diff mbox

OMAP: I2C: Add mpu wake up latency constraint in i2c

Message ID 1259172229-25386-1-git-send-email-kalle.jokiniemi@nokia.com (mailing list archive)
State Awaiting Upstream, archived
Headers show

Commit Message

kalle.jokiniemi@nokia.com Nov. 25, 2009, 6:03 p.m. UTC
None
diff mbox

Patch

diff --git a/arch/arm/plat-omap/i2c.c b/arch/arm/plat-omap/i2c.c
index 8b84839..3c122cd 100644
--- a/arch/arm/plat-omap/i2c.c
+++ b/arch/arm/plat-omap/i2c.c
@@ -26,8 +26,10 @@ 
 #include <linux/kernel.h>
 #include <linux/platform_device.h>
 #include <linux/i2c.h>
+#include <linux/i2c-omap.h>
 #include <mach/irqs.h>
 #include <mach/mux.h>
+#include <mach/omap-pm.h>
 
 #define OMAP_I2C_SIZE		0x3f
 #define OMAP1_I2C_BASE		0xfffb3800
@@ -69,14 +71,14 @@  static struct resource i2c_resources[][2] = {
 		},					\
 	}
 
-static u32 i2c_rate[ARRAY_SIZE(i2c_resources)];
+static struct omap_i2c_bus_platform_data i2c_pdata[ARRAY_SIZE(i2c_resources)];
 static struct platform_device omap_i2c_devices[] = {
-	I2C_DEV_BUILDER(1, i2c_resources[0], &i2c_rate[0]),
+	I2C_DEV_BUILDER(1, i2c_resources[0], &i2c_pdata[0]),
 #if	defined(CONFIG_ARCH_OMAP24XX) || defined(CONFIG_ARCH_OMAP34XX)
-	I2C_DEV_BUILDER(2, i2c_resources[1], &i2c_rate[1]),
+	I2C_DEV_BUILDER(2, i2c_resources[1], &i2c_pdata[1]),
 #endif
 #if	defined(CONFIG_ARCH_OMAP34XX)
-	I2C_DEV_BUILDER(3, i2c_resources[2], &i2c_rate[2]),
+	I2C_DEV_BUILDER(3, i2c_resources[2], &i2c_pdata[2]),
 #endif
 };
 
@@ -100,6 +102,31 @@  static const int omap34xx_pins[][2] = {};
 
 #define OMAP_I2C_CMDLINE_SETUP	(BIT(31))
 
+#ifdef CONFIG_ARCH_OMAP34XX
+/*
+ * omap_i2c_set_wfc_mpu_wkup_lat - sets mpu wake up constraint
+ * @dev:	i2c bus device pointer
+ * @val:	latency constraint to set, -1 to disable constraint
+ *
+ * When waiting for completion of a i2c transfer, we need to set a wake up
+ * latency constraint for the MPU. This is to ensure quick enough wakeup from
+ * idle, when transfer completes.
+ */
+static void omap_i2c_set_wfc_mpu_wkup_lat(struct device *dev, int val)
+{
+	omap_pm_set_max_mpu_wakeup_lat(dev, val);
+}
+#endif
+
+static void __init omap_set_i2c_constraint_func(
+				struct omap_i2c_bus_platform_data *pd)
+{
+	if (cpu_is_omap34xx())
+		pd->set_mpu_wkup_lat = omap_i2c_set_wfc_mpu_wkup_lat;
+	else
+		pd->set_mpu_wkup_lat = NULL;
+}
+
 static void __init omap_i2c_mux_pins(int bus)
 {
 	int scl, sda;
@@ -180,8 +207,8 @@  static int __init omap_i2c_bus_setup(char *str)
 	get_options(str, 3, ints);
 	if (ints[0] < 2 || ints[1] < 1 || ints[1] > ports)
 		return 0;
-	i2c_rate[ints[1] - 1] = ints[2];
-	i2c_rate[ints[1] - 1] |= OMAP_I2C_CMDLINE_SETUP;
+	i2c_pdata[ints[1] - 1].clkrate = ints[2];
+	i2c_pdata[ints[1] - 1].clkrate |= OMAP_I2C_CMDLINE_SETUP;
 
 	return 1;
 }
@@ -195,9 +222,10 @@  static int __init omap_register_i2c_bus_cmdline(void)
 {
 	int i, err = 0;
 
-	for (i = 0; i < ARRAY_SIZE(i2c_rate); i++)
-		if (i2c_rate[i] & OMAP_I2C_CMDLINE_SETUP) {
-			i2c_rate[i] &= ~OMAP_I2C_CMDLINE_SETUP;
+	for (i = 0; i < ARRAY_SIZE(i2c_pdata); i++)
+		if (i2c_pdata[i].clkrate & OMAP_I2C_CMDLINE_SETUP) {
+			i2c_pdata[i].clkrate &= ~OMAP_I2C_CMDLINE_SETUP;
+			omap_set_i2c_constraint_func(&i2c_pdata[i]);
 			err = omap_i2c_add_bus(i + 1);
 			if (err)
 				goto out;
@@ -231,9 +259,11 @@  int __init omap_register_i2c_bus(int bus_id, u32 clkrate,
 			return err;
 	}
 
-	if (!i2c_rate[bus_id - 1])
-		i2c_rate[bus_id - 1] = clkrate;
-	i2c_rate[bus_id - 1] &= ~OMAP_I2C_CMDLINE_SETUP;
+	if (!i2c_pdata[bus_id - 1].clkrate)
+		i2c_pdata[bus_id - 1].clkrate = clkrate;
+
+	omap_set_i2c_constraint_func(&i2c_pdata[bus_id - 1]);
+	i2c_pdata[bus_id - 1].clkrate &= ~OMAP_I2C_CMDLINE_SETUP;
 
 	return omap_i2c_add_bus(bus_id);
 }
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index 827da08..ac0bfd2 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -37,6 +37,7 @@ 
 #include <linux/platform_device.h>
 #include <linux/clk.h>
 #include <linux/io.h>
+#include <linux/i2c-omap.h>
 
 /* I2C controller revisions */
 #define OMAP_I2C_REV_2			0x20
@@ -165,6 +166,9 @@  struct omap_i2c_dev {
 	struct clk		*fclk;		/* Functional clock */
 	struct completion	cmd_complete;
 	struct resource		*ioarea;
+	u32			latency;	/* maximum mpu wkup latency */
+	void			(*set_mpu_wkup_lat)(struct device *dev,
+						    int latency);
 	u32			speed;		/* Speed of bus in Khz */
 	u16			cmd_err;
 	u8			*buf;
@@ -508,8 +512,12 @@  static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
 	 * REVISIT: We should abort the transfer on signals, but the bus goes
 	 * into arbitration and we're currently unable to recover from it.
 	 */
+	if (dev->set_mpu_wkup_lat != NULL)
+		dev->set_mpu_wkup_lat(dev->dev, dev->latency);
 	r = wait_for_completion_timeout(&dev->cmd_complete,
 					OMAP_I2C_TIMEOUT);
+	if (dev->set_mpu_wkup_lat != NULL)
+		dev->set_mpu_wkup_lat(dev->dev, -1);
 	dev->buf_len = 0;
 	if (r < 0)
 		return r;
@@ -826,6 +834,7 @@  omap_i2c_probe(struct platform_device *pdev)
 	struct omap_i2c_dev	*dev;
 	struct i2c_adapter	*adap;
 	struct resource		*mem, *irq, *ioarea;
+	struct omap_i2c_bus_platform_data *pdata = pdev->dev.platform_data;
 	irq_handler_t isr;
 	int r;
 	u32 speed = 0;
@@ -855,10 +864,13 @@  omap_i2c_probe(struct platform_device *pdev)
 		goto err_release_region;
 	}
 
-	if (pdev->dev.platform_data != NULL)
-		speed = *(u32 *)pdev->dev.platform_data;
-	else
-		speed = 100;	/* Defualt speed */
+	if (pdata != NULL) {
+		speed = pdata->clkrate;
+		dev->set_mpu_wkup_lat = pdata->set_mpu_wkup_lat;
+	} else {
+		speed = 100;	/* Default speed */
+		dev->set_mpu_wkup_lat = NULL;
+	}
 
 	dev->speed = speed;
 	dev->idle = 1;
@@ -893,6 +905,11 @@  omap_i2c_probe(struct platform_device *pdev)
 		 */
 		dev->fifo_size = (dev->fifo_size / 2);
 		dev->b_hw = 1; /* Enable hardware fixes */
+
+		/* calculate wakeup latency constraint for MPU */
+		if (dev->set_mpu_wkup_lat != NULL)
+			dev->latency = (1000000 * dev->fifo_size) /
+				       (1000 * speed / 8);
 	}
 
 	/* reset ASAP, clearing any IRQs */
diff --git a/include/linux/i2c-omap.h b/include/linux/i2c-omap.h
new file mode 100644
index 0000000..1362fba
--- /dev/null
+++ b/include/linux/i2c-omap.h
@@ -0,0 +1,9 @@ 
+#ifndef __I2C_OMAP_H__
+#define __I2C_OMAP_H__
+
+struct omap_i2c_bus_platform_data {
+	u32		clkrate;
+	void		(*set_mpu_wkup_lat)(struct device *dev, int set);
+};
+
+#endif