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SubjectRe: [PATCH 2/3] gpio: davinci: Redesign driver to accommodate ngpios in one gpio chip
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On 01/10/2017 11:00 PM, Keerthy wrote:
> The Davinci GPIO driver is implemented to work with one monolithic
> Davinci GPIO platform device which may have up to Y(144) gpios.
> The Davinci GPIO driver instantiates number of GPIO chips with
> max 32 gpio pins per each during initialization and one IRQ domain.
> So, the current GPIO's opjects structure is:
>
> <platform device> Davinci GPIO controller
> |- <gpio0_chip0> ------|
> ... |--- irq_domain (hwirq [0..143])
> |- <gpio0_chipN> ------|
>
> Current driver creates one chip for every 32 GPIOs in a controller.
> This was a limitation earlier now there is no need for that. Hence
> redesigning the driver to create one gpio chip for all the ngpio
> in the controller.
>
> |- <gpio0_chip0> ------|--- irq_domain (hwirq [0..143]).
>
> The previous discussion on this can be found here:
> https://www.spinics.net/lists/linux-omap/msg132869.html

nice rework.

>
> Signed-off-by: Keerthy <j-keerthy@ti.com>
> ---
>
> Boot tested on Davinci platform.
>
> drivers/gpio/gpio-davinci.c | 127 +++++++++++++++++------------
> include/linux/platform_data/gpio-davinci.h | 13 ++-
> 2 files changed, 84 insertions(+), 56 deletions(-)
>
> diff --git a/drivers/gpio/gpio-davinci.c b/drivers/gpio/gpio-davinci.c
> index 26b874a..6c1c00a 100644
> --- a/drivers/gpio/gpio-davinci.c
> +++ b/drivers/gpio/gpio-davinci.c
> @@ -63,11 +63,13 @@ static inline int __davinci_direction(struct gpio_chip *chip,
> unsigned offset, bool out, int value)
> {
> struct davinci_gpio_controller *d = gpiochip_get_data(chip);
> - struct davinci_gpio_regs __iomem *g = d->regs;
> + struct davinci_gpio_regs __iomem *g;
> unsigned long flags;
> u32 temp;
> - u32 mask = 1 << offset;
> + int bank = offset / 32;
> + u32 mask = 1 << (offset % 32);
>
> + g = d->regs[bank];
> spin_lock_irqsave(&d->lock, flags);
> temp = readl_relaxed(&g->dir);
> if (out) {
> @@ -103,9 +105,12 @@ static int davinci_direction_in(struct gpio_chip *chip, unsigned offset)
> static int davinci_gpio_get(struct gpio_chip *chip, unsigned offset)
> {
> struct davinci_gpio_controller *d = gpiochip_get_data(chip);
> - struct davinci_gpio_regs __iomem *g = d->regs;
> + struct davinci_gpio_regs __iomem *g;
> + int bank = offset / 32;
>
> - return !!((1 << offset) & readl_relaxed(&g->in_data));
> + g = d->regs[bank];
> +
> + return !!((1 << (offset % 32)) & readl_relaxed(&g->in_data));

(1 << (offset % 32) is __gpio_mask()

> }
>
> /*
> @@ -115,9 +120,13 @@ static int davinci_gpio_get(struct gpio_chip *chip, unsigned offset)
> davinci_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
> {
> struct davinci_gpio_controller *d = gpiochip_get_data(chip);
> - struct davinci_gpio_regs __iomem *g = d->regs;
> + struct davinci_gpio_regs __iomem *g;
> + int bank = offset / 32;
>
> - writel_relaxed((1 << offset), value ? &g->set_data : &g->clr_data);
> + g = d->regs[bank];
> +
> + writel_relaxed((1 << (offset % 32)),
> + value ? &g->set_data : &g->clr_data);
> }
>
> static struct davinci_gpio_platform_data *
> @@ -165,7 +174,7 @@ static int davinci_gpio_of_xlate(struct gpio_chip *gc,
> if (gpiospec->args[0] > pdata->ngpio)
> return -EINVAL;
>
> - if (gc != &chips[gpiospec->args[0] / 32].chip)
> + if (gc != &chips->chip)
> return -EINVAL;
>
> if (flags)
> @@ -177,11 +186,11 @@ static int davinci_gpio_of_xlate(struct gpio_chip *gc,
>
> static int davinci_gpio_probe(struct platform_device *pdev)
> {
> - int i, base;
> + static int ctrl_num;
> + int gpio, bank;
> unsigned ngpio, nbank;
> struct davinci_gpio_controller *chips;
> struct davinci_gpio_platform_data *pdata;
> - struct davinci_gpio_regs __iomem *regs;
> struct device *dev = &pdev->dev;
> struct resource *res;
> char label[MAX_LABEL_SIZE];
> @@ -220,38 +229,30 @@ static int davinci_gpio_probe(struct platform_device *pdev)
> if (IS_ERR(gpio_base))
> return PTR_ERR(gpio_base);
>
> - for (i = 0, base = 0; base < ngpio; i++, base += 32) {
> - snprintf(label, MAX_LABEL_SIZE, "davinci_gpio.%d", i);
> - chips[i].chip.label = devm_kstrdup(dev, label, GFP_KERNEL);
> - if (!chips[i].chip.label)
> + snprintf(label, MAX_LABEL_SIZE, "davinci_gpio.%d", ctrl_num++);
> + chips->chip.label = devm_kstrdup(dev, label, GFP_KERNEL);
> + if (!chips->chip.label)
> return -ENOMEM;
>
> - chips[i].chip.direction_input = davinci_direction_in;
> - chips[i].chip.get = davinci_gpio_get;
> - chips[i].chip.direction_output = davinci_direction_out;
> - chips[i].chip.set = davinci_gpio_set;
> + chips->chip.direction_input = davinci_direction_in;
> + chips->chip.get = davinci_gpio_get;
> + chips->chip.direction_output = davinci_direction_out;
> + chips->chip.set = davinci_gpio_set;
>
> - chips[i].chip.base = base;
> - chips[i].chip.ngpio = ngpio - base;
> - if (chips[i].chip.ngpio > 32)
> - chips[i].chip.ngpio = 32;
> + chips->chip.ngpio = ngpio;
>
> #ifdef CONFIG_OF_GPIO
> - chips[i].chip.of_gpio_n_cells = 2;
> - chips[i].chip.of_xlate = davinci_gpio_of_xlate;
> - chips[i].chip.parent = dev;
> - chips[i].chip.of_node = dev->of_node;
> + chips->chip.of_gpio_n_cells = 2;
> + chips->chip.of_xlate = davinci_gpio_of_xlate;

I think It's not necessary to have custom .xlate() and
it can be removed, then gpiolib will assign default one of_gpio_simple_xlate().

> + chips->chip.parent = dev;
> + chips->chip.of_node = dev->of_node;
> #endif
> - spin_lock_init(&chips[i].lock);
> -
> - regs = gpio_base + offset_array[i];
> - if (!regs)
> - return -ENXIO;
> - chips[i].regs = regs;
> + spin_lock_init(&chips->lock);
>
> - gpiochip_add_data(&chips[i].chip, &chips[i]);
> - }
> + for (gpio = 0, bank = 0; gpio < ngpio; gpio += 32, bank++)
> + chips->regs[bank] = gpio_base + offset_array[bank];
>
> + gpiochip_add_data(&chips->chip, chips);
> platform_set_drvdata(pdev, chips);
> davinci_gpio_irq_setup(pdev);
> return 0;
> @@ -312,16 +313,19 @@ static int gpio_irq_type(struct irq_data *d, unsigned trigger)
>
> static void gpio_irq_handler(struct irq_desc *desc)
> {
> - unsigned int irq = irq_desc_get_irq(desc);
> struct davinci_gpio_regs __iomem *g;
> u32 mask = 0xffff;
> + int bank_num;
> struct davinci_gpio_controller *d;
> + struct davinci_gpio_irq_data *irqdata;
>
> - d = (struct davinci_gpio_controller *)irq_desc_get_handler_data(desc);
> - g = (struct davinci_gpio_regs __iomem *)d->regs;
> + irqdata = (struct davinci_gpio_irq_data *)irq_desc_get_handler_data(desc);
> + bank_num = irqdata->bank_num;
> + g = irqdata->regs;
> + d = irqdata->chip;
>
> /* we only care about one bank */
> - if (irq & 1)
> + if ((bank_num % 2) == 1)
> mask <<= 16;
>
> /* temporarily mask (level sensitive) parent IRQ */
> @@ -329,6 +333,7 @@ static void gpio_irq_handler(struct irq_desc *desc)
> while (1) {
> u32 status;
> int bit;
> + irq_hw_number_t hw_irq;
>
> /* ack any irqs */
> status = readl_relaxed(&g->intstat) & mask;
> @@ -341,9 +346,13 @@ static void gpio_irq_handler(struct irq_desc *desc)
> while (status) {
> bit = __ffs(status);
> status &= ~BIT(bit);
> + /* Max number of gpios per controller is 144 so
> + * hw_irq will be in [0..143]
> + */
> + hw_irq = (bank_num / 2) * 32 + bit;
> +
> generic_handle_irq(
> - irq_find_mapping(d->irq_domain,
> - d->chip.base + bit));
> + irq_find_mapping(d->irq_domain, hw_irq));
> }
> }
> chained_irq_exit(irq_desc_get_chip(desc), desc);
> @@ -355,7 +364,7 @@ static int gpio_to_irq_banked(struct gpio_chip *chip, unsigned offset)
> struct davinci_gpio_controller *d = gpiochip_get_data(chip);
>
> if (d->irq_domain)
> - return irq_create_mapping(d->irq_domain, d->chip.base + offset);
> + return irq_create_mapping(d->irq_domain, offset);
> else
> return -ENXIO;
> }
> @@ -369,7 +378,7 @@ static int gpio_to_irq_unbanked(struct gpio_chip *chip, unsigned offset)
> * can provide direct-mapped IRQs to AINTC (up to 32 GPIOs).
> */
> if (offset < d->gpio_unbanked)
> - return d->gpio_irq + offset;
> + return d->base_irq + offset;
> else
> return -ENODEV;
> }
> @@ -382,7 +391,7 @@ static int gpio_irq_type_unbanked(struct irq_data *data, unsigned trigger)
>
> d = (struct davinci_gpio_controller *)irq_data_get_irq_handler_data(data);
> g = (struct davinci_gpio_regs __iomem *)d->regs;
> - mask = __gpio_mask(data->irq - d->gpio_irq);
> + mask = __gpio_mask(data->irq - d->base_irq);
>
> if (trigger & ~(IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
> return -EINVAL;
> @@ -401,7 +410,7 @@ static int gpio_irq_type_unbanked(struct irq_data *data, unsigned trigger)
> {
> struct davinci_gpio_controller *chips =
> (struct davinci_gpio_controller *)d->host_data;
> - struct davinci_gpio_regs __iomem *g = chips[hw / 32].regs;
> + struct davinci_gpio_regs __iomem *g = chips->regs[hw / 32];
>
> irq_set_chip_and_handler_name(irq, &gpio_irqchip, handle_simple_irq,
> "davinci_gpio");
> @@ -459,6 +468,7 @@ static int davinci_gpio_irq_setup(struct platform_device *pdev)
> struct irq_domain *irq_domain = NULL;
> const struct of_device_id *match;
> struct irq_chip *irq_chip;
> + struct davinci_gpio_irq_data *irqdata[MAX_BANKED_IRQS];

You declare irqdata as array here but it has not been used anywhere
except for assignment. Could you remove this array and MAX_BANKED_IRQS define?

Seems you can just use struct davinci_gpio_irq_data *irqdata;

> gpio_get_irq_chip_cb_t gpio_get_irq_chip;
>
> /*
> @@ -514,10 +524,8 @@ static int davinci_gpio_irq_setup(struct platform_device *pdev)
> * IRQs, while the others use banked IRQs, would need some setup
> * tweaks to recognize hardware which can do that.
> */
> - for (gpio = 0, bank = 0; gpio < ngpio; bank++, gpio += 32) {
> - chips[bank].chip.to_irq = gpio_to_irq_banked;
> - chips[bank].irq_domain = irq_domain;
> - }
> + chips->chip.to_irq = gpio_to_irq_banked;
> + chips->irq_domain = irq_domain;
>
> /*
> * AINTC can handle direct/unbanked IRQs for GPIOs, with the GPIO
> @@ -526,9 +534,9 @@ static int davinci_gpio_irq_setup(struct platform_device *pdev)
> */
> if (pdata->gpio_unbanked) {
> /* pass "bank 0" GPIO IRQs to AINTC */
> - chips[0].chip.to_irq = gpio_to_irq_unbanked;
> - chips[0].gpio_irq = bank_irq;
> - chips[0].gpio_unbanked = pdata->gpio_unbanked;
> + chips->chip.to_irq = gpio_to_irq_unbanked;
> + chips->base_irq = bank_irq;
> + chips->gpio_unbanked = pdata->gpio_unbanked;
> binten = GENMASK(pdata->gpio_unbanked / 16, 0);
>
> /* AINTC handles mask/unmask; GPIO handles triggering */
> @@ -538,14 +546,14 @@ static int davinci_gpio_irq_setup(struct platform_device *pdev)
> irq_chip->irq_set_type = gpio_irq_type_unbanked;
>
> /* default trigger: both edges */
> - g = chips[0].regs;
> + g = chips->regs[0];
> writel_relaxed(~0, &g->set_falling);
> writel_relaxed(~0, &g->set_rising);
>
> /* set the direct IRQs up to use that irqchip */
> for (gpio = 0; gpio < pdata->gpio_unbanked; gpio++, irq++) {
> irq_set_chip(irq, irq_chip);
> - irq_set_handler_data(irq, &chips[gpio / 32]);
> + irq_set_handler_data(irq, chips);
> irq_set_status_flags(irq, IRQ_TYPE_EDGE_BOTH);
> }
>
> @@ -558,7 +566,7 @@ static int davinci_gpio_irq_setup(struct platform_device *pdev)
> */
> for (gpio = 0, bank = 0; gpio < ngpio; bank++, bank_irq++, gpio += 16) {
> /* disabled by default, enabled only as needed */
> - g = chips[bank / 2].regs;
> + g = chips->regs[bank / 2];
> writel_relaxed(~0, &g->clr_falling);
> writel_relaxed(~0, &g->clr_rising);
>
> @@ -567,8 +575,19 @@ static int davinci_gpio_irq_setup(struct platform_device *pdev)
> * gpio irqs. Pass the irq bank's corresponding controller to
> * the chained irq handler.
> */
> + irqdata[bank] = devm_kzalloc(&pdev->dev,
> + sizeof(struct
> + davinci_gpio_irq_data),
> + GFP_KERNEL);
> + if (!irqdata[bank])
> + return -ENOMEM;
> +
> + irqdata[bank]->regs = g;
> + irqdata[bank]->bank_num = bank;
> + irqdata[bank]->chip = chips;
> +
> irq_set_chained_handler_and_data(bank_irq, gpio_irq_handler,
> - &chips[gpio / 32]);
> + irqdata[bank]);
>
> binten |= BIT(bank);
> }
> diff --git a/include/linux/platform_data/gpio-davinci.h b/include/linux/platform_data/gpio-davinci.h
> index 18127c4..ca09686 100644
> --- a/include/linux/platform_data/gpio-davinci.h
> +++ b/include/linux/platform_data/gpio-davinci.h
> @@ -21,19 +21,28 @@
>
> #include <asm-generic/gpio.h>
>
> +#define MAX_BANKS 5

probably MAX_REGS_BANKS will be better, as it defines
max number of idnetical registers sets and not number of gpio banks.

> +#define MAX_BANKED_IRQS 9
> +
> struct davinci_gpio_platform_data {
> u32 ngpio;
> u32 gpio_unbanked;
> };
>
> +struct davinci_gpio_irq_data {
> + void __iomem *regs;
> + struct davinci_gpio_controller *chip;
> + int bank_num;
> +};
> +
> struct davinci_gpio_controller {
> struct gpio_chip chip;
> struct irq_domain *irq_domain;
> /* Serialize access to GPIO registers */
> spinlock_t lock;
> - void __iomem *regs;
> + void __iomem *regs[MAX_BANKS];
> int gpio_unbanked;
> - unsigned gpio_irq;
> + unsigned int base_irq;
> };
>
> /*
>

--
regards,
-grygorii

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