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Date: Wed, 29 Oct 2014 10:35:01 +0100
From: Linus Walleij <linus.walleij@...aro.org>
To: Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc: Alexandre Courbot <gnurou@...il.com>,
Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
Mathias Nyman <mathias.nyman@...ux.intel.com>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Ning Li <ning.li@...el.com>, Alan Cox <alan@...ux.intel.com>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 4/4] pinctrl: Add Intel Cherryview/Braswell pin controller support
On Fri, Oct 24, 2014 at 2:16 PM, Mika Westerberg
<mika.westerberg@...ux.intel.com> wrote:
> This driver supports the pin/GPIO controllers found in newer Intel SoCs
> like Cherryview and Braswell. The driver provides full GPIO support and
> minimal set of pin controlling funtionality.
>
> The driver is based on the original Cherryview GPIO driver authored by Ning
> Li and Alan Cox.
>
> Signed-off-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
*VERY* nice work Mika! Just minor nitpicks...
(...)
> +static int chv_config_get(struct pinctrl_dev *pctldev, unsigned pin,
> + unsigned long *config)
> +{
> + struct chv_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
> + enum pin_config_param param = pinconf_to_config_param(*config);
> + unsigned long flags;
> + u32 ctrl0, ctrl1;
> + u16 arg = 0;
> + u32 term;
> +
> + spin_lock_irqsave(&pctrl->lock, flags);
> + ctrl0 = readl(chv_padreg(pctrl, pin, CHV_PADCTRL0));
> + ctrl1 = readl(chv_padreg(pctrl, pin, CHV_PADCTRL1));
> + spin_unlock_irqrestore(&pctrl->lock, flags);
> +
> + term = (ctrl0 & CHV_PADCTRL0_TERM_MASK) >> CHV_PADCTRL0_TERM_SHIFT;
> +
> + switch (param) {
> + case PIN_CONFIG_BIAS_DISABLE:
> + if (term)
> + return -EINVAL;
> + break;
> +
> + case PIN_CONFIG_BIAS_PULL_UP:
> + if (!(ctrl0 & CHV_PADCTRL0_TERM_UP))
> + return -EINVAL;
> +
> + switch (term) {
> + case CHV_PADCTRL0_TERM_20K:
> + arg = 20;
These are in Ohms IIRC so should be 20000
> + break;
> + case CHV_PADCTRL0_TERM_5K:
> + arg = 5;
5000
> + break;
> + case CHV_PADCTRL0_TERM_1K:
> + arg = 1;
1000
> + break;
> + }
> +
> + break;
> +
> + case PIN_CONFIG_BIAS_PULL_DOWN:
> + if (!term || (ctrl0 & CHV_PADCTRL0_TERM_UP))
> + return -EINVAL;
> +
> + switch (term) {
> + case CHV_PADCTRL0_TERM_20K:
> + arg = 20;
20000
> + break;
> + case CHV_PADCTRL0_TERM_5K:
> + arg = 5;
5000
(...)
> +static int chv_config_set_pull(struct chv_pinctrl *pctrl, unsigned pin,
> + enum pin_config_param param, u16 arg)
> +{
> + void __iomem *reg = chv_padreg(pctrl, pin, CHV_PADCTRL0);
> + unsigned long flags;
> + u32 ctrl0, pull;
> +
> + spin_lock_irqsave(&pctrl->lock, flags);
> + ctrl0 = readl(reg);
> +
> + pull = CHV_PADCTRL0_TERM_20K << CHV_PADCTRL0_TERM_SHIFT;
> + switch (arg) {
This looks seriously convoluted: you can't inspect an argument before
checking what parameter you're dealing with. This should be
under a case PIN_CONFIG_BIAS_PULL_UP in the switch (param)
below I think?
> + case 1:
case 1000
> + /* For 1k there is only pull up */
> + if (param == PIN_CONFIG_BIAS_PULL_UP)
> + pull = CHV_PADCTRL0_TERM_1K << CHV_PADCTRL0_TERM_SHIFT;
Well you do check it here but...0
> + break;
> + case 5:
case 5000
> + pull = CHV_PADCTRL0_TERM_5K << CHV_PADCTRL0_TERM_SHIFT;
This will be applied to whatever config with arg == 5000 comes here!
(...)
> +static unsigned chv_gpio_offset_to_pin(struct chv_pinctrl *pctrl,
> + unsigned offset)
> +{
> + return pctrl->community->pins[offset].number;
> +}
I'm a bit worried about the massive pin<->offsets<->gpio# translations
happening in this and patch 1/4 etc. It's a bit unsettling. Are you
sure we are translating in the simplest way?
> +static int chv_gpio_get(struct gpio_chip *chip, unsigned offset)
> +{
> + struct chv_pinctrl *pctrl = gpiochip_to_pinctrl(chip);
> + int pin = chv_gpio_offset_to_pin(pctrl, offset);
> + unsigned long flags;
> + u32 ctrl0, cfg;
> +
> + spin_lock_irqsave(&pctrl->lock, flags);
> + ctrl0 = readl(chv_padreg(pctrl, pin, CHV_PADCTRL0));
> + spin_unlock_irqrestore(&pctrl->lock, flags);
If you need a lock before and after reading every register in this
range, consider regmap-mmio, because that is part of what
it does. Just a hint...
(...)
> +static void chv_gpio_irq_mask_unmask(struct irq_data *d, bool mask)
> +{
> + struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> + struct chv_pinctrl *pctrl = gpiochip_to_pinctrl(gc);
> + int pin = chv_gpio_offset_to_pin(pctrl, irqd_to_hwirq(d));
> + u32 value, intr_line;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&pctrl->lock, flags);
> +
> + intr_line = readl(chv_padreg(pctrl, pin, CHV_PADCTRL0));
> + intr_line &= CHV_PADCTRL0_INTSEL_MASK;
> + intr_line >>= CHV_PADCTRL0_INTSEL_SHIFT;
> +
> + value = readl(pctrl->regs + CHV_INTMASK);
> + if (mask)
> + value &= ~(1 << intr_line);
I usually do this kind of stuff with
#include <linux/bitops.h>
value &= ~BIT(intr_line);
> + else
> + value |= (1 << intr_line);
value |= BIT(intr_line);
(probably a few more occasions in the driver)
Yours,
Linus Walleij
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