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SubjectRe: [PATCH v4 05/10] mfd: max77650: new core mfd driver
On Tue, 12 Feb 2019, Bartosz Golaszewski wrote:

> wt., 12 lut 2019 o 10:55 Lee Jones <lee.jones@linaro.org> napisał(a):
> >
> > On Tue, 12 Feb 2019, Bartosz Golaszewski wrote:
> >
> > > wt., 12 lut 2019 o 09:36 Lee Jones <lee.jones@linaro.org> napisał(a):
> > > >
> > > > On Tue, 05 Feb 2019, Bartosz Golaszewski wrote:
> > > >
> > > > > From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > > > >
> > > > > Add the core mfd driver for max77650 PMIC. We define five sub-devices
> > > > > for which the drivers will be added in subsequent patches.
> > > > >
> > > > > Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > > > > ---
> > > > > drivers/mfd/Kconfig | 11 ++
> > > > > drivers/mfd/Makefile | 1 +
> > > > > drivers/mfd/max77650.c | 342 +++++++++++++++++++++++++++++++++++
> > > > > include/linux/mfd/max77650.h | 59 ++++++
> > > > > 4 files changed, 413 insertions(+)
> > > > > create mode 100644 drivers/mfd/max77650.c
> > > > > create mode 100644 include/linux/mfd/max77650.h
> >
> > [...]
> >
> > > > > +static const struct max77650_irq_mapping max77650_irq_mapping_table[] = {
> > > > > + {
> > > > > + .cell_num = MAX77650_CELL_CHARGER,
> > > > > + .irqs = max77650_charger_irqs,
> > > > > + .irq_names = max77650_charger_irq_names,
> > > > > + .num_irqs = ARRAY_SIZE(max77650_charger_irqs),
> > > > > + },
> > > > > + {
> > > > > + .cell_num = MAX77650_CELL_GPIO,
> > > > > + .irqs = max77650_gpio_irqs,
> > > > > + .irq_names = max77650_gpio_irq_names,
> > > > > + .num_irqs = ARRAY_SIZE(max77650_gpio_irqs),
> > > > > + },
> > > > > + {
> > > > > + .cell_num = MAX77650_CELL_ONKEY,
> > > > > + .irqs = max77650_onkey_irqs,
> > > > > + .irq_names = max77650_onkey_irq_names,
> > > > > + .num_irqs = ARRAY_SIZE(max77650_onkey_irqs),
> > > > > + },
> > > > > +};
> > > >
> > > > This is all a bit convoluted and nasty TBH.
> > > >
> > > > > +static const struct mfd_cell max77650_cells[] = {
> > > > > + [MAX77650_CELL_REGULATOR] = {
> > > > > + .name = "max77650-regulator",
> > > > > + .of_compatible = "maxim,max77650-regulator",
> > > > > + },
> > > > > + [MAX77650_CELL_CHARGER] = {
> > > > > + .name = "max77650-charger",
> > > > > + .of_compatible = "maxim,max77650-charger",
> > > > > + },
> > > > > + [MAX77650_CELL_GPIO] = {
> > > > > + .name = "max77650-gpio",
> > > > > + .of_compatible = "maxim,max77650-gpio",
> > > > > + },
> > > > > + [MAX77650_CELL_LED] = {
> > > > > + .name = "max77650-led",
> > > > > + .of_compatible = "maxim,max77650-led",
> > > > > + },
> > > > > + [MAX77650_CELL_ONKEY] = {
> > > > > + .name = "max77650-onkey",
> > > > > + .of_compatible = "maxim,max77650-onkey",
> > > > > + },
> > > > > +};
> > > >
> > > > Why are you numbering the cells? There is no need to do this.
> > > >
> > >
> > > Just for better readability. It makes sense to me coupled with
> > > MAX77650_NUM_CELLS.
> >
> > You have it the wrong way around. You define the cell data, then
> > provide the number of them using ARRAY_SIZE(). The enum containing
> > MAX77650_NUM_CELLS should not exist.
> >
> > > > > +static const struct regmap_irq max77650_irqs[] = {
> > > > > + [MAX77650_INT_GPI] = {
> > > > > + .reg_offset = MAX77650_INT_GLBL_OFFSET,
> > > > > + .mask = MAX77650_INT_GPI_MSK,
> > > > > + .type = {
> > > > > + .type_falling_val = MAX77650_INT_GPI_F_MSK,
> > > > > + .type_rising_val = MAX77650_INT_GPI_R_MSK,
> > > > > + .types_supported = IRQ_TYPE_EDGE_BOTH,
> > > > > + },
> > > > > + },
> > > > > + [MAX77650_INT_nEN_F] = {
> > > > > + .reg_offset = MAX77650_INT_GLBL_OFFSET,
> > > > > + .mask = MAX77650_INT_nEN_F_MSK,
> > > > > + },
> > > > > + [MAX77650_INT_nEN_R] = {
> > > > > + .reg_offset = MAX77650_INT_GLBL_OFFSET,
> > > > > + .mask = MAX77650_INT_nEN_R_MSK,
> > > > > + },
> > > > > + [MAX77650_INT_TJAL1_R] = {
> > > > > + .reg_offset = MAX77650_INT_GLBL_OFFSET,
> > > > > + .mask = MAX77650_INT_TJAL1_R_MSK,
> > > > > + },
> > > > > + [MAX77650_INT_TJAL2_R] = {
> > > > > + .reg_offset = MAX77650_INT_GLBL_OFFSET,
> > > > > + .mask = MAX77650_INT_TJAL2_R_MSK,
> > > > > + },
> > > > > + [MAX77650_INT_DOD_R] = {
> > > > > + .reg_offset = MAX77650_INT_GLBL_OFFSET,
> > > > > + .mask = MAX77650_INT_DOD_R_MSK,
> > > > > + },
> > > > > + [MAX77650_INT_THM] = {
> > > > > + .reg_offset = MAX77650_INT_CHG_OFFSET,
> > > > > + .mask = MAX77650_INT_THM_MSK,
> > > > > + },
> > > > > + [MAX77650_INT_CHG] = {
> > > > > + .reg_offset = MAX77650_INT_CHG_OFFSET,
> > > > > + .mask = MAX77650_INT_CHG_MSK,
> > > > > + },
> > > > > + [MAX77650_INT_CHGIN] = {
> > > > > + .reg_offset = MAX77650_INT_CHG_OFFSET,
> > > > > + .mask = MAX77650_INT_CHGIN_MSK,
> > > > > + },
> > > > > + [MAX77650_INT_TJ_REG] = {
> > > > > + .reg_offset = MAX77650_INT_CHG_OFFSET,
> > > > > + .mask = MAX77650_INT_TJ_REG_MSK,
> > > > > + },
> > > > > + [MAX77650_INT_CHGIN_CTRL] = {
> > > > > + .reg_offset = MAX77650_INT_CHG_OFFSET,
> > > > > + .mask = MAX77650_INT_CHGIN_CTRL_MSK,
> > > > > + },
> > > > > + [MAX77650_INT_SYS_CTRL] = {
> > > > > + .reg_offset = MAX77650_INT_CHG_OFFSET,
> > > > > + .mask = MAX77650_INT_SYS_CTRL_MSK,
> > > > > + },
> > > > > + [MAX77650_INT_SYS_CNFG] = {
> > > > > + .reg_offset = MAX77650_INT_CHG_OFFSET,
> > > > > + .mask = MAX77650_INT_SYS_CNFG_MSK,
> > > > > + },
> > > > > +};
> > > >
> > > > If you get rid of all of the horrible hoop jumping in *_setup_irqs(),
> > > > you can use REGMAP_IRQ_REG() like everyone else does.
> > > >
> > >
> > > I could even use it now - except for the first interrupt. I decided to
> > > not use it everywhere as it looks much better that way than having
> > > REGMAP_IRQ_REG() for all definitions and then the first one sticking
> > > out like that. It just looks better.
> >
> > The way it's done at the moment looks terrible.
> >
> > Please use the MACROs to simplify as much of the code as possible.
> >
> > > > > +static const struct regmap_irq_chip max77650_irq_chip = {
> > > > > + .name = "max77650-irq",
> > > > > + .irqs = max77650_irqs,
> > > > > + .num_irqs = ARRAY_SIZE(max77650_irqs),
> > > > > + .num_regs = 2,
> > > > > + .status_base = MAX77650_REG_INT_GLBL,
> > > > > + .mask_base = MAX77650_REG_INTM_GLBL,
> > > > > + .type_in_mask = true,
> > > > > + .type_invert = true,
> > > > > + .init_ack_masked = true,
> > > > > + .clear_on_unmask = true,
> > > > > +};
> > > > > +
> > > > > +static const struct regmap_config max77650_regmap_config = {
> > > > > + .name = "max77650",
> > > > > + .reg_bits = 8,
> > > > > + .val_bits = 8,
> > > > > +};
> > > > > +
> > > > > +static int max77650_setup_irqs(struct device *dev, struct mfd_cell *cells)
> > > > > +{
> > > > > + const struct max77650_irq_mapping *mapping;
> > > > > + struct regmap_irq_chip_data *irq_data;
> > > > > + struct i2c_client *i2c;
> > > > > + struct mfd_cell *cell;
> > > > > + struct resource *res;
> > > > > + struct regmap *map;
> > > > > + int i, j, irq, rv;
> > > > > +
> > > > > + i2c = to_i2c_client(dev);
> > > > > +
> > > > > + map = dev_get_regmap(dev, NULL);
> > > > > + if (!map)
> > > > > + return -ENODEV;
> > > > > +
> > > > > + rv = devm_regmap_add_irq_chip(dev, map, i2c->irq,
> > > > > + IRQF_ONESHOT | IRQF_SHARED, -1,
> > > >
> > > > What is -1? Are you sure this isn't defined somewhere?
> > > >
> > >
> > > I don't see any define for negative irq_base argument. I can add that
> > > in a separate series and convert the users, but for now I'd stick with
> > > -1.
> >
> > IMO it should be defined. You can define it locally for now.
> >
> > > > > + &max77650_irq_chip, &irq_data);
> > > > > + if (rv)
> > > > > + return rv;
> > > > > +
> > > > > + for (i = 0; i < ARRAY_SIZE(max77650_irq_mapping_table); i++) {
> > > > > + mapping = &max77650_irq_mapping_table[i];
> > > > > + cell = &cells[mapping->cell_num];
> > > > > +
> > > > > + res = devm_kcalloc(dev, sizeof(*res),
> > > > > + mapping->num_irqs, GFP_KERNEL);
> > > > > + if (!res)
> > > > > + return -ENOMEM;
> > > > > +
> > > > > + cell->resources = res;
> > > > > + cell->num_resources = mapping->num_irqs;
> > > > > +
> > > > > + for (j = 0; j < mapping->num_irqs; j++) {
> > > > > + irq = regmap_irq_get_virq(irq_data, mapping->irqs[j]);
> > > > > + if (irq < 0)
> > > > > + return irq;
> > > > > +
> > > > > + res[j].start = res[j].end = irq;
> > > > > + res[j].flags = IORESOURCE_IRQ;
> > > > > + res[j].name = mapping->irq_names[j];
> > > > > + }
> > > > > + }
> > > >
> > > > This is the first time I've seen it done like this (and I hate it).
> > > >
> > > > Why are you storing the virqs in resources?
> > > >
> > > > I think this is highly irregular.
> > > >
> > >
> > > I initially just passed the regmap_irq_chip_data over i2c clientdata
> > > and sub-drivers would look up virq numbers from it but was advised by
> > > Dmitry Torokhov to use resources instead. After implementing it this
> > > way I too think it's more elegant in sub-drivers who can simply do
> > > platform_get_irq_byname(). Do you have a different idea?
> >
> > > What exactly don't you like about this?
> >
> > * The declaration of a superfluous struct
> > * 100 lines of additional/avoidable code
> > * Hacky hoop jumping trying to fudge VIRQs into resources
> > * Resources were designed for HWIRQs (unless a domain is present)
> > * Loads of additional/avoidable CPU cycles setting all this up
>
> While the above may be right, this one is negligible and you know it. :)

You have nested for() loops. You *are* wasting lots of cycles.

> > Need I go on? :)
> >
> > Surely the fact that you are using both sides of an API
> > (devm_regmap_init_i2c and regmap_irq_get_*) in the same driver, must
> > set some alarm bells ringing?
> >
> > This whole HWIRQ setting, VIRQ getting, resource hacking is a mess.
> >
> > And for what? To avoid passing IRQ data to a child driver?
>
> What do you propose? Should I go back to the approach in v1 and pass
> the regmap_irq_chip_data to child drivers?

I'm saying you should remove all of this hackery and pass IRQs as they
are supposed to be passed (like everyone else does).

> @Dmitry: what do you think?

--
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
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