In order to use i2c from a cold boot, the i2c peripheral must be taken
out of reset. We request a shared reset controller each time a bus
driver is loaded, as the reset is shared between the 14 i2c buses.
On remove the reset is asserted, which only touches the hardware once
the last i2c bus is removed.
The reset is required as the I2C buses will not work without releasing
the reset. Previously the driver only worked with out of tree hacks
that released this reset before the driver was loaded. Update the
device tree bindings to reflect this.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Pull i2c updates from Wolfram Sang:
- new drivers for Spreadtrum I2C, Intel Cherry Trail Whiskey Cove SMBUS
- quite some driver updates
- cleanups for the i2c-mux subsystem
- some subsystem-wide constification
- further cleanup of include/linux/i2c
* 'i2c/for-4.14' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (50 commits)
i2c: sprd: Fix undefined reference errors
i2c: nomadik: constify amba_id
i2c: versatile: Make i2c_algo_bit_data const
i2c: busses: make i2c_adapter_quirks const
i2c: busses: make i2c_adapter const
i2c: busses: make i2c_algorithm const
i2c: Add Spreadtrum I2C controller driver
dt-bindings: i2c: Add Spreadtrum I2C controller documentation
i2c-cht-wc: make cht_wc_i2c_adap_driver static
MAINTAINERS: Add entry for drivers/i2c/busses/i2c-cht-wc.c
i2c: aspeed: Retain delay/setup/hold values when configuring bus frequency
dt-bindings: i2c: eeprom: Document vendor to be used and deprecated ones
i2c: i801: Restore the presence state of P2SB PCI device after reading BAR
MAINTAINERS: drop entry for Blackfin I2C and Sonic's email
blackfin: merge the two TWI header files
i2c: davinci: Preserve return value of devm_clk_get
i2c: mediatek: Add i2c compatible for MediaTek MT7622
dt-bindings: i2c: Add MediaTek MT7622 i2c binding
dt-bindings: i2c: modify information formats
i2c: mux: i2c-arb-gpio-challenge: allow compiling w/o OF support
...
In addition to the base, low and high clock configuration, the AC timing
register #1 on the AST2400 houses fields controlling:
1. tBUF: Minimum delay between Stop and Start conditions
2. tHDSTA: Hold time for the Start condition
3. tACST: Setup time for Start and Stop conditions, and hold time for the
Repeated Start condition
These values are defined in hardware on the AST2500 and therefore don't
need to be set.
aspeed_i2c_init_clk() was performing a direct write of the generated
clock values rather than a read/mask/modify/update sequence to retain
tBUF, tHDSTA and tACST, and therefore cleared the tBUF, tHDSTA and tACST
fields on the AST2400. This resulted in a delay/setup/hold time of 1
base clock, which in some configurations is not enough for some devices
(e.g. the MAX31785 fan controller, with an APB of 48MHz and a desired
bus speed of 100kHz).
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Tested-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Before I skipped null checks when the master is in the STOP state; this
fixes that.
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Fixes: f327c686d3 ("i2c: aspeed: added driver for Aspeed I2C")
24xx BMCs have larger clock divider granularity which can cause problems
when trying to set them as 25xx clock dividers; this adds clock setting
code specific to 24xx.
This also fixes a potential issue where clock dividers were rounded down
instead of up.
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Added slave support for Aspeed I2C controller. Supports fourteen busses
present in AST24XX and AST25XX BMC SoCs by Aspeed.
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Added initial master support for Aspeed I2C controller. Supports
fourteen busses present in AST24XX and AST25XX BMC SoCs by Aspeed.
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Joel Stanley
Linus Torvalds
Andrew Jeffery
Brendan Higgins