soc: rockchip: opp_select: Fix sleeping inside atomic context

This patch fixes the following warning:
[    2.226264] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:620
[    2.226341] in_atomic(): 0, irqs_disabled(): 0, pid: 1, name: swapper/0
[    2.226366] 4 locks held by swapper/0/1:
[    2.226385]  #0:  (&dev->mutex){......}, at: [<ffffff800851c664>] __device_attach+0x3c/0x134
[    2.226515]  #1:  (cpu_hotplug.lock){......}, at: [<ffffff800809feb0>] get_online_cpus+0x38/0x9c
[    2.226594]  #2:  (subsys mutex#7){......}, at: [<ffffff800851b0e4>] subsys_interface_register+0x54/0xfc
[    2.226684]  #3:  (rcu_read_lock){......}, at: [<ffffff800845c764>] rockchip_adjust_power_scale+0x88/0x450
[    2.226771] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 4.4.132 #600
[    2.226790] Hardware name: Rockchip PX30 evb ddr3 board (DT)
[    2.226809] Call trace:
[    2.226840] [<ffffff800808a0d4>] dump_backtrace+0x0/0x1ec
[    2.226889] [<ffffff800808a2d4>] show_stack+0x14/0x1c
[    2.226918] [<ffffff80083c41b4>] dump_stack+0x94/0xbc
[    2.226946] [<ffffff80080cb708>] ___might_sleep+0x108/0x118
[    2.226972] [<ffffff80080cb788>] __might_sleep+0x70/0x80
[    2.227001] [<ffffff8008b6d1d0>] mutex_lock_nested+0x54/0x38c
[    2.227031] [<ffffff8008858714>] __of_clk_get_from_provider+0x44/0xec
[    2.227061] [<ffffff8008852814>] __of_clk_get_by_name+0xd4/0x14c
[    2.227112] [<ffffff80088528a4>] of_clk_get_by_name+0x18/0x28
[    2.227140] [<ffffff800845c980>] rockchip_adjust_power_scale+0x2a4/0x450
[    2.227171] [<ffffff800877f630>] cpufreq_init+0x154/0x394
[    2.227199] [<ffffff8008776ac4>] cpufreq_online+0x1b0/0x68c
[    2.227225] [<ffffff8008777040>] cpufreq_add_dev+0x3c/0x94
[    2.227253] [<ffffff800851b168>] subsys_interface_register+0xd8/0xfc
[    2.227281] [<ffffff80087772d8>] cpufreq_register_driver+0x10c/0x1a8
[    2.227332] [<ffffff800877f93c>] dt_cpufreq_probe+0xcc/0xe8
[    2.227360] [<ffffff800851e7b8>] platform_drv_probe+0x54/0xa8
[    2.227385] [<ffffff800851c924>] driver_probe_device+0x194/0x278
[    2.227411] [<ffffff800851cb40>] __device_attach_driver+0x60/0x9c
[    2.227439] [<ffffff800851ae14>] bus_for_each_drv+0x9c/0xbc
[    2.227464] [<ffffff800851c6f0>] __device_attach+0xc8/0x134
[    2.227488] [<ffffff800851ccb8>] device_initial_probe+0x10/0x18
[    2.227514] [<ffffff800851bcec>] bus_probe_device+0x2c/0x90
[    2.227541] [<ffffff8008519e90>] device_add+0x44c/0x510
[    2.227570] [<ffffff800851e4d4>] platform_device_add+0xa0/0x1e4
[    2.227597] [<ffffff800851ef28>] platform_device_register_full+0xa4/0xe4
[    2.227627] [<ffffff80090f8680>] rockchip_cpufreq_driver_init+0xd4/0x31c
[    2.227654] [<ffffff8008083468>] do_one_initcall+0x84/0x1a4
[    2.227682] [<ffffff80090c0e98>] kernel_init_freeable+0x260/0x264
[    2.227708] [<ffffff8008b6ab68>] kernel_init+0x10/0xf8
[    2.227734] [<ffffff80080832a0>] ret_from_fork+0x10/0x30

Fixes: 197a2d3 ("soc: rockchip: opp_select: add missing rcu lock")
Change-Id: Ib52b6f7bc77bb207a1c8c6880f7a5e916fa3d2ee
Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com>

drivers/soc/rockchip/rockchip_opp_select.c

@@ -590,15 +590,15 @@ static int rockchip_adjust_opp_by_irdrop(struct device *dev,
 	count = dev_pm_opp_get_opp_count(dev);
 	if (count <= 0) {
 		ret = count ? count : -ENODATA;
-		goto out;
+		goto unlock;
 	}
 
 	for (i = 0, rate = 0; i < count; i++, rate++) {
 		/* find next rate */
 		opp = dev_pm_opp_find_freq_ceil(dev, &rate);
 		if (IS_ERR(opp)) {
 			ret = PTR_ERR(opp);
-			goto out;
+			goto unlock;
 		}
 		board_irdrop = rockchip_of_get_irdrop(np, opp->rate);
 		if (IS_ERR_VALUE(board_irdrop))
@@ -621,9 +621,18 @@ static int rockchip_adjust_opp_by_irdrop(struct device *dev,
 		}
 	}
 
+unlock:
+#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 11, 0)
+	rcu_read_unlock();
+#endif
+	if (ret)
+		goto out;
+
 	clk = of_clk_get_by_name(np, NULL);
-	if (IS_ERR(clk))
+	if (IS_ERR(clk)) {
+		ret = PTR_ERR(clk);
 		goto out;
+	}
 	if (safe_opp && safe_opp != opp && irdrop_scale) {
 		*irdrop_scale = rockchip_pll_clk_rate_to_scale(clk,
 							       safe_opp->rate);
@@ -634,9 +643,6 @@ static int rockchip_adjust_opp_by_irdrop(struct device *dev,
 	clk_put(clk);
 
 out:
-#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 11, 0)
-	rcu_read_unlock();
-#endif
 	return ret;
 }