msm 模拟i2c使用过程分析

//配置原有i2为GPIO模式

--- a/arch/arm/mach-msm/board-msm7x27a.c
+++ b/arch/arm/mach-msm/board-msm7x27a.c
@@ -4569,9 +4569,9 @@ static void __init msm_device_i2c_init(void)
        gpio_tlmm_config(GPIO_CFG(I2C0_SCL, 0, GPIO_CFG_OUTPUT,
                                               GPIO_CFG_PULL_UP, GPIO_CFG_8MA),GPIO_CFG_ENABLE);
        gpio_tlmm_config(GPIO_CFG(I2C1_SDA, 0, GPIO_CFG_OUTPUT,
-                                                  GPIO_CFG_PULL_UP, GPIO_CFG_8MA),GPIO_CFG_ENABLE);
+                                                  GPIO_CFG_PULL_UP, GPIO_CFG_6MA),GPIO_CFG_ENABLE);
        gpio_tlmm_config(GPIO_CFG(I2C1_SCL, 0, GPIO_CFG_OUTPUT,
-                                              GPIO_CFG_PULL_UP, GPIO_CFG_8MA),GPIO_CFG_ENABLE);
+                                              GPIO_CFG_PULL_UP, GPIO_CFG_6MA),GPIO_CFG_ENABLE);
 #else
        msm_gsbi0_qup_i2c_device.dev.platform_data = &msm_gsbi0_qup_i2c_pdata;
        msm_gsbi1_qup_i2c_device.dev.platform_data = &msm_gsbi1_qup_i2c_pdata;

由于硬件设计问题.硬件i2c不稳定,导致FM打开时而失败.

现在采用把原来的硬件i2c改成模拟i2c控制

高通模拟GPIO的GPIO配置, 因为板子在8MA的情况 i2c非常不稳定, 改到6ma改善很大.所以目前采用6ma的大小.

--- a/arch/arm/mach-msm/Kconfig
+++ b/arch/arm/mach-msm/Kconfig
@@ -1708,4 +1708,11 @@ config MSM_L2_SPM
          Enabling this driver allows configuring L2 SPM for low power modes
          on supported chipsets.
 
+config HY_I2C_DEVICE_USE_GPIO
+       bool "HY_I2C_DEVICE_USE_GPIO"
+   depends on I2C_GPIO
+   default n
+       help
+         This is the macro all i2c devices use i2c-gpio mode.
+

--- a/arch/arm/mach-msm/board-msm7x27a.c
+++ b/arch/arm/mach-msm/board-msm7x27a.c
@@ -96,6 +96,43 @@
 #define FM_GPIO        83
 #define GPIO_INVALID NR_MSM_GPIOS
 
 
+#ifdef CONFIG_HY_I2C_DEVICE_USE_GPIO
+#include <linux/i2c-gpio.h> // ynn add 
+#define I2C0_SCL 60
+#define I2C0_SDA 61
+#define I2C1_SCL 131
+#define I2C1_SDA 132

//创建i2c 平台设备相关结构体
+struct i2c_gpio_platform_data platform_data_gpio_i2c1 = { 
+       .scl_pin = I2C1_SCL,
+       .sda_pin = I2C1_SDA,
+       .udelay =2,
+     // .scl_is_output_only=0,
+};
+
+struct platform_device msm_device_gpio_i2c1 = {
+       .name   = "i2c-gpio",
+       .id     = MSM_GSBI1_QUP_I2C_BUS_ID,//1,
+       .dev    = {
+               .platform_data = &platform_data_gpio_i2c1,
+       }
+};
+
+struct i2c_gpio_platform_data platform_data_gpio_i2c0 = {
+       .scl_pin = I2C0_SCL,
+       .sda_pin = I2C0_SDA,
+       .udelay =2,
+};
+
+struct platform_device msm_device_gpio_i2c0 = { // for camera
+       .name   = "i2c-gpio",
+       .id     = MSM_GSBI0_QUP_I2C_BUS_ID,//0, 
+       .dev    = {
+               .platform_data = &platform_data_gpio_i2c0,
+       }
+};     
+#endif
 

// 注册i2c adapter 设备

@@ -4089,8 +4126,13 @@ static struct platform_device *rumi_sim_devices[] __initdata = {
        &msm_device_uart1,
        &msm_device_nand,
        &msm_device_uart_dm1,
+#ifdef CONFIG_HY_I2C_DEVICE_USE_GPIO
+       &msm_device_gpio_i2c0,
+       &msm_device_gpio_i2c1,
+#else  

        &msm_gsbi0_qup_i2c_device,
        &msm_gsbi1_qup_i2c_device,
+#endif

驱动采用ls drivers/i2c/busses/i2c-gpio.c