Revert "ARM: OMAP: convert I2C driver to PM QoS for MPU latency constraints"

This reverts commit 3db11feffc1ad2ab9dea27789e6b5b3032827adc
(ARM: OMAP: convert I2C driver to PM QoS for MPU latency constraints).
This commit causes I2C timeouts to appear on several OMAP3430/3530-based
boards:

  http://marc.info/?l=linux-arm-kernel&m=135071372426971&w=2
  http://marc.info/?l=linux-arm-kernel&m=135067558415214&w=2
  http://marc.info/?l=linux-arm-kernel&m=135216013608196&w=2

and appears to have been sent for merging before one of its prerequisites
was merged:

  http://marc.info/?l=linux-arm-kernel&m=135219411617621&w=2

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

3 files changed, 36 insertions, 18 deletions

diff --git a/arch/arm/plat-omap/i2c.c b/arch/arm/plat-omap/i2c.c
index a5683a84c6ee..6013831a043e 100644
--- a/arch/arm/plat-omap/i2c.c
+++ b/arch/arm/plat-omap/i2c.c
@@ -26,12 +26,14 @@
 #include <linux/kernel.h>
 #include <linux/platform_device.h>
 #include <linux/i2c.h>
+#include <linux/i2c-omap.h>
 #include <linux/slab.h>
 #include <linux/err.h>
 #include <linux/clk.h>
 
 #include <mach/irqs.h>
 #include <plat/i2c.h>
+#include <plat/omap-pm.h>
 #include <plat/omap_device.h>
 
 #define OMAP_I2C_SIZE           0x3f
@@ -127,6 +129,16 @@ static inline int omap1_i2c_add_bus(int bus_id)
 
 
 #ifdef CONFIG_ARCH_OMAP2PLUS
+/*
+ * XXX This function is a temporary compatibility wrapper - only
+ * needed until the I2C driver can be converted to call
+ * omap_pm_set_max_dev_wakeup_lat() and handle a return code.
+ */
+static void omap_pm_set_max_mpu_wakeup_lat_compat(struct device *dev, long t)
+{
+        omap_pm_set_max_mpu_wakeup_lat(dev, t);
+}
+
 static inline int omap2_i2c_add_bus(int bus_id)
 {
         int l;
@@ -158,6 +170,15 @@ static inline int omap2_i2c_add_bus(int bus_id)
         dev_attr = (struct omap_i2c_dev_attr *)oh->dev_attr;
         pdata->flags = dev_attr->flags;
 
+        /*
+         * 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.
+         * Only omap3 has support for constraints
+         */
+        if (cpu_is_omap34xx())
+                pdata->set_mpu_wkup_lat = omap_pm_set_max_mpu_wakeup_lat_compat;
         pdev = omap_device_build(name, bus_id, oh, pdata,
                         sizeof(struct omap_i2c_bus_platform_data),
                         NULL, 0, 0);
diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index db31eaed6ea5..0b0254312d21 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -43,7 +43,6 @@
 #include <linux/slab.h>
 #include <linux/i2c-omap.h>
 #include <linux/pm_runtime.h>
-#include <linux/pm_qos.h>
 
 /* I2C controller revisions */
 #define OMAP_I2C_OMAP1_REV_2            0x20
@@ -187,8 +186,9 @@ struct omap_i2c_dev {
         int                     reg_shift;      /* bit shift for I2C register addresses */
         struct completion       cmd_complete;
         struct resource         *ioarea;
-        u32                     latency;        /* maximum MPU wkup latency */
-        struct pm_qos_request   pm_qos_request;
+        u32                     latency;        /* maximum mpu wkup latency */
+        void                    (*set_mpu_wkup_lat)(struct device *dev,
+                                                    long latency);
         u32                     speed;          /* Speed of bus in kHz */
         u32                     dtrev;          /* extra revision from DT */
         u32                     flags;
@@ -494,7 +494,9 @@ static void omap_i2c_resize_fifo(struct omap_i2c_dev *dev, u8 size, bool is_rx)
                 dev->b_hw = 1; /* Enable hardware fixes */
 
         /* calculate wakeup latency constraint for MPU */
-        dev->latency = (1000000 * dev->threshold) / (1000 * dev->speed / 8);
+        if (dev->set_mpu_wkup_lat != NULL)
+                dev->latency = (1000000 * dev->threshold) /
+                        (1000 * dev->speed / 8);
 }
 
 /*
@@ -629,16 +631,8 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
         if (r < 0)
                 goto out;
 
-        /*
-         * 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.
-         */
-        if (dev->latency)
-                pm_qos_add_request(&dev->pm_qos_request,
-                                   PM_QOS_CPU_DMA_LATENCY,
-                                   dev->latency);
+        if (dev->set_mpu_wkup_lat != NULL)
+                dev->set_mpu_wkup_lat(dev->dev, dev->latency);
 
         for (i = 0; i < num; i++) {
                 r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1)));
@@ -646,8 +640,8 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
                         break;
         }
 
-        if (dev->latency)
-                pm_qos_remove_request(&dev->pm_qos_request);
+        if (dev->set_mpu_wkup_lat != NULL)
+                dev->set_mpu_wkup_lat(dev->dev, -1);
 
         if (r == 0)
                 r = num;
@@ -1104,6 +1098,7 @@ omap_i2c_probe(struct platform_device *pdev)
         } else if (pdata != NULL) {
                 dev->speed = pdata->clkrate;
                 dev->flags = pdata->flags;
+                dev->set_mpu_wkup_lat = pdata->set_mpu_wkup_lat;
                 dev->dtrev = pdata->rev;
         }
 
@@ -1159,8 +1154,9 @@ omap_i2c_probe(struct platform_device *pdev)
                         dev->b_hw = 1; /* Enable hardware fixes */
 
                 /* calculate wakeup latency constraint for MPU */
-                dev->latency = (1000000 * dev->fifo_size) /
-                               (1000 * dev->speed / 8);
+                if (dev->set_mpu_wkup_lat != NULL)
+                        dev->latency = (1000000 * dev->fifo_size) /
+                                       (1000 * dev->speed / 8);
         }
 
         /* reset ASAP, clearing any IRQs */
diff --git a/include/linux/i2c-omap.h b/include/linux/i2c-omap.h
index df804ba73e0b..92a0dc75bc74 100644
--- a/include/linux/i2c-omap.h
+++ b/include/linux/i2c-omap.h
@@ -34,6 +34,7 @@ struct omap_i2c_bus_platform_data {
         u32             clkrate;
         u32             rev;
         u32             flags;
+        void            (*set_mpu_wkup_lat)(struct device *dev, long set);
 };
 
 #endif