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authorTejun Heo <tj@kernel.org>2011-11-28 09:46:22 -0800
committerTejun Heo <tj@kernel.org>2011-11-28 09:46:22 -0800
commitd4bbf7e7759afc172e2bfbc5c416324590049cdd (patch)
tree7eab5ee5481cd3dcf1162329fec827177640018a /arch/arm/mach-omap2/i2c.c
parenta150439c4a97db379f0ed6faa46fbbb6e7bf3cb2 (diff)
parent401d0069cb344f401bc9d264c31db55876ff78c0 (diff)
Merge branch 'master' into x86/memblock
Conflicts & resolutions: * arch/x86/xen/setup.c dc91c728fd "xen: allow extra memory to be in multiple regions" 24aa07882b "memblock, x86: Replace memblock_x86_reserve/free..." conflicted on xen_add_extra_mem() updates. The resolution is trivial as the latter just want to replace memblock_x86_reserve_range() with memblock_reserve(). * drivers/pci/intel-iommu.c 166e9278a3f "x86/ia64: intel-iommu: move to drivers/iommu/" 5dfe8660a3d "bootmem: Replace work_with_active_regions() with..." conflicted as the former moved the file under drivers/iommu/. Resolved by applying the chnages from the latter on the moved file. * mm/Kconfig 6661672053a "memblock: add NO_BOOTMEM config symbol" c378ddd53f9 "memblock, x86: Make ARCH_DISCARD_MEMBLOCK a config option" conflicted trivially. Both added config options. Just letting both add their own options resolves the conflict. * mm/memblock.c d1f0ece6cdc "mm/memblock.c: small function definition fixes" ed7b56a799c "memblock: Remove memblock_memory_can_coalesce()" confliected. The former updates function removed by the latter. Resolution is trivial. Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'arch/arm/mach-omap2/i2c.c')
-rw-r--r--arch/arm/mach-omap2/i2c.c68
1 files changed, 68 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/i2c.c b/arch/arm/mach-omap2/i2c.c
index 79c478c4cb1c..ace99944e96f 100644
--- 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;
+}