Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 743cc375 authored by Julia Cartwright's avatar Julia Cartwright Committed by Peter Rosin
Browse files

i2c: mux: pca954x: make use of raw_spinlock variants 



The pca954x i2c mux driver currently implements an irq_chip for handling
interrupts; due to how irq_chip handling is done, it's necessary for the
irq_chip methods to be invoked from hardirq context, even on a a
real-time kernel.  Because the spinlock_t type becomes a "sleeping"
spinlock w/ RT kernels, it is not suitable to be used with irq_chips.

A quick audit of the operations under the lock reveal that they do only
minimal, bounded work, and are therefore safe to do under a raw spinlock.

Signed-off-by: default avatarJulia Cartwright <julia@ni.com>
Signed-off-by: default avatarPeter Rosin <peda@axentia.se>
parent 4495c08e

drivers/i2c/muxes/i2c-mux-pca954x.c

+6 −6
Original line number Diff line number Diff line
@@ -85,7 +85,7 @@ struct pca954x { 


	struct irq_domain *irq;

	unsigned int irq_mask;

	spinlock_t lock;

	raw_spinlock_t lock;

};



/* Provide specs for the PCA954x types we know about */
@@ -264,13 +264,13 @@ static void pca954x_irq_mask(struct irq_data *idata) 
	unsigned int pos = idata->hwirq;

	unsigned long flags;



	spin_lock_irqsave(&data->lock, flags);

	raw_spin_lock_irqsave(&data->lock, flags);



	data->irq_mask &= ~BIT(pos);

	if (!data->irq_mask)

		disable_irq(data->client->irq);



	spin_unlock_irqrestore(&data->lock, flags);

	raw_spin_unlock_irqrestore(&data->lock, flags);

}



static void pca954x_irq_unmask(struct irq_data *idata)
@@ -279,13 +279,13 @@ static void pca954x_irq_unmask(struct irq_data *idata) 
	unsigned int pos = idata->hwirq;

	unsigned long flags;



	spin_lock_irqsave(&data->lock, flags);

	raw_spin_lock_irqsave(&data->lock, flags);



	if (!data->irq_mask)

		enable_irq(data->client->irq);

	data->irq_mask |= BIT(pos);



	spin_unlock_irqrestore(&data->lock, flags);

	raw_spin_unlock_irqrestore(&data->lock, flags);

}



static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
@@ -311,7 +311,7 @@ static int pca954x_irq_setup(struct i2c_mux_core *muxc) 
	if (!data->chip->has_irq || client->irq <= 0)

		return 0;



	spin_lock_init(&data->lock);

	raw_spin_lock_init(&data->lock);



	data->irq = irq_domain_add_linear(client->dev.of_node,

					  data->chip->nchans,