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/torvalds/linux-2.6.git * master branch. * 693d92a commit. (Linux 2.6.39-rc7) 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 from v3: - Addressed comments from Paul Walmsley. - http://www.spinics.net/lists/arm-kernel/msg124120.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. 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 | 54 ++++++++++++++++++++++++++ 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/plat-omap/include/plat/i2c.h | 4 ++ arch/arm/plat-omap/include/plat/omap_hwmod.h | 1 + 7 files changed, 89 insertions(+), 0 deletions(-) diff --git a/arch/arm/mach-omap2/i2c.c b/arch/arm/mach-omap2/i2c.c index 79c478c..de9c51a 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. + * @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..08c803c 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/plat-omap/include/plat/i2c.h b/arch/arm/plat-omap/include/plat/i2c.h index 878d632..3ffb94e 100644 --- a/arch/arm/plat-omap/include/plat/i2c.h +++ b/arch/arm/plat-omap/include/plat/i2c.h @@ -23,6 +23,8 @@ #include <linux/i2c.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, @@ -52,4 +54,6 @@ 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..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 -- 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
