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OMAP: hwmod: fix the i2c-reset timeout during bootup 

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@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Kevin Hilman <khilman@ti.com>
Signed-off-by: Avinash.H.M <avinashhm@ti.com>
[paul@pwsan.com: combined this patch with a patch to remove
 HWMOD_INIT_NO_RESET from the 44xx hwmod flags; change register
 offset conditional code to use the IP block revision; minor code
 cleanup]
Signed-off-by: Paul Walmsley <paul@pwsan.com>
This commit is contained in:
Avinash.H.M 2011-07-10 05:27:16 -06:00 committed by Paul Walmsley
parent 4d4441a622
commit 6d3c55fd4f
8 changed files with 111 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

68
arch/arm/mach-omap2/i2c.c
View File

@ -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;
}

27
arch/arm/mach-omap2/omap_hwmod.c
View File

@ -1655,6 +1655,33 @@ void omap_hwmod_write(u32 v, struct omap_hwmod *oh, u16 reg_offs)
__raw_writel(v, oh->_mpu_rt_va + 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 *

1
arch/arm/mach-omap2/omap_hwmod_2420_data.c
View File

@ -1030,6 +1030,7 @@ static struct omap_hwmod_class i2c_class = {
.name = "i2c",
.sysc = &i2c_sysc,
.rev = OMAP_I2C_IP_VERSION_1,
.reset = &omap_i2c_reset,
};
static struct omap_i2c_dev_attr i2c_dev_attr = {

1
arch/arm/mach-omap2/omap_hwmod_2430_data.c
View File

@ -1079,6 +1079,7 @@ static struct omap_hwmod_class i2c_class = {
.name = "i2c",
.sysc = &i2c_sysc,
.rev = OMAP_I2C_IP_VERSION_1,
.reset = &omap_i2c_reset,
};
static struct omap_i2c_dev_attr i2c_dev_attr = {

7
arch/arm/mach-omap2/omap_hwmod_3xxx_data.c
View File

@ -1306,9 +1306,10 @@ static struct omap_hwmod omap3xxx_uart4_hwmod = {
};
static struct omap_hwmod_class i2c_class = {
.name = "i2c",
.sysc = &i2c_sysc,
.rev = OMAP_I2C_IP_VERSION_1,
.name = "i2c",
.sysc = &i2c_sysc,
.rev = OMAP_I2C_IP_VERSION_1,
.reset = &omap_i2c_reset,
};
static struct omap_hwmod_dma_info omap3xxx_dss_sdma_chs[] = {

10
arch/arm/mach-omap2/omap_hwmod_44xx_data.c
View File

@ -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>
@ -2162,6 +2163,7 @@ static struct omap_hwmod_class omap44xx_i2c_hwmod_class = {
.name = "i2c",
.sysc = &omap44xx_i2c_sysc,
.rev = OMAP_I2C_IP_VERSION_2,
.reset = &omap_i2c_reset,
};
static struct omap_i2c_dev_attr i2c_dev_attr = {
@ -2207,7 +2209,7 @@ static struct omap_hwmod_ocp_if *omap44xx_i2c1_slaves[] = {
static struct omap_hwmod omap44xx_i2c1_hwmod = {
.name = "i2c1",
.class = &omap44xx_i2c_hwmod_class,
.flags = HWMOD_16BIT_REG | HWMOD_INIT_NO_RESET,
.flags = HWMOD_16BIT_REG,
.mpu_irqs = omap44xx_i2c1_irqs,
.sdma_reqs = omap44xx_i2c1_sdma_reqs,
.main_clk = "i2c1_fck",
@ -2261,7 +2263,7 @@ static struct omap_hwmod_ocp_if *omap44xx_i2c2_slaves[] = {
static struct omap_hwmod omap44xx_i2c2_hwmod = {
.name = "i2c2",
.class = &omap44xx_i2c_hwmod_class,
.flags = HWMOD_16BIT_REG | HWMOD_INIT_NO_RESET,
.flags = HWMOD_16BIT_REG,
.mpu_irqs = omap44xx_i2c2_irqs,
.sdma_reqs = omap44xx_i2c2_sdma_reqs,
.main_clk = "i2c2_fck",
@ -2315,7 +2317,7 @@ static struct omap_hwmod_ocp_if *omap44xx_i2c3_slaves[] = {
static struct omap_hwmod omap44xx_i2c3_hwmod = {
.name = "i2c3",
.class = &omap44xx_i2c_hwmod_class,
.flags = HWMOD_16BIT_REG | HWMOD_INIT_NO_RESET,
.flags = HWMOD_16BIT_REG,
.mpu_irqs = omap44xx_i2c3_irqs,
.sdma_reqs = omap44xx_i2c3_sdma_reqs,
.main_clk = "i2c3_fck",
@ -2369,7 +2371,7 @@ static struct omap_hwmod_ocp_if *omap44xx_i2c4_slaves[] = {
static struct omap_hwmod omap44xx_i2c4_hwmod = {
.name = "i2c4",
.class = &omap44xx_i2c_hwmod_class,
.flags = HWMOD_16BIT_REG | HWMOD_INIT_NO_RESET,
.flags = HWMOD_16BIT_REG,
.mpu_irqs = omap44xx_i2c4_irqs,
.sdma_reqs = omap44xx_i2c4_sdma_reqs,
.main_clk = "i2c4_fck",

3
arch/arm/plat-omap/include/plat/i2c.h
View File

@ -53,4 +53,7 @@ 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 */

1
arch/arm/plat-omap/include/plat/omap_hwmod.h
View File

@ -566,6 +566,7 @@ 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);