video: imxfb: Do not crash on reboot
Issuing a "reboot" command after the LCD times out causes the following warnings: Requesting system reboot ------------[ cut here ]------------ WARNING: at drivers/clk/clk.c:471 clk_disable+0x24/0x50() Modules linked in: [<c001ad90>] (unwind_backtrace+0x0/0xf4) from [<c0025aac>] (warn_slowpath_common+0x48/0x60) [<c0025aac>] (warn_slowpath_common+0x48/0x60) from [<c0025ae0>] (warn_slowpath_null+0x1c/0x24) [<c0025ae0>] (warn_slowpath_null+0x1c/0x24) from [<c03960a0>] (clk_disable+0x24/0x50) [<c03960a0>] (clk_disable+0x24/0x50) from [<c02695a0>] (imxfb_disable_controller+0x48/0x7c) [<c02695a0>] (imxfb_disable_controller+0x48/0x7c) from [<c029d838>] (platform_drv_shutdown+0x18/0x1c) [<c029d838>] (platform_drv_shutdown+0x18/0x1c) from [<c02990fc>] (device_shutdown+0x48/0x14c) [<c02990fc>] (device_shutdown+0x48/0x14c) from [<c003d09c>] (kernel_restart_prepare+0x2c/0x3c) [<c003d09c>] (kernel_restart_prepare+0x2c/0x3c) from [<c003d0e4>] (kernel_restart+0xc/0x48) [<c003d0e4>] (kernel_restart+0xc/0x48) from [<c003d1e8>] (sys_reboot+0xc0/0x1bc) [<c003d1e8>] (sys_reboot+0xc0/0x1bc) from [<c0014ca0>] (ret_fast_syscall+0x0/0x2c) ---[ end trace da6b502ca79c854f ]--- ------------[ cut here ]------------ WARNING: at drivers/clk/clk.c:380 clk_unprepare+0x1c/0x2c() Modules linked in: [<c001ad90>] (unwind_backtrace+0x0/0xf4) from [<c0025aac>] (warn_slowpath_common+0x48/0x60) [<c0025aac>] (warn_slowpath_common+0x48/0x60) from [<c0025ae0>] (warn_slowpath_null+0x1c/0x24) [<c0025ae0>] (warn_slowpath_null+0x1c/0x24) from [<c0396338>] (clk_unprepare+0x1c/0x2c) [<c0396338>] (clk_unprepare+0x1c/0x2c) from [<c02695a8>] (imxfb_disable_controller+0x50/0x7c) [<c02695a8>] (imxfb_disable_controller+0x50/0x7c) from [<c029d838>] (platform_drv_shutdown+0x18/0x1c) [<c029d838>] (platform_drv_shutdown+0x18/0x1c) from [<c02990fc>] (device_shutdown+0x48/0x14c) [<c02990fc>] (device_shutdown+0x48/0x14c) from [<c003d09c>] (kernel_restart_prepare+0x2c/0x3c) [<c003d09c>] (kernel_restart_prepare+0x2c/0x3c) from [<c003d0e4>] (kernel_restart+0xc/0x48) [<c003d0e4>] (kernel_restart+0xc/0x48) from [<c003d1e8>] (sys_reboot+0xc0/0x1bc) [<c003d1e8>] (sys_reboot+0xc0/0x1bc) from [<c0014ca0>] (ret_fast_syscall+0x0/0x2c) ---[ end trace da6b502ca79c8550 ]--- ------------[ cut here ]------------ This happens because "reboot" triggers imxfb_shutdown(), which calls imxfb_disable_controller with the clocks already disabled. To prevent this, add a clock enabled status so that we can check if the clocks are enabled before disabling them. Acked-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com> Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
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83ae20981a
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@ -139,6 +139,7 @@ struct imxfb_info {
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struct clk *clk_ahb;
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struct clk *clk_per;
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enum imxfb_type devtype;
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bool enabled;
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/*
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* These are the addresses we mapped
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@ -536,6 +537,10 @@ static void imxfb_exit_backlight(struct imxfb_info *fbi)
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static void imxfb_enable_controller(struct imxfb_info *fbi)
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{
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if (fbi->enabled)
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return;
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pr_debug("Enabling LCD controller\n");
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writel(fbi->screen_dma, fbi->regs + LCDC_SSA);
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@ -556,6 +561,7 @@ static void imxfb_enable_controller(struct imxfb_info *fbi)
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clk_prepare_enable(fbi->clk_ipg);
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clk_prepare_enable(fbi->clk_ahb);
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clk_prepare_enable(fbi->clk_per);
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fbi->enabled = true;
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if (fbi->backlight_power)
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fbi->backlight_power(1);
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@ -565,6 +571,9 @@ static void imxfb_enable_controller(struct imxfb_info *fbi)
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static void imxfb_disable_controller(struct imxfb_info *fbi)
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{
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if (!fbi->enabled)
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return;
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pr_debug("Disabling LCD controller\n");
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if (fbi->backlight_power)
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@ -575,6 +584,7 @@ static void imxfb_disable_controller(struct imxfb_info *fbi)
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clk_disable_unprepare(fbi->clk_per);
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clk_disable_unprepare(fbi->clk_ipg);
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clk_disable_unprepare(fbi->clk_ahb);
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fbi->enabled = false;
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writel(0, fbi->regs + LCDC_RMCR);
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}
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