PADMUX参考说明
1. Padmux是什么¶
Padmux是位于kernel\drivers\sstar\padmux的一个linux platform驱动。因为gpio pin复用的关系,通常同一个gpio可以用作不同的功能,所以我们就用padmux驱动在开机的时候统一将需要使用的gpio pin功能配置好。
2. PadMux驱动介绍¶
Padmux驱动定义如下:
static struct platform_driver sstar_padmux_driver = { .driver = { .name = "padmux", .owner = THIS_MODULE, .of_match_table = sstar_padmux_of_match, .pm = &sstar_padmux_pm_ops, }, .probe = sstar_padmux_probe, };
需要关注的成员如下,下面会分别介绍。
sstar_padmux_of_match sstar_padmux_pm_ops sstar_padmux_probe
2.1. sstar_padmux_of_match¶
用来匹配开机需要配置的gpio table设备:
static const struct of_device_id sstar_padmux_of_match[] = { {.compatible = "sstar-padmux"}, {}, };
通过sstar-padmux在dts(例如:kernel\arch\arm\boot\dts\pioneer5-ssc028a-s01a-demo-padmux.dtsi)中匹配到设备:
padmux { compatible = "sstar-padmux"; schematic = //I2C0 Mode1,sensorif_mipi_grp0_i2c <PAD_I2C0_SDA PINMUX_FOR_I2C0_MODE_1 MDRV_PUSE_I2C0_SDA>, <PAD_I2C0_SCL PINMUX_FOR_I2C0_MODE_1 MDRV_PUSE_I2C0_SCL>, //I2C1 Mode1,sensorif_mipi_grp1_i2c <PAD_I2C1_SCL PINMUX_FOR_I2C1_MODE_1 MDRV_PUSE_I2C1_SCL>, <PAD_I2C1_SDA PINMUX_FOR_I2C1_MODE_1 MDRV_PUSE_I2C1_SDA>, //ToucheScreen goodix <PAD_I2C5_SCL PINMUX_FOR_I2C5_MODE_1 MDRV_PUSE_I2C5_SCL>, <PAD_I2C5_SDA PINMUX_FOR_I2C5_MODE_1 MDRV_PUSE_I2C5_SDA>, <GPIO_NR PINMUX_FOR_UNKNOWN_MODE MDRV_PUSE_NA>; status = "ok"; // ok or disable };
2.2. sstar_padmux_pm_ops¶
实现str待机对应的resume和suspend函数:
static const struct dev_pm_ops sstar_padmux_pm_ops = { .suspend_late = sstar_padmux_suspend, .resume_early = sstar_padmux_resume, };
2.3. sstar_padmux_probe¶
在匹配到padmux设备后,系统会call sstar_padmux_probe进行gpio功能配置:
static int sstar_padmux_probe(struct platform_device *pdev) { _mdrv_padmux_dts(pdev->dev.of_node); return 0; } static int _mdrv_padmux_dts(struct device_node *np) { int nPad; if (0 >= (nPad = of_property_count_elems_of_size(np, PADINFO_NAME, sizeof(pad_info_t)))) { PAD_PRINT("[%s][%d] invalid dts of padmux.schematic\n", __FUNCTION__, __LINE__); return -1; } if (NULL == (_pPadInfo = kmalloc(nPad * sizeof(pad_info_t), GFP_KERNEL))) { PAD_PRINT("[%s][%d] kmalloc fail\n", __FUNCTION__, __LINE__); return -1; } if (of_property_read_u32_array(np, PADINFO_NAME, (u32 *)_pPadInfo, nPad * sizeof(pad_info_t) / sizeof(U32))) { PAD_PRINT("[%s][%d] of_property_read_u32_array fail\n", __FUNCTION__, __LINE__); kfree(_pPadInfo); _pPadInfo = NULL; return -1; } _nPad = nPad; { int i; PAD_PRINT("[%s][%d] *******************************\n", __FUNCTION__, __LINE__); for (i = 0; i < _nPad; i++) { PAD_PRINT("[%s][%d] (PadId, Mode, Puse) = (%d, 0x%02x, 0x%08x)\n", __FUNCTION__, __LINE__, _pPadInfo[i].u32PadId, _pPadInfo[i].u32Mode, _pPadInfo[i].u32Puse); MDrv_GPIO_PadVal_Set((U8)_pPadInfo[i].u32PadId & 0xFF, _pPadInfo[i].u32Mode); } PAD_PRINT("[%s][%d] *******************************\n", __FUNCTION__, __LINE__); } return 0; }
最终通过MDrv_GPIO_PadVal_Set将gpio配置成对应的功能:
kernel\drivers\sstar\gpio\mdrv_gpio.c
int MDrv_GPIO_PadVal_Set(U8 u8IndexGPIO, U32 u32PadMode) { return MHal_GPIO_PadVal_Set(u8IndexGPIO, u32PadMode); }
kernel\drivers\sstar\gpio\pioneer5\mhal_gpio.c
int MHal_GPIO_PadVal_Set(U8 u8IndexGPIO, U32 u32PadMode) { return HalPadSetVal((U32)u8IndexGPIO, u32PadMode); }
kernel\drivers\sstar\gpio\pioneer5\mhal_pinmux.c
S32 HalPadSetVal(U32 u32PadID, U32 u32Mode) { if (FALSE == _HalCheckPin(u32PadID)) { return FALSE; } if(u32PadID>=PAD_ETH_RN && u32PadID <= PAD_SAR_GPIO3) return HalPadSetMode_MISC(u32PadID, u32Mode); return HalPadSetMode_General(u32PadID, u32Mode); } static S32 HalPadSetMode_General(U32 u32PadID, U32 u32Mode) { U32 u32RegAddr = 0; U16 u16RegVal = 0; U8 u8ModeIsFind = 0; U16 i = 0; for (i = 0; i < m_stPadMuxEntry[u32PadID].size; i++) { u32RegAddr = _RIUA_16BIT(m_stPadMuxEntry[u32PadID].padmux[i].base, m_stPadMuxEntry[u32PadID].padmux[i].offset); if (u32Mode == m_stPadMuxEntry[u32PadID].padmux[i].mode) { u16RegVal = _GPIO_R_WORD_MASK(u32RegAddr, 0xFFFF); u16RegVal &= ~(m_stPadMuxEntry[u32PadID].padmux[i].mask); u16RegVal |= m_stPadMuxEntry[u32PadID].padmux[i].val; // CHECK Multi-Pad Mode _GPIO_W_WORD_MASK(u32RegAddr, u16RegVal, 0xFFFF); u8ModeIsFind = 1; Pad_Mode[u32PadID] = u32Mode; #if (ENABLE_CHECK_ALL_PAD_CONFLICT == 0) break; #endif } else { if ((u32Mode == PINMUX_FOR_GPIO_MODE) && (m_stPadMuxEntry[u32PadID].padmux[i].mode > PRIORITY_GREATER_GPIO)) continue; u16RegVal = _GPIO_R_WORD_MASK(u32RegAddr, m_stPadMuxEntry[u32PadID].padmux[i].mask); if (u16RegVal == m_stPadMuxEntry[u32PadID].padmux[i].val) { printk(KERN_INFO "[Padmux]reset PAD%d(reg 0x%x:%x; mask0x%x) t0 %s (org: %s)\n", u32PadID, m_stPadMuxEntry[u32PadID].padmux[i].base, m_stPadMuxEntry[u32PadID].padmux[i].offset, m_stPadMuxEntry[u32PadID].padmux[i].mask, m_stPadModeInfoTbl[u32Mode].u8PadName, m_stPadModeInfoTbl[m_stPadMuxEntry[u32PadID].padmux[i].mode].u8PadName); if (m_stPadMuxEntry[u32PadID].padmux[i].val != 0) { _GPIO_W_WORD_MASK(u32RegAddr, 0, m_stPadMuxEntry[u32PadID].padmux[i].mask); } else { _GPIO_W_WORD_MASK(u32RegAddr, m_stPadMuxEntry[u32PadID].padmux[i].mask, m_stPadMuxEntry[u32PadID].padmux[i].mask); } } } } return (u8ModeIsFind) ? 0 : 1; }
通过在m_stPadMuxTbl里面找到需要配置的gpio和mode设定对应的reg。
以PAD_PM_PWM0配置成PINMUX_FOR_PWM0_MODE_1为例:
当在dts padmux里面配置了:
<PAD_PM_PWM0 PINMUX_FOR_PWM0_MODE_1 MDRV_PUSE_PWM0>,
在probe的时候会根据m_stPadMuxTbl的寄存器设定将寄存器bank 0x103c offset 0x65的bit2设置为1:
#define PADTOP_BANK 0x103C00 #define REG_PWM0_MODE 0x51 #define REG_PWM0_MODE_MASK BIT0 | BIT1 {PAD_PM_PWM0, PM_PADTOP_BANK, REG_PWM0_MODE, REG_PWM0_MODE_MASK, BIT0, PINMUX_FOR_PWM0_MODE_1},
可以在板子通过读取reg确认设定有没有生效:
3. PadMux怎么用¶
通过上面padmux驱动的介绍,我们知道只要确认padmux驱动有enable,并在dts里面将需要配置的pin和对应的mode写进去,开机padmux probe的时候就会将gpio对应的功能配置好。需要注意的是pamdux驱动依赖gpio驱动,所以这两个驱动都要build进kernel。目前公板默认的配置gpio和padmux都有默认打开buildin:
CONFIG_MS_GPIO=y CONFIG_MS_PADMUX=y
下面介绍如何在dts的padmux中配置对应的gpio功能。
3.1. 用哪个padmux dts文件¶
根据下面的follow由kernel config文件确定用哪个padmux dts文件。
kernel\arch\arm\configs\pioneer5_ssc028a_s01a_demo_defconfig:
CONFIG_SS_DTB_NAME="pioneer5-ssc028a-s01a-demo"
kernel\arch\arm\boot\dts\pioneer3-ssc020a-s01a-demo.dts:
#include "pioneer5.dtsi" #include "pioneer5-demo.dtsi" #include "pioneer5-ssc028a-s01a-demo-padmux.dtsi"
kernel\arch\arm\boot\dts\pioneer5-ssc028a-s01a-demo-padmux.dtsi
3.2. 配置gpio mode¶
根据SDK release的硬件发布资料SSU9383_2L HW Checklist V1.0_20220924.xlsx,找到padmux这栏;
以将PAD_PM_PWM0配置成PWM0为例,可以看到PAD_PM_PWM0要配置成PWM0只能将其配置成pwm0 mode 1,所以在padmux dts里面配置如下:
<PAD_PM_PWM0 PINMUX_FOR_PWM0_MODE_1 MDRV_PUSE_PWM0>,
其中MDRV_PUSE_PWM0一般只做说明注释没有特殊用途,除非对应功能驱动有特别设定。其他i2c,spi,uart,ttl,mipi的设定也可以参考hw checklist在padmux dts配置。
4. 注意事项¶
同一个gpio pin只能复用成一种功能,不能同时在padmux配置成两种功能。如果在padmux配置的功能不生效,需要在dts确认是否被配置成其他功能了。