diff options
Diffstat (limited to 'drivers/power/reset/keystone-reset.c')
| -rw-r--r-- | drivers/power/reset/keystone-reset.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/power/reset/keystone-reset.c b/drivers/power/reset/keystone-reset.c new file mode 100644 index 000000000..c70f1bffe --- /dev/null +++ b/drivers/power/reset/keystone-reset.c @@ -0,0 +1,175 @@ +/* + * TI keystone reboot driver + * + * Copyright (C) 2014 Texas Instruments Incorporated. http://www.ti.com/ + * + * Author: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com> + * + * 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/io.h> +#include <linux/module.h> +#include <linux/notifier.h> +#include <linux/reboot.h> +#include <linux/regmap.h> +#include <linux/mfd/syscon.h> +#include <linux/of_platform.h> + +#define RSTYPE_RG 0x0 +#define RSCTRL_RG 0x4 +#define RSCFG_RG 0x8 +#define RSISO_RG 0xc + +#define RSCTRL_KEY_MASK 0x0000ffff +#define RSCTRL_RESET_MASK BIT(16) +#define RSCTRL_KEY 0x5a69 + +#define RSMUX_OMODE_MASK 0xe +#define RSMUX_OMODE_RESET_ON 0xa +#define RSMUX_OMODE_RESET_OFF 0x0 +#define RSMUX_LOCK_MASK 0x1 +#define RSMUX_LOCK_SET 0x1 + +#define RSCFG_RSTYPE_SOFT 0x300f +#define RSCFG_RSTYPE_HARD 0x0 + +#define WDT_MUX_NUMBER 0x4 + +static int rspll_offset; +static struct regmap *pllctrl_regs; + +/** + * rsctrl_enable_rspll_write - enable access to RSCTRL, RSCFG + * To be able to access to RSCTRL, RSCFG registers + * we have to write a key before + */ +static inline int rsctrl_enable_rspll_write(void) +{ + return regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG, + RSCTRL_KEY_MASK, RSCTRL_KEY); +} + +static int rsctrl_restart_handler(struct notifier_block *this, + unsigned long mode, void *cmd) +{ + /* enable write access to RSTCTRL */ + rsctrl_enable_rspll_write(); + + /* reset the SOC */ + regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG, + RSCTRL_RESET_MASK, 0); + + return NOTIFY_DONE; +} + +static struct notifier_block rsctrl_restart_nb = { + .notifier_call = rsctrl_restart_handler, + .priority = 128, +}; + +static const struct of_device_id rsctrl_of_match[] = { + {.compatible = "ti,keystone-reset", }, + {}, +}; + +static int rsctrl_probe(struct platform_device *pdev) +{ + int i; + int ret; + u32 val; + unsigned int rg; + u32 rsmux_offset; + struct regmap *devctrl_regs; + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + + if (!np) + return -ENODEV; + + /* get regmaps */ + pllctrl_regs = syscon_regmap_lookup_by_phandle(np, "ti,syscon-pll"); + if (IS_ERR(pllctrl_regs)) + return PTR_ERR(pllctrl_regs); + + devctrl_regs = syscon_regmap_lookup_by_phandle(np, "ti,syscon-dev"); + if (IS_ERR(devctrl_regs)) + return PTR_ERR(devctrl_regs); + + ret = of_property_read_u32_index(np, "ti,syscon-pll", 1, &rspll_offset); + if (ret) { + dev_err(dev, "couldn't read the reset pll offset!\n"); + return -EINVAL; + } + + ret = of_property_read_u32_index(np, "ti,syscon-dev", 1, &rsmux_offset); + if (ret) { + dev_err(dev, "couldn't read the rsmux offset!\n"); + return -EINVAL; + } + + /* set soft/hard reset */ + val = of_property_read_bool(np, "ti,soft-reset"); + val = val ? RSCFG_RSTYPE_SOFT : RSCFG_RSTYPE_HARD; + + ret = rsctrl_enable_rspll_write(); + if (ret) + return ret; + + ret = regmap_write(pllctrl_regs, rspll_offset + RSCFG_RG, val); + if (ret) + return ret; + + /* disable a reset isolation for all module clocks */ + ret = regmap_write(pllctrl_regs, rspll_offset + RSISO_RG, 0); + if (ret) + return ret; + + /* enable a reset for watchdogs from wdt-list */ + for (i = 0; i < WDT_MUX_NUMBER; i++) { + ret = of_property_read_u32_index(np, "ti,wdt-list", i, &val); + if (ret == -EOVERFLOW && !i) { + dev_err(dev, "ti,wdt-list property has to contain at" + "least one entry\n"); + return -EINVAL; + } else if (ret) { + break; + } + + if (val >= WDT_MUX_NUMBER) { + dev_err(dev, "ti,wdt-list property can contain" + "only numbers < 4\n"); + return -EINVAL; + } + + rg = rsmux_offset + val * 4; + + ret = regmap_update_bits(devctrl_regs, rg, RSMUX_OMODE_MASK, + RSMUX_OMODE_RESET_ON | + RSMUX_LOCK_SET); + if (ret) + return ret; + } + + ret = register_restart_handler(&rsctrl_restart_nb); + if (ret) + dev_err(dev, "cannot register restart handler (err=%d)\n", ret); + + return ret; +} + +static struct platform_driver rsctrl_driver = { + .probe = rsctrl_probe, + .driver = { + .name = KBUILD_MODNAME, + .of_match_table = rsctrl_of_match, + }, +}; +module_platform_driver(rsctrl_driver); + +MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>"); +MODULE_DESCRIPTION("Texas Instruments keystone reset driver"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:" KBUILD_MODNAME); |