From 0dbdb29de29ffa360c095c4bbe43aa18b98126bd Mon Sep 17 00:00:00 2001 From: David Wu Date: Wed, 3 Aug 2016 11:27:31 +0800 Subject: [PATCH] i2c: rk3x: Make sure the i2c transfer to be finished before system reboot If the system rebooted, there might be i2c transfer at the same time, it will make something unpredictable, because the i2c host was reseted, but the slave device wasn't, such as rk808 pmic, so make sure the i2c transfer to be finished before system shutdown at the reset mode. Change-Id: I3c09f3acbe86595c295edc191aa38351adb7d5dc Signed-off-by: David Wu Signed-off-by: Jianqun Xu --- arch/arm/kernel/reboot.c | 2 ++ arch/arm64/kernel/process.c | 2 ++ drivers/i2c/busses/i2c-rk3x.c | 51 +++++++++++++++++++++++++++++++++-- include/linux/reboot.h | 4 +++ kernel/reboot.c | 19 +++++++++++++ 5 files changed, 76 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c index 3b2aa9a9fe26..438fa4d525c7 100644 --- a/arch/arm/kernel/reboot.c +++ b/arch/arm/kernel/reboot.c @@ -141,6 +141,8 @@ void machine_restart(char *cmd) local_irq_disable(); smp_send_stop(); + do_kernel_i2c_restart(cmd); + if (arm_pm_restart) arm_pm_restart(reboot_mode, cmd); else diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 7f1628effe6d..1e056bd8b726 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -150,6 +150,8 @@ void machine_restart(char *cmd) local_irq_disable(); smp_send_stop(); + do_kernel_i2c_restart(cmd); + /* * UpdateCapsule() depends on the system being reset via * ResetSystem(). diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c index 83ac23019f29..693048511871 100644 --- a/drivers/i2c/busses/i2c-rk3x.c +++ b/drivers/i2c/busses/i2c-rk3x.c @@ -25,6 +25,8 @@ #include #include #include +#include +#include /* Register Map */ @@ -191,6 +193,7 @@ struct rk3x_i2c_soc_data { * @state: state of i2c transfer * @processed: byte length which has been send or received * @error: error code for i2c transfer + * @i2c_restart_nb: make sure the i2c transfer to be finished */ struct rk3x_i2c { struct i2c_adapter adap; @@ -221,6 +224,8 @@ struct rk3x_i2c { enum rk3x_i2c_state state; unsigned int processed; int error; + + struct notifier_block i2c_restart_nb; }; static inline void i2c_writel(struct rk3x_i2c *i2c, u32 value, @@ -1076,10 +1081,10 @@ static int rk3x_i2c_xfer(struct i2c_adapter *adap, if (i + ret >= num) i2c->is_last_msg = true; - spin_unlock_irqrestore(&i2c->lock, flags); - rk3x_i2c_start(i2c); + spin_unlock_irqrestore(&i2c->lock, flags); + timeout = wait_event_timeout(i2c->wait, !i2c->busy, msecs_to_jiffies(WAIT_TIMEOUT)); @@ -1115,6 +1120,39 @@ static int rk3x_i2c_xfer(struct i2c_adapter *adap, return ret < 0 ? ret : num; } +static int rk3x_i2c_restart_notify(struct notifier_block *this, + unsigned long mode, void *cmd) +{ + struct rk3x_i2c *i2c = container_of(this, struct rk3x_i2c, + i2c_restart_nb); + int tmo = WAIT_TIMEOUT * USEC_PER_MSEC; + u32 val; + + if (i2c->state != STATE_IDLE) { + /* complete the unfinished job */ + while (tmo-- && i2c->busy) { + udelay(1); + rk3x_i2c_irq(0, i2c); + } + } + + if (tmo <= 0) { + dev_err(i2c->dev, "restart timeout, ipd: 0x%02x, state: %d\n", + i2c_readl(i2c, REG_IPD), i2c->state); + + /* Force a STOP condition without interrupt */ + i2c_writel(i2c, 0, REG_IEN); + val = i2c_readl(i2c, REG_CON) & REG_CON_TUNING_MASK; + val |= REG_CON_EN | REG_CON_STOP; + i2c_writel(i2c, val, REG_CON); + + udelay(10); + i2c->state = STATE_IDLE; + } + + return NOTIFY_DONE; +} + static __maybe_unused int rk3x_i2c_resume(struct device *dev) { struct rk3x_i2c *i2c = dev_get_drvdata(dev); @@ -1228,6 +1266,14 @@ static int rk3x_i2c_probe(struct platform_device *pdev) spin_lock_init(&i2c->lock); init_waitqueue_head(&i2c->wait); + i2c->i2c_restart_nb.notifier_call = rk3x_i2c_restart_notify; + i2c->i2c_restart_nb.priority = 128; + ret = register_i2c_restart_handler(&i2c->i2c_restart_nb); + if (ret) { + dev_err(&pdev->dev, "failed to setup i2c restart handler.\n"); + return ret; + } + mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); i2c->regs = devm_ioremap_resource(&pdev->dev, mem); if (IS_ERR(i2c->regs)) @@ -1346,6 +1392,7 @@ static int rk3x_i2c_remove(struct platform_device *pdev) i2c_del_adapter(&i2c->adap); clk_notifier_unregister(i2c->clk, &i2c->clk_rate_nb); + unregister_i2c_restart_handler(&i2c->i2c_restart_nb); clk_unprepare(i2c->pclk); clk_unprepare(i2c->clk); diff --git a/include/linux/reboot.h b/include/linux/reboot.h index e63799a6e895..30aa098b45e4 100644 --- a/include/linux/reboot.h +++ b/include/linux/reboot.h @@ -47,6 +47,10 @@ extern int register_restart_handler(struct notifier_block *); extern int unregister_restart_handler(struct notifier_block *); extern void do_kernel_restart(char *cmd); +extern int register_i2c_restart_handler(struct notifier_block *); +extern int unregister_i2c_restart_handler(struct notifier_block *); +extern void do_kernel_i2c_restart(char *cmd); + /* * Architecture-specific implementations of sys_reboot commands. */ diff --git a/kernel/reboot.c b/kernel/reboot.c index 8fb44dec9ad7..931ac602621c 100644 --- a/kernel/reboot.c +++ b/kernel/reboot.c @@ -212,6 +212,25 @@ void do_kernel_restart(char *cmd) atomic_notifier_call_chain(&restart_handler_list, reboot_mode, cmd); } +static ATOMIC_NOTIFIER_HEAD(i2c_restart_handler_list); + +int register_i2c_restart_handler(struct notifier_block *nb) +{ + return atomic_notifier_chain_register(&i2c_restart_handler_list, nb); +} +EXPORT_SYMBOL(register_i2c_restart_handler); + +int unregister_i2c_restart_handler(struct notifier_block *nb) +{ + return atomic_notifier_chain_unregister(&i2c_restart_handler_list, nb); +} +EXPORT_SYMBOL(unregister_i2c_restart_handler); + +void do_kernel_i2c_restart(char *cmd) +{ + atomic_notifier_call_chain(&i2c_restart_handler_list, reboot_mode, cmd); +} + void migrate_to_reboot_cpu(void) { /* The boot cpu is always logical cpu 0 */