| Message ID | 20130507091734.GM3658@sgi.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hello, On Tue, May 07, 2013 at 04:17:34AM -0500, Robin Holt wrote: > I noticed a warning while cross-compiling all arm defconfigs. > > The mmp2_defconfig gave this warning: > > drivers/video/backlight/max8925_bl.c: In function 'max8925_backlight_probe': > drivers/video/backlight/max8925_bl.c:177:3: warning: statement with no effect [-Wunused-value] > > This appears to have been introduced by the above commit when !CONFIG_OF > > Looking at this more closely, I am not sure how this was ever intended > to be handled or how the errors returned in the CONFIG_OF case were > intended to be handled as the return from max8925_backlight_dt_init is > always ignored. > > I think this needs some more attention, but do not feel like I know > enough about it or have any means to test it to weigh in. > > Thanks, > Robin > > > commit 47ec340cb8e232671e7c4a4689ff32c3bdf329da > Author: Qing Xu <qingx@marvell.com> > Date: Mon Feb 4 23:40:45 2013 +0800 > > mfd: max8925: Support dt for backlight > > Add device tree support in max8925 backlight. > > Signed-off-by: Qing Xu <qingx@marvell.com> > Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com> > Signed-off-by: Samuel Ortiz <sameo@linux.intel.com> > > diff --git a/drivers/video/backlight/max8925_bl.c b/drivers/video/backlight/max8925_bl.c > index 2c9bce0..5ca11b0 100644 > --- a/drivers/video/backlight/max8925_bl.c > +++ b/drivers/video/backlight/max8925_bl.c > @@ -101,6 +101,29 @@ static const struct backlight_ops max8925_backlight_ops = { > .get_brightness = max8925_backlight_get_brightness, > }; > > +#ifdef CONFIG_OF > +static int max8925_backlight_dt_init(struct platform_device *pdev, > + struct max8925_backlight_pdata *pdata) > +{ > + struct device_node *nproot = pdev->dev.parent->of_node, *np; > + int dual_string; > + > + if (!nproot) > + return -ENODEV; > + np = of_find_node_by_name(nproot, "backlight"); > + if (!np) { > + dev_err(&pdev->dev, "failed to find backlight node\n"); > + return -ENODEV; > + } > + > + of_property_read_u32(np, "maxim,max8925-dual-string", &dual_string); > + pdata->dual_string = dual_string; > + return 0; > +} > +#else > +#define max8925_backlight_dt_init(x, y) (-1) It's probably best to make this: static inline max8925_backlight_dt_init(struct platform_device *pdev, struct max8925_backlight_pdata *pdata) { return -ENODEV; } > +#endif > + > static int max8925_backlight_probe(struct platform_device *pdev) > { > struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent); > @@ -147,6 +170,13 @@ static int max8925_backlight_probe(struct platform_device *pdev) > platform_set_drvdata(pdev, bl); > > value = 0; > + if (pdev->dev.parent->of_node && !pdata) { > + pdata = devm_kzalloc(&pdev->dev, > + sizeof(struct max8925_backlight_pdata), > + GFP_KERNEL); > + max8925_backlight_dt_init(pdev, pdata); > + } > + > if (pdata) { > if (pdata->lxw_scl) > value |= (1 << 7); > @@ -158,7 +188,6 @@ static int max8925_backlight_probe(struct platform_device *pdev) > ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 0xfe, value); > if (ret < 0) > goto out_brt; > - > backlight_update_status(bl); > return 0; > out_brt: > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
On Tue, May 7, 2013 at 5:24 PM, Uwe Kleine-König <u.kleine-koenig@pengutronix.de> wrote: > Hello, > > On Tue, May 07, 2013 at 04:17:34AM -0500, Robin Holt wrote: >> I noticed a warning while cross-compiling all arm defconfigs. >> >> The mmp2_defconfig gave this warning: >> >> drivers/video/backlight/max8925_bl.c: In function 'max8925_backlight_probe': >> drivers/video/backlight/max8925_bl.c:177:3: warning: statement with no effect [-Wunused-value] >> >> This appears to have been introduced by the above commit when !CONFIG_OF >> >> Looking at this more closely, I am not sure how this was ever intended >> to be handled or how the errors returned in the CONFIG_OF case were >> intended to be handled as the return from max8925_backlight_dt_init is >> always ignored. >> >> I think this needs some more attention, but do not feel like I know >> enough about it or have any means to test it to weigh in. >> >> Thanks, >> Robin >> >> >> commit 47ec340cb8e232671e7c4a4689ff32c3bdf329da >> Author: Qing Xu <qingx@marvell.com> >> Date: Mon Feb 4 23:40:45 2013 +0800 >> >> mfd: max8925: Support dt for backlight >> >> Add device tree support in max8925 backlight. >> >> Signed-off-by: Qing Xu <qingx@marvell.com> >> Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com> >> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com> >> >> diff --git a/drivers/video/backlight/max8925_bl.c b/drivers/video/backlight/max8925_bl.c >> index 2c9bce0..5ca11b0 100644 >> --- a/drivers/video/backlight/max8925_bl.c >> +++ b/drivers/video/backlight/max8925_bl.c >> @@ -101,6 +101,29 @@ static const struct backlight_ops max8925_backlight_ops = { >> .get_brightness = max8925_backlight_get_brightness, >> }; >> >> +#ifdef CONFIG_OF >> +static int max8925_backlight_dt_init(struct platform_device *pdev, >> + struct max8925_backlight_pdata *pdata) >> +{ >> + struct device_node *nproot = pdev->dev.parent->of_node, *np; >> + int dual_string; >> + >> + if (!nproot) >> + return -ENODEV; >> + np = of_find_node_by_name(nproot, "backlight"); >> + if (!np) { >> + dev_err(&pdev->dev, "failed to find backlight node\n"); >> + return -ENODEV; >> + } >> + >> + of_property_read_u32(np, "maxim,max8925-dual-string", &dual_string); >> + pdata->dual_string = dual_string; >> + return 0; >> +} >> +#else >> +#define max8925_backlight_dt_init(x, y) (-1) > It's probably best to make this: > > static inline max8925_backlight_dt_init(struct platform_device *pdev, > struct max8925_backlight_pdata *pdata) > { > return -ENODEV; > } > I've submitted this patch to fix this issue for a long time. Samuel, Should I send it again? Regards Haojian
On Tue, May 07, 2013 at 05:35:28PM +0800, Haojian Zhuang wrote: > On Tue, May 7, 2013 at 5:24 PM, Uwe Kleine-König > <u.kleine-koenig@pengutronix.de> wrote: > > Hello, > > > > On Tue, May 07, 2013 at 04:17:34AM -0500, Robin Holt wrote: > >> I noticed a warning while cross-compiling all arm defconfigs. > >> > >> The mmp2_defconfig gave this warning: > >> > >> drivers/video/backlight/max8925_bl.c: In function 'max8925_backlight_probe': > >> drivers/video/backlight/max8925_bl.c:177:3: warning: statement with no effect [-Wunused-value] > >> > >> This appears to have been introduced by the above commit when !CONFIG_OF > >> > >> Looking at this more closely, I am not sure how this was ever intended > >> to be handled or how the errors returned in the CONFIG_OF case were > >> intended to be handled as the return from max8925_backlight_dt_init is > >> always ignored. > >> > >> I think this needs some more attention, but do not feel like I know > >> enough about it or have any means to test it to weigh in. > >> > >> Thanks, > >> Robin > >> > >> > >> commit 47ec340cb8e232671e7c4a4689ff32c3bdf329da > >> Author: Qing Xu <qingx@marvell.com> > >> Date: Mon Feb 4 23:40:45 2013 +0800 > >> > >> mfd: max8925: Support dt for backlight > >> > >> Add device tree support in max8925 backlight. > >> > >> Signed-off-by: Qing Xu <qingx@marvell.com> > >> Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com> > >> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com> > >> > >> diff --git a/drivers/video/backlight/max8925_bl.c b/drivers/video/backlight/max8925_bl.c > >> index 2c9bce0..5ca11b0 100644 > >> --- a/drivers/video/backlight/max8925_bl.c > >> +++ b/drivers/video/backlight/max8925_bl.c > >> @@ -101,6 +101,29 @@ static const struct backlight_ops max8925_backlight_ops = { > >> .get_brightness = max8925_backlight_get_brightness, > >> }; > >> > >> +#ifdef CONFIG_OF > >> +static int max8925_backlight_dt_init(struct platform_device *pdev, > >> + struct max8925_backlight_pdata *pdata) > >> +{ > >> + struct device_node *nproot = pdev->dev.parent->of_node, *np; > >> + int dual_string; > >> + > >> + if (!nproot) > >> + return -ENODEV; > >> + np = of_find_node_by_name(nproot, "backlight"); > >> + if (!np) { > >> + dev_err(&pdev->dev, "failed to find backlight node\n"); > >> + return -ENODEV; > >> + } > >> + > >> + of_property_read_u32(np, "maxim,max8925-dual-string", &dual_string); > >> + pdata->dual_string = dual_string; > >> + return 0; > >> +} > >> +#else > >> +#define max8925_backlight_dt_init(x, y) (-1) > > It's probably best to make this: > > > > static inline max8925_backlight_dt_init(struct platform_device *pdev, > > struct max8925_backlight_pdata *pdata) > > { > > return -ENODEV; > > } > > > > I've submitted this patch to fix this issue for a long time. > > Samuel, > > Should I send it again? It fixes nothing. The return value is not used. There is more to this bug report than the -1. You need to handle that error case. Otherwise, you could just change it into a void return. Robin
On Tue, May 07, 2013 at 05:35:28PM +0800, Haojian Zhuang wrote: > > It's probably best to make this: > > > > static inline max8925_backlight_dt_init(struct platform_device *pdev, > > struct max8925_backlight_pdata *pdata) > > { > > return -ENODEV; > > } > > > > I've submitted this patch to fix this issue for a long time. > > Samuel, > > Should I send it again? To the backlight maintainers, yes. I carried 47ec340c as it was part of an MFD patchset, but now that it's upstream I shouldn't take any patches for it. Cheers, Samuel.
diff --git a/drivers/video/backlight/max8925_bl.c b/drivers/video/backlight/max8925_bl.c index 2c9bce0..5ca11b0 100644 --- a/drivers/video/backlight/max8925_bl.c +++ b/drivers/video/backlight/max8925_bl.c @@ -101,6 +101,29 @@ static const struct backlight_ops max8925_backlight_ops = { .get_brightness = max8925_backlight_get_brightness, }; +#ifdef CONFIG_OF +static int max8925_backlight_dt_init(struct platform_device *pdev, + struct max8925_backlight_pdata *pdata) +{ + struct device_node *nproot = pdev->dev.parent->of_node, *np; + int dual_string; + + if (!nproot) + return -ENODEV; + np = of_find_node_by_name(nproot, "backlight"); + if (!np) { + dev_err(&pdev->dev, "failed to find backlight node\n"); + return -ENODEV; + } + + of_property_read_u32(np, "maxim,max8925-dual-string", &dual_string); + pdata->dual_string = dual_string; + return 0; +} +#else +#define max8925_backlight_dt_init(x, y) (-1) +#endif + static int max8925_backlight_probe(struct platform_device *pdev) { struct max8925_chip *chip = dev_get_drvdata(pdev->dev.parent); @@ -147,6 +170,13 @@ static int max8925_backlight_probe(struct platform_device *pdev) platform_set_drvdata(pdev, bl); value = 0; + if (pdev->dev.parent->of_node && !pdata) { + pdata = devm_kzalloc(&pdev->dev, + sizeof(struct max8925_backlight_pdata), + GFP_KERNEL); + max8925_backlight_dt_init(pdev, pdata); + } + if (pdata) { if (pdata->lxw_scl) value |= (1 << 7); @@ -158,7 +188,6 @@ static int max8925_backlight_probe(struct platform_device *pdev) ret = max8925_set_bits(chip->i2c, data->reg_mode_cntl, 0xfe, value); if (ret < 0) goto out_brt; - backlight_update_status(bl); return 0; out_brt:
I noticed a warning while cross-compiling all arm defconfigs. The mmp2_defconfig gave this warning: drivers/video/backlight/max8925_bl.c: In function 'max8925_backlight_probe': drivers/video/backlight/max8925_bl.c:177:3: warning: statement with no effect [-Wunused-value] This appears to have been introduced by the above commit when !CONFIG_OF Looking at this more closely, I am not sure how this was ever intended to be handled or how the errors returned in the CONFIG_OF case were intended to be handled as the return from max8925_backlight_dt_init is always ignored. I think this needs some more attention, but do not feel like I know enough about it or have any means to test it to weigh in. Thanks, Robin commit 47ec340cb8e232671e7c4a4689ff32c3bdf329da Author: Qing Xu <qingx@marvell.com> Date: Mon Feb 4 23:40:45 2013 +0800 mfd: max8925: Support dt for backlight Add device tree support in max8925 backlight. Signed-off-by: Qing Xu <qingx@marvell.com> Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>