On 2017-01-05 05:11, Phil Reid wrote:
> Unfortunately some hardware device will assert their irq line immediately
> on power on and provide no mechanism to mask the irq. As the i2c muxes
> provide no method to mask irq line this provides a work around by keeping
> the parent irq masked until enough device drivers have loaded to service
> all pending interrupts.
>
> For example the the ltc1760 assert its SMBALERT irq immediately on power
> on. With two ltc1760 attached to bus 0 & 1 on a pca954x mux when the first
> device is registered irq are enabled and fire continuously as the second
> device driver has not yet loaded. Setting this parameter to 0x3 while
> delay the irq being enabled until both devices are ready.
>
> Acked-by: Peter Rosin <peda@xxxxxxxxxx>
Ooops, too soon apparently, but the below nitpicks are not that important.
Maybe Wolfram can fix it up instead of you sending a new version?
Cheers,
peda
> Signed-off-by: Phil Reid <preid@xxxxxxxxxxxxxxxxx>
> ---
> drivers/i2c/muxes/i2c-mux-pca954x.c | 22 +++++++++++++++++++++-
> 1 file changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
> index 84fc767..581a75d 100644
> --- a/drivers/i2c/muxes/i2c-mux-pca954x.c
> +++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
> @@ -75,6 +75,19 @@ struct chip_desc {
> } muxtype;
> };
>
> +/*
> + * irq_mask_enable: Provides a mechanism to work around hardware that asserts
> + * their irq immediately on power on. It allows the enabling of the irq to be
double space: "the irq"
> + * delayed until the corresponding bits in the the irq_mask are set thru
> + * irq_unmask.
> + * For example the the ltc1760 assert its SMBALERT irq immediately on power
"the the"
> + * on. With two ltc1760 attached to bus 0 & 1 on a pca954x mux when the first
> + * device is registered irq are enabled and fire continuously as the second
> + * device driver has not yet loaded. Setting this parameter to 0x3 while
> + * delay the irq being enabled until both devices are ready.
> + * This workaround will not work if two devices share an interrupt on the
> + * same bus segment.
> + */
> struct pca954x {
> const struct chip_desc *chip;
>
> @@ -84,6 +97,7 @@ struct pca954x {
>
> struct irq_domain *irq;
> unsigned int irq_mask;
> + unsigned int irq_mask_enable;
> };
>
> /* Provide specs for the PCA954x types we know about */
> @@ -270,9 +284,12 @@ static void pca954x_irq_unmask(struct irq_data *idata)
> struct pca954x *data = irq_data_get_irq_chip_data(idata);
> unsigned int pos = idata->hwirq;
>
> - if (!data->irq_mask)
> + if (!data->irq_mask_enable && !data->irq_mask)
> enable_irq(data->client->irq);
> data->irq_mask |= BIT(pos);
> + if (data->irq_mask_enable &&
> + (data->irq_mask & data->irq_mask) == data->irq_mask_enable)
> + enable_irq(data->client->irq);
> }
>
> static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
> @@ -395,6 +412,9 @@ static int pca954x_probe(struct i2c_client *client,
> idle_disconnect_dt = of_node &&
> of_property_read_bool(of_node, "i2c-mux-idle-disconnect");
>
> + of_property_read_u32(of_node, "nxp,irq-mask-enable",
> + &data->irq_mask_enable);
> +
> ret = pca954x_irq_setup(muxc);
> if (ret)
> goto fail_del_adapters;
>
--
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