platform/x86: Enable Atom PMC platform clocks

The BayTrail and CherryTrail platforms provide platform clocks
through their Power Management Controller (PMC).

The SoC supports up to 6 clocks (PMC_PLT_CLK[0..5]) with a
frequency of either 19.2 MHz (PLL) or 25 MHz (XTAL) for BayTrail
and a frequency of 19.2 MHz (XTAL) for CherryTrail. These clocks
are available for general system use, where appropriate. For example,
the usage for platform clocks suggested in the datasheet is the
following:
  PLT_CLK[0..2] - Camera
  PLT_CLK[3] - Audio Codec
  PLT_CLK[4] -
  PLT_CLK[5] - COMMs

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/platform/x86/Kconfig

@@ -1081,3 +1081,4 @@ endif # X86_PLATFORM_DEVICES
 config PMC_ATOM
        def_bool y
        depends on PCI
+       select COMMON_CLK

drivers/platform/x86/pmc_atom.c

@@ -19,7 +19,9 @@
 #include <linux/device.h>
 #include <linux/init.h>
 #include <linux/io.h>
+#include <linux/platform_data/x86/clk-pmc-atom.h>
 #include <linux/platform_data/x86/pmc_atom.h>
+#include <linux/platform_device.h>
 #include <linux/pci.h>
 #include <linux/seq_file.h>
 
@@ -36,6 +38,11 @@ struct pmc_reg_map {
 	const struct pmc_bit_map *pss;
 };
 
+struct pmc_data {
+	const struct pmc_reg_map *map;
+	const struct pmc_clk *clks;
+};
+
 struct pmc_dev {
 	u32 base_addr;
 	void __iomem *regmap;
@@ -49,6 +56,29 @@ struct pmc_dev {
 static struct pmc_dev pmc_device;
 static u32 acpi_base_addr;
 
+static const struct pmc_clk byt_clks[] = {
+	{
+		.name = "xtal",
+		.freq = 25000000,
+		.parent_name = NULL,
+	},
+	{
+		.name = "pll",
+		.freq = 19200000,
+		.parent_name = "xtal",
+	},
+	{},
+};
+
+static const struct pmc_clk cht_clks[] = {
+	{
+		.name = "xtal",
+		.freq = 19200000,
+		.parent_name = NULL,
+	},
+	{},
+};
+
 static const struct pmc_bit_map d3_sts_0_map[] = {
 	{"LPSS1_F0_DMA",	BIT_LPSS1_F0_DMA},
 	{"LPSS1_F1_PWM1",	BIT_LPSS1_F1_PWM1},
@@ -168,6 +198,16 @@ static const struct pmc_reg_map cht_reg_map = {
 	.pss		= cht_pss_map,
 };
 
+static const struct pmc_data byt_data = {
+	.map = &byt_reg_map,
+	.clks = byt_clks,
+};
+
+static const struct pmc_data cht_data = {
+	.map = &cht_reg_map,
+	.clks = cht_clks,
+};
+
 static inline u32 pmc_reg_read(struct pmc_dev *pmc, int reg_offset)
 {
 	return readl(pmc->regmap + reg_offset);
@@ -381,10 +421,37 @@ static int pmc_dbgfs_register(struct pmc_dev *pmc)
 }
 #endif /* CONFIG_DEBUG_FS */
 
+static int pmc_setup_clks(struct pci_dev *pdev, void __iomem *pmc_regmap,
+			  const struct pmc_data *pmc_data)
+{
+	struct platform_device *clkdev;
+	struct pmc_clk_data *clk_data;
+
+	clk_data = kzalloc(sizeof(*clk_data), GFP_KERNEL);
+	if (!clk_data)
+		return -ENOMEM;
+
+	clk_data->base = pmc_regmap; /* offset is added by client */
+	clk_data->clks = pmc_data->clks;
+
+	clkdev = platform_device_register_data(&pdev->dev, "clk-pmc-atom",
+					       PLATFORM_DEVID_NONE,
+					       clk_data, sizeof(*clk_data));
+	if (IS_ERR(clkdev)) {
+		kfree(clk_data);
+		return PTR_ERR(clkdev);
+	}
+
+	kfree(clk_data);
+
+	return 0;
+}
+
 static int pmc_setup_dev(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
 	struct pmc_dev *pmc = &pmc_device;
-	const struct pmc_reg_map *map = (struct pmc_reg_map *)ent->driver_data;
+	const struct pmc_data *data = (struct pmc_data *)ent->driver_data;
+	const struct pmc_reg_map *map = data->map;
 	int ret;
 
 	/* Obtain ACPI base address */
@@ -413,6 +480,12 @@ static int pmc_setup_dev(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (ret)
 		dev_warn(&pdev->dev, "debugfs register failed\n");
 
+	/* Register platform clocks - PMC_PLT_CLK [0..5] */
+	ret = pmc_setup_clks(pdev, pmc->regmap, data);
+	if (ret)
+		dev_warn(&pdev->dev, "platform clocks register failed: %d\n",
+			 ret);
+
 	pmc->init = true;
 	return ret;
 }
@@ -423,8 +496,8 @@ static int pmc_setup_dev(struct pci_dev *pdev, const struct pci_device_id *ent)
  * used by pci_match_id() call below.
  */
 static const struct pci_device_id pmc_pci_ids[] = {
-	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_VLV_PMC), (kernel_ulong_t)&byt_reg_map },
-	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_CHT_PMC), (kernel_ulong_t)&cht_reg_map },
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_VLV_PMC), (kernel_ulong_t)&byt_data },
+	{ PCI_VDEVICE(INTEL, PCI_DEVICE_ID_CHT_PMC), (kernel_ulong_t)&cht_data },
 	{ 0, },
 };