Re: [PATCH v2 3/5] watchdog: ts4800: add driver for TS-4800 watchdog

Lee Jones
2015-10-30T17:28:17Z

Where is your change-log?

I have no idea what the intention of this patch is.

> Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
> ---
> .../devicetree/bindings/mfd/ts4800-syscon.txt | 8 +
> .../devicetree/bindings/watchdog/ts4800-wdt.txt | 12 ++

These should be in a seperate patch.

> drivers/mfd/Kconfig | 1 +
> drivers/mfd/ts4800-syscon.c | 13 +-
> drivers/watchdog/Kconfig | 10 +
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/ts4800_wdt.c | 216 +++++++++++++++++++++
> 7 files changed, 260 insertions(+), 1 deletion(-)
> create mode 100644 Documentation/devicetree/bindings/watchdog/ts4800-wdt.txt
> create mode 100644 drivers/watchdog/ts4800_wdt.c
>
> diff --git a/Documentation/devicetree/bindings/mfd/ts4800-syscon.txt b/Documentation/devicetree/bindings/mfd/ts4800-syscon.txt
> index 8dbc12c..8c0fd1d 100644
> --- a/Documentation/devicetree/bindings/mfd/ts4800-syscon.txt
> +++ b/Documentation/devicetree/bindings/mfd/ts4800-syscon.txt
> @@ -4,9 +4,17 @@ Required properties:
> - compatible : must be "ts,ts4800-syscon"
> - reg : physical base address and length of memory mapped region
>
> +The driver exposes following subdevices:
> +- a watchdog: see ../watchdog/ts4800-wdt.txt
> +
> Example:
>
> syscon@b0010000 {
> compatible = "ts,ts4800-syscon";
> reg = <0xb0010000 0x3d>;
> +
> + wdt@e {
> + compatible = "ts,ts4800-wdt";
> + offset = <0xe>;
> + };
> };
> diff --git a/Documentation/devicetree/bindings/watchdog/ts4800-wdt.txt b/Documentation/devicetree/bindings/watchdog/ts4800-wdt.txt
> new file mode 100644
> index 0000000..a9305c2
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/watchdog/ts4800-wdt.txt
> @@ -0,0 +1,12 @@
> +Technologic Systems Watchdog
> +
> +Required properties:
> +- compatible : must be "ts,ts4800-wdt"
> +- offset : offset of the feed register from syscon base
> +
> +Example:
> +
> +wdt1: wdt@b0010000 {
> + compatible = "ts,ts4800-wdt";
> + offset = <0xe>;
> +};
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 8f03dce..95ba036 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -1304,6 +1304,7 @@ config MFD_TC6393XB
>
> config MFD_TS4800_SYSCON
> tristate "TS-4800 Syscon Support"
> + select MFD_CORE
> select REGMAP
> select REGMAP_MMIO
> help

This change is orthogonal and has not place in this patch.

> diff --git a/drivers/mfd/ts4800-syscon.c b/drivers/mfd/ts4800-syscon.c
> index 1e42e96..03b3b04a 100644
> --- a/drivers/mfd/ts4800-syscon.c
> +++ b/drivers/mfd/ts4800-syscon.c
> @@ -24,6 +24,13 @@
> #include <linux/mfd/ts4800-syscon.h>
>
>
> +static const struct mfd_cell ts4800_syscon_cells[] = {
> + {
> + .name = "ts4800-watchdog",
> + .of_compatible = "ts,ts4800-wdt",
> + },
> +};
> +
> static const struct regmap_config ts4800_regmap_config = {
> .reg_bits = 32,
> .reg_stride = 2,
> @@ -56,11 +63,15 @@ static int ts4800_syscon_probe(struct platform_device *pdev)
>
> platform_set_drvdata(pdev, syscon);
>
> - return 0;
> + return mfd_add_devices(&pdev->dev, -1, ts4800_syscon_cells,
> + ARRAY_SIZE(ts4800_syscon_cells),
> + NULL, 0, NULL);
> }
>
> static int ts4800_syscon_remove(struct platform_device *pdev)
> {
> + mfd_remove_devices(&pdev->dev);
> +
> return 0;
> }
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 241fafd..aaa42b8 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -417,6 +417,16 @@ config NUC900_WATCHDOG
> To compile this driver as a module, choose M here: the
> module will be called nuc900_wdt.
>
> +config TS4800_WATCHDOG
> + tristate "TS-4800 Watchdog"
> + depends on OF
> + depends on MFD_TS4800_SYSCON
> + select WATCHDOG_CORE
> + help
> + Technologic Systems TS-4800 has watchdog timer implemented in
> + an external FPGA. Say Y here if you want to support for the
> + watchdog timer on TS-4800 board.
> +
> config TS72XX_WATCHDOG
> tristate "TS-72XX SBC Watchdog"
> depends on MACH_TS72XX
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 59ea9a1..435fc93 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -52,6 +52,7 @@ obj-$(CONFIG_RN5T618_WATCHDOG) += rn5t618_wdt.o
> obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o
> obj-$(CONFIG_STMP3XXX_RTC_WATCHDOG) += stmp3xxx_rtc_wdt.o
> obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
> +obj-$(CONFIG_TS4800_WATCHDOG) += ts4800_wdt.o
> obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
> obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
> obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
> diff --git a/drivers/watchdog/ts4800_wdt.c b/drivers/watchdog/ts4800_wdt.c
> new file mode 100644
> index 0000000..9b9e638
> --- /dev/null
> +++ b/drivers/watchdog/ts4800_wdt.c
> @@ -0,0 +1,216 @@
> +/*
> + * ts4800_wdt.c - Watchdog driver for TS-4800 based boards
> + *
> + * Copyright (c) 2015 - Savoir-faire Linux
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/watchdog.h>
> +#include <linux/platform_device.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/mfd/ts4800-syscon.h>
> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +module_param(nowayout, bool, 0);
> +MODULE_PARM_DESC(nowayout,
> + "Watchdog cannot be stopped once started (default="
> + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> +
> +
> +/* possible feed values */
> +#define TS4800_WDT_FEED_2S 0x1
> +#define TS4800_WDT_FEED_10S 0x2
> +#define TS4800_WDT_DISABLE 0x3
> +
> +
> +struct ts4800_wdt {
> + struct watchdog_device wdd;
> + struct regmap *regmap;
> + u32 feed_offset;
> + u16 feed_val;
> +};
> +
> +/*
> + * TS-4800 supports the following timeout values:
> + *
> + * value desc
> + * ---------------------
> + * 0 feed for 338ms
> + * 1 feed for 2.706s
> + * 2 feed for 10.824s
> + * 3 disable watchdog
> + *
> + * Keep the regmap/timeout map ordered by timeout
> + */
> +static const struct {
> + const int timeout;
> + const int regval;
> +} ts4800_wdt_map[] = {
> + { 2, TS4800_WDT_FEED_2S },
> + { 10, TS4800_WDT_FEED_10S },
> +};
> +
> +static int timeout_to_regval(struct watchdog_device *wdd, int new_timeout)
> +{
> + int i;
> +
> + new_timeout = clamp_val(new_timeout,
> + wdd->min_timeout, wdd->max_timeout);
> +
> + for (i = 0; i < ARRAY_SIZE(ts4800_wdt_map); i++) {
> + if (ts4800_wdt_map[i].timeout >= new_timeout)
> + return ts4800_wdt_map[i].timeout;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static void ts4800_write_feed(struct ts4800_wdt *wdt, u16 val)
> +{
> + regmap_write(wdt->regmap, wdt->feed_offset, val);
> +}
> +
> +static int ts4800_wdt_ping(struct watchdog_device *wdd)
> +{
> + struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);
> +
> + ts4800_write_feed(wdt, wdt->feed_val);
> + return 0;
> +}
> +
> +static int ts4800_wdt_stop(struct watchdog_device *wdd)
> +{
> + struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);
> +
> + ts4800_write_feed(wdt, TS4800_WDT_DISABLE);
> + return 0;
> +}
> +
> +static int ts4800_wdt_set_timeout(struct watchdog_device *wdd,
> + unsigned int new_timeout)
> +{
> + struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);
> + int val = timeout_to_regval(wdd, new_timeout);
> +
> + if (val < 0)
> + return val;
> +
> + wdt->feed_val = (u16) val;
> +
> + return 0;
> +}
> +
> +static const struct watchdog_ops ts4800_wdt_ops = {
> + .owner = THIS_MODULE,
> + /*
> + * pinging the watchdog enables it, so use same function
> + * for pinging and starting the watchdog
> + */
> + .start = ts4800_wdt_ping,
> + .stop = ts4800_wdt_stop,
> + .ping = ts4800_wdt_ping,
> + .set_timeout = ts4800_wdt_set_timeout,
> +};
> +
> +static const struct watchdog_info ts4800_wdt_info = {
> + .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
> + .identity = "TS-4800 Watchdog",
> +};
> +
> +static int ts4800_wdt_probe(struct platform_device *pdev)
> +{
> + int max_timeout_index = ARRAY_SIZE(ts4800_wdt_map) - 1;
> + struct device_node *np = pdev->dev.of_node;
> + struct ts4800_syscon *syscon;
> + struct watchdog_device *wdd;
> + struct ts4800_wdt *wdt;
> + u32 offset;
> + int ret;
> +
> + ret = of_property_read_u32(np, "offset", &offset);
> + if (ret) {
> + dev_err(&pdev->dev, "An offset must be provided\n");
> + return -EINVAL;
> + }
> +
> + /* allocate memory for watchdog struct */
> + wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
> + if (!wdt)
> + return -ENOMEM;
> +
> + /* set regmap and offset to know where to write */
> + syscon = dev_get_drvdata(pdev->dev.parent);
> + wdt->regmap = syscon->regmap;
> + wdt->feed_offset = offset;
> +
> + /* Initialize struct watchdog_device */
> + wdd = &wdt->wdd;
> + wdd->info = &ts4800_wdt_info;
> + wdd->ops = &ts4800_wdt_ops;
> + wdd->min_timeout = ts4800_wdt_map[0].timeout;
> + wdd->max_timeout = ts4800_wdt_map[max_timeout_index].timeout;
> + wdd->timeout = wdd->max_timeout;
> + wdt->feed_val = ts4800_wdt_map[max_timeout_index].regval;
> +
> + watchdog_set_drvdata(wdd, wdt);
> + watchdog_set_nowayout(wdd, nowayout);
> +
> + /*
> + * Must be called after watchdog_set_drvdata to dereference a valid
> + * pointer. The feed register is write-only, so it is not possible to
> + * determine if watchdog is already started or not. Disable it to be in
> + * a known state.
> + */
> + ts4800_wdt_stop(wdd);
> +
> + ret = watchdog_register_device(wdd);
> + if (ret) {
> + dev_err(&pdev->dev,
> + "failed to register watchdog device\n");
> + return ret;
> + }
> +
> + platform_set_drvdata(pdev, wdt);
> +
> + dev_info(&pdev->dev,
> + "initialized (timeout = %d sec, nowayout = %d)\n",
> + wdd->timeout, nowayout);
> +
> + return 0;
> +}
> +
> +static int ts4800_wdt_remove(struct platform_device *pdev)
> +{
> + struct ts4800_wdt *wdt = platform_get_drvdata(pdev);
> +
> + watchdog_unregister_device(&wdt->wdd);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id ts4800_wdt_of_match[] = {
> + { .compatible = "ts,ts4800-wdt", },
> + { },
> +};
> +MODULE_DEVICE_TABLE(of, ts4800_wdt_of_match);
> +
> +static struct platform_driver ts4800_wdt_driver = {
> + .probe = ts4800_wdt_probe,
> + .remove = ts4800_wdt_remove,
> + .driver = {
> + .name = "ts4800_wdt",
> + .of_match_table = ts4800_wdt_of_match,
> + },
> +};
> +
> +module_platform_driver(ts4800_wdt_driver);
> +
> +MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:ts4800_wdt");

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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