Merge branch 'slub/lockless' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg...

[pandora-kernel.git] / arch / arm / mach-omap2 / i2c.c

diff --git a/arch/arm/mach-omap2/i2c.c b/arch/arm/mach-omap2/i2c.c
index 79c478c..ace9994 100644 (file)
--- a/arch/arm/mach-omap2/i2c.c
+++ b/arch/arm/mach-omap2/i2c.c
@@ -21,9 +21,19 @@
 
 #include <plat/cpu.h>
 #include <plat/i2c.h>
+#include <plat/common.h>
+#include <plat/omap_hwmod.h>
 
 #include "mux.h"
 
+/* In register I2C_CON, Bit 15 is the I2C enable bit */
+#define I2C_EN                                 BIT(15)
+#define OMAP2_I2C_CON_OFFSET                   0x24
+#define OMAP4_I2C_CON_OFFSET                   0xA4
+
+/* Maximum microseconds to wait for OMAP module to softreset */
+#define MAX_MODULE_SOFTRESET_WAIT      10000
+
 void __init omap2_i2c_mux_pins(int bus_id)
 {
        char mux_name[sizeof("i2c2_scl.i2c2_scl")];
@@ -37,3 +47,61 @@ void __init omap2_i2c_mux_pins(int bus_id)
        sprintf(mux_name, "i2c%i_sda.i2c%i_sda", bus_id, bus_id);
        omap_mux_init_signal(mux_name, OMAP_PIN_INPUT);
 }
+
+/**
+ * omap_i2c_reset - reset the omap i2c module.
+ * @oh: struct omap_hwmod *
+ *
+ * The i2c moudle in omap2, omap3 had a special sequence to reset. The
+ * sequence is:
+ * - Disable the I2C.
+ * - Write to SOFTRESET bit.
+ * - Enable the I2C.
+ * - Poll on the RESETDONE bit.
+ * The sequence is implemented in below function. This is called for 2420,
+ * 2430 and omap3.
+ */
+int omap_i2c_reset(struct omap_hwmod *oh)
+{
+       u32 v;
+       u16 i2c_con;
+       int c = 0;
+
+       if (oh->class->rev == OMAP_I2C_IP_VERSION_2) {
+               i2c_con = OMAP4_I2C_CON_OFFSET;
+       } else if (oh->class->rev == OMAP_I2C_IP_VERSION_1) {
+               i2c_con = OMAP2_I2C_CON_OFFSET;
+       } else {
+               WARN(1, "Cannot reset I2C block %s: unsupported revision\n",
+                    oh->name);
+               return -EINVAL;
+       }
+
+       /* Disable I2C */
+       v = omap_hwmod_read(oh, i2c_con);
+       v &= ~I2C_EN;
+       omap_hwmod_write(v, oh, i2c_con);
+
+       /* Write to the SOFTRESET bit */
+       omap_hwmod_softreset(oh);
+
+       /* Enable I2C */
+       v = omap_hwmod_read(oh, i2c_con);
+       v |= I2C_EN;
+       omap_hwmod_write(v, oh, i2c_con);
+
+       /* Poll on RESETDONE bit */
+       omap_test_timeout((omap_hwmod_read(oh,
+                               oh->class->sysc->syss_offs)
+                               & SYSS_RESETDONE_MASK),
+                               MAX_MODULE_SOFTRESET_WAIT, c);
+
+       if (c == MAX_MODULE_SOFTRESET_WAIT)
+               pr_warning("%s: %s: softreset failed (waited %d usec)\n",
+                       __func__, oh->name, MAX_MODULE_SOFTRESET_WAIT);
+       else
+               pr_debug("%s: %s: softreset in %d usec\n", __func__,
+                       oh->name, c);
+
+       return 0;
+}