On Mon, 2017-03-27 at 22:12 -0700, Brendan Higgins wrote: > The Aspeed 24XX/25XX chips share a single hardware interrupt across > 14 > separate I2C busses. This adds a dummy irqchip which maps the single > hardware interrupt to software interrupts for each of the busses. > > Signed-off-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx> I do think as I said earlier that is' a tiny bit overkill, I do worry about the overhead of the added layer of indirections on a 400Mhz ARMv9 (AST2400) core but otherwise: Acked-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> > --- > Added in v6: > - Pulled "aspeed_i2c_controller" out into a interrupt controller > since that is > what it actually does. > --- > drivers/irqchip/Makefile | 2 +- > drivers/irqchip/irq-aspeed-i2c-ic.c | 102 > ++++++++++++++++++++++++++++++++++++ > 2 files changed, 103 insertions(+), 1 deletion(-) > create mode 100644 drivers/irqchip/irq-aspeed-i2c-ic.c > > diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile > index 152bc40b6762..c136c2bd1761 100644 > --- a/drivers/irqchip/Makefile > +++ b/drivers/irqchip/Makefile > @@ -74,6 +74,6 @@ obj-$(CONFIG_MVEBU_ODMI) += irq- > mvebu-odmi.o > obj-$(CONFIG_MVEBU_PIC) += irq-mvebu-pic.o > obj-$(CONFIG_LS_SCFG_MSI) += irq-ls-scfg-msi.o > obj-$(CONFIG_EZNPS_GIC) += irq-eznps.o > -obj-$(CONFIG_ARCH_ASPEED) += irq-aspeed-vic.o > +obj-$(CONFIG_ARCH_ASPEED) += irq-aspeed-vic.o irq- > aspeed-i2c-ic.o > obj-$(CONFIG_STM32_EXTI) += irq-stm32-exti.o > obj-$(CONFIG_QCOM_IRQ_COMBINER) += qcom-irq- > combiner.o > diff --git a/drivers/irqchip/irq-aspeed-i2c-ic.c > b/drivers/irqchip/irq-aspeed-i2c-ic.c > new file mode 100644 > index 000000000000..59c50b28dec0 > --- /dev/null > +++ b/drivers/irqchip/irq-aspeed-i2c-ic.c > @@ -0,0 +1,102 @@ > +/* > + * Aspeed 24XX/25XX I2C Interrupt Controller. > + * > + * Copyright (C) 2012-2017 ASPEED Technology Inc. > + * Copyright 2017 IBM Corporation > + * Copyright 2017 Google, Inc. > + * > + * This program is free software; you can redistribute it and/or > modify > + * it under the terms of the GNU General Public License version 2 > as > + * published by the Free Software Foundation. > + */ > + > +#include <linux/irq.h> > +#include <linux/irqchip.h> > +#include <linux/irqchip/chained_irq.h> > +#include <linux/irqdomain.h> > +#include <linux/of_address.h> > +#include <linux/of_irq.h> > +#include <linux/io.h> > + > + > +#define ASPEED_I2C_IC_NUM_BUS 14 > + > +struct aspeed_i2c_ic { > + void __iomem *base; > + int parent_irq; > + struct irq_domain *irq_domain; > +}; > + > +/* > + * The aspeed chip provides a single hardware interrupt for all of > the I2C > + * busses, so we use a dummy interrupt chip to translate this single > interrupt > + * into multiple interrupts, each associated with a single I2C bus. > + */ > +static void aspeed_i2c_ic_irq_handler(struct irq_desc *desc) > +{ > + struct aspeed_i2c_ic *i2c_ic = > irq_desc_get_handler_data(desc); > + struct irq_chip *chip = irq_desc_get_chip(desc); > + unsigned long bit, status; > + unsigned int bus_irq; > + > + chained_irq_enter(chip, desc); > + status = readl(i2c_ic->base); > + for_each_set_bit(bit, &status, ASPEED_I2C_IC_NUM_BUS) { > + bus_irq = irq_find_mapping(i2c_ic->irq_domain, bit); > + generic_handle_irq(bus_irq); > + } > + chained_irq_exit(chip, desc); > +} > + > +/* > + * Set simple handler and mark IRQ as valid. Nothing interesting to > do here > + * since we are using a dummy interrupt chip. > + */ > +static int aspeed_i2c_ic_map_irq_domain(struct irq_domain *domain, > + unsigned int irq, > irq_hw_number_t hwirq) > +{ > + irq_set_chip_and_handler(irq, &dummy_irq_chip, > handle_simple_irq); > + irq_set_chip_data(irq, domain->host_data); > + > + return 0; > +} > + > +static const struct irq_domain_ops aspeed_i2c_ic_irq_domain_ops = { > + .map = aspeed_i2c_ic_map_irq_domain, > +}; > + > +static int __init aspeed_i2c_ic_of_init(struct device_node *node, > + struct device_node *parent) > +{ > + struct aspeed_i2c_ic *i2c_ic; > + > + i2c_ic = kzalloc(sizeof(*i2c_ic), GFP_KERNEL); > + if (!i2c_ic) > + return -ENOMEM; > + > + i2c_ic->base = of_iomap(node, 0); > + if (IS_ERR(i2c_ic->base)) > + return PTR_ERR(i2c_ic->base); > + > + i2c_ic->parent_irq = irq_of_parse_and_map(node, 0); > + if (i2c_ic->parent_irq < 0) > + return i2c_ic->parent_irq; > + > + i2c_ic->irq_domain = irq_domain_add_linear( > + node, ASPEED_I2C_IC_NUM_BUS, > + &aspeed_i2c_ic_irq_domain_ops, NULL); > + if (!i2c_ic->irq_domain) > + return -ENOMEM; > + > + i2c_ic->irq_domain->name = "ast-i2c-domain"; > + > + irq_set_chained_handler_and_data(i2c_ic->parent_irq, > + aspeed_i2c_ic_irq_handler, > i2c_ic); > + > + pr_info("i2c controller registered, irq %d\n", i2c_ic- > >parent_irq); > + > + return 0; > +} > + > +IRQCHIP_DECLARE(ast2400_i2c_ic, "aspeed,ast2400-i2c-ic", > aspeed_i2c_ic_of_init); > +IRQCHIP_DECLARE(ast2500_i2c_ic, "aspeed,ast2500-i2c-ic", > aspeed_i2c_ic_of_init); -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html