Re: [PATCH v2] power: reset: at91-shdwc: add new shutdown controller driver

From: Alexandre Belloni
Date: Thu Sep 24 2015 - 07:06:59 EST


On 22/09/2015 at 17:57:52 +0200, Nicolas Ferre wrote :
> +config POWER_RESET_AT91_SHDWC

Maybe we should start numbering, at91-poweroff is already a driver for
an shdwc.

> +#define SLOW_CLOCK_FREQ 32768
> +

The slow clock is an input to the shdwc, then you have to get it,
prepare and enable it. The you could use clk_get_rate.
By duplicating the driver, you are repeating mistakes from the past ;)


> +static void at91_poweroff(void)
> +{
> + BUG_ON(!at91_shdwc);

Is that condition even possible?

> +
> + writel(AT91_SHDW_KEY | AT91_SHDW_SHDW,
> + at91_shdwc->at91_shdwc_base + AT91_SHDW_CR);

This is 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);
ditto


> + 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;
> + const char *pm;
> + 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_string(cnp, "atmel,wakeup-type", &pm)) {
> + if (!strcasecmp(pm, "high"))
> + /*
> + * only add a type if "high" is specified. Low
> + * is the default.
> + */
> + wuir |= AT91_SHDW_WKUPT(wk_input);
> + }
> + dev_dbg(&pdev->dev, "%s: (child %d) wuir = %#x\n",
> + __func__, wk_input, wuir);

ditto

> +static int at91_shdwc_probe(struct platform_device *pdev)
> +{
> + struct resource *res;
> + const struct of_device_id *match;
> +
> + if (!pdev->dev.of_node)
> + return -ENODEV;
> +
> + at91_shdwc = devm_kzalloc(&pdev->dev, sizeof(*at91_shdwc), GFP_KERNEL);
> + if (!at91_shdwc)
> + return -ENOMEM;
> +
> + platform_set_drvdata(pdev, at91_shdwc);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + at91_shdwc->at91_shdwc_base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(at91_shdwc->at91_shdwc_base)) {
> + dev_err(&pdev->dev, "Could not map reset controller address\n");
> + return PTR_ERR(at91_shdwc->at91_shdwc_base);
> + }
> +
> + match = of_match_node(at91_shdwc_of_match, pdev->dev.of_node);
> + if (match != NULL)

match will never be NULL, else you wouldn't be probed. You can remove that test.

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