clk: x86: Do not gate clocks enabled by the firmware

Read the enable register to determine if the clock is already in use by
the firmware. In this case avoid gating the clock.

Tested-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Darren Hart (VMware) <dvhart@infradead.org>
Signed-off-by: Carlo Caione <carlo@endlessm.com>
Fixes: 282a4e4ce5f9 ("platform/x86: Enable Atom PMC platform clocks")
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

diff --git a/drivers/clk/x86/clk-pmc-atom.c b/drivers/clk/x86/clk-pmc-atom.c
index f99abc1106f0cb725ff7c63e9bc84b75596a4e75..08ef69945ffbf425efa001d48c6c9b5b0f4333eb 100644 (file)
--- a/drivers/clk/x86/clk-pmc-atom.c
+++ b/drivers/clk/x86/clk-pmc-atom.c
@@ -186,6 +186,13 @@ static struct clk_plt *plt_clk_register(struct platform_device *pdev, int id,
        pclk->reg = base + PMC_CLK_CTL_OFFSET + id * PMC_CLK_CTL_SIZE;
        spin_lock_init(&pclk->lock);
 
+       /*
+        * If the clock was already enabled by the firmware mark it as critical
+        * to avoid it being gated by the clock framework if no driver owns it.
+        */
+       if (plt_clk_is_enabled(&pclk->hw))
+               init.flags |= CLK_IS_CRITICAL;
+
        ret = devm_clk_hw_register(&pdev->dev, &pclk->hw);
        if (ret) {
                pclk = ERR_PTR(ret);