Thread (6 messages) 6 messages, 2 authors, 2016-03-16

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

From: Nicolas Ferre <hidden>
Date: 2016-03-16 11:36:52
Also in: linux-arm-kernel, lkml

Le 14/03/2016 21:22, Alexandre Belloni a écrit :
On 10/03/2016 at 16:37:40 +0100, Nicolas Ferre wrote :
quoted
+ATMEL AT91 Alternative Shutdown Controller
Can't that be sama5d2 instead of alternative?
quoted
+M:	Nicolas Ferre [off-list ref]
+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.
quoted
+config POWER_RESET_AT91_SHDWC
I would also include that in the config name.
quoted
+	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.
+
quoted
+#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 :)
Ok for this one.

quoted
+}
+
+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.
quoted
+		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
I don't agree with you on the 2 last ones. In Documentation/CodingStyle,
it is said that:

"Chapter 2: Breaking long lines and strings
[..]
Descendants are always substantially shorter than the parent and
are placed substantially to the right."

Together with the 80 column requirement that I also fulfil, I think that
my code is well aligned.

So I keep it like this ;-)

Bye,
-- 
Nicolas Ferre
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