On Wed, Aug 02, 2017 at 02:15:29PM +0930, Andrew Jeffery wrote: > Add support for configuring the drive strength and polarity on the > AST2500, and the pulse duration on both the AST2400 and AST2500. > > Signed-off-by: Andrew Jeffery <[email protected]> > Tested-by: Matt Spinler <[email protected]>
Reviewed-by: Guenter Roeck <[email protected]> > --- > drivers/watchdog/aspeed_wdt.c | 105 > ++++++++++++++++++++++++++++++++++++++++-- > 1 file changed, 102 insertions(+), 3 deletions(-) > > diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c > index c707ab647922..79cc766cd30f 100644 > --- a/drivers/watchdog/aspeed_wdt.c > +++ b/drivers/watchdog/aspeed_wdt.c > @@ -23,9 +23,21 @@ struct aspeed_wdt { > u32 ctrl; > }; > > +struct aspeed_wdt_config { > + u32 ext_pulse_width_mask; > +}; > + > +static const struct aspeed_wdt_config ast2400_config = { > + .ext_pulse_width_mask = 0xff, > +}; > + > +static const struct aspeed_wdt_config ast2500_config = { > + .ext_pulse_width_mask = 0xfffff, > +}; > + > static const struct of_device_id aspeed_wdt_of_table[] = { > - { .compatible = "aspeed,ast2400-wdt" }, > - { .compatible = "aspeed,ast2500-wdt" }, > + { .compatible = "aspeed,ast2400-wdt", .data = &ast2400_config }, > + { .compatible = "aspeed,ast2500-wdt", .data = &ast2500_config }, > { }, > }; > MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table); > @@ -43,6 +55,38 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table); > #define WDT_CTRL_RESET_SYSTEM BIT(1) > #define WDT_CTRL_ENABLE BIT(0) > > +/* > + * WDT_RESET_WIDTH controls the characteristics of the external pulse (if > + * enabled), specifically: > + * > + * * Pulse duration > + * * Drive mode: push-pull vs open-drain > + * * Polarity: Active high or active low > + * > + * Pulse duration configuration is available on both the AST2400 and AST2500, > + * though the field changes between SoCs: > + * > + * AST2400: Bits 7:0 > + * AST2500: Bits 19:0 > + * > + * This difference is captured in struct aspeed_wdt_config. > + * > + * The AST2500 exposes the drive mode and polarity options, but not in a > + * regular fashion. For read purposes, bit 31 represents active high or low, > + * and bit 30 represents push-pull or open-drain. With respect to write, > magic > + * values need to be written to the top byte to change the state of the drive > + * mode and polarity bits. Any other value written to the top byte has no > + * effect on the state of the drive mode or polarity bits. However, the pulse > + * width value must be preserved (as desired) if written. > + */ > +#define WDT_RESET_WIDTH 0x18 > +#define WDT_RESET_WIDTH_ACTIVE_HIGH BIT(31) > +#define WDT_ACTIVE_HIGH_MAGIC (0xA5 << 24) > +#define WDT_ACTIVE_LOW_MAGIC (0x5A << 24) > +#define WDT_RESET_WIDTH_PUSH_PULL BIT(30) > +#define WDT_PUSH_PULL_MAGIC (0xA8 << 24) > +#define WDT_OPEN_DRAIN_MAGIC (0x8A << 24) > + > #define WDT_RESTART_MAGIC 0x4755 > > /* 32 bits at 1MHz, in milliseconds */ > @@ -139,10 +183,13 @@ static const struct watchdog_info aspeed_wdt_info = { > > static int aspeed_wdt_probe(struct platform_device *pdev) > { > + const struct aspeed_wdt_config *config; > + const struct of_device_id *ofdid; > struct aspeed_wdt *wdt; > struct resource *res; > struct device_node *np; > const char *reset_type; > + u32 duration; > int ret; > > wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); > @@ -167,13 +214,19 @@ static int aspeed_wdt_probe(struct platform_device > *pdev) > wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT; > watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev); > > + np = pdev->dev.of_node; > + > + ofdid = of_match_node(aspeed_wdt_of_table, np); > + if (!ofdid) > + return -EINVAL; > + config = ofdid->data; > + > wdt->ctrl = WDT_CTRL_1MHZ_CLK; > > /* > * Control reset on a per-device basis to ensure the > * host is not affected by a BMC reboot > */ > - np = pdev->dev.of_node; > ret = of_property_read_string(np, "aspeed,reset-type", &reset_type); > if (ret) { > wdt->ctrl |= WDT_CTRL_RESET_MODE_SOC | WDT_CTRL_RESET_SYSTEM; > @@ -197,6 +250,52 @@ static int aspeed_wdt_probe(struct platform_device *pdev) > set_bit(WDOG_HW_RUNNING, &wdt->wdd.status); > } > > + if (of_device_is_compatible(np, "aspeed,ast2500-wdt")) { > + u32 reg = readl(wdt->base + WDT_RESET_WIDTH); > + > + reg &= config->ext_pulse_width_mask; > + if (of_property_read_bool(np, "aspeed,ext-push-pull")) > + reg |= WDT_PUSH_PULL_MAGIC; > + else > + reg |= WDT_OPEN_DRAIN_MAGIC; > + > + writel(reg, wdt->base + WDT_RESET_WIDTH); > + > + reg &= config->ext_pulse_width_mask; > + if (of_property_read_bool(np, "aspeed,ext-active-high")) > + reg |= WDT_ACTIVE_HIGH_MAGIC; > + else > + reg |= WDT_ACTIVE_LOW_MAGIC; > + > + writel(reg, wdt->base + WDT_RESET_WIDTH); > + } > + > + if (!of_property_read_u32(np, "aspeed,ext-pulse-duration", &duration)) { > + u32 max_duration = config->ext_pulse_width_mask + 1; > + > + if (duration == 0 || duration > max_duration) { > + dev_err(&pdev->dev, "Invalid pulse duration: %uus\n", > + duration); > + duration = max(1U, min(max_duration, duration)); > + dev_info(&pdev->dev, "Pulse duration set to %uus\n", > + duration); > + } > + > + /* > + * The watchdog is always configured with a 1MHz source, so > + * there is no need to scale the microsecond value. However we > + * need to offset it - from the datasheet: > + * > + * "This register decides the asserting duration of wdt_ext and > + * wdt_rstarm signal. The default value is 0xFF. It means the > + * default asserting duration of wdt_ext and wdt_rstarm is > + * 256us." > + * > + * This implies a value of 0 gives a 1us pulse. > + */ > + writel(duration - 1, wdt->base + WDT_RESET_WIDTH); > + } > + > ret = devm_watchdog_register_device(&pdev->dev, &wdt->wdd); > if (ret) { > dev_err(&pdev->dev, "failed to register\n");
