i2c: designware_i2c: Support ACPI table generation

Update the PCI driver to generate ACPI information so that Linux has the
full information about each I2C bus.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
[bmeng: Correct one typo in dw_i2c_gen_speed_config() comments]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>

drivers/i2c/designware_i2c.c

@@ -333,6 +333,32 @@ static int _dw_i2c_set_bus_speed(struct dw_i2c *priv, struct i2c_regs *i2c_base,
 	/* Restore back i2c now speed set */
 	if (ena == IC_ENABLE_0B)
 		dw_i2c_enable(i2c_base, true);
+	if (priv)
+		priv->config = config;
+
+	return 0;
+}
+
+int dw_i2c_gen_speed_config(const struct udevice *dev, int speed_hz,
+			    struct dw_i2c_speed_config *config)
+{
+	struct dw_i2c *priv = dev_get_priv(dev);
+	ulong rate;
+	int ret;
+
+#if CONFIG_IS_ENABLED(CLK)
+	rate = clk_get_rate(&priv->clk);
+	if (IS_ERR_VALUE(rate))
+		return log_msg_ret("clk", -EINVAL);
+#else
+	rate = IC_CLK;
+#endif
+
+	ret = calc_bus_speed(priv, priv->regs, speed_hz, rate, config);
+	if (ret)
+		printf("%s: ret=%d\n", __func__, ret);
+	if (ret)
+		return log_msg_ret("calc_bus_speed", ret);
 
 	return 0;
 }

drivers/i2c/designware_i2c.h

@@ -205,6 +205,7 @@ struct dw_i2c {
 #if CONFIG_IS_ENABLED(CLK)
 	struct clk clk;
 #endif
+	struct dw_i2c_speed_config config;
 };
 
 extern const struct dm_i2c_ops designware_i2c_ops;
@@ -213,4 +214,18 @@ int designware_i2c_probe(struct udevice *bus);
 int designware_i2c_remove(struct udevice *dev);
 int designware_i2c_ofdata_to_platdata(struct udevice *bus);
 
+/**
+ * dw_i2c_gen_speed_config() - Calculate config info from requested speed
+ *
+ * Calculate the speed config from the given @speed_hz and return it so that
+ * it can be incorporated in ACPI tables
+ *
+ * @dev: I2C bus to check
+ * @speed_hz: Requested speed in Hz
+ * @config: Returns config to use for that speed
+ * @return 0 if OK, -ve on error
+ */
+int dw_i2c_gen_speed_config(const struct udevice *dev, int speed_hz,
+			    struct dw_i2c_speed_config *config);
+
 #endif /* __DW_I2C_H_ */

drivers/i2c/designware_i2c_pci.c

@@ -9,7 +9,12 @@
 #include <dm.h>
 #include <log.h>
 #include <spl.h>
+#include <acpi/acpigen.h>
+#include <acpi/acpi_device.h>
 #include <asm/lpss.h>
+#include <dm/acpi.h>
+#include <dm/device-internal.h>
+#include <dm/uclass-internal.h>
 #include "designware_i2c.h"
 
 enum {
@@ -87,6 +92,9 @@ static int designware_i2c_pci_bind(struct udevice *dev)
 {
 	char name[20];
 
+	if (dev_of_valid(dev))
+		return 0;
+
 	/*
 	 * Create a unique device name for PCI type devices
 	 * ToDo:
@@ -100,13 +108,98 @@ static int designware_i2c_pci_bind(struct udevice *dev)
 	 * be possible. We cannot use static data in drivers since they may be
 	 * used in SPL or before relocation.
 	 */
-	dev->req_seq = gd->arch.dw_i2c_num_cards++;
+	dev->req_seq = uclass_find_next_free_req_seq(UCLASS_I2C);
 	sprintf(name, "i2c_designware#%u", dev->req_seq);
 	device_set_name(dev, name);
 
 	return 0;
 }
 
+/*
+ * Write ACPI object to describe speed configuration.
+ *
+ * ACPI Object: Name ("xxxx", Package () { scl_lcnt, scl_hcnt, sda_hold }
+ *
+ * SSCN: I2C_SPEED_STANDARD
+ * FMCN: I2C_SPEED_FAST
+ * FPCN: I2C_SPEED_FAST_PLUS
+ * HSCN: I2C_SPEED_HIGH
+ */
+static void dw_i2c_acpi_write_speed_config(struct acpi_ctx *ctx,
+					   struct dw_i2c_speed_config *config)
+{
+	switch (config->speed_mode) {
+	case IC_SPEED_MODE_HIGH:
+		acpigen_write_name(ctx, "HSCN");
+		break;
+	case IC_SPEED_MODE_FAST_PLUS:
+		acpigen_write_name(ctx, "FPCN");
+		break;
+	case IC_SPEED_MODE_FAST:
+		acpigen_write_name(ctx, "FMCN");
+		break;
+	case IC_SPEED_MODE_STANDARD:
+	default:
+		acpigen_write_name(ctx, "SSCN");
+	}
+
+	/* Package () { scl_lcnt, scl_hcnt, sda_hold } */
+	acpigen_write_package(ctx, 3);
+	acpigen_write_word(ctx, config->scl_hcnt);
+	acpigen_write_word(ctx, config->scl_lcnt);
+	acpigen_write_dword(ctx, config->sda_hold);
+	acpigen_pop_len(ctx);
+}
+
+/*
+ * Generate I2C timing information into the SSDT for the OS driver to consume,
+ * optionally applying override values provided by the caller.
+ */
+static int dw_i2c_acpi_fill_ssdt(const struct udevice *dev,
+				 struct acpi_ctx *ctx)
+{
+	struct dw_i2c_speed_config config;
+	char path[ACPI_PATH_MAX];
+	u32 speeds[4];
+	uint speed;
+	int size;
+	int ret;
+
+	/* If no device-tree node, ignore this since we assume it isn't used */
+	if (!dev_of_valid(dev))
+		return 0;
+
+	ret = acpi_device_path(dev, path, sizeof(path));
+	if (ret)
+		return log_msg_ret("path", ret);
+
+	size = dev_read_size(dev, "i2c,speeds");
+	if (size < 0)
+		return log_msg_ret("i2c,speeds", -EINVAL);
+
+	size /= sizeof(u32);
+	if (size > ARRAY_SIZE(speeds))
+		return log_msg_ret("array", -E2BIG);
+
+	ret = dev_read_u32_array(dev, "i2c,speeds", speeds, size);
+	if (ret)
+		return log_msg_ret("read", -E2BIG);
+
+	speed = dev_read_u32_default(dev, "clock-frequency", 100000);
+	acpigen_write_scope(ctx, path);
+	ret = dw_i2c_gen_speed_config(dev, speed, &config);
+	if (ret)
+		return log_msg_ret("config", ret);
+	dw_i2c_acpi_write_speed_config(ctx, &config);
+	acpigen_pop_len(ctx);
+
+	return 0;
+}
+
+struct acpi_ops dw_i2c_acpi_ops = {
+	.fill_ssdt	= dw_i2c_acpi_fill_ssdt,
+};
+
 static const struct udevice_id designware_i2c_pci_ids[] = {
 	{ .compatible = "snps,designware-i2c-pci" },
 	{ .compatible = "intel,apl-i2c", .data = INTEL_APL },
@@ -124,6 +217,7 @@ U_BOOT_DRIVER(i2c_designware_pci) = {
 	.remove = designware_i2c_remove,
 	.flags = DM_FLAG_OS_PREPARE,
 	.ops	= &designware_i2c_ops,
+	ACPI_OPS_PTR(&dw_i2c_acpi_ops)
 };
 
 static struct pci_device_id designware_pci_supported[] = {