[PATCH v4 2/2] power: reset: at91-shdwc: add new shutdown controller driver

[Alexandre Belloni]

On 10/03/2016 at 16:37:40 +0100, Nicolas Ferre wrote :
> +ATMEL AT91 Alternative Shutdown Controller

Can't that be sama5d2 instead of alternative?

> +M:	Nicolas Ferre <nicolas.ferre at atmel.com>
> +S:	Supported
> +F:	drivers/power/reset/at91-shdwc.c

I would also use that in the filename. Because once there is a third
shdwc, I'm not sure how you will be able to name it.

> +config POWER_RESET_AT91_SHDWC

I would also include that in the config name.

> +	tristate "Atmel AT91 shutdown controller driver"
> +	depends on ARCH_AT91 || COMPILE_TEST
> +	default SOC_SAMA5
> +	help
> +	  This driver supports the alternate shutdown controller for some Atmel
> +	  SAMA5 SoCs. It is present for example on SAMA5D2 SoC.
> +

> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/printk.h>
> +
> +#define SLOW_CLOCK_FREQ	32768
> +
> +#define AT91_SHDW_CR	0x00		/* Shut Down Control Register */
> +#define AT91_SHDW_SHDW		BIT(0)			/* Shut Down command */
> +#define AT91_SHDW_KEY		(0xa5UL << 24)		/* KEY Password */
> +
> +#define AT91_SHDW_MR	0x04		/* Shut Down Mode Register */
> +#define AT91_SHDW_WKUPDBC_SHIFT	24
> +#define AT91_SHDW_WKUPDBC_MASK	GENMASK(31, 16)
> +#define AT91_SHDW_WKUPDBC(x)	(((x) << AT91_SHDW_WKUPDBC_SHIFT) \
> +						& AT91_SHDW_WKUPDBC_MASK)
> +
> +#define AT91_SHDW_SR	0x08		/* Shut Down Status Register */
> +#define AT91_SHDW_WKUPIS_SHIFT	16
> +#define AT91_SHDW_WKUPIS_MASK	GENMASK(31, 16)
> +#define AT91_SHDW_WKUPIS(x)	((1 << (x)) << AT91_SHDW_WKUPIS_SHIFT \
> +						& AT91_SHDW_WKUPIS_MASK)
> +
> +#define AT91_SHDW_WUIR	0x0c		/* Shutdown Wake-up Inputs Register */
> +#define AT91_SHDW_WKUPEN_MASK	GENMASK(15, 0)
> +#define AT91_SHDW_WKUPEN(x)	((1 << (x)) & AT91_SHDW_WKUPEN_MASK)
> +#define AT91_SHDW_WKUPT_SHIFT	16
> +#define AT91_SHDW_WKUPT_MASK	GENMASK(31, 16)
> +#define AT91_SHDW_WKUPT(x)	((1 << (x)) << AT91_SHDW_WKUPT_SHIFT \
> +						& AT91_SHDW_WKUPT_MASK)
> +
> +#define SHDW_WK_PIN(reg, cfg)	((reg) & AT91_SHDW_WKUPIS((cfg)->wkup_pin_input))
> +#define SHDW_RTCWK(reg, cfg)	(((reg) >> ((cfg)->sr_rtcwk_shift)) & 0x1)
> +#define SHDW_RTCWKEN(cfg)	(1 << ((cfg)->mr_rtcwk_shift))
> +
> +#define DBC_PERIOD_US(x)	DIV_ROUND_UP_ULL((1000000 * (x)), \
> +							SLOW_CLOCK_FREQ)
> +
> +struct shdwc_config {
> +	u8 wkup_pin_input;
> +	u8 mr_rtcwk_shift;
> +	u8 sr_rtcwk_shift;
> +};
> +
> +struct shdwc {
> +	struct shdwc_config *cfg;
> +	void __iomem *at91_shdwc_base;
> +};
> +
> +/*
> + * Hold configuration here, cannot be more than one instance of the driver
> + * since pm_power_off itself is global.
> + */
> +static struct shdwc *at91_shdwc;
> +static struct clk *sclk;
> +
> +static const unsigned long long sdwc_dbc_period[] = {
> +	0, 3, 32, 512, 4096, 32768,
> +};
> +
> +static void __init at91_wakeup_status(struct platform_device *pdev)
> +{
> +	struct shdwc *shdw = platform_get_drvdata(pdev);
> +	u32 reg;
> +	char *reason = "unknown";
> +
> +	reg = readl(shdw->at91_shdwc_base + AT91_SHDW_SR);
> +
> +	dev_dbg(&pdev->dev, "%s: status = %#x\n", __func__, reg);
> +
> +	/* Simple power-on, just bail out */
> +	if (!reg)
> +		return;
> +
> +	if (SHDW_WK_PIN(reg, shdw->cfg))
> +		reason = "WKUP pin";
> +	else if (SHDW_RTCWK(reg, shdw->cfg))
> +		reason = "RTC";
> +
> +	pr_info("AT91: Wake-Up source: %s\n", reason);
> +}
> +
> +static void at91_poweroff(void)
> +{
> +	writel(AT91_SHDW_KEY | AT91_SHDW_SHDW,
> +			at91_shdwc->at91_shdwc_base + AT91_SHDW_CR);

This is still not properly aligned :)

> +}
> +
> +static u32 at91_shdwc_debouncer_value(struct platform_device *pdev,
> +				      u32 in_period_us)
> +{
> +	int i;
> +	int max_idx = ARRAY_SIZE(sdwc_dbc_period) - 1;
> +	unsigned long long period_us;
> +	unsigned long long max_period_us = DBC_PERIOD_US(sdwc_dbc_period[max_idx]);
> +
> +	if (in_period_us > max_period_us) {
> +		dev_warn(&pdev->dev,
> +			 "debouncer period %u too big, reduced to %llu us\n",
> +			 in_period_us, max_period_us);
> +		return max_idx;
> +	}
> +
> +	for (i = max_idx - 1; i > 0; i--) {
> +		period_us = DBC_PERIOD_US(sdwc_dbc_period[i]);
> +		dev_dbg(&pdev->dev, "%s: ref[%d] = %llu\n",
> +						__func__, i, period_us);

Alignment is not correct.

> +		if (in_period_us > period_us)
> +			break;
> +	}
> +
> +	return i + 1;
> +}
> +
> +static u32 at91_shdwc_get_wakeup_input(struct platform_device *pdev,
> +				       struct device_node *np)
> +{
> +	struct device_node *cnp;
> +	u32 wk_input_mask;
> +	u32 wuir = 0;
> +	u32 wk_input;
> +
> +	for_each_child_of_node(np, cnp) {
> +		if (of_property_read_u32(cnp, "reg", &wk_input)) {
> +			dev_warn(&pdev->dev, "reg property is missing for %s\n",
> +				 cnp->full_name);
> +			continue;
> +		}
> +
> +		wk_input_mask = 1 << wk_input;
> +		if (!(wk_input_mask & AT91_SHDW_WKUPEN_MASK)) {
> +			dev_warn(&pdev->dev,
> +				 "wake-up input %d out of bounds ignore\n",
> +				 wk_input);
> +			continue;
> +		}
> +		wuir |= wk_input_mask;
> +
> +		if (of_property_read_bool(cnp, "atmel,wakeup-active-high"))
> +			wuir |= AT91_SHDW_WKUPT(wk_input);
> +
> +		dev_dbg(&pdev->dev, "%s: (child %d) wuir = %#x\n",
> +						__func__, wk_input, wuir);

Alignment is not correct

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com