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Date: Thu, 22 Jan 2015 09:10:40 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Lee Jones <lee.jones@...aro.org>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
CC: kernel@...inux.com, rtc-linux@...glegroups.com, wim@...ana.be,
linux-watchdog@...r.kernel.org, devicetree@...r.kernel.org,
david.paris@...com
Subject: Re: [PATCH v2 6/9] watchdog: st_wdt: Add new driver for ST's LPC
Watchdog
On 01/22/2015 03:56 AM, Lee Jones wrote:
> Signed-off-by: David Paris <david.paris@...com>
> Signed-off-by: Lee Jones <lee.jones@...aro.org>
> ---
> drivers/watchdog/Kconfig | 13 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/st_lpc_wdt.c | 335 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 349 insertions(+)
> create mode 100644 drivers/watchdog/st_lpc_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 08f41ad..a3b483c 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -471,6 +471,19 @@ config SIRFSOC_WATCHDOG
> Support for CSR SiRFprimaII and SiRFatlasVI watchdog. When
> the watchdog triggers the system will be reset.
>
> +config ST_LPC_WATCHDOG
> + tristate "STMicroelectronics LPC Watchdog"
> + depends on ARCH_STI
> + depends on OF
> + select WATCHDOG_CORE
> + select MFD_ST_LPC
> + help
> + Say Y here to include STMicroelectronics Low Power Controller
> + (LPC) based Watchdog timer support.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called st_wdt.
> +
> config TEGRA_WATCHDOG
> tristate "Tegra watchdog"
> depends on (ARCH_TEGRA || COMPILE_TEST) && HAS_IOMEM
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index c569ec8..31dd6a0 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -59,6 +59,7 @@ obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
> obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
> obj-$(CONFIG_MOXART_WDT) += moxart_wdt.o
> obj-$(CONFIG_SIRFSOC_WATCHDOG) += sirfsoc_wdt.o
> +obj-$(CONFIG_ST_LPC_WATCHDOG) += st_lpc_wdt.o
> obj-$(CONFIG_QCOM_WDT) += qcom-wdt.o
> obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o
> obj-$(CONFIG_TEGRA_WATCHDOG) += tegra_wdt.o
> diff --git a/drivers/watchdog/st_lpc_wdt.c b/drivers/watchdog/st_lpc_wdt.c
> new file mode 100644
> index 0000000..19a7e889
> --- /dev/null
> +++ b/drivers/watchdog/st_lpc_wdt.c
> @@ -0,0 +1,335 @@
> +/*
> + * st-wdt.c - ST's LPC Watchdog
> + *
> + * Copyright (C) 2014 STMicroelectronics -- All Rights Reserved
> + *
> + * Author: David Paris <david.paris@...com> for STMicroelectronics
> + * Lee Jones <lee.jones@...aro.org> for STMicroelectronics
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public Licence
> + * as published by the Free Software Foundation; either version
> + * 2 of the Licence, or (at your option) any later version.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/watchdog.h>
> +
> +#include <dt-bindings/mfd/st-lpc.h>
> +
> +/* Low Power Alarm */
> +#define LPC_LPA_LSB_OFF 0x410
> +#define LPC_LPA_START_OFF 0x418
> +
> +/* LPC as WDT */
> +#define LPC_WDT_OFF 0x510
> +
> +static struct watchdog_device st_wdog_dev;
> +
> +struct st_wdog_syscfg {
> + struct regmap *regmap;
Hi David & Lee,
Why did you add the regmap pointer to this structure and not to st_wdog ?
It is not a configuration value, after all, and it is always dereferenced
through wt_wdog->syscfg. So all it does is to make the code more complicated.
Am I missing something ?
> + unsigned int reset_type_reg;
> + unsigned int reset_type_mask;
> + unsigned int enable_reg;
> + unsigned int enable_mask;
> +};
> +
> +struct st_wdog {
> + void __iomem *base;
> + struct device *dev;
> + struct st_wdog_syscfg *syscfg;
> + struct clk *clk;
> + unsigned long clkrate;
> + bool warm_reset;
> +};
> +
> +static struct st_wdog_syscfg stid127_syscfg = {
> + .reset_type_reg = 0x004,
> + .reset_type_mask = BIT(2),
> + .enable_reg = 0x000,
> + .enable_mask = BIT(2),
> +};
> +
> +static struct st_wdog_syscfg stih415_syscfg = {
> + .reset_type_reg = 0x0B8,
> + .reset_type_mask = BIT(6),
> + .enable_reg = 0x0B4,
> + .enable_mask = BIT(7),
> +};
> +
> +static struct st_wdog_syscfg stih416_syscfg = {
> + .reset_type_reg = 0x88C,
> + .reset_type_mask = BIT(6),
> + .enable_reg = 0x888,
> + .enable_mask = BIT(7),
> +};
> +
> +static struct st_wdog_syscfg stih407_syscfg = {
> + .enable_reg = 0x204,
> + .enable_mask = BIT(19),
> +};
> +
> +static struct of_device_id st_wdog_match[] = {
> + {
> + .compatible = "st,stih407-lpc",
> + .data = &stih407_syscfg,
> + },
> + {
> + .compatible = "st,stih416-lpc",
> + .data = &stih416_syscfg,
> + },
> + {
> + .compatible = "st,stih415-lpc",
> + .data = &stih415_syscfg,
> + },
> + {
> + .compatible = "st,stid127-lpc",
> + .data = &stid127_syscfg,
> + },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, st_wdog_match);
> +
> +static void st_wdog_setup(struct st_wdog *st_wdog, bool enable)
> +{
> + /* Type of watchdog reset - 0: Cold 1: Warm */
> + if (st_wdog->syscfg->reset_type_reg)
> + regmap_update_bits(st_wdog->syscfg->regmap,
> + st_wdog->syscfg->reset_type_reg,
> + st_wdog->syscfg->reset_type_mask,
> + st_wdog->warm_reset);
> +
> + /* Mask/unmask watchdog reset */
> + regmap_update_bits(st_wdog->syscfg->regmap,
> + st_wdog->syscfg->enable_reg,
> + st_wdog->syscfg->enable_mask,
> + enable ? 0 : st_wdog->syscfg->enable_mask);
> +}
> +
> +static void st_wdog_load_timer(struct st_wdog *st_wdog, unsigned int timeout)
> +{
> + unsigned long clkrate = st_wdog->clkrate;
> +
> + writel_relaxed(timeout * clkrate, st_wdog->base + LPC_LPA_LSB_OFF);
> + writel_relaxed(1, st_wdog->base + LPC_LPA_START_OFF);
> +}
> +
> +static int st_wdog_start(struct watchdog_device *wdd)
> +{
> + struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
> +
> + writel_relaxed(1, st_wdog->base + LPC_WDT_OFF);
> +
> + return 0;
> +}
> +
> +static int st_wdog_stop(struct watchdog_device *wdd)
> +{
> + struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
> +
> + writel_relaxed(0, st_wdog->base + LPC_WDT_OFF);
> +
> + return 0;
> +}
> +
> +static int st_wdog_set_timeout(struct watchdog_device *wdd,
> + unsigned int timeout)
> +{
> + struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
> +
> + wdd->timeout = timeout;
> + st_wdog_load_timer(st_wdog, timeout);
> +
> + return 0;
> +}
> +
> +static int st_wdog_keepalive(struct watchdog_device *wdd)
> +{
> + struct st_wdog *st_wdog = watchdog_get_drvdata(wdd);
> +
> + st_wdog_load_timer(st_wdog, wdd->timeout);
> +
> + return 0;
> +}
> +
> +static const struct watchdog_info st_wdog_info = {
> + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
> + .identity = "ST LPC WDT",
> +};
> +
> +static const struct watchdog_ops st_wdog_ops = {
> + .owner = THIS_MODULE,
> + .start = st_wdog_start,
> + .stop = st_wdog_stop,
> + .ping = st_wdog_keepalive,
> + .set_timeout = st_wdog_set_timeout,
> +};
> +
> +static struct watchdog_device st_wdog_dev = {
> + .info = &st_wdog_info,
> + .ops = &st_wdog_ops,
> +};
> +
> +static int st_wdog_probe(struct platform_device *pdev)
> +{
> + const struct of_device_id *match;
> + struct device_node *np = pdev->dev.of_node;
> + struct st_wdog *st_wdog;
> + struct regmap *regmap;
> + struct resource *res;
> + struct clk *clk;
> + void __iomem *base;
> + uint32_t mode;
> + int ret;
> +
> + ret = of_property_read_u32(np, "st,lpc-mode", &mode);
> + if (ret) {
> + dev_err(&pdev->dev, "An LPC mode must be provided\n");
> + return -EINVAL;
> + }
> +
> + /* LPC can either run in RTC or WDT mode */
> + if (mode != ST_LPC_MODE_WDT)
> + return -ENODEV;
> +
> + st_wdog = devm_kzalloc(&pdev->dev, sizeof(*st_wdog), GFP_KERNEL);
> + if (!st_wdog)
> + return -ENOMEM;
> +
> + match = of_match_device(st_wdog_match, &pdev->dev);
> + if (!match) {
> + dev_err(&pdev->dev, "Couldn't match device\n");
> + return -ENODEV;
> + }
> + st_wdog->syscfg = (struct st_wdog_syscfg *)match->data;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(base)) {
> + dev_err(&pdev->dev, "Failed to ioremap base\n");
devm_ioremap_resource already displays an error message, do this one is unnecessary.
> + return PTR_ERR(base);
> + }
> +
> + regmap = syscon_regmap_lookup_by_phandle(np, "st,syscfg");
> + if (IS_ERR(regmap)) {
> + dev_err(&pdev->dev, "No syscfg phandle specified\n");
> + return PTR_ERR(regmap);
> + }
> +
> + clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(clk)) {
> + dev_err(&pdev->dev, "Unable to request clock\n");
> + return PTR_ERR(clk);
> + }
> +
> + st_wdog->dev = &pdev->dev;
> + st_wdog->base = base;
> + st_wdog->clk = clk;
> + st_wdog->syscfg->regmap = regmap;
> + st_wdog->warm_reset = of_property_read_bool(np, "st,warm_reset");
> + st_wdog->clkrate = clk_get_rate(st_wdog->clk);
> +
> + if (!st_wdog->clkrate) {
> + dev_err(&pdev->dev, "Unable to fetch clock rate\n");
> + return -EINVAL;
> + }
> + st_wdog_dev.max_timeout = 0xFFFFFFFF / st_wdog->clkrate;
> +
> + ret = clk_prepare_enable(clk);
> + if (ret) {
> + dev_err(&pdev->dev, "Unable to enable clock\n");
> + return ret;
> + }
> +
> + watchdog_set_drvdata(&st_wdog_dev, st_wdog);
> + watchdog_set_nowayout(&st_wdog_dev, WATCHDOG_NOWAYOUT);
> +
> + /* Init Watchdog timeout with value in DT */
> + ret = watchdog_init_timeout(&st_wdog_dev, 0, &pdev->dev);
> + if (ret) {
> + dev_err(&pdev->dev, "Unable to initialise watchdog timeout\n");
> + clk_disable_unprepare(clk);
> + return ret;
> + }
> +
> + ret = watchdog_register_device(&st_wdog_dev);
> + if (ret) {
> + dev_err(&pdev->dev, "Unable to register watchdog\n");
> + clk_disable_unprepare(clk);
> + return ret;
> + }
> +
> + st_wdog_setup(st_wdog, true);
> +
> + dev_info(&pdev->dev, "LPC Watchdog driver registered, reset type is %s",
> + st_wdog->warm_reset ? "warm" : "cold");
> +
> + return ret;
> +}
> +
> +static int st_wdog_remove(struct platform_device *pdev)
> +{
> + struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
> +
> + st_wdog_setup(st_wdog, false);
> + watchdog_unregister_device(&st_wdog_dev);
> + clk_disable_unprepare(st_wdog->clk);
> +
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int st_wdog_suspend(struct device *dev)
> +{
> + struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
> +
> + if (watchdog_active(&st_wdog_dev))
> + st_wdog_stop(&st_wdog_dev);
> +
> + st_wdog_setup(st_wdog, false);
> +
> + return 0;
> +}
> +
> +static int st_wdog_resume(struct device *dev)
> +{
> + struct st_wdog *st_wdog = watchdog_get_drvdata(&st_wdog_dev);
> +
> + st_wdog_setup(st_wdog, true);
> +
> + if (watchdog_active(&st_wdog_dev)) {
> + st_wdog_load_timer(st_wdog, st_wdog_dev.timeout);
> + st_wdog_start(&st_wdog_dev);
> + }
> +
> + return 0;
> +}
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(st_wdog_pm_ops,
> + st_wdog_suspend,
> + st_wdog_resume);
> +
> +static struct platform_driver st_wdog_driver = {
> + .driver = {
> + .name = "st-lpc-wdt",
> + .pm = &st_wdog_pm_ops,
> + .of_match_table = st_wdog_match,
> + },
> + .probe = st_wdog_probe,
> + .remove = st_wdog_remove,
> +};
> +module_platform_driver(st_wdog_driver);
> +
> +MODULE_AUTHOR("David Paris <david.paris@...com>");
> +MODULE_DESCRIPTION("ST LPC Watchdog Driver");
> +MODULE_LICENSE("GPL v2");
>
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