Qcom wled 方式背光控制
1 .注册部分
kernel/msm-3.18/drivers/leds/leds-qpnp-wled.c
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static int qpnp_wled_probe(struct spmi_device *spmi)
{
.................................
INIT_WORK(&wled->work, qpnp_wled_work);
wled->ramp_ms = QPNP_WLED_RAMP_DLY_MS;
wled->ramp_step = 1;
wled->cdev.brightness_set = qpnp_wled_set;
wled->cdev.brightness_get = qpnp_wled_get;
wled->cdev.max_brightness = WLED_MAX_LEVEL_4095;
rc = led_classdev_register(&spmi->dev, &wled->cdev);
.................................
}
2. 应用部分
kernel/msm-3.18/drivers/leds/leds-qpnp-wled.c
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static void qpnp_wled_set(struct led_classdev *led_cdev, enum led_brightness level)
{
.................................
schedule_work(&wled->work);
................................
}
static void qpnp_wled_work(struct work_struct *work)
{
...........................................
// 设置亮度
rc = qpnp_wled_set_level(wled, level);
..........................................
// 当打开或关闭背光时，设置使能寄存器
rc = qpnp_wled_module_en(wled, wled->ctrl_base, !!level);
.........................................
}
static int qpnp_wled_set_level(struct qpnp_wled *wled, int level)
{
................................
// 写低位
reg = level & QPNP_WLED_BRIGHT_LSB_MASK;
rc = qpnp_wled_write_reg(wled, ®, QPNP_WLED_BRIGHT_LSB_REG(wled->sink_base, wled->strings[i]));
// 写高位
reg = level >> QPNP_WLED_BRIGHT_MSB_SHIFT;
reg = reg & QPNP_WLED_BRIGHT_MSB_MASK;
rc = qpnp_wled_write_reg(wled, ®, QPNP_WLED_BRIGHT_MSB_REG(wled->sink_base, wled->strings[i]));
...................................
}
static int qpnp_wled_module_en(struct qpnp_wled *wled, u16 base_addr, bool state)
{
rc = qpnp_wled_read_reg(wled, ®,
QPNP_WLED_MODULE_EN_REG(base_addr));
if (rc < 0)
return rc;
reg &= QPNP_WLED_MODULE_EN_MASK;
reg |= (state << QPNP_WLED_MODULE_EN_SHIFT);
rc = qpnp_wled_write_reg(wled, ®,
QPNP_WLED_MODULE_EN_REG(base_addr));
if (rc)
return rc;
}
static int qpnp_wled_write_reg(struct qpnp_wled *wled, u8 *data, u16 addr)
{
// 写 pmi 寄存器
rc = spmi_ext_register_writel(wled->spmi->ctrl, wled->spmi->sid, addr, data, 1);
}
kernel/msm-3.18/drivers/platform/msm/spmi/spmi.c
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int spmi_ext_register_writel(struct spmi_controller *ctrl, u8 sid, u16 addr, u8 *buf, int len)
{
}