Hi Ben, Could you take this patch to i2c tree? The patch has been discussed in linux-omap list, and this version was the one that was agreed to pushed forward. http://marc.info/?l=linux-omap&m=125907598412786&w=2 I tried it on top of linus' tree and it applied fine. - Kalle > -----Original Message----- > From: linux-omap-owner@xxxxxxxxxxxxxxx > [mailto:linux-omap-owner@xxxxxxxxxxxxxxx] On Behalf Of > Jokiniemi Kalle (Nokia-D/Tampere) > Sent: 25. marraskuuta 2009 20:04 > To: ben-linux@xxxxxxxxx; linux-i2c@xxxxxxxxxxxxxxx > Cc: linux-omap@xxxxxxxxxxxxxxx; Ujfalusi Peter > (Nokia-D/Tampere); Hogander Jouni (Nokia-D/Tampere); > khilman@xxxxxxxxxxxxxxxxxxx; ext Kalle Jokiniemi; Moiz > Sonasath; Jarkko Nikula; Paul Walmsley; Nishanth Menon > Subject: [PATCH] OMAP: I2C: Add mpu wake up latency constraint in i2c > > From: ext Kalle Jokiniemi <kalle.jokiniemi@xxxxxxxxx> > > While waiting for completion of the i2c transfer, the MPU > could hit OFF mode and cause several msecs of delay that made > i2c transfers fail more often. The extra delays and > subsequent re-trys cause i2c clocks to be active more often. > This has also an negative effect on power consumption. > > Created a mechanism for passing and using the constraint > setting function in driver code. The used mpu wake up latency > constraints are now set individually per bus, and they are > calculated based on clock rate and fifo size. > > Thanks to Jarkko Nikula, Moiz Sonasath, Paul Walmsley, and > Nishanth Menon for tuning out the details of this patch. > > Cc: Moiz Sonasath <m-sonasath@xxxxxx> > Cc: Jarkko Nikula <jhnikula@xxxxxxxxx> > Cc: Paul Walmsley <paul@xxxxxxxxx> > Cc: Nishanth Menon <nm@xxxxxx> > Signed-off-by: Kalle Jokiniemi <kalle.jokiniemi@xxxxxxxxx> > --- > arch/arm/plat-omap/i2c.c | 54 > +++++++++++++++++++++++++++++++--------- > drivers/i2c/busses/i2c-omap.c | 25 ++++++++++++++++--- > include/linux/i2c-omap.h | 9 +++++++ > 3 files changed, 72 insertions(+), 16 deletions(-) create > mode 100644 include/linux/i2c-omap.h > > diff --git a/arch/arm/plat-omap/i2c.c > b/arch/arm/plat-omap/i2c.c index 8b84839..3c122cd 100644 > --- a/arch/arm/plat-omap/i2c.c > +++ b/arch/arm/plat-omap/i2c.c > @@ -26,8 +26,10 @@ > #include <linux/kernel.h> > #include <linux/platform_device.h> > #include <linux/i2c.h> > +#include <linux/i2c-omap.h> > #include <mach/irqs.h> > #include <mach/mux.h> > +#include <mach/omap-pm.h> > > #define OMAP_I2C_SIZE 0x3f > #define OMAP1_I2C_BASE 0xfffb3800 > @@ -69,14 +71,14 @@ static struct resource i2c_resources[][2] = { > }, \ > } > > -static u32 i2c_rate[ARRAY_SIZE(i2c_resources)]; > +static struct omap_i2c_bus_platform_data > +i2c_pdata[ARRAY_SIZE(i2c_resources)]; > static struct platform_device omap_i2c_devices[] = { > - I2C_DEV_BUILDER(1, i2c_resources[0], &i2c_rate[0]), > + I2C_DEV_BUILDER(1, i2c_resources[0], &i2c_pdata[0]), > #if defined(CONFIG_ARCH_OMAP24XX) || defined(CONFIG_ARCH_OMAP34XX) > - I2C_DEV_BUILDER(2, i2c_resources[1], &i2c_rate[1]), > + I2C_DEV_BUILDER(2, i2c_resources[1], &i2c_pdata[1]), > #endif > #if defined(CONFIG_ARCH_OMAP34XX) > - I2C_DEV_BUILDER(3, i2c_resources[2], &i2c_rate[2]), > + I2C_DEV_BUILDER(3, i2c_resources[2], &i2c_pdata[2]), > #endif > }; > > @@ -100,6 +102,31 @@ static const int omap34xx_pins[][2] = {}; > > #define OMAP_I2C_CMDLINE_SETUP (BIT(31)) > > +#ifdef CONFIG_ARCH_OMAP34XX > +/* > + * omap_i2c_set_wfc_mpu_wkup_lat - sets mpu wake up constraint > + * @dev: i2c bus device pointer > + * @val: latency constraint to set, -1 to disable constraint > + * > + * When waiting for completion of a i2c transfer, we need to > set a wake > +up > + * latency constraint for the MPU. This is to ensure quick enough > +wakeup from > + * idle, when transfer completes. > + */ > +static void omap_i2c_set_wfc_mpu_wkup_lat(struct device > *dev, int val) > +{ > + omap_pm_set_max_mpu_wakeup_lat(dev, val); } #endif > + > +static void __init omap_set_i2c_constraint_func( > + struct omap_i2c_bus_platform_data *pd) { > + if (cpu_is_omap34xx()) > + pd->set_mpu_wkup_lat = omap_i2c_set_wfc_mpu_wkup_lat; > + else > + pd->set_mpu_wkup_lat = NULL; > +} > + > static void __init omap_i2c_mux_pins(int bus) { > int scl, sda; > @@ -180,8 +207,8 @@ static int __init omap_i2c_bus_setup(char *str) > get_options(str, 3, ints); > if (ints[0] < 2 || ints[1] < 1 || ints[1] > ports) > return 0; > - i2c_rate[ints[1] - 1] = ints[2]; > - i2c_rate[ints[1] - 1] |= OMAP_I2C_CMDLINE_SETUP; > + i2c_pdata[ints[1] - 1].clkrate = ints[2]; > + i2c_pdata[ints[1] - 1].clkrate |= OMAP_I2C_CMDLINE_SETUP; > > return 1; > } > @@ -195,9 +222,10 @@ static int __init > omap_register_i2c_bus_cmdline(void) > { > int i, err = 0; > > - for (i = 0; i < ARRAY_SIZE(i2c_rate); i++) > - if (i2c_rate[i] & OMAP_I2C_CMDLINE_SETUP) { > - i2c_rate[i] &= ~OMAP_I2C_CMDLINE_SETUP; > + for (i = 0; i < ARRAY_SIZE(i2c_pdata); i++) > + if (i2c_pdata[i].clkrate & OMAP_I2C_CMDLINE_SETUP) { > + i2c_pdata[i].clkrate &= ~OMAP_I2C_CMDLINE_SETUP; > + omap_set_i2c_constraint_func(&i2c_pdata[i]); > err = omap_i2c_add_bus(i + 1); > if (err) > goto out; > @@ -231,9 +259,11 @@ int __init omap_register_i2c_bus(int > bus_id, u32 clkrate, > return err; > } > > - if (!i2c_rate[bus_id - 1]) > - i2c_rate[bus_id - 1] = clkrate; > - i2c_rate[bus_id - 1] &= ~OMAP_I2C_CMDLINE_SETUP; > + if (!i2c_pdata[bus_id - 1].clkrate) > + i2c_pdata[bus_id - 1].clkrate = clkrate; > + > + omap_set_i2c_constraint_func(&i2c_pdata[bus_id - 1]); > + i2c_pdata[bus_id - 1].clkrate &= ~OMAP_I2C_CMDLINE_SETUP; > > return omap_i2c_add_bus(bus_id); > } > diff --git a/drivers/i2c/busses/i2c-omap.c > b/drivers/i2c/busses/i2c-omap.c index 827da08..ac0bfd2 100644 > --- a/drivers/i2c/busses/i2c-omap.c > +++ b/drivers/i2c/busses/i2c-omap.c > @@ -37,6 +37,7 @@ > #include <linux/platform_device.h> > #include <linux/clk.h> > #include <linux/io.h> > +#include <linux/i2c-omap.h> > > /* I2C controller revisions */ > #define OMAP_I2C_REV_2 0x20 > @@ -165,6 +166,9 @@ struct omap_i2c_dev { > struct clk *fclk; /* Functional clock */ > struct completion cmd_complete; > struct resource *ioarea; > + u32 latency; /* maximum mpu > wkup latency */ > + void (*set_mpu_wkup_lat)(struct device *dev, > + int latency); > u32 speed; /* Speed of bus > in Khz */ > u16 cmd_err; > u8 *buf; > @@ -508,8 +512,12 @@ static int omap_i2c_xfer_msg(struct > i2c_adapter *adap, > * REVISIT: We should abort the transfer on signals, > but the bus goes > * into arbitration and we're currently unable to > recover from it. > */ > + if (dev->set_mpu_wkup_lat != NULL) > + dev->set_mpu_wkup_lat(dev->dev, dev->latency); > r = wait_for_completion_timeout(&dev->cmd_complete, > OMAP_I2C_TIMEOUT); > + if (dev->set_mpu_wkup_lat != NULL) > + dev->set_mpu_wkup_lat(dev->dev, -1); > dev->buf_len = 0; > if (r < 0) > return r; > @@ -826,6 +834,7 @@ omap_i2c_probe(struct platform_device *pdev) > struct omap_i2c_dev *dev; > struct i2c_adapter *adap; > struct resource *mem, *irq, *ioarea; > + struct omap_i2c_bus_platform_data *pdata = > pdev->dev.platform_data; > irq_handler_t isr; > int r; > u32 speed = 0; > @@ -855,10 +864,13 @@ omap_i2c_probe(struct platform_device *pdev) > goto err_release_region; > } > > - if (pdev->dev.platform_data != NULL) > - speed = *(u32 *)pdev->dev.platform_data; > - else > - speed = 100; /* Defualt speed */ > + if (pdata != NULL) { > + speed = pdata->clkrate; > + dev->set_mpu_wkup_lat = pdata->set_mpu_wkup_lat; > + } else { > + speed = 100; /* Default speed */ > + dev->set_mpu_wkup_lat = NULL; > + } > > dev->speed = speed; > dev->idle = 1; > @@ -893,6 +905,11 @@ omap_i2c_probe(struct platform_device *pdev) > */ > dev->fifo_size = (dev->fifo_size / 2); > dev->b_hw = 1; /* Enable hardware fixes */ > + > + /* calculate wakeup latency constraint for MPU */ > + if (dev->set_mpu_wkup_lat != NULL) > + dev->latency = (1000000 * dev->fifo_size) / > + (1000 * speed / 8); > } > > /* reset ASAP, clearing any IRQs */ > diff --git a/include/linux/i2c-omap.h > b/include/linux/i2c-omap.h new file mode 100644 index 0000000..1362fba > --- /dev/null > +++ b/include/linux/i2c-omap.h > @@ -0,0 +1,9 @@ > +#ifndef __I2C_OMAP_H__ > +#define __I2C_OMAP_H__ > + > +struct omap_i2c_bus_platform_data { > + u32 clkrate; > + void (*set_mpu_wkup_lat)(struct device *dev, > int set); > +}; > + > +#endif > -- > 1.6.3.3 > > -- > 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 > -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
