bit += up; + if ((bit == 0) || (bit == (hd->nr_bits)-1)) + up = -up; + + mod_timer(&hd->timer, jiffies + (110 - ((300 << FSHIFT) / + ((avenrun[0] / 5) + (3 << FSHIFT))))); +} + +static int heartbeat_drv_probe(struct platform_device *pdev) +{ + struct resource *res; + struct heartbeat_data *hd; + int i; + + if (unlikely(pdev->num_resources != 1)) { + dev_err(&pdev->dev, "invalid number of resources\n"); + return -EINVAL; + } + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (unlikely(res == NULL)) { + dev_err(&pdev->dev, "invalid resource\n"); + return -EINVAL; + } + + if (pdev->dev.platform_data) { + hd = pdev->dev.platform_data; + } else { + hd = kzalloc(sizeof(struct heartbeat_data), GFP_KERNEL); + if (unlikely(!hd)) + return -ENOMEM; + } + + hd->base = ioremap(res->start, resource_size(res)); + if (unlikely(!hd->base)) { + dev_err(&pdev->dev, "ioremap failed\n"); + + if (!pdev->dev.platform_data) + kfree(hd); + + return -ENXIO; + } + + if (!hd->nr_bits) { + hd->bit_pos = default_bit_pos; + hd->nr_bits = ARRAY_SIZE(default_bit_pos); + } + + hd->mask = 0; + for (i = 0; i < hd->nr_bits; i++) + hd->mask |= (1 << hd->bit_pos[i]); + + if (!hd->regsize) { + switch (res->flags & IORESOURCE_MEM_TYPE_MASK) { + case IORESOURCE_MEM_32BIT: + hd->regsize = 32; + break; + case IORESOURCE_MEM_16BIT: + hd->regsize = 16; + break; + case IORESOURCE_MEM_8BIT: + default: + hd->regsize = 8; + break; + } + } + + timer_setup(&hd->timer, heartbeat_timer, 0); + platform_set_drvdata(pdev, hd); + + return mod_timer(&hd->timer, jiffies + 1); +} + +static struct platform_driver heartbeat_driver = { + .probe = heartbeat_drv_probe, + .driver = { + .name = DRV_NAME, + .suppress_bind_attrs = true, + }, +}; + +static int __init heartbeat_init(void) +{ + printk(KERN_NOTICE DRV_NAME ": version %s loaded\n", DRV_VERSION); + return platform_driver_register(&heartbeat_driver); +} +device_initcall(heartbeat_init); |