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pinctrl: intel: Allow to request locked pads 

Some firmwares would like to protect pads from being modified by OS
and at the same time provide them to OS as a resource. So, the driver
in such circumstances may request pad and may not change its state.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
alistair/sunxi64-5.4-dsi
Andy Shevchenko 2019-08-12 19:14:01 +03:00
parent bf5ab1bded
commit 1bd231538c
1 changed files with 52 additions and 17 deletions
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69
drivers/pinctrl/intel/pinctrl-intel.c
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@ -220,47 +220,71 @@ static bool intel_pad_acpi_mode(struct intel_pinctrl *pctrl, unsigned int pin)
return !(readl(hostown) & BIT(gpp_offset));
}
static bool intel_pad_locked(struct intel_pinctrl *pctrl, unsigned int pin)
/**
* enum - Locking variants of the pad configuration
*
* @PAD_UNLOCKED: pad is fully controlled by the configuration registers
* @PAD_LOCKED: pad configuration registers, except TX state, are locked
* @PAD_LOCKED_TX: pad configuration TX state is locked
* @PAD_LOCKED_FULL: pad configuration registers are locked completely
*
* Locking is considered as read-only mode for corresponding registers and
* their respective fields. That said, TX state bit is locked separately from
* the main locking scheme.
*/
enum {
PAD_UNLOCKED = 0,
PAD_LOCKED = 1,
PAD_LOCKED_TX = 2,
PAD_LOCKED_FULL = PAD_LOCKED | PAD_LOCKED_TX,
};
static int intel_pad_locked(struct intel_pinctrl *pctrl, unsigned int pin)
{
struct intel_community *community;
const struct intel_padgroup *padgrp;
unsigned int offset, gpp_offset;
u32 value;
int ret = PAD_UNLOCKED;
community = intel_get_community(pctrl, pin);
if (!community)
return true;
return PAD_LOCKED_FULL;
if (!community->padcfglock_offset)
return false;
return PAD_UNLOCKED;
padgrp = intel_community_get_padgroup(community, pin);
if (!padgrp)
return true;
return PAD_LOCKED_FULL;
gpp_offset = padgroup_offset(padgrp, pin);
/*
* If PADCFGLOCK and PADCFGLOCKTX bits are both clear for this pad,
* the pad is considered unlocked. Any other case means that it is
* either fully or partially locked and we don't touch it.
* either fully or partially locked.
*/
offset = community->padcfglock_offset + padgrp->reg_num * 8;
offset = community->padcfglock_offset + 0 + padgrp->reg_num * 8;
value = readl(community->regs + offset);
if (value & BIT(gpp_offset))
return true;
ret |= PAD_LOCKED;
offset = community->padcfglock_offset + 4 + padgrp->reg_num * 8;
value = readl(community->regs + offset);
if (value & BIT(gpp_offset))
return true;
ret |= PAD_LOCKED_TX;
return false;
return ret;
}
static bool intel_pad_is_unlocked(struct intel_pinctrl *pctrl, unsigned int pin)
{
return (intel_pad_locked(pctrl, pin) & PAD_LOCKED) == PAD_UNLOCKED;
}
static bool intel_pad_usable(struct intel_pinctrl *pctrl, unsigned int pin)
{
return intel_pad_owned_by_host(pctrl, pin) &&
!intel_pad_locked(pctrl, pin);
return intel_pad_owned_by_host(pctrl, pin) && intel_pad_is_unlocked(pctrl, pin);
}
static int intel_get_groups_count(struct pinctrl_dev *pctldev)
@ -294,7 +318,8 @@ static void intel_pin_dbg_show(struct pinctrl_dev *pctldev, struct seq_file *s,
struct intel_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
void __iomem *padcfg;
u32 cfg0, cfg1, mode;
bool locked, acpi;
int locked;
bool acpi;
if (!intel_pad_owned_by_host(pctrl, pin)) {
seq_puts(s, "not available");
@ -322,11 +347,16 @@ static void intel_pin_dbg_show(struct pinctrl_dev *pctldev, struct seq_file *s,
if (locked || acpi) {
seq_puts(s, " [");
if (locked) {
if (locked)
seq_puts(s, "LOCKED");
if (acpi)
seq_puts(s, ", ");
}
if ((locked & PAD_LOCKED_FULL) == PAD_LOCKED_TX)
seq_puts(s, " tx");
else if ((locked & PAD_LOCKED_FULL) == PAD_LOCKED_FULL)
seq_puts(s, " full");
if (locked && acpi)
seq_puts(s, ", ");
if (acpi)
seq_puts(s, "ACPI");
seq_puts(s, "]");
@ -448,11 +478,16 @@ static int intel_gpio_request_enable(struct pinctrl_dev *pctldev,
raw_spin_lock_irqsave(&pctrl->lock, flags);
if (!intel_pad_usable(pctrl, pin)) {
if (!intel_pad_owned_by_host(pctrl, pin)) {
raw_spin_unlock_irqrestore(&pctrl->lock, flags);
return -EBUSY;
}
if (!intel_pad_is_unlocked(pctrl, pin)) {
raw_spin_unlock_irqrestore(&pctrl->lock, flags);
return 0;
}
padcfg0 = intel_get_padcfg(pctrl, pin, PADCFG0);
intel_gpio_set_gpio_mode(padcfg0);
/* Disable TX buffer and enable RX (this will be input) */