diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.c b/drivers/pinctrl/sunxi/pinctrl-sunxi.c index 25489beeb312..2881a83be99c 100644 --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.c +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.c @@ -837,6 +837,21 @@ static void sunxi_pmx_set(struct pinctrl_dev *pctldev, writel((readl(pctl->membase + reg) & ~mask) | config << shift, pctl->membase + reg); + /* + * A pin muxed to gpio_out directly through a pinmux node bypasses + * sunxi_pinctrl_gpio_set() and drives whatever its output latch + * holds. Now that the pin is in output mode the data register + * reads back the latch, so refresh the shadow to keep such pins + * driving their pre-existing level. + */ + if (config == SUN4I_FUNC_OUTPUT) { + u32 *shadow = &pctl->dat_shadow[pin / PINS_PER_BANK]; + + sunxi_data_reg(pctl, pin, ®, &shift, &mask); + *shadow = (*shadow & ~mask) | + (readl(pctl->membase + reg) & mask); + } + raw_spin_unlock_irqrestore(&pctl->lock, flags); } @@ -1017,21 +1032,29 @@ static int sunxi_pinctrl_gpio_set(struct gpio_chip *chip, unsigned int offset, int value) { struct sunxi_pinctrl *pctl = gpiochip_get_data(chip); - u32 reg, shift, mask, val; + u32 *shadow = &pctl->dat_shadow[offset / PINS_PER_BANK]; + u32 reg, shift, mask; unsigned long flags; sunxi_data_reg(pctl, offset, ®, &shift, &mask); raw_spin_lock_irqsave(&pctl->lock, flags); - val = readl(pctl->membase + reg); - + /* + * Reading the data register returns the pin level, not the output + * latch, for pins muxed as inputs. A read-modify-write based on + * the register would therefore corrupt the latches of input-muxed + * pins in the same bank (e.g. an emulated open-drain I2C line + * released high), making them drive the wrong level once switched + * to output. Base the read-modify-write on a shadow copy of the + * latches instead. + */ if (value) - val |= mask; + *shadow |= mask; else - val &= ~mask; + *shadow &= ~mask; - writel(val, pctl->membase + reg); + writel(*shadow, pctl->membase + reg); raw_spin_unlock_irqrestore(&pctl->lock, flags); @@ -1572,7 +1595,7 @@ int sunxi_pinctrl_init_with_flags(struct platform_device *pdev, struct pinctrl_pin_desc *pins; struct sunxi_pinctrl *pctl; struct pinmux_ops *pmxops; - int i, ret, last_pin, pin_idx; + int i, ret, last_pin, pin_idx, nbanks; struct clk *clk; pctl = devm_kzalloc(&pdev->dev, sizeof(*pctl), GFP_KERNEL); @@ -1610,6 +1633,37 @@ int sunxi_pinctrl_init_with_flags(struct platform_device *pdev, if (!pctl->irq_array) return -ENOMEM; + /* + * The bus clock has to be enabled before the pinctrl device + * registers, as the pin hogs claimed from there access registers. + */ + ret = of_clk_get_parent_count(node); + clk = devm_clk_get_enabled(&pdev->dev, ret == 1 ? NULL : "apb"); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + /* + * Seed the output latch shadow from the hardware so pins the + * bootloader left in output mode keep their state; see + * sunxi_pinctrl_gpio_set() for why a shadow is needed. This must + * happen before the pinctrl device registers, as pin hogs can mux + * pins to gpio_out and thereby update the shadow. + */ + last_pin = pctl->desc->pins[pctl->desc->npins - 1].pin.number; + nbanks = DIV_ROUND_UP(last_pin + 1 - pctl->desc->pin_base, + PINS_PER_BANK); + pctl->dat_shadow = devm_kcalloc(&pdev->dev, nbanks, + sizeof(*pctl->dat_shadow), GFP_KERNEL); + if (!pctl->dat_shadow) + return -ENOMEM; + + for (i = 0; i < nbanks; i++) { + u32 reg, shift, mask; + + sunxi_data_reg(pctl, i * PINS_PER_BANK, ®, &shift, &mask); + pctl->dat_shadow[i] = readl(pctl->membase + reg); + } + ret = sunxi_pinctrl_build_state(pdev); if (ret) { dev_err(&pdev->dev, "dt probe failed: %d\n", ret); @@ -1665,7 +1719,6 @@ int sunxi_pinctrl_init_with_flags(struct platform_device *pdev, if (!pctl->chip) return -ENOMEM; - last_pin = pctl->desc->pins[pctl->desc->npins - 1].pin.number; pctl->chip->owner = THIS_MODULE; pctl->chip->request = gpiochip_generic_request; pctl->chip->free = gpiochip_generic_free; @@ -1699,13 +1752,6 @@ int sunxi_pinctrl_init_with_flags(struct platform_device *pdev, goto gpiochip_error; } - ret = of_clk_get_parent_count(node); - clk = devm_clk_get_enabled(&pdev->dev, ret == 1 ? NULL : "apb"); - if (IS_ERR(clk)) { - ret = PTR_ERR(clk); - goto gpiochip_error; - } - pctl->irq = devm_kcalloc(&pdev->dev, pctl->desc->irq_banks, sizeof(*pctl->irq), diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.h b/drivers/pinctrl/sunxi/pinctrl-sunxi.h index 0daf7600e2fb..498e88a19f71 100644 --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.h +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.h @@ -85,6 +85,7 @@ #define IO_BIAS_MASK GENMASK(3, 0) #define SUN4I_FUNC_INPUT 0 +#define SUN4I_FUNC_OUTPUT 1 #define SUN4I_FUNC_IRQ 6 #define SUN4I_FUNC_DISABLED_OLD 7 #define SUN4I_FUNC_DISABLED_NEW 15 @@ -175,6 +176,12 @@ struct sunxi_pinctrl { int *irq; unsigned *irq_array; raw_spinlock_t lock; + /* + * Output latch shadow, one word per bank. Seeded lockless at + * probe before the pinctrl device registers, protected by @lock + * afterwards. + */ + u32 *dat_shadow; struct pinctrl_dev *pctl_dev; unsigned long flags; u32 bank_mem_size;