ENGR00253947 EPDC: fix reboot failure

This patch is to

1) add clock enablement before access EPDC registers, otherwise system may hang.

And,
2) fix unbalanced disablement for PMIC regulators

------------[ cut here ]------------
WARNING: at drivers/regulator/core.c:1422 _regulator_disable+0xf8/0x12c()
unbalanced disables for VCOM
Modules linked in:
[<80040518>] (unwind_backtrace+0x0/0xf8) from [<800671d8>]
		(warn_slowpath_common +0x4c/0x64)
[<800671d8>] (warn_slowpath_common+0x4c/0x64) from [<80067284>]
		(warn_slowpath_fmt+0x30/0x40)
[<80067284>] (warn_slowpath_fmt+0x30/0x40) from [<8024ef60>]
		(_regulator_disable+0xf8/0x12c)
[<8024ef60>] (_regulator_disable+0xf8/0x12c) from [<8024efc4>]
		(regulator_disable+0x30/0x70)
[<8024efc4>] (regulator_disable+0x30/0x70) from [<80241044>]
		(mxc_epdc_fb_shutdown+0x18/0x84)
[<80241044>] (mxc_epdc_fb_shutdown+0x18/0x84) from [<80277f64>]
		(platform_drv_shutdown+0x18/0x1c)
[<80277f64>] (platform_drv_shutdown+0x18/0x1c) from [<802751d0>]
		(device_shutdown+0xac/0x124)
[<802751d0>] (device_shutdown+0xac/0x124) from [<8007812c>]
		(kernel_restart_prepare+0x30/0x38)
[<8007812c>] (kernel_restart_prepare+0x30/0x38) from [<80078140>]
		(kernel_restart+0xc/0x48)
[<80078140>] (kernel_restart+0xc/0x48) from [<80078290>]
		(sys_reboot+0x10c/0x1c4)
[<80078290>] (sys_reboot+0x10c/0x1c4) from [<8003ad40>]
		(ret_fast_syscall+0x0/0x30)
---[ end trace e392f5dd2f75e1a5 ]---
------------[ cut here ]------------
WARNING: at drivers/regulator/core.c:1422 _regulator_disable+0xf8/0x12c()
unbalanced disables for DISPLAY
Modules linked in:
[<80040518>] (unwind_backtrace+0x0/0xf8) from [<800671d8>]
		(warn_slowpath_common+0x4c/0x64)
[<800671d8>] (warn_slowpath_common+0x4c/0x64) from [<80067284>]
		(warn_slowpath_fmt+0x30/0x40)
[<80067284>] (warn_slowpath_fmt+0x30/0x40) from [<8024ef60>]
		(_regulator_disable+0xf8/0x12c)
[<8024ef60>] (_regulator_disable+0xf8/0x12c) from [<8024efc4>]
		(regulator_disable+0x30/0x70)
[<8024efc4>] (regulator_disable+0x30/0x70) from [<8024104c>]
		(mxc_epdc_fb_shutdown+0x20/0x84)
[<8024104c>] (mxc_epdc_fb_shutdown+0x20/0x84) from [<80277f64>]
		(platform_drv_shutdown+0x18/0x1c)
[<80277f64>] (platform_drv_shutdown+0x18/0x1c) from [<802751d0>]
		(device_shutdown+0xac/0x124)
[<802751d0>] (device_shutdown+0xac/0x124) from [<8007812c>]
		(kernel_restart_prepare+0x30/0x38)
[<8007812c>] (kernel_restart_prepare+0x30/0x38) from [<80078140>]
		(kernel_restart+0xc/0x48)
[<80078140>] (kernel_restart+0xc/0x48) from [<80078290>]
		(sys_reboot+0x10c/0x1c4)
[<80078290>] (sys_reboot+0x10c/0x1c4) from [<8003ad40>]
		(ret_fast_syscall+0x0/0x30)
---[ end trace e392f5dd2f75e1a6 ]---

Signed-off-by: Robby Cai <R63905@freescale.com>

diff --git a/drivers/video/mxc/mxc_epdc_fb.c b/drivers/video/mxc/mxc_epdc_fb.c
index 743b084df8ca1a7ffbf1e30d36b44b5dec3e9557..1122e219642b1e10dc3c12dd2abc286fb8ff0eb5 100644 (file)
--- a/drivers/video/mxc/mxc_epdc_fb.c
+++ b/drivers/video/mxc/mxc_epdc_fb.c
@@ -5031,10 +5031,14 @@ static void mxc_epdc_fb_shutdown(struct platform_device *pdev)
        struct mxc_epdc_fb_data *fb_data = platform_get_drvdata(pdev);
 
        /* Disable power to the EPD panel */
-       regulator_disable(fb_data->vcom_regulator);
-       regulator_disable(fb_data->display_regulator);
+       if (regulator_is_enabled(fb_data->vcom_regulator))
+               regulator_disable(fb_data->vcom_regulator);
+       if (regulator_is_enabled(fb_data->display_regulator))
+               regulator_disable(fb_data->display_regulator);
 
        /* Disable clocks to EPDC */
+       clk_enable(fb_data->epdc_clk_axi);
+       clk_enable(fb_data->epdc_clk_pix);
        __raw_writel(EPDC_CTRL_CLKGATE, EPDC_CTRL_SET);
        clk_disable(fb_data->epdc_clk_pix);
        clk_disable(fb_data->epdc_clk_axi);
@@ -5044,7 +5048,8 @@ static void mxc_epdc_fb_shutdown(struct platform_device *pdev)
                fb_data->pdata->disable_pins();
 
        /* turn off the V3p3 */
-       regulator_disable(fb_data->v3p3_regulator);
+       if (regulator_is_enabled(fb_data->v3p3_regulator))
+               regulator_disable(fb_data->v3p3_regulator);
 }
 #else
 #define mxc_epdc_fb_suspend    NULL