On Wed, Aug 01, 2018 at 01:12:06PM +0300, Andy Shevchenko wrote: > On Tue, Jul 31, 2018 at 12:09 PM, Wolfram Sang <wsa@xxxxxxxxxxxxx> wrote: > > > >> After this happens we try to shutdown the PMIC that interact over I2C. > >> I2C writes will need I2C interrupts to be enabled but in an interrupt > >> disabled context if shutting PMIC is the last thing in the sequence > >> which needs I2C writes is there an already existing solution to this > >> scenario? Any pointers would help. > > > > No existing solution. Long standing, known problem. > > > > IIRC the latest design we discussed is to add a new callback to struct > > i2c_algorithm like 'master_xfer_irqless' and teach the I2C core when to > > call which callback. Which might not be so super straightforward because > > for most drivers (except PMICs probably) using I2C when interrupts are > > disabled is a bug and we also shouldn't hide that by providing a generic > > fallback. > > Perhaps we should call it like i2c_pmic_xfer() to deliberately show > that this is dedicated solely for PMICs? Mark, wearing his regmap maintainer hat, would prefer to have the I2C core figuring it out. I do understand that, otherwise you need flags and such preserving the information across layers. I came up with the idea of a flag I2C_M_IRQLESS but it creates the same set of "problems".
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