Naidu,
On Tue, Nov 18, 2014 at 4:07 AM, <[email protected]> wrote:
> From: Naidu Tellapati <[email protected]>
>
> This commit adds support for ImgTec PowerDown Controller Watchdog Timer.
>
> Signed-off-by: Jude Abraham <[email protected]>
> Signed-off-by: Naidu Tellapati <[email protected]>
Almost there, just a couple of comments:
> --- /dev/null
> +++ b/drivers/watchdog/imgpdc_wdt.c
> +#define PDC_WD_CONFIG 0x004
> +#define PDC_WD_MAX_DELAY 31 /* 4:0 bits */
> +#define PDC_WD_CONFIG_ENABLE BIT(31)
> +#define PDC_WD_CONFIG_DELAY_MASK 0x0000001f
PDC_WD_MAX_DELAY and PDC_WD_CONFIG_DELAY_MASK are the same thing -
just pick one (probably PDC_WD_CONFIG_DELAY_MASK).
> +struct pdc_wdt_dev {
> + struct device *dev;
> + struct watchdog_device wdt_dev;
> + struct clk *wdt_clk;
> + struct clk *sys_clk;
> + unsigned long clk_rate;
> + unsigned int min_delay;
> + void __iomem *base;
> + spinlock_t lock;
Now that there's no clock notifier, I don't think you need this
spinlock anymore.
> +static int pdc_wdt_set_timeout(struct watchdog_device *wdt_dev,
> + unsigned int new_timeout)
> +{
> + unsigned int val;
> + struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
> +
> + if (new_timeout < wdt->wdt_dev.min_timeout ||
> + new_timeout > wdt->wdt_dev.max_timeout)
> + return -EINVAL;
The watchdog core already does this check for us.
> + spin_lock(&wdt->lock);
> + wdt->wdt_dev.timeout = new_timeout;
> + /* round up to the next power of 2 */
> + new_timeout = order_base_2(new_timeout);
> + val = readl(wdt->base + PDC_WD_CONFIG);
> + val &= ~(PDC_WD_CONFIG_DELAY_MASK << PDC_WD_CONFIG_DELAY_SHIFT);
> + val |= (new_timeout + wdt->min_delay);
This should be shifted by PDC_WD_CONFIG_DELAY_SHIFT.
> +static struct watchdog_info pdc_wdt_info = {
> + .options = WDIOF_SETTIMEOUT |
> + WDIOF_KEEPALIVEPING |
> + WDIOF_MAGICCLOSE,
> + .identity = "PDC Watchdog",
Maybe "IMG PDC Watchdog"?
> +static int pdc_wdt_probe(struct platform_device *pdev)
> +{
> + int ret, val;
> + struct resource *res;
> + struct pdc_wdt_dev *pdc_wdt;
> +
> + pdc_wdt = devm_kzalloc(&pdev->dev, sizeof(*pdc_wdt), GFP_KERNEL);
> + if (!pdc_wdt)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + pdc_wdt->base = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(pdc_wdt->base))
> + return PTR_ERR(pdc_wdt->base);
> +
> + pdc_wdt->sys_clk = devm_clk_get(&pdev->dev, "sys");
> + if (IS_ERR(pdc_wdt->sys_clk)) {
> + dev_err(&pdev->dev, "failed to get the sys clock.\n");
> + ret = PTR_ERR(pdc_wdt->wdt_clk);
> + goto out_wdt;
> + }
> +
> + spin_lock_init(&pdc_wdt->lock);
> +
> + pdc_wdt->wdt_clk = devm_clk_get(&pdev->dev, "wdt");
> + if (IS_ERR(pdc_wdt->wdt_clk)) {
> + dev_err(&pdev->dev, "failed to get the wdt clock.\n");
> + ret = PTR_ERR(pdc_wdt->wdt_clk);
> + goto out_wdt;
> + }
> +
> + ret = clk_prepare_enable(pdc_wdt->sys_clk);
> + if (ret) {
> + dev_err(&pdev->dev, "could not prepare or enable sys
> clock.\n");
> + goto out_wdt;
> + }
> +
> + ret = clk_prepare_enable(pdc_wdt->wdt_clk);
> + if (ret) {
> + dev_err(&pdev->dev, "could not prepare or enable wdt
> clock.\n");
> + goto disable_sys_clk;
> + }
> + /* We use the clock rate to calculate the max timeout */
> + pdc_wdt->clk_rate = clk_get_rate(pdc_wdt->wdt_clk);
> + if (pdc_wdt->clk_rate < 1 || pdc_wdt->clk_rate > PDC_WD_MAX_CLK_RATE)
> {
> + dev_err(&pdev->dev, "invalid clock rate\n");
> + ret = -EINVAL;
> + goto disable_wdt_clk;
> + }
Does a maximum rate really need to be enforced? I know rates greater
than 50Mhz aren't recommended, but I believe you can still configure
the clock controller to do so.
The check for a clock rate of 0 is fine - that would indicate that
clk_get_rate() failed to get the rate.
> + if (order_base_2(pdc_wdt->clk_rate) == 0)
> + pdc_wdt->min_delay = 0;
> + else
> + pdc_wdt->min_delay = order_base_2(pdc_wdt->clk_rate) - 1;
> +
> + pdc_wdt->wdt_dev.info = &pdc_wdt_info;
> + pdc_wdt->wdt_dev.ops = &pdc_wdt_ops;
> + pdc_wdt->wdt_dev.min_timeout = PDC_WD_MIN_TIMEOUT;
> + pdc_wdt->wdt_dev.max_timeout =
> + (1 << (PDC_WD_MAX_DELAY -
> pdc_wdt->min_delay));
> + pdc_wdt->wdt_dev.parent = &pdev->dev;
> + pdc_wdt->dev = &pdev->dev;
> +
> + ret = watchdog_init_timeout(&pdc_wdt->wdt_dev, timeout, &pdev->dev);
> + if (ret < 0)
> + pdc_wdt->wdt_dev.timeout = pdc_wdt->wdt_dev.max_timeout;
> +
> + pdc_wdt_stop(&pdc_wdt->wdt_dev);
> + /* Set timeouts before userland has a chance to start the timer */
> + pdc_wdt_set_timeout(&pdc_wdt->wdt_dev, pdc_wdt->wdt_dev.timeout);
The stop() is fine, but I don't think it's necessary to set the timeout.
> +static int pdc_wdt_remove(struct platform_device *pdev)
> +{
> + struct pdc_wdt_dev *pdc_wdt = platform_get_drvdata(pdev);
> +
> + pdc_wdt_shutdown(pdev);
Just call pdc_wdt_stop() directly.
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