i2c: designware: Move ACPI parts into common module

For possible code reuse in the future, move ACPI parts into common module.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

1 files changed, 131 insertions, 4 deletions

diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c
index 2fd5372b1237..e1697ed8b54a 100644
--- a/drivers/i2c/busses/i2c-designware-common.c
+++ b/drivers/i2c/busses/i2c-designware-common.c
@@ -8,17 +8,21 @@
  * Copyright (C) 2007 MontaVista Software Inc.
  * Copyright (C) 2009 Provigent Ltd.
  */
+#include <linux/acpi.h>
 #include <linux/clk.h>
 #include <linux/delay.h>
-#include <linux/export.h>
-#include <linux/errno.h>
+#include <linux/device.h>
 #include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/export.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
 #include <linux/swab.h>
+#include <linux/types.h>
 
 #include "i2c-designware-core.h"
 
@@ -116,6 +120,13 @@ int i2c_dw_set_reg_access(struct dw_i2c_dev *dev)
 	return 0;
 }
 
+static const u32 supported_speeds[] = {
+	I2C_MAX_HIGH_SPEED_MODE_FREQ,
+	I2C_MAX_FAST_MODE_PLUS_FREQ,
+	I2C_MAX_FAST_MODE_FREQ,
+	I2C_MAX_STANDARD_MODE_FREQ,
+};
+
 int i2c_dw_validate_speed(struct dw_i2c_dev *dev)
 {
 	struct i2c_timings *t = &dev->timings;
@@ -125,8 +136,8 @@ int i2c_dw_validate_speed(struct dw_i2c_dev *dev)
 	 * Only standard mode at 100kHz, fast mode at 400kHz,
 	 * fast mode plus at 1MHz and high speed mode at 3.4MHz are supported.
 	 */
-	for (i = 0; i < ARRAY_SIZE(i2c_dw_supported_speeds); i++) {
-		if (t->bus_freq_hz == i2c_dw_supported_speeds[i])
+	for (i = 0; i < ARRAY_SIZE(supported_speeds); i++) {
+		if (t->bus_freq_hz == supported_speeds[i])
 			return 0;
 	}
 
@@ -138,6 +149,122 @@ int i2c_dw_validate_speed(struct dw_i2c_dev *dev)
 }
 EXPORT_SYMBOL_GPL(i2c_dw_validate_speed);
 
+#ifdef CONFIG_ACPI
+
+#include <linux/dmi.h>
+
+/*
+ * The HCNT/LCNT information coming from ACPI should be the most accurate
+ * for given platform. However, some systems get it wrong. On such systems
+ * we get better results by calculating those based on the input clock.
+ */
+static const struct dmi_system_id i2c_dw_no_acpi_params[] = {
+	{
+		.ident = "Dell Inspiron 7348",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7348"),
+		},
+	},
+	{}
+};
+
+static void i2c_dw_acpi_params(struct device *device, char method[],
+			       u16 *hcnt, u16 *lcnt, u32 *sda_hold)
+{
+	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
+	acpi_handle handle = ACPI_HANDLE(device);
+	union acpi_object *obj;
+
+	if (dmi_check_system(i2c_dw_no_acpi_params))
+		return;
+
+	if (ACPI_FAILURE(acpi_evaluate_object(handle, method, NULL, &buf)))
+		return;
+
+	obj = (union acpi_object *)buf.pointer;
+	if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 3) {
+		const union acpi_object *objs = obj->package.elements;
+
+		*hcnt = (u16)objs[0].integer.value;
+		*lcnt = (u16)objs[1].integer.value;
+		*sda_hold = (u32)objs[2].integer.value;
+	}
+
+	kfree(buf.pointer);
+}
+
+int i2c_dw_acpi_configure(struct device *device)
+{
+	struct dw_i2c_dev *dev = dev_get_drvdata(device);
+	struct i2c_timings *t = &dev->timings;
+	u32 ss_ht = 0, fp_ht = 0, hs_ht = 0, fs_ht = 0;
+
+	dev->tx_fifo_depth = 32;
+	dev->rx_fifo_depth = 32;
+
+	/*
+	 * Try to get SDA hold time and *CNT values from an ACPI method for
+	 * selected speed modes.
+	 */
+	i2c_dw_acpi_params(device, "SSCN", &dev->ss_hcnt, &dev->ss_lcnt, &ss_ht);
+	i2c_dw_acpi_params(device, "FPCN", &dev->fp_hcnt, &dev->fp_lcnt, &fp_ht);
+	i2c_dw_acpi_params(device, "HSCN", &dev->hs_hcnt, &dev->hs_lcnt, &hs_ht);
+	i2c_dw_acpi_params(device, "FMCN", &dev->fs_hcnt, &dev->fs_lcnt, &fs_ht);
+
+	switch (t->bus_freq_hz) {
+	case I2C_MAX_STANDARD_MODE_FREQ:
+		dev->sda_hold_time = ss_ht;
+		break;
+	case I2C_MAX_FAST_MODE_PLUS_FREQ:
+		dev->sda_hold_time = fp_ht;
+		break;
+	case I2C_MAX_HIGH_SPEED_MODE_FREQ:
+		dev->sda_hold_time = hs_ht;
+		break;
+	case I2C_MAX_FAST_MODE_FREQ:
+	default:
+		dev->sda_hold_time = fs_ht;
+		break;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(i2c_dw_acpi_configure);
+
+void i2c_dw_acpi_adjust_bus_speed(struct device *device)
+{
+	struct dw_i2c_dev *dev = dev_get_drvdata(device);
+	struct i2c_timings *t = &dev->timings;
+	u32 acpi_speed;
+	int i;
+
+	acpi_speed = i2c_acpi_find_bus_speed(device);
+	/*
+	 * Some DSTDs use a non standard speed, round down to the lowest
+	 * standard speed.
+	 */
+	for (i = 0; i < ARRAY_SIZE(supported_speeds); i++) {
+		if (acpi_speed >= supported_speeds[i])
+			break;
+	}
+	acpi_speed = i < ARRAY_SIZE(supported_speeds) ? supported_speeds[i] : 0;
+
+	/*
+	 * Find bus speed from the "clock-frequency" device property, ACPI
+	 * or by using fast mode if neither is set.
+	 */
+	if (acpi_speed && t->bus_freq_hz)
+		t->bus_freq_hz = min(t->bus_freq_hz, acpi_speed);
+	else if (acpi_speed || t->bus_freq_hz)
+		t->bus_freq_hz = max(t->bus_freq_hz, acpi_speed);
+	else
+		t->bus_freq_hz = I2C_MAX_FAST_MODE_FREQ;
+}
+EXPORT_SYMBOL_GPL(i2c_dw_acpi_adjust_bus_speed);
+
+#endif	/* CONFIG_ACPI */
+
 u32 i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset)
 {
 	/*