[PATCH 3/3 v6] clk: Add Gemini SoC clock controller
From: Stephen Boyd <hidden>
Date: 2017-06-20 00:24:51
Also in:
linux-clk
On 06/18, Linus Walleij wrote:
The Cortina Systems Gemini (SL3516/CS3516) has an on-chip clock controller that derive all clocks from a single crystal, using some documented and some undocumented PLLs, half dividers, counters and gates. This is a best attempt to construct a clock driver for the clocks so at least we can gate off unused hardware and driver the PCI bus clock. Signed-off-by: Linus Walleij <redacted> --- Mike/Stephen: please merge this into the clk subsystem along with the <dt-bindings> patch once you're happy with it.
Looking good overall. Just the small things now.
quoted hunk ↗ jump to hunk
diff --git a/drivers/clk/clk-gemini.c b/drivers/clk/clk-gemini.c new file mode 100644 index 000000000000..810c35008d6a --- /dev/null +++ b/drivers/clk/clk-gemini.c@@ -0,0 +1,455 @@ + +static int gemini_clk_probe(struct platform_device *pdev) +{ + /* Gives the fracions 1x, 1.5x, 1.85x and 2x */ + unsigned int cpu_ahb_mult[4] = { 1, 3, 24, 2 }; + unsigned int cpu_ahb_div[4] = { 1, 2, 13, 1 }; + void __iomem *base; + struct gemini_reset *gr; + struct regmap *map; + struct clk_hw *hw; + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + unsigned int mult, div; + u32 val; + int ret; + int i; + + gr = devm_kzalloc(dev, sizeof(*gr), GFP_KERNEL); + if (!gr) + return -ENOMEM; + + /* Remap the system controller for the exclusive register */ + base = of_iomap(np, 0); + if (!base) { + dev_err(dev, "no memory base\n"); + return -ENODEV; + }
We can use normal platform device driver APIs now instead of of_iomap()?
+
+ map = syscon_node_to_regmap(np);
+ if (IS_ERR(map)) {
+ dev_err(dev, "no syscon regmap\n");
+ return PTR_ERR(map);
+ }
+
+ gr->map = map;
+ gr->rcdev.owner = THIS_MODULE;[..]
+
+static void __init gemini_cc_init(struct device_node *np)
+{
+ struct regmap *map;
+ struct clk_hw *hw;
+ unsigned long freq;
+ unsigned int mult, div;
+ u32 val;
+ int ret;
+ int i;
+
+ gemini_clk_data = kzalloc(sizeof(*gemini_clk_data) +
+ sizeof(*gemini_clk_data->hws) * GEMINI_NUM_CLKS,
+ GFP_KERNEL);
+ if (!gemini_clk_data) {
+ pr_err("out of memory for clocks\n");We don't need out of memory error messages.
+ return;
+ }
+ /*
+ * This way all clock fetched before the platform device probes,
+ * except those we assign here for early use, will be deferred.
+ */
+ for (i = 0; i < GEMINI_NUM_CLKS; i++)
+ gemini_clk_data->hws[i] = ERR_PTR(-EPROBE_DEFER);
+
+ map = syscon_node_to_regmap(np);
+ if (IS_ERR(map)) {
+ pr_err("no syscon regmap\n");
+ return;
+ }
+ /*
+ * We check that the regmap works on this very first access,
+ * but as this is an MMIO-backed regmap, subsequent regmap
+ * access is not going to fail and we skip error checks from
+ * this point.
+ */
+ ret = regmap_read(map, GEMINI_GLOBAL_STATUS, &val);
+ if (ret) {
+ pr_err("failed to read global status register\n");
+ return;
+ }
+
+ /*
+ * XTAL is the crystal oscillator, 60 or 30 MHz selected from
+ * strap pin E6
+ */
+ if (val & PLL_OSC_SEL)
+ freq = 30000000;
+ else
+ freq = 60000000;
+ hw = clk_hw_register_fixed_rate(NULL, "xtal", NULL, 0, freq);
+ pr_info("main crystal @%lu MHz\n", (freq / 1000000));Debug printk? Also drop the parenthesis around that division please.
+ + /* VCO clock derived from the crystal */ + mult = 13 + ((val >> AHBSPEED_SHIFT) & AHBSPEED_MASK); + div = 2; + /* If we run on 30 MHz crystal we have to multiply with two */ + if (val & PLL_OSC_SEL) + mult *= 2; + hw = clk_hw_register_fixed_factor(NULL, "vco", "xtal", 0, mult, div); + + /* The AHB clock is always 1/3 of the VCO */ + hw = clk_hw_register_fixed_factor(NULL, "ahb", "vco", 0, 1, 3); + gemini_clk_data->hws[GEMINI_CLK_AHB] = hw; + + /* The APB clock is always 1/6 of the AHB */ + hw = clk_hw_register_fixed_factor(NULL, "apb", "ahb", 0, 1, 6); + gemini_clk_data->hws[GEMINI_CLK_APB] = hw; + + /* Register the clocks to be accessed by the device tree */ + gemini_clk_data->num = GEMINI_NUM_CLKS; + of_clk_add_hw_provider(np, of_clk_hw_onecell_get, gemini_clk_data); +} +CLK_OF_DECLARE_DRIVER(gemini_cc, "cortina,gemini-syscon", gemini_cc_init);
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