Re: [PATCH v2 1/5] PCI: rockchip: fix sign issues for current limits

[Bjorn Helgaas]

On Thu, Mar 23, 2017 at 05:27:17PM -0500, Bjorn Helgaas wrote:
> On Thu, Mar 09, 2017 at 06:46:13PM -0800, Brian Norris wrote:
> > The regulator framework can return negative error codes via
> > regulator_get_current_limit() for regulators that don't provide current
> > information. The subsequent check for postive values isn't very useful,
> > if the variable is unsigned.
> > 
> > Let's just match the signedness of the return value.
> > 
> > Prevents error messages like this, seen on Samsung Chromebook Plus:
> > 
> > [    1.069372] rockchip-pcie f8000000.pcie: invalid power supply
> > 
> > Fixes: 4816c4c7b82b ("PCI: rockchip: Provide captured slot power limit and scale")
> > Signed-off-by: Brian Norris <briannorris@xxxxxxxxxxxx>
> > Acked-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
> 
> I applied the first two patches (this already has Shawn's ack and the
> second is trivially obvious) to pci/host-rockchip.  I'm not sure what the
> current state of the others is.

I applied patches 3-5 with Shawn's ack to pci/host-rockchip for v4.12,
thanks!

> > ---
> > v2: add Shawn's ack
> > ---
> >  drivers/pci/host/pcie-rockchip.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/pci/host/pcie-rockchip.c b/drivers/pci/host/pcie-rockchip.c
> > index 26ddd3535272..d785f64ec03b 100644
> > --- a/drivers/pci/host/pcie-rockchip.c
> > +++ b/drivers/pci/host/pcie-rockchip.c
> > @@ -425,7 +425,8 @@ static struct pci_ops rockchip_pcie_ops = {
> >  
> >  static void rockchip_pcie_set_power_limit(struct rockchip_pcie *rockchip)
> >  {
> > -	u32 status, curr, scale, power;
> > +	int curr;
> > +	u32 status, scale, power;
> >  
> >  	if (IS_ERR(rockchip->vpcie3v3))
> >  		return;
> > -- 
> > 2.12.0.246.ga2ecc84866-goog
> > 
> 
> commit 73edd2b180a18024605c599074596a9e22d745d6
> Author: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Date:   Thu Mar 23 17:21:26 2017 -0500
> 
>     PCI: rockchip: Unindent rockchip_pcie_set_power_limit()
>     
>     If regulator_get_current_limit() returns 0 or error, return early so the
>     body of the function doesn't have to be indented as the body of an "if"
>     statement.  No functional change intended.
>     
>     Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> 
> diff --git a/drivers/pci/host/pcie-rockchip.c b/drivers/pci/host/pcie-rockchip.c
> index d785f64ec03b..7f76ff6af0ba 100644
> --- a/drivers/pci/host/pcie-rockchip.c
> +++ b/drivers/pci/host/pcie-rockchip.c
> @@ -438,24 +438,25 @@ static void rockchip_pcie_set_power_limit(struct rockchip_pcie *rockchip)
>  	 * to the actual power supply.
>  	 */
>  	curr = regulator_get_current_limit(rockchip->vpcie3v3);
> -	if (curr > 0) {
> -		scale = 3; /* 0.001x */
> -		curr = curr / 1000; /* convert to mA */
> -		power = (curr * 3300) / 1000; /* milliwatt */
> -		while (power > PCIE_RC_CONFIG_DCR_CSPL_LIMIT) {
> -			if (!scale) {
> -				dev_warn(rockchip->dev, "invalid power supply\n");
> -				return;
> -			}
> -			scale--;
> -			power = power / 10;
> -		}
> +	if (curr <= 0)
> +		return;
>  
> -		status = rockchip_pcie_read(rockchip, PCIE_RC_CONFIG_DCR);
> -		status |= (power << PCIE_RC_CONFIG_DCR_CSPL_SHIFT) |
> -			  (scale << PCIE_RC_CONFIG_DCR_CPLS_SHIFT);
> -		rockchip_pcie_write(rockchip, status, PCIE_RC_CONFIG_DCR);
> +	scale = 3; /* 0.001x */
> +	curr = curr / 1000; /* convert to mA */
> +	power = (curr * 3300) / 1000; /* milliwatt */
> +	while (power > PCIE_RC_CONFIG_DCR_CSPL_LIMIT) {
> +		if (!scale) {
> +			dev_warn(rockchip->dev, "invalid power supply\n");
> +			return;
> +		}
> +		scale--;
> +		power = power / 10;
>  	}
> +
> +	status = rockchip_pcie_read(rockchip, PCIE_RC_CONFIG_DCR);
> +	status |= (power << PCIE_RC_CONFIG_DCR_CSPL_SHIFT) |
> +		  (scale << PCIE_RC_CONFIG_DCR_CPLS_SHIFT);
> +	rockchip_pcie_write(rockchip, status, PCIE_RC_CONFIG_DCR);
>  }
>  
>  /**