[PATCH v5 2/2] OMAP: hwmod: fix the i2c-reset timeout during bootup
Avinash.H.M
avinashhm at ti.com
Wed Jun 22 07:46:14 EDT 2011
The sequence of _ocp_softreset doesn't work for i2c. The i2c module has a
special sequence to reset the module. The sequence is
- Disable the I2C.
- Write to SOFTRESET bit.
- Enable the I2C.
- Poll on the RESETDONE bit.
The sequence is implemented as a function and the i2c_class is updated with
the correct 'reset' pointer. omap_hwmod_softreset function is implemented
which triggers the softreset by writing into sysconfig register. On following
this sequence, i2c module resets properly and timeouts are not seen.
Cc: Rajendra Nayak <rnayak at ti.com>
Cc: Paul Walmsley <paul at pwsan.com>
Cc: Benoit Cousson <b-cousson at ti.com>
Cc: Kevin Hilman <khilman at ti.com>
Signed-off-by: Avinash.H.M <avinashhm at ti.com>
---
The patch is based on
* git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
* master branch.
* 5629937 commit (Linux 3.0-rc4).
Changes from previous versions:
from v4:
- Fixed Tomi's comment. Removed including hwmod.h in i2c.h
- The sequence is applicable even for omap4. So removed the
INIT_NO_RESET flags from i2c hwmods and extend the patch to omap4
also. ( .reset pointer is populated accordingly ).
- http://www.spinics.net/lists/linux-omap/msg51377.html
from v3:
- Addressed comments from Paul Walmsley.
- http://www.spinics.net/lists/arm-kernel/msg124120.html
from v2:
- Avoided direct SYSCONFIG access in i2c.c
- http://www.spinics.net/lists/linux-omap/msg49632.html
from v1:
- moved i2c specific things from hwmod files to i2c files.
- fixed comments from Paul.
- http://www.spinics.net/lists/linux-omap/msg49483.html
Testing:
* build tested omap2plus_defconfig for warnings and errors. none introduced.
* boot tested on 2430, 4430. No timeouts are seen with this patch.
* tested for 'core off' in suspend resume on 3430 sdp. core off counters
increment after suspend resume.
Dependency:
* This needs "OMAP2+: hwmod data: Set hwmod flags to only allow 16-bit
accesses to i2c" from Andry Green for accessing i2c_sysc. Without this even
with this patch, we will see i2c reset timeouts.
arch/arm/mach-omap2/i2c.c | 63 ++++++++++++++++++++++++++
arch/arm/mach-omap2/omap_hwmod.c | 27 +++++++++++
arch/arm/mach-omap2/omap_hwmod_2420_data.c | 1 +
arch/arm/mach-omap2/omap_hwmod_2430_data.c | 1 +
arch/arm/mach-omap2/omap_hwmod_3xxx_data.c | 1 +
arch/arm/mach-omap2/omap_hwmod_44xx_data.c | 2 +
arch/arm/plat-omap/include/plat/i2c.h | 3 +
arch/arm/plat-omap/include/plat/omap_hwmod.h | 1 +
8 files changed, 99 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mach-omap2/i2c.c b/arch/arm/mach-omap2/i2c.c
index 79c478c..5c2445e 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 +47,56 @@ 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 (cpu_is_omap44xx())
+ i2c_con = OMAP4_I2C_CON_OFFSET;
+ else
+ i2c_con = OMAP2_I2C_CON_OFFSET;
+
+ /* Disable I2C */
+ v = omap_hwmod_read(oh, i2c_con);
+ v = 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;
+}
diff --git a/arch/arm/mach-omap2/omap_hwmod.c b/arch/arm/mach-omap2/omap_hwmod.c
index 293fa6c..64ffec4 100644
--- a/arch/arm/mach-omap2/omap_hwmod.c
+++ b/arch/arm/mach-omap2/omap_hwmod.c
@@ -1562,6 +1562,33 @@ void omap_hwmod_write(u32 v, struct omap_hwmod *oh, u16 reg_offs)
}
/**
+ * omap_hwmod_softreset - reset a module via SYSCONFIG.SOFTRESET bit
+ * @oh: struct omap_hwmod *
+ *
+ * This is a public function exposed to drivers. Some drivers may need to do
+ * some settings before and after resetting the device. Those drivers after
+ * doing the necessary settings could use this function to start a reset by
+ * setting the SYSCONFIG.SOFTRESET bit.
+ */
+int omap_hwmod_softreset(struct omap_hwmod *oh)
+{
+ u32 v;
+ int ret;
+
+ if (!oh || !(oh->_sysc_cache))
+ return -EINVAL;
+
+ v = oh->_sysc_cache;
+ ret = _set_softreset(oh, &v);
+ if (ret)
+ goto error;
+ _write_sysconfig(v, oh);
+
+error:
+ return ret;
+}
+
+/**
* omap_hwmod_set_slave_idlemode - set the hwmod's OCP slave idlemode
* @oh: struct omap_hwmod *
* @idlemode: SIDLEMODE field bits (shifted to bit 0)
diff --git a/arch/arm/mach-omap2/omap_hwmod_2420_data.c b/arch/arm/mach-omap2/omap_hwmod_2420_data.c
index c4d0ae8..8950ad3 100644
--- a/arch/arm/mach-omap2/omap_hwmod_2420_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_2420_data.c
@@ -1447,6 +1447,7 @@ static struct omap_hwmod_class_sysconfig i2c_sysc = {
static struct omap_hwmod_class i2c_class = {
.name = "i2c",
.sysc = &i2c_sysc,
+ .reset = &omap_i2c_reset,
};
static struct omap_i2c_dev_attr i2c_dev_attr;
diff --git a/arch/arm/mach-omap2/omap_hwmod_2430_data.c b/arch/arm/mach-omap2/omap_hwmod_2430_data.c
index 9682dd5..6b5413b 100644
--- a/arch/arm/mach-omap2/omap_hwmod_2430_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_2430_data.c
@@ -1524,6 +1524,7 @@ static struct omap_hwmod_class_sysconfig i2c_sysc = {
static struct omap_hwmod_class i2c_class = {
.name = "i2c",
.sysc = &i2c_sysc,
+ .reset = &omap_i2c_reset,
};
static struct omap_i2c_dev_attr i2c_dev_attr = {
diff --git a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
index 909a84d..2e21e2d 100644
--- a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
@@ -1460,6 +1460,7 @@ static struct omap_hwmod omap3xxx_uart4_hwmod = {
static struct omap_hwmod_class i2c_class = {
.name = "i2c",
.sysc = &i2c_sysc,
+ .reset = &omap_i2c_reset,
};
/*
diff --git a/arch/arm/mach-omap2/omap_hwmod_44xx_data.c b/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
index 2eaf40a..5e11c0b 100644
--- a/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
+++ b/arch/arm/mach-omap2/omap_hwmod_44xx_data.c
@@ -22,6 +22,7 @@
#include <plat/omap_hwmod.h>
#include <plat/cpu.h>
+#include <plat/i2c.h>
#include <plat/gpio.h>
#include <plat/dma.h>
#include <plat/mcspi.h>
@@ -2125,6 +2126,7 @@ static struct omap_hwmod_class_sysconfig omap44xx_i2c_sysc = {
static struct omap_hwmod_class omap44xx_i2c_hwmod_class = {
.name = "i2c",
.sysc = &omap44xx_i2c_sysc,
+ .reset = &omap_i2c_reset,
};
/* i2c1 */
diff --git a/arch/arm/plat-omap/include/plat/i2c.h b/arch/arm/plat-omap/include/plat/i2c.h
index 878d632..ad53959 100644
--- a/arch/arm/plat-omap/include/plat/i2c.h
+++ b/arch/arm/plat-omap/include/plat/i2c.h
@@ -52,4 +52,7 @@ struct omap_i2c_dev_attr {
void __init omap1_i2c_mux_pins(int bus_id);
void __init omap2_i2c_mux_pins(int bus_id);
+struct omap_hwmod;
+int omap_i2c_reset(struct omap_hwmod *oh);
+
#endif /* __ASM__ARCH_OMAP_I2C_H */
diff --git a/arch/arm/plat-omap/include/plat/omap_hwmod.h b/arch/arm/plat-omap/include/plat/omap_hwmod.h
index 1adea9c..fe8a0a2 100644
--- a/arch/arm/plat-omap/include/plat/omap_hwmod.h
+++ b/arch/arm/plat-omap/include/plat/omap_hwmod.h
@@ -572,6 +572,7 @@ void omap_hwmod_ocp_barrier(struct omap_hwmod *oh);
void omap_hwmod_write(u32 v, struct omap_hwmod *oh, u16 reg_offs);
u32 omap_hwmod_read(struct omap_hwmod *oh, u16 reg_offs);
+int omap_hwmod_softreset(struct omap_hwmod *oh);
int omap_hwmod_count_resources(struct omap_hwmod *oh);
int omap_hwmod_fill_resources(struct omap_hwmod *oh, struct resource *res);
--
1.7.1
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