[PATCH] pinctrl: renesas: Remove unneeded locking around sh_pfc_read() calls
From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: 2021-11-17 11:20:12
Also in:
linux-renesas-soc
Subsystem:
pin control subsystem, pin controller - renesas, the rest · Maintainers:
Linus Walleij, Geert Uytterhoeven, Linus Torvalds
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>
---
To be queued in renesas-pinctrl-for-v5.17.
drivers/pinctrl/renesas/pinctrl.c | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)
diff --git a/drivers/pinctrl/renesas/pinctrl.c b/drivers/pinctrl/renesas/pinctrl.c
index f3eecb20c0869a41..96b9de974246ac23 100644
--- a/drivers/pinctrl/renesas/pinctrl.c
+++ b/drivers/pinctrl/renesas/pinctrl.c@@ -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;
--
2.25.1