drivers: clock: Add dumb clock driver for SiWx91x

This driver is mostly the initial seed for further implementation of a
real clock driver.

It doesn't allow the user to choose the clock source for the various
peripherals. The driver hardcodes some sane values.

Note that for now, the driver snps,designware-i2c does not support
"clocks" attribute. So this patch hardcode the clock configuration in
the init of the clock driver.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>

drivers/clock_control/CMakeLists.txt

@@ -26,6 +26,7 @@ zephyr_library_sources_ifdef(CONFIG_CLOCK_CONTROL_NRF_DRIVER_CALIBRATION nrf_clo
 zephyr_library_sources_ifdef(CONFIG_CLOCK_CONTROL_RV32M1_PCC          clock_control_rv32m1_pcc.c)
 zephyr_library_sources_ifdef(CONFIG_CLOCK_CONTROL_INFINEON_CAT1       clock_control_ifx_cat1.c)
 zephyr_library_sources_ifdef(CONFIG_CLOCK_CONTROL_SAM                 clock_control_sam_pmc.c)
+zephyr_library_sources_ifdef(CONFIG_CLOCK_CONTROL_SILABS_SIWX91X      clock_control_silabs_siwx91x.c)
 zephyr_library_sources_ifdef(CONFIG_CLOCK_CONTROL_SILABS_SERIES       clock_control_silabs_series.c)
 zephyr_library_sources_ifdef(CONFIG_CLOCK_CONTROL_SI32_PLL            clock_control_si32_pll.c)
 zephyr_library_sources_ifdef(CONFIG_CLOCK_CONTROL_SI32_AHB            clock_control_si32_ahb.c)

drivers/clock_control/Kconfig

@@ -102,6 +102,8 @@ source "drivers/clock_control/Kconfig.arm_scmi"
 
 source "drivers/clock_control/Kconfig.silabs"
 
+source "drivers/clock_control/Kconfig.siwx91x"
+
 source "drivers/clock_control/Kconfig.wch_rcc"
 
 endif # CLOCK_CONTROL

drivers/clock_control/Kconfig.siwx91x

@@ -0,0 +1,15 @@
+# Copyright (c) 2024 Silicon Laboratories Inc.
+# SPDX-License-Identifier: Apache-2.0
+
+config CLOCK_CONTROL_SILABS_SIWX91X
+	bool "SiWx91x clock control driver"
+	default y
+	depends on DT_HAS_SILABS_SIWX91X_CLOCK_ENABLED
+	help
+	 Enable clock management on Silicon Labs SiWx91x chips. This driver
+	 includes support for HP (High Performace), ULP (Ultra Low Power), and
+	 ULP VBAT clocks.
+
+	 The original hardware allow to customize the various clocks offered for
+	 every devices. This driver does not provide such  customizations. It
+	 just hardcodes sane default parameters for every devices.

drivers/clock_control/clock_control_silabs_siwx91x.c

@@ -0,0 +1,186 @@
+/* Copyright (c) 2024 Silicon Laboratories Inc.
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Poor man driver for 917 clocks. 917 includes High Performace (HP) clock
+ * (@46000000), Ultra Lower Power (ULP) clock (@24041400) and ULP VBAT (@24048000)
+ *
+ */
+#include <zephyr/dt-bindings/clock/silabs/siwx91x-clock.h>
+#include <zephyr/drivers/clock_control.h>
+#include <zephyr/logging/log.h>
+
+#include "rsi_power_save.h"
+#include "rsi_rom_ulpss_clk.h"
+#include "rsi_rom_clks.h"
+#include "clock_update.h"
+#include "sl_si91x_clock_manager.h"
+
+#define DT_DRV_COMPAT silabs_siwx91x_clock
+
+LOG_MODULE_REGISTER(siwx91x_clock, CONFIG_CLOCK_CONTROL_LOG_LEVEL);
+
+struct siwx91x_clock_data {
+	uint32_t enable;
+};
+
+static int siwx91x_clock_on(const struct device *dev, clock_control_subsys_t sys)
+{
+	struct siwx91x_clock_data *data = dev->data;
+	uintptr_t clockid = (uintptr_t)sys;
+
+	switch (clockid) {
+	case SIWX91X_CLK_ULP_UART:
+		RSI_PS_UlpssPeriPowerUp(ULPSS_PWRGATE_ULP_UART);
+		RSI_ULPSS_UlpUartClkConfig(ULPCLK, ENABLE_STATIC_CLK,
+					   false, ULP_UART_ULP_MHZ_RC_CLK, 1);
+		break;
+	case SIWX91X_CLK_ULP_I2C:
+		RSI_PS_UlpssPeriPowerUp(ULPSS_PWRGATE_ULP_I2C);
+		RSI_ULPSS_PeripheralEnable(ULPCLK, ULP_I2C_CLK, ENABLE_STATIC_CLK);
+		break;
+	case SIWX91X_CLK_ULP_DMA:
+		RSI_PS_UlpssPeriPowerUp(ULPSS_PWRGATE_ULP_UDMA);
+		RSI_ULPSS_PeripheralEnable(ULPCLK, ULP_UDMA_CLK, ENABLE_STATIC_CLK);
+		break;
+	case SIWX91X_CLK_UART1:
+		RSI_PS_M4ssPeriPowerUp(M4SS_PWRGATE_ULP_EFUSE_PERI);
+		/* RSI_CLK_UsartClkConfig() calls RSI_CLK_PeripheralClkEnable(); */
+		RSI_CLK_UsartClkConfig(M4CLK, ENABLE_STATIC_CLK, 0, USART1, 0, 1);
+		break;
+	case SIWX91X_CLK_UART2:
+		RSI_PS_M4ssPeriPowerUp(M4SS_PWRGATE_ULP_EFUSE_PERI);
+		/* RSI_CLK_UsartClkConfig() calls RSI_CLK_PeripheralClkEnable(); */
+		RSI_CLK_UsartClkConfig(M4CLK, ENABLE_STATIC_CLK, 0, USART2, 0, 1);
+		break;
+	case SIWX91X_CLK_I2C0:
+		RSI_PS_M4ssPeriPowerUp(M4SS_PWRGATE_ULP_EFUSE_PERI);
+		RSI_CLK_I2CClkConfig(M4CLK, true, 0);
+		break;
+	case SIWX91X_CLK_I2C1:
+		RSI_PS_M4ssPeriPowerUp(M4SS_PWRGATE_ULP_EFUSE_PERI);
+		RSI_CLK_I2CClkConfig(M4CLK, true, 1);
+		break;
+	case SIWX91X_CLK_DMA0:
+		RSI_PS_M4ssPeriPowerUp(M4SS_PWRGATE_ULP_EFUSE_PERI);
+		RSI_CLK_PeripheralClkEnable(M4CLK, UDMA_CLK, ENABLE_STATIC_CLK);
+		break;
+	default:
+		return -EINVAL;
+	}
+	data->enable |= BIT(clockid);
+
+	return 0;
+}
+
+static int siwx91x_clock_off(const struct device *dev, clock_control_subsys_t sys)
+{
+	struct siwx91x_clock_data *data = dev->data;
+	uintptr_t clockid = (uintptr_t)sys;
+
+	switch (clockid) {
+	case SIWX91X_CLK_ULP_I2C:
+		RSI_ULPSS_PeripheralDisable(ULPCLK, ULP_I2C_CLK);
+		break;
+	case SIWX91X_CLK_ULP_DMA:
+		RSI_ULPSS_PeripheralDisable(ULPCLK, ULP_UDMA_CLK);
+		break;
+	case SIWX91X_CLK_UART1:
+		RSI_CLK_PeripheralClkDisable(M4CLK, USART1_CLK);
+		break;
+	case SIWX91X_CLK_UART2:
+		RSI_CLK_PeripheralClkDisable(M4CLK, USART2_CLK);
+		break;
+	case SIWX91X_CLK_DMA0:
+		RSI_CLK_PeripheralClkDisable(M4CLK, UDMA_CLK);
+		break;
+	case SIWX91X_CLK_ULP_UART:
+	case SIWX91X_CLK_I2C0:
+	case SIWX91X_CLK_I2C1:
+		/* Not supported */
+		return 0;
+	default:
+		return -EINVAL;
+	}
+
+	data->enable &= ~BIT(clockid);
+	return 0;
+}
+
+static int siwx91x_clock_get_rate(const struct device *dev, clock_control_subsys_t sys,
+				  uint32_t *rate)
+{
+	uintptr_t clockid = (uintptr_t)sys;
+
+	switch (clockid) {
+	case SIWX91X_CLK_ULP_UART:
+		*rate = RSI_CLK_GetBaseClock(ULPSS_UART);
+		return 0;
+	case SIWX91X_CLK_UART1:
+		*rate = RSI_CLK_GetBaseClock(M4_USART0);
+		return 0;
+	case SIWX91X_CLK_UART2:
+		*rate = RSI_CLK_GetBaseClock(M4_UART1);
+		return 0;
+	default:
+		/* For now, no other driver need clock rate */
+		return -EINVAL;
+	}
+}
+
+static enum clock_control_status siwx91x_clock_get_status(const struct device *dev,
+							  clock_control_subsys_t sys)
+{
+	struct siwx91x_clock_data *data = dev->data;
+	uintptr_t clockid = (uintptr_t)sys;
+
+	if (data->enable & BIT(clockid)) {
+		return CLOCK_CONTROL_STATUS_ON;
+	} else {
+		return CLOCK_CONTROL_STATUS_OFF;
+	}
+}
+
+static int siwx91x_clock_init(const struct device *dev)
+{
+	SystemCoreClockUpdate();
+
+	/* Use SoC PLL at configured frequency as core clock */
+	sl_si91x_clock_manager_m4_set_core_clk(M4_SOCPLLCLK, CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC);
+
+	/* Use interface PLL at configured frequency as peripheral clock */
+	sl_si91x_clock_manager_set_pll_freq(INFT_PLL, CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC,
+					    PLL_REF_CLK_VAL_XTAL);
+
+	/* FIXME: Currently the clock consumer use clocks without power on them.
+	 * This should be fixed in drivers. Meanwhile, get the list of required
+	 * clocks using DT labels.
+	 */
+#if DT_NODE_HAS_STATUS(DT_NODELABEL(ulpi2c), okay)
+	siwx91x_clock_on(dev, (clock_control_subsys_t)SIWX91X_CLK_ULP_I2C);
+#endif
+
+#if DT_NODE_HAS_STATUS(DT_NODELABEL(i2c0), okay)
+	siwx91x_clock_on(dev, (clock_control_subsys_t)SIWX91X_CLK_I2C0);
+#endif
+
+#if DT_NODE_HAS_STATUS(DT_NODELABEL(i2c1), okay)
+	siwx91x_clock_on(dev, (clock_control_subsys_t)SIWX91X_CLK_I2C1);
+#endif
+
+	return 0;
+}
+
+static DEVICE_API(clock_control, siwx91x_clock_api) = {
+	.on = siwx91x_clock_on,
+	.off = siwx91x_clock_off,
+	.get_rate = siwx91x_clock_get_rate,
+	.get_status = siwx91x_clock_get_status,
+};
+
+#define SIWX91X_CLOCK_INIT(p)                                                                \
+	static struct siwx91x_clock_data siwx91x_clock_data_##p;                             \
+	DEVICE_DT_INST_DEFINE(p, siwx91x_clock_init, NULL, &siwx91x_clock_data_##p, NULL,    \
+			      PRE_KERNEL_1, CONFIG_CLOCK_CONTROL_INIT_PRIORITY,              \
+			      &siwx91x_clock_api);
+
+DT_INST_FOREACH_STATUS_OKAY(SIWX91X_CLOCK_INIT)

dts/bindings/clock/silabs,siwx91x-clock.yaml

@@ -0,0 +1,18 @@
+# Copyright (c) 2024 Silicon Laboratories Inc.
+# SPDX-License-Identifier: Apache-2.0
+
+description: Clocks embedded on Silabs SiWx91x chips
+
+compatible: "silabs,siwx91x-clock"
+
+include: [clock-controller.yaml, base.yaml]
+
+properties:
+  reg:
+    required: true
+
+  "#clock-cells":
+    const: 1
+
+clock-cells:
+  - clkid

include/zephyr/dt-bindings/clock/silabs/siwx91x-clock.h

@@ -0,0 +1,16 @@
+/* Copyright (c) 2024 Silicon Laboratories Inc.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#ifndef ZEPHYR_INCLUDE_DT_BINDINGS_CLOCK_SILABS_SIWX91X_CLOCK_H_
+#define ZEPHYR_INCLUDE_DT_BINDINGS_CLOCK_SILABS_SIWX91X_CLOCK_H_
+
+#define SIWX91X_CLK_ULP_UART      0
+#define SIWX91X_CLK_ULP_I2C       1
+#define SIWX91X_CLK_ULP_DMA       2
+#define SIWX91X_CLK_UART1         3
+#define SIWX91X_CLK_UART2         4
+#define SIWX91X_CLK_I2C0          5
+#define SIWX91X_CLK_I2C1          6
+#define SIWX91X_CLK_DMA0          7
+
+#endif