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pinctrl: renesas: Remove unneeded locking around sh_pfc_read() calls 

There is no need to acquire the spinlock when reading from a pin
controller register:
  1. Reading a single MMIO register is an atomic operation,
  2. While sh_pfc_phys_to_virt() inside sh_pfc_read() has to traverse
     all mapped windows to find the appropriate virtual address, this
     does not need any locking, as the window mappings are never
     changed.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/2008ca99f0079fd5d4e640b7ef78710c98cc9f77.1637143108.git.geert+renesas@glider.be
This commit is contained in:
Geert Uytterhoeven 2021-11-17 10:59:32 +01:00
parent adb613f84a
commit 7c50a407b8
1 changed files with 1 additions and 8 deletions
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9
drivers/pinctrl/renesas/pinctrl.c
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@ -504,7 +504,6 @@ static u32 sh_pfc_pinconf_find_drive_strength_reg(struct sh_pfc *pfc,
static int sh_pfc_pinconf_get_drive_strength(struct sh_pfc *pfc,
unsigned int pin)
{
unsigned long flags;
unsigned int offset;
unsigned int size;
u32 reg;
@ -514,11 +513,7 @@ static int sh_pfc_pinconf_get_drive_strength(struct sh_pfc *pfc,
if (!reg)
return -EINVAL;
spin_lock_irqsave(&pfc->lock, flags);
val = sh_pfc_read(pfc, reg);
spin_unlock_irqrestore(&pfc->lock, flags);
val = (val >> offset) & GENMASK(size - 1, 0);
val = (sh_pfc_read(pfc, reg) >> offset) & GENMASK(size - 1, 0);
/* Convert the value to mA based on a full drive strength value of 24mA.
* We can make the full value configurable later if needed.
@ -648,9 +643,7 @@ static int sh_pfc_pinconf_get(struct pinctrl_dev *pctldev, unsigned _pin,
if (WARN(bit < 0, "invalid pin %#x", _pin))
return bit;
spin_lock_irqsave(&pfc->lock, flags);
val = sh_pfc_read(pfc, pocctrl);
spin_unlock_irqrestore(&pfc->lock, flags);
lower_voltage = (pin->configs & SH_PFC_PIN_VOLTAGE_25_33) ?
2500 : 1800;