qcom平台LK 阶段配置IIC
版本号：V 1.0
作者：Leo
本文着重介绍，如何在qcom 平台的LK 阶段配置和使用I2C。
硬件平台：msm8909
软件平台：Android5.0、Android8.0
I2C设备：ADV7533
参考博客和文档：
80-np408-2x_c_msm8909_msm8209_msm8208_hardware_register_description_document_for_oems.pdf
80-nu767-1_h_linux_bam_low-speed_peripherals_configuration_and_debug_guide.pdf
https://blog.csdn.net/eliot_shao/article/details/53351759
1. 确定硬件
查看原理图确定gpio
确定芯片I2C内部的qup地址、中断号、通道等参数
根据文档：80-nu767-1_h_linux_bam_low-speed_peripherals_configuration_and_debug_guide.pdf
从以上信息可以确定：
- 我们要使用的是 gpio10、gpio11对应的IIC
- 芯片内部参数是
- QUP ID: BLSP6
- QUP BASE Addr: 78BA000
- IRQ#: 100
- src clk：qup6_i2c_apps_clk
2. LK I2C 函数接口
根据qcom文档：
80-nu767-1_h_linux_bam_low-speed_peripherals_configuration_and_debug_guide.pdf
可知：qcom LK 阶段的I2C 函数接口为：qup_blsp_i2c_init
函数定义：
struct qup_i2c_dev *
qup_blsp_i2c_init(uint8_t blsp_id, uint8_t qup_id, uint32_t clk_freq, uint32_t src_clk_freq)
参数含义：
uint8_t blsp_id: (msm8909 上用 BLSP_ID_1)
enum {
BLSP_ID_1 = 1,
BLSP_ID_2,
} blsp_instance;
uint8_t qup_id:
enum {
QUP_ID_0 = 0,
QUP_ID_1,
QUP_ID_2,
QUP_ID_3,
QUP_ID_4,
QUP_ID_5,
} qup_instance;
(具体多少，以qup的base addr 为准。如使用IIC-6对应地址78ba000，那么传参QUP_ID_5)
uint32_t clk_freq:
IIC总线速率，默认 100Kuint32_t src_clk_freq:
时钟源频率，默认19.2MHz老规矩，先分析下这个函数的实现流程。
struct qup_i2c_dev *qup_blsp_i2c_init(uint8_t blsp_id, uint8_t qup_id,
uint32_t clk_freq, uint32_t src_clk_freq)
{
struct qup_i2c_dev *dev;
if (dev_addr != NULL) {
return dev_addr;
}
dev = malloc(sizeof(struct qup_i2c_dev));
if (!dev) {
return NULL;
}
dev = memset(dev, 0, sizeof(struct qup_i2c_dev));
/* Platform uses BLSP */
dev->qup_irq = BLSP_QUP_IRQ(blsp_id, qup_id);
dev->qup_base = BLSP_QUP_BASE(blsp_id, qup_id);
/* This must be done for qup_i2c_interrupt to work. */
dev_addr = dev;
/* Initialize the GPIO for BLSP i2c */
gpio_config_blsp_i2c(blsp_id, qup_id);
clock_config_blsp_i2c(blsp_id, qup_id);
qup_i2c_sec_init(dev, clk_freq, src_clk_freq);
return dev;
}
从以上流程看，有5个需要关注的地方
1. dev->qup_irq = BLSP_QUP_IRQ(blsp_id, qup_id);
2. dev->qup_base = BLSP_QUP_BASE(blsp_id, qup_id);
3. gpio_config_blsp_i2c(blsp_id, qup_id);
4. clock_config_blsp_i2c(blsp_id, qup_id);
5. qup_i2c_sec_init(dev, clk_freq, src_clk_freq); // 略过，I2C的初始化过程
一个一个分析：
2.1 qup irq 中断号赋值
dev->qup_irq = BLSP_QUP_IRQ(blsp_id, qup_id);中断号，使用 BLSP_QUP_IRQ 这个宏来赋值，那么找到它的定义：
bootable\bootloader\lk\platform\msm8909\include\platform\irqs.h
#define GIC_SPI_START 32
#define BLSP_QUP_IRQ(blsp_id, qup_id) (GIC_SPI_START + 95 + qup_id)从章节1的qup 信息可知，qup6的中断号为100，那么传参qup_id 为5，中断号为
GIC_SPI_START + 95 + 5， GIC_SPI_START 是一个偏移量，不用管它。这里大概可以推测，qup_id 应该传参为5。
2.2 qup base addr 赋值
dev->qup_base = BLSP_QUP_BASE(blsp_id, qup_id);qup 基地址的赋值，使用 BLSP_QUP_BASE来赋值，找到它的定义
bootable\bootloader\lk\platform\msm8909\include\platform\iomap.h
#define PERIPH_SS_BASE 0x07800000
bootable\bootloader\lk\platform\msm8909\include\platform\iomap.h
#define BLSP_QUP_BASE(blsp_id, qup_id) (PERIPH_SS_BASE + 0xB5000 + 0x1000 * qup_id)从章节1的qup信息图得知，qup6的 base addr 为78ba000，那么这里qup_id 传参应该为5
即：0x70800000 + 0x0B5000 + 0x1000 * 5 = 0x78bA000到此为止，从qup irq的信息和qup base addr的信息确认，那么I2C-6(gpio10、gpio11)对应的qup 传参应该是 QUP_ID_5。
2.3 blsp6 gpio 初始化
/* Initialize the GPIO for BLSP i2c */
gpio_config_blsp_i2c(blsp_id, qup_id);
看gpio_config_blsp_i2c函数定义.
void gpio_config_blsp_i2c(uint8_t blsp_id, uint8_t qup_id)
{
#if DSI2DPI_TC358762
uint32_t hw_id = board_hardware_id();
uint32_t hw_subtype = board_hardware_subtype();
#endif
if(blsp_id == BLSP_ID_1) {
switch (qup_id) {
case QUP_ID_1:
/* configure I2C SDA gpio */
gpio_tlmm_config(6, 3, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
/* configure I2C SCL gpio */
gpio_tlmm_config(7, 3, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
break;
case QUP_ID_2:
/* configure I2C SDA gpio */
gpio_tlmm_config(111, 3, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
/* configure I2C SCL gpio */
gpio_tlmm_config(112, 3, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
break;
case QUP_ID_3:
/* configure I2C SDA gpio */
gpio_tlmm_config(29, 3, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
/* configure I2C SCL gpio */
gpio_tlmm_config(30, 3, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
break;
case QUP_ID_4:
#if DSI2DPI_TC358762
if ((HW_PLATFORM_SUBTYPE_LR3001 == hw_subtype)
&& (HW_PLATFORM_MTP == hw_id)) {
/* configure I2C SDA gpio */
gpio_tlmm_config(18, 2, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_2MA, GPIO_DISABLE);
/* configure I2C SCL gpio */
gpio_tlmm_config(19, 2, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_2MA, GPIO_DISABLE);
} else {
#endif
/* configure I2C SDA gpio */
gpio_tlmm_config(14, 3, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
/* configure I2C SCL gpio */
gpio_tlmm_config(15, 3, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
#if DSI2DPI_TC358762
}
#endif
break;
case QUP_ID_5:
/* configure I2C SDA gpio */
gpio_tlmm_config(18, 3, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
/* configure I2C SCL gpio */
gpio_tlmm_config(19, 3, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
/* Begin: add by leo for add i2c-6(gpio_10 & gpio_11) */
#if 1
/* configure I2C SDA gpio */
gpio_tlmm_config(10, 2, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
/* configure I2C SCL gpio */
gpio_tlmm_config(11, 2, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
dprintf(CRITICAL, "leo i2c-%d (gpio10 & gpio11)\n", qup_id + 1);
#endif
/* End: add by leo for add i2c-6(gpio_10 & gpio_11) */
break;
default:
dprintf(CRITICAL, "Incorrect QUP id %d\n",qup_id);
ASSERT(0);
};
} else {
dprintf(CRITICAL, "Incorrect BLSP id %d\n",blsp_id);
ASSERT(0);
}
}
从以上调用流程可以看出，整个流程就是根据BLSP_ID 和QUP_ID 去初始化不同的gpio。
所以在这里，需要判断在 case QUP_ID_5 中是否已经包含我们需要的gpio管脚(gpio10、gpio11)的初配置。
代码修改：
/* Begin: add by leo for add i2c-6(gpio_10 & gpio_11) */
#if 1
/* configure I2C SDA gpio */
gpio_tlmm_config(10, 2, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
/* configure I2C SCL gpio */
gpio_tlmm_config(11, 2, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
dprintf(CRITICAL, "leo i2c-%d (gpio10 & gpio11)\n", qup_id + 1);
#endif
/* End: add by leo for add i2c-6(gpio_10 & gpio_11) */显然没有，那么就需要在case QUP_ID_5：新增 gpio10、gpio11的初始化。
注意这里：这里配置为功能2，是复用为i2c功能
依据：
80-np408-2x_c_msm8909_msm8209_msm8208_hardware_register_description_document_for_oems.pdf
page-2624 介绍：
配置为功能 2 是 IIC功能。
2.4 blsp6 时钟源的配置
clock_config_blsp_i2c(blsp_id, qup_id);
看函数定义：
void clock_config_blsp_i2c(uint8_t blsp_id, uint8_t qup_id)
{
uint8_t ret = 0;
char clk_name[64];
struct clk *qup_clk;
qup_id = qup_id + 1;
if((blsp_id != BLSP_ID_1)) {
dprintf(CRITICAL, "Incorrect BLSP-%d configuration\n", blsp_id);
ASSERT(0);
}
snprintf(clk_name, sizeof(clk_name), "blsp1_qup%u_ahb_iface_clk", qup_id);
dprintf(CRITICAL, "leo i2c-%d clk_name=%s \n", qup_id, clk_name);
ret = clk_get_set_enable(clk_name, 0 , 1);
if (ret) {
dprintf(CRITICAL, "Failed to enable %s clock\n", clk_name);
return;
}
snprintf(clk_name, sizeof(clk_name), "gcc_blsp1_qup%u_i2c_apps_clk", qup_id);
dprintf(CRITICAL, "leo i2c-%d clk_name=%s \n", qup_id, clk_name);
qup_clk = clk_get(clk_name);
if (!qup_clk) {
dprintf(CRITICAL, "Failed to get %s\n", clk_name);
return;
}
ret = clk_enable(qup_clk);
if (ret) {
dprintf(CRITICAL, "Failed to enable %s\n", clk_name);
return;
}
}
首先，qup_id = qup_id + 1; 这里，对qup进行了自加1，那么下面对应的时钟源参数就变成了blsp6。
且能看出，需要的是 blsp1_qup6_ahb_iface_clk 和 gcc_blsp1_qup6_i2c_apps_clk，这两个时钟源。
snprintf(clk_name, sizeof(clk_name), "blsp1_qup%u_ahb_iface_clk", qup_id);
dprintf(CRITICAL, "leo i2c-%d clk_name=%s \n", qup_id, clk_name);
ret = clk_get_set_enable(clk_name, 0 , 1);
if (ret) {
dprintf(CRITICAL, "Failed to enable %s clock\n", clk_name);
return;
}
snprintf(clk_name, sizeof(clk_name), "gcc_blsp1_qup%u_i2c_apps_clk", qup_id);
dprintf(CRITICAL, "leo i2c-%d clk_name=%s \n", qup_id, clk_name);
qup_clk = clk_get(clk_name);
可以看clk_get_set_enable 和 clk_get 的定义
clk_get_set_enable：
bootable\bootloader\lk\platform\msm_shared\clock.c
函数定义略
clk_get：
bootable\bootloader\lk\platform\msm_shared\clock.c
struct clk *clk_get (const char * cid)
{
unsigned i;
struct clk_lookup *cl= msm_clk_list.clist;
unsigned num = msm_clk_list.num;
if(!cl || !num)
{
dprintf (CRITICAL, "Alert!! clock list not defined!\n");
return NULL;
}
for(i=0; i < num; i++, cl++)
{
if(!strcmp(cl->con_id, cid))
{
return cl->clk;
}
}
dprintf(CRITICAL, "Alert!! Requested clock \"%s\" is not supported!\n", cid);
return NULL;
}分析：都是从 bootable\bootloader\lk\platform\msm_shared\clock.c 中的static struct clk_list msm_clk_list; 全局clk list 中获取的信息。
找到在哪初始化的：
路径：
bootable\bootloader\lk\platform\msm_shared\clock.c
void clk_init(struct clk_lookup *clist, unsigned num)
{
if(clist && num)
{
msm_clk_list.clist = (struct clk_lookup *)clist;
msm_clk_list.num = num;
}
}找到在哪调用的：
路径：
bootable\bootloader\lk\platform\msm8909\msm8909-clock.c
void platform_clock_init(void)
{
clk_init(msm_clocks_msm8909, ARRAY_SIZE(msm_clocks_msm8909));
}其中msm_clocks_msm8909 这个clk 结构体数组，就是我们要修改的目标 。
此处需对应 clock_config_blsp_i2c 函数中的分析。
最终我们需要的有三个时钟源配置，根据实际代码去修改。
bootable\bootloader\lk\platform\msm8909\msm8909-clock.c
msm_clocks_msm8909 数组中
#else
CLK_LOOKUP("blsp1_qup6_ahb_iface_clk", gcc_blsp1_ahb_clk.c),
CLK_LOOKUP("gcc_blsp1_qup6_i2c_apps_clk_src", gcc_blsp1_qup6_i2c_apps_clk_src.c),
CLK_LOOKUP("gcc_blsp1_qup6_i2c_apps_clk", gcc_blsp1_qup6_i2c_apps_clk.c),
#endif那么总结下，所有的配置修改。
1. 调用I2C 初始化函数
struct qup_i2c_dev *
qup_blsp_i2c_init(uint8_t blsp_id, uint8_t qup_id, uint32_t clk_freq, uint32_t src_clk_freq)
2. 检查gpio配置
查看I2C对应的gpio配置是否包含，否则去添加
/* Begin: add by leo for add i2c-6(gpio_10 & gpio_11) */
#if 1
/* configure I2C SDA gpio */
gpio_tlmm_config(10, 2, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
/* configure I2C SCL gpio */
gpio_tlmm_config(11, 2, GPIO_OUTPUT, GPIO_NO_PULL,
GPIO_8MA, GPIO_DISABLE);
dprintf(CRITICAL, "leo i2c-%d (gpio10 & gpio11)\n", qup_id + 1);
#endif
/* End: add by leo for add i2c-6(gpio_10 & gpio_11) */3. 检查I2C src clk 配置，没有则添加
bootable\bootloader\lk\platform\msm8909\msm8909-clock.c
msm_clocks_msm8909 数组中
#else
CLK_LOOKUP("blsp1_qup6_ahb_iface_clk", gcc_blsp1_ahb_clk.c),
CLK_LOOKUP("gcc_blsp1_qup6_i2c_apps_clk_src", gcc_blsp1_qup6_i2c_apps_clk_src.c),
CLK_LOOKUP("gcc_blsp1_qup6_i2c_apps_clk", gcc_blsp1_qup6_i2c_apps_clk.c),
#endif
4. I2C 读函数demo。 (寄存器地址和数据都以8bit为例)
static uint8_t adv7533_i2c_read(uint8_t slave_addr, uint8_t reg)
{
int ret;
int err_return = -1;
uint8_t value;
dprintf(SPEW, "%s: Leo enter \n", __func__);
uint8_t tx_data[] = {
reg & 0xff,
};
uint8_t rx_data[1];
struct i2c_msg msgs[] = {
{
.addr = slave_addr,
.flags = I2C_M_WR,
.buf = tx_data,
.len = ADV_ARRAY_SIZE(tx_data),
},
{
.addr = slave_addr,
.flags = I2C_M_RD,
.buf = rx_data,
.len = ADV_ARRAY_SIZE(rx_data),
}
};
ret = qup_i2c_xfer(i2c6_dev, msgs, ADV_ARRAY_SIZE(msgs));
if (ret < 0) {
dprintf(CRITICAL, "%s: reg 0x%04x error %d\n", __func__, reg, ret);
return ret;
}
if (ret < ADV_ARRAY_SIZE(msgs)) {
dprintf(CRITICAL, "%s: reg 0x%04x msgs %d\n", __func__, reg, ret);
return err_return;
}
value = rx_data[0];
dprintf(CRITICAL, "%s: reg 0x%x 0x%x\n", __func__, reg, value);
return value;
}
5. I2C 写函数 demo
static int adv7533_i2c_write(uint8_t slave_addr, uint8_t reg, uint8_t value)
{
int ret = 0;
uint8_t tx_data[2] = {reg, value};
/* Send commands via I2C */
struct i2c_msg msgs[1] = {
{
.addr = slave_addr,
.flags = I2C_M_WR, // 0
.len = 2,
.buf = tx_data,
},
};
ret = qup_i2c_xfer(i2c6_dev, msgs, 1);
if (ret < 0) {
dprintf(CRITICAL, "%s failed ret=%d\n", __func__, ret);
return ret;
}
mdelay(2);
return 0;
}