[PATCH v4 11/14] clk: stm32mp13: add safe mux management

gabriel.fernandez
2022-05-16T07:08:33Z

Some muxes need to set a the safe position when clock is off.

Signed-off-by: Gabriel Fernandez <gabriel.fernandez@foss.st.com>
---
drivers/clk/stm32/clk-stm32-core.c | 54 ++++++++++++++++++++++++++++++
drivers/clk/stm32/clk-stm32-core.h | 1 +
drivers/clk/stm32/clk-stm32mp13.c | 11 +++---
3 files changed, 62 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/stm32/clk-stm32-core.c b/drivers/clk/stm32/clk-stm32-core.c
index e5a22bb09495..45a279e73779 100644
--- a/drivers/clk/stm32/clk-stm32-core.c
+++ b/drivers/clk/stm32/clk-stm32-core.c
@@ -495,6 +495,54 @@ static int clk_stm32_composite_is_enabled(struct clk_hw *hw)
return stm32_gate_is_enabled(composite->base, composite->clock_data, composite->gate_id);
}

+#define MUX_SAFE_POSITION 0
+
+static int clk_stm32_has_safe_mux(struct clk_hw *hw)
+{
+ struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);
+ const struct stm32_mux_cfg *mux = &composite->clock_data->muxes[composite->mux_id];
+
+ return !!(mux->flags & MUX_SAFE);
+}
+
+static void clk_stm32_set_safe_position_mux(struct clk_hw *hw)
+{
+ struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);
+
+ if (!clk_stm32_composite_is_enabled(hw)) {
+ unsigned long flags = 0;
+
+ if (composite->clock_data->is_multi_mux) {
+ struct clk_hw *other_mux_hw = NULL;
+
+ other_mux_hw = composite->clock_data->is_multi_mux(hw);
+
+ if (!other_mux_hw || clk_stm32_composite_is_enabled(other_mux_hw))
+ return;
+ }
+
+ spin_lock_irqsave(composite->lock, flags);
+
+ stm32_mux_set_parent(composite->base, composite->clock_data,
+ composite->mux_id, MUX_SAFE_POSITION);
+
+ spin_unlock_irqrestore(composite->lock, flags);
+ }
+}
+
+static void clk_stm32_safe_restore_position_mux(struct clk_hw *hw)
+{
+ struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);
+ int sel = clk_hw_get_parent_index(hw);
+ unsigned long flags = 0;
+
+ spin_lock_irqsave(composite->lock, flags);
+
+ stm32_mux_set_parent(composite->base, composite->clock_data, composite->mux_id, sel);
+
+ spin_unlock_irqrestore(composite->lock, flags);
+}
+
static void clk_stm32_composite_gate_endisable(struct clk_hw *hw, int enable)
{
struct clk_stm32_composite *composite = to_clk_stm32_composite(hw);
@@ -516,6 +564,9 @@ static int clk_stm32_composite_gate_enable(struct clk_hw *hw)

clk_stm32_composite_gate_endisable(hw, 1);

+ if (composite->mux_id != NO_STM32_MUX && clk_stm32_has_safe_mux(hw))
+ clk_stm32_safe_restore_position_mux(hw);
+
return 0;
}

@@ -527,6 +578,9 @@ static void clk_stm32_composite_gate_disable(struct clk_hw *hw)
return;

clk_stm32_composite_gate_endisable(hw, 0);
+
+ if (composite->mux_id != NO_STM32_MUX && clk_stm32_has_safe_mux(hw))
+ clk_stm32_set_safe_position_mux(hw);
}

static void clk_stm32_composite_disable_unused(struct clk_hw *hw)
diff --git a/drivers/clk/stm32/clk-stm32-core.h b/drivers/clk/stm32/clk-stm32-core.h
index dab1b65b2537..76cffda02308 100644
--- a/drivers/clk/stm32/clk-stm32-core.h
+++ b/drivers/clk/stm32/clk-stm32-core.h
@@ -84,6 +84,7 @@ int stm32_rcc_init(struct device *dev, const struct of_device_id *match_data,

/* MUX define */
#define MUX_NO_RDY 0xFF
+#define MUX_SAFE BIT(7)

/* DIV define */
#define DIV_NO_RDY 0xFF
diff --git a/drivers/clk/stm32/clk-stm32mp13.c b/drivers/clk/stm32/clk-stm32mp13.c
index 08e3fe05d6d0..1192eee8abe4 100644
--- a/drivers/clk/stm32/clk-stm32mp13.c
+++ b/drivers/clk/stm32/clk-stm32mp13.c
@@ -359,6 +359,9 @@ enum enum_mux_cfg {
#define CFG_MUX(_id, _offset, _shift, _witdh)\
_CFG_MUX(_id, _offset, _shift, _witdh, MUX_NO_RDY, 0)

+#define CFG_MUX_SAFE(_id, _offset, _shift, _witdh)\
+ _CFG_MUX(_id, _offset, _shift, _witdh, MUX_NO_RDY, MUX_SAFE)
+
static const struct stm32_mux_cfg stm32mp13_muxes[] = {
CFG_MUX(MUX_I2C12, RCC_I2C12CKSELR, 0, 3),
CFG_MUX(MUX_LPTIM45, RCC_LPTIM45CKSELR, 0, 3),
@@ -394,10 +397,10 @@ static const struct stm32_mux_cfg stm32mp13_muxes[] = {
CFG_MUX(MUX_UART6, RCC_UART6CKSELR, 0, 3),
CFG_MUX(MUX_USBO, RCC_USBCKSELR, 4, 1),
CFG_MUX(MUX_USBPHY, RCC_USBCKSELR, 0, 2),
- CFG_MUX(MUX_FMC, RCC_FMCCKSELR, 0, 2),
- CFG_MUX(MUX_QSPI, RCC_QSPICKSELR, 0, 2),
- CFG_MUX(MUX_SDMMC1, RCC_SDMMC12CKSELR, 0, 3),
- CFG_MUX(MUX_SDMMC2, RCC_SDMMC12CKSELR, 3, 3),
+ CFG_MUX_SAFE(MUX_FMC, RCC_FMCCKSELR, 0, 2),
+ CFG_MUX_SAFE(MUX_QSPI, RCC_QSPICKSELR, 0, 2),
+ CFG_MUX_SAFE(MUX_SDMMC1, RCC_SDMMC12CKSELR, 0, 3),
+ CFG_MUX_SAFE(MUX_SDMMC2, RCC_SDMMC12CKSELR, 3, 3),
};

struct clk_stm32_securiy {
--
2.25.1