pwm: imx-tpm: fix probe crash due to access registers without clock

The following commit abf6569d6482 ("pwm: imx-tpm: Make use of
devm_pwmchip_alloc() function") introduced an issue that accessing
registers without clock which results in the following boot crash
on MX7ULP platform. Fixed it by enabling clock properly.

Unhandled fault: external abort on non-linefetch (0x1008) at 0xf0978004
[f0978004] *pgd=64009811, *pte=40250653, *ppte=40250453
Internal error: : 1008 [#1] SMP ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.8.0-rc6-next-20240301 #18
Hardware name: Freescale i.MX7ULP (Device Tree)
PC is at pwm_imx_tpm_probe+0x1c/0xd8
LR is at __devm_ioremap_resource+0xf8/0x1dc
pc : [<c0629e58>]    lr : [<c0562d4c>]    psr: 80000053
sp : f0825e10  ip : 00000000  fp : 00000000
r10: c148f8c0  r9 : c41fc338  r8 : c164b000
r7 : 00000000  r6 : c406b400  r5 : c406b410  r4 : f0978000
r3 : 00000005  r2 : 00000000  r1 : a0000053  r0 : f0978000
Flags: Nzcv  IRQs on  FIQs off  Mode SVC_32  ISA ARM  Segment none
Control: 10c5387d  Table: 6000406a  DAC: 00000051
...
Call trace:
 pwm_imx_tpm_probe from platform_probe+0x58/0xb0
 platform_probe from really_probe+0xc4/0x2e0
 really_probe from __driver_probe_device+0x84/0x19c
 __driver_probe_device from driver_probe_device+0x2c/0x104
 driver_probe_device from __driver_attach+0x90/0x170
 __driver_attach from bus_for_each_dev+0x7c/0xd0
 bus_for_each_dev from bus_add_driver+0xc4/0x1cc
 bus_add_driver from driver_register+0x7c/0x114
 driver_register from do_one_initcall+0x58/0x270
 do_one_initcall from kernel_init_freeable+0x170/0x218
 kernel_init_freeable from kernel_init+0x14/0x140
 kernel_init from ret_from_fork+0x14/0x20

Fixes: abf6569d6482 ("pwm: imx-tpm: Make use of devm_pwmchip_alloc() function")
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Link: https://lore.kernel.org/r/20240304102929.893542-1-aisheng.dong@nxp.com
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

diff --git a/drivers/pwm/pwm-imx-tpm.c b/drivers/pwm/pwm-imx-tpm.c
index b04b974..c50ddba 100644 (file)
--- a/drivers/pwm/pwm-imx-tpm.c
+++ b/drivers/pwm/pwm-imx-tpm.c
@@ -337,6 +337,7 @@ static int pwm_imx_tpm_probe(struct platform_device *pdev)
 {
        struct pwm_chip *chip;
        struct imx_tpm_pwm_chip *tpm;
+       struct clk *clk;
        void __iomem *base;
        int ret;
        unsigned int npwm;
@@ -346,6 +347,11 @@ static int pwm_imx_tpm_probe(struct platform_device *pdev)
        if (IS_ERR(base))
                return PTR_ERR(base);
 
+       clk = devm_clk_get_enabled(&pdev->dev, NULL);
+       if (IS_ERR(clk))
+               return dev_err_probe(&pdev->dev, PTR_ERR(clk),
+                                    "failed to get PWM clock\n");
+
        /* get number of channels */
        val = readl(base + PWM_IMX_TPM_PARAM);
        npwm = FIELD_GET(PWM_IMX_TPM_PARAM_CHAN, val);
@@ -358,11 +364,7 @@ static int pwm_imx_tpm_probe(struct platform_device *pdev)
        platform_set_drvdata(pdev, tpm);
 
        tpm->base = base;
-
-       tpm->clk = devm_clk_get_enabled(&pdev->dev, NULL);
-       if (IS_ERR(tpm->clk))
-               return dev_err_probe(&pdev->dev, PTR_ERR(tpm->clk),
-                                    "failed to get PWM clock\n");
+       tpm->clk = clk;
 
        chip->ops = &imx_tpm_pwm_ops;