Hello Avinash On Mon, 2 May 2011, Avinash.H.M wrote: > 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@xxxxxx> > Cc: Paul Walmsley <paul@xxxxxxxxx> > Cc: Benoit Cousson <b-cousson@xxxxxx> > Cc: Kevin Hilman <khilman@xxxxxx> > Signed-off-by: Avinash.H.M <avinashhm@xxxxxx> > --- > > The patch is based on > * git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6.git > * master branch. > * 9be20f0 commit. ( Linux-omap rebuilt: Updated to -rc5 ) Please base all your patches against mainline commits. I suggest using v2.6.39-rc6. Also some comments: > Changes from previous versions: > 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 > > from v2: > - Avoided direct SYSCONFIG access in i2c.c > - http://www.spinics.net/lists/linux-omap/msg49632.html > > Testing: > * build tested omap2plus_defconfig for warnings and errors. none introduced. > * boot tested on 2430. > * tested for 'core off' in suspend resume on 3430 sdp. core off counters > increment after suspend resume. > > arch/arm/mach-omap2/i2c.c | 54 ++++++++++++++++++++++++++ > arch/arm/mach-omap2/omap_hwmod.c | 12 ++++++ > 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/plat-omap/include/plat/i2c.h | 4 ++ > arch/arm/plat-omap/include/plat/omap_hwmod.h | 1 + > 7 files changed, 74 insertions(+), 0 deletions(-) > > diff --git a/arch/arm/mach-omap2/i2c.c b/arch/arm/mach-omap2/i2c.c > index 79c478c..bd50e26 100644 > --- a/arch/arm/mach-omap2/i2c.c > +++ b/arch/arm/mach-omap2/i2c.c > @@ -21,9 +21,16 @@ > > #include <plat/cpu.h> > #include <plat/i2c.h> > +#include <plat/common.h> > > #include "mux.h" > > +/* In register I2C_CON, Bit 15 is the I2C enable bit */ > +#define I2C_EN BIT(15) > +#define I2C_CON_OFFSET 0x24 > +/* 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 +44,50 @@ 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. Please put a space before the dash. > + * @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; > + int c = 0; > + > + /* Disable I2C */ > + v = omap_hwmod_read(oh, I2C_CON_OFFSET); > + v = v & ~I2C_EN; > + omap_hwmod_write(v, oh, I2C_CON_OFFSET); > + > + /* Write to the SOFTRESET bit */ > + omap_hwmod_softreset(oh); > + > + /* Enable I2C */ > + v = omap_hwmod_read(oh, I2C_CON_OFFSET); > + v |= I2C_EN; > + omap_hwmod_write(v, oh, I2C_CON_OFFSET); > + > + /* 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 e034294..771fc15 100644 > --- a/arch/arm/mach-omap2/omap_hwmod.c > +++ b/arch/arm/mach-omap2/omap_hwmod.c > @@ -1561,6 +1561,18 @@ void omap_hwmod_write(u32 v, struct omap_hwmod *oh, u16 reg_offs) > __raw_writel(v, oh->_mpu_rt_va + reg_offs); > } > You're missing kerneldoc here. Please add it. > +void omap_hwmod_softreset(struct omap_hwmod *oh) > +{ > + u32 v; > + > + /* Write to the SOFTRESET bit in SYSCONFIG */ > + v = oh->_sysc_cache; > + v |= (0x1 << oh->class->sysc->sysc_fields->srst_shift); > + > + oh->_sysc_cache = v; > + omap_hwmod_write(v, oh, oh->class->sysc->sysc_offs); > +} This is a public function, so you need to validate your oh argument and return an error if something isn't right. Similarly, you should use the existing function _set_softreset() to set the bit, because it also does some errorchecking. > + > /** > * omap_hwmod_set_slave_idlemode - set the hwmod's OCP slave idlemode > * @oh: struct omap_hwmod * > diff --git a/arch/arm/mach-omap2/omap_hwmod_2420_data.c b/arch/arm/mach-omap2/omap_hwmod_2420_data.c > index e9a416c..fd386af 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, > .rev = OMAP_I2C_IP_VERSION_1, > }; > > diff --git a/arch/arm/mach-omap2/omap_hwmod_2430_data.c b/arch/arm/mach-omap2/omap_hwmod_2430_data.c > index beedda6..4ad4188 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, > .rev = OMAP_I2C_IP_VERSION_1, > }; > > diff --git a/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c b/arch/arm/mach-omap2/omap_hwmod_3xxx_data.c > index dec1a38..e938810 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, > .rev = OMAP_I2C_IP_VERSION_1, > }; > > diff --git a/arch/arm/plat-omap/include/plat/i2c.h b/arch/arm/plat-omap/include/plat/i2c.h > index fd75dad..20237c1 100644 > --- a/arch/arm/plat-omap/include/plat/i2c.h > +++ b/arch/arm/plat-omap/include/plat/i2c.h > @@ -24,6 +24,8 @@ > #include <linux/i2c.h> > #include <linux/i2c-omap.h> > > +#include <plat/omap_hwmod.h> > + > #if defined(CONFIG_I2C_OMAP) || defined(CONFIG_I2C_OMAP_MODULE) > extern int omap_register_i2c_bus(int bus_id, u32 clkrate, > struct i2c_board_info const *info, > @@ -53,4 +55,6 @@ struct omap_i2c_dev_attr { > void __init omap1_i2c_mux_pins(int bus_id); > void __init omap2_i2c_mux_pins(int bus_id); > > +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..9637130 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); > +void 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 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > - Paul -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
