diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-09-24 16:48:02 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-09-24 16:48:02 -0700 |
| commit | 351c8a09b00b5c51c8f58b016fffe51f87e2d820 (patch) | |
| tree | 8bced5a9ff152bdcf2bb15a194c97b856c6358d5 /drivers/i2c/busses/i2c-cht-wc.c | |
| parent | 3cf7487c5de713b706ca2e1f66ec5f9b27fe265a (diff) | |
| parent | 8ebf15e9c869e764b3aab4928938ee68c0e2bd6d (diff) | |
Merge branch 'i2c/for-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c updates from Wolfram Sang:
- new driver for ICY, an Amiga Zorro card :)
- axxia driver gained slave mode support, NXP driver gained ACPI
- the slave EEPROM backend gained 16 bit address support
- and lots of regular driver updates and reworks
* 'i2c/for-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (52 commits)
i2c: tegra: Move suspend handling to NOIRQ phase
i2c: imx: ACPI support for NXP i2c controller
i2c: uniphier(-f): remove all dev_dbg()
i2c: uniphier(-f): use devm_platform_ioremap_resource()
i2c: slave-eeprom: Add comment about address handling
i2c: exynos5: Remove IRQF_ONESHOT
i2c: stm32f7: Make structure stm32f7_i2c_algo constant
i2c: cht-wc: drop check because i2c_unregister_device() is NULL safe
i2c-eeprom_slave: Add support for more eeprom models
i2c: fsi: Add of_put_node() before break
i2c: synquacer: Make synquacer_i2c_ops constant
i2c: hix5hd2: Remove IRQF_ONESHOT
i2c: i801: Use iTCO version 6 in Cannon Lake PCH and beyond
watchdog: iTCO: Add support for Cannon Lake PCH iTCO
i2c: iproc: Make bcm_iproc_i2c_quirks constant
i2c: iproc: Add full name of devicetree node to adapter name
i2c: piix4: Add ACPI support
i2c: piix4: Fix probing of reserved ports on AMD Family 16h Model 30h
i2c: ocores: use request_any_context_irq() to register IRQ handler
i2c: designware: Fix optional reset error handling
...
Diffstat (limited to 'drivers/i2c/busses/i2c-cht-wc.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-cht-wc.c | 49 |
1 files changed, 47 insertions, 2 deletions
diff --git a/drivers/i2c/busses/i2c-cht-wc.c b/drivers/i2c/busses/i2c-cht-wc.c index 66af44bfa67d..b8fde61bb5d8 100644 --- a/drivers/i2c/busses/i2c-cht-wc.c +++ b/drivers/i2c/busses/i2c-cht-wc.c @@ -178,6 +178,51 @@ static const struct i2c_algorithm cht_wc_i2c_adap_algo = { .smbus_xfer = cht_wc_i2c_adap_smbus_xfer, }; +/* + * We are an i2c-adapter which itself is part of an i2c-client. This means that + * transfers done through us take adapter->bus_lock twice, once for our parent + * i2c-adapter and once to take our own bus_lock. Lockdep does not like this + * nested locking, to make lockdep happy in the case of busses with muxes, the + * i2c-core's i2c_adapter_lock_bus function calls: + * rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter)); + * + * But i2c_adapter_depth only works when the direct parent of the adapter is + * another adapter, as it is only meant for muxes. In our case there is an + * i2c-client and MFD instantiated platform_device in the parent->child chain + * between the 2 devices. + * + * So we override the default i2c_lock_operations and pass a hardcoded + * depth of 1 to rt_mutex_lock_nested, to make lockdep happy. + * + * Note that if there were to be a mux attached to our adapter, this would + * break things again since the i2c-mux code expects the root-adapter to have + * a locking depth of 0. But we always have only 1 client directly attached + * in the form of the Charger IC paired with the CHT Whiskey Cove PMIC. + */ +static void cht_wc_i2c_adap_lock_bus(struct i2c_adapter *adapter, + unsigned int flags) +{ + rt_mutex_lock_nested(&adapter->bus_lock, 1); +} + +static int cht_wc_i2c_adap_trylock_bus(struct i2c_adapter *adapter, + unsigned int flags) +{ + return rt_mutex_trylock(&adapter->bus_lock); +} + +static void cht_wc_i2c_adap_unlock_bus(struct i2c_adapter *adapter, + unsigned int flags) +{ + rt_mutex_unlock(&adapter->bus_lock); +} + +static const struct i2c_lock_operations cht_wc_i2c_adap_lock_ops = { + .lock_bus = cht_wc_i2c_adap_lock_bus, + .trylock_bus = cht_wc_i2c_adap_trylock_bus, + .unlock_bus = cht_wc_i2c_adap_unlock_bus, +}; + /**** irqchip for the client connected to the extchgr i2c adapter ****/ static void cht_wc_i2c_irq_lock(struct irq_data *data) { @@ -286,6 +331,7 @@ static int cht_wc_i2c_adap_i2c_probe(struct platform_device *pdev) adap->adapter.owner = THIS_MODULE; adap->adapter.class = I2C_CLASS_HWMON; adap->adapter.algo = &cht_wc_i2c_adap_algo; + adap->adapter.lock_ops = &cht_wc_i2c_adap_lock_ops; strlcpy(adap->adapter.name, "PMIC I2C Adapter", sizeof(adap->adapter.name)); adap->adapter.dev.parent = &pdev->dev; @@ -363,8 +409,7 @@ static int cht_wc_i2c_adap_i2c_remove(struct platform_device *pdev) { struct cht_wc_i2c_adap *adap = platform_get_drvdata(pdev); - if (adap->client) - i2c_unregister_device(adap->client); + i2c_unregister_device(adap->client); i2c_del_adapter(&adap->adapter); irq_domain_remove(adap->irq_domain); |