| Message ID | 20240827055548.901285-3-s-vadapalli@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add ACSPCIE refclk support on J784S4-EVM | expand |
On Tue, Aug 27, 2024 at 11:25:48AM +0530, Siddharth Vadapalli wrote: > The ACSPCIE module is capable of driving the reference clock required by > the PCIe Endpoint device. It is an alternative to on-board and external > reference clock generators. Enabling the output from the ACSPCIE module's > PAD IO Buffers requires clearing the "PAD IO disable" bits of the > ACSPCIE_PROXY_CTRL register in the CTRL_MMR register space. > > Add support to enable the ACSPCIE reference clock output using the optional > device-tree property "ti,syscon-acspcie-proxy-ctrl". > > Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com> > --- > > v2: > https://lore.kernel.org/r/20240729092855.1945700-3-s-vadapalli@ti.com/ > Changes since v2: > - Rebased patch on next-20240826. > > v1: > https://lore.kernel.org/r/20240715120936.1150314-4-s-vadapalli@ti.com/ > Changes since v1: > - Addressed Bjorn's feedback at: > https://lore.kernel.org/r/20240725211841.GA859405@bhelgaas/ > with the following changes: > 1) Updated $subject and commit message to indicate that this patch > enables ACSPCIE reference clock output if the DT property is present. > 2) Updated macro and comments to indicate that the BITS correspond to > disabling ACSPCIE output, due to which clearing them enables the > reference clock output. > 3) Replaced "PAD" with "refclk" both in the function name and in the > error prints. > 4) Wrapped lines to be within the 80 character limit to match the rest > of the driver. > > drivers/pci/controller/cadence/pci-j721e.c | 38 ++++++++++++++++++++++ > 1 file changed, 38 insertions(+) > > diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c > index 85718246016b..ed42b2229483 100644 > --- a/drivers/pci/controller/cadence/pci-j721e.c > +++ b/drivers/pci/controller/cadence/pci-j721e.c > @@ -44,6 +44,7 @@ enum link_status { > #define J721E_MODE_RC BIT(7) > #define LANE_COUNT(n) ((n) << 8) > > +#define ACSPCIE_PAD_DISABLE_MASK GENMASK(1, 0) > #define GENERATION_SEL_MASK GENMASK(1, 0) > > struct j721e_pcie { > @@ -220,6 +221,34 @@ static int j721e_pcie_set_lane_count(struct j721e_pcie *pcie, > return ret; > } > > +static int j721e_enable_acspcie_refclk(struct j721e_pcie *pcie, > + struct regmap *syscon) > +{ > + struct device *dev = pcie->cdns_pcie->dev; > + struct device_node *node = dev->of_node; > + u32 mask = ACSPCIE_PAD_DISABLE_MASK; > + struct of_phandle_args args; > + u32 val; > + int ret; > + > + ret = of_parse_phandle_with_fixed_args(node, > + "ti,syscon-acspcie-proxy-ctrl", > + 1, 0, &args); > + if (!ret) { > + /* Clear PAD IO disable bits to enable refclk output */ > + val = ~(args.args[0]); > + ret = regmap_update_bits(syscon, 0, mask, val); > + if (ret) > + dev_err(dev, "failed to enable ACSPCIE refclk: %d\n", > + ret); > + } else { > + dev_err(dev, > + "ti,syscon-acspcie-proxy-ctrl has invalid arguments\n"); > + } I should have mentioned this the first time, but this would be easier to read if structured as: ret = of_parse_phandle_with_fixed_args(...); if (ret) { dev_err(...); return ret; } /* Clear PAD IO disable bits to enable refclk output */ val = ~(args.args[0]); ret = regmap_update_bits(syscon, 0, mask, val); if (ret) { dev_err(...); return ret; } return 0; > + return ret; > +} > + > static int j721e_pcie_ctrl_init(struct j721e_pcie *pcie) > { > struct device *dev = pcie->cdns_pcie->dev; > @@ -259,6 +288,15 @@ static int j721e_pcie_ctrl_init(struct j721e_pcie *pcie) > return ret; > } > > + /* Enable ACSPCIE refclk output if the optional property exists */ > + syscon = syscon_regmap_lookup_by_phandle_optional(node, > + "ti,syscon-acspcie-proxy-ctrl"); > + if (syscon) { > + ret = j721e_enable_acspcie_refclk(pcie, syscon); > + if (ret) > + return ret; > + } > + > return 0; Not as dramatic here, but I think the following would be a little simpler since the final "return" isn't used for two purposes ((1) syscon property absent, (2) syscon present and refclk successfully enabled): syscon = syscon_regmap_lookup_by_phandle_optional(...); if (!syscon) return 0; return j721e_enable_acspcie_refclk(...); > } > > -- > 2.40.1 >
On Wed, Aug 28, 2024 at 04:19:06PM -0500, Bjorn Helgaas wrote: Hello Bjorn, > On Tue, Aug 27, 2024 at 11:25:48AM +0530, Siddharth Vadapalli wrote: > > The ACSPCIE module is capable of driving the reference clock required by > > the PCIe Endpoint device. It is an alternative to on-board and external > > reference clock generators. Enabling the output from the ACSPCIE module's > > PAD IO Buffers requires clearing the "PAD IO disable" bits of the > > ACSPCIE_PROXY_CTRL register in the CTRL_MMR register space. > > > > Add support to enable the ACSPCIE reference clock output using the optional > > device-tree property "ti,syscon-acspcie-proxy-ctrl". > > > > Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com> > > --- > > [...] > > + > > + ret = of_parse_phandle_with_fixed_args(node, > > + "ti,syscon-acspcie-proxy-ctrl", > > + 1, 0, &args); > > + if (!ret) { > > + /* Clear PAD IO disable bits to enable refclk output */ > > + val = ~(args.args[0]); > > + ret = regmap_update_bits(syscon, 0, mask, val); > > + if (ret) > > + dev_err(dev, "failed to enable ACSPCIE refclk: %d\n", > > + ret); > > + } else { > > + dev_err(dev, > > + "ti,syscon-acspcie-proxy-ctrl has invalid arguments\n"); > > + } > > I should have mentioned this the first time, but this would be easier > to read if structured as: > > ret = of_parse_phandle_with_fixed_args(...); > if (ret) { > dev_err(...); > return ret; > } > > /* Clear PAD IO disable bits to enable refclk output */ > val = ~(args.args[0]); > ret = regmap_update_bits(syscon, 0, mask, val); > if (ret) { > dev_err(...); > return ret; > } > > return 0; Yes, this removes the nested IF conditions and is definitely a cleaner approach. I will update this in the next version of the patch. > > > + return ret; > > +} > > + > > static int j721e_pcie_ctrl_init(struct j721e_pcie *pcie) > > { > > struct device *dev = pcie->cdns_pcie->dev; > > @@ -259,6 +288,15 @@ static int j721e_pcie_ctrl_init(struct j721e_pcie *pcie) > > return ret; > > } > > > > + /* Enable ACSPCIE refclk output if the optional property exists */ > > + syscon = syscon_regmap_lookup_by_phandle_optional(node, > > + "ti,syscon-acspcie-proxy-ctrl"); > > + if (syscon) { > > + ret = j721e_enable_acspcie_refclk(pcie, syscon); > > + if (ret) > > + return ret; > > + } > > + > > return 0; > > Not as dramatic here, but I think the following would be a little > simpler since the final "return" isn't used for two purposes > ((1) syscon property absent, (2) syscon present and refclk > successfully enabled): > > syscon = syscon_regmap_lookup_by_phandle_optional(...); > if (!syscon) > return 0; > > return j721e_enable_acspcie_refclk(...); Sure. I will implement the above in the next patch. Thank you for reviewing this patch and sharing your feedback. Regards, Siddharth.
diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c index 85718246016b..ed42b2229483 100644 --- a/drivers/pci/controller/cadence/pci-j721e.c +++ b/drivers/pci/controller/cadence/pci-j721e.c @@ -44,6 +44,7 @@ enum link_status { #define J721E_MODE_RC BIT(7) #define LANE_COUNT(n) ((n) << 8) +#define ACSPCIE_PAD_DISABLE_MASK GENMASK(1, 0) #define GENERATION_SEL_MASK GENMASK(1, 0) struct j721e_pcie { @@ -220,6 +221,34 @@ static int j721e_pcie_set_lane_count(struct j721e_pcie *pcie, return ret; } +static int j721e_enable_acspcie_refclk(struct j721e_pcie *pcie, + struct regmap *syscon) +{ + struct device *dev = pcie->cdns_pcie->dev; + struct device_node *node = dev->of_node; + u32 mask = ACSPCIE_PAD_DISABLE_MASK; + struct of_phandle_args args; + u32 val; + int ret; + + ret = of_parse_phandle_with_fixed_args(node, + "ti,syscon-acspcie-proxy-ctrl", + 1, 0, &args); + if (!ret) { + /* Clear PAD IO disable bits to enable refclk output */ + val = ~(args.args[0]); + ret = regmap_update_bits(syscon, 0, mask, val); + if (ret) + dev_err(dev, "failed to enable ACSPCIE refclk: %d\n", + ret); + } else { + dev_err(dev, + "ti,syscon-acspcie-proxy-ctrl has invalid arguments\n"); + } + + return ret; +} + static int j721e_pcie_ctrl_init(struct j721e_pcie *pcie) { struct device *dev = pcie->cdns_pcie->dev; @@ -259,6 +288,15 @@ static int j721e_pcie_ctrl_init(struct j721e_pcie *pcie) return ret; } + /* Enable ACSPCIE refclk output if the optional property exists */ + syscon = syscon_regmap_lookup_by_phandle_optional(node, + "ti,syscon-acspcie-proxy-ctrl"); + if (syscon) { + ret = j721e_enable_acspcie_refclk(pcie, syscon); + if (ret) + return ret; + } + return 0; }
The ACSPCIE module is capable of driving the reference clock required by the PCIe Endpoint device. It is an alternative to on-board and external reference clock generators. Enabling the output from the ACSPCIE module's PAD IO Buffers requires clearing the "PAD IO disable" bits of the ACSPCIE_PROXY_CTRL register in the CTRL_MMR register space. Add support to enable the ACSPCIE reference clock output using the optional device-tree property "ti,syscon-acspcie-proxy-ctrl". Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com> --- v2: https://lore.kernel.org/r/20240729092855.1945700-3-s-vadapalli@ti.com/ Changes since v2: - Rebased patch on next-20240826. v1: https://lore.kernel.org/r/20240715120936.1150314-4-s-vadapalli@ti.com/ Changes since v1: - Addressed Bjorn's feedback at: https://lore.kernel.org/r/20240725211841.GA859405@bhelgaas/ with the following changes: 1) Updated $subject and commit message to indicate that this patch enables ACSPCIE reference clock output if the DT property is present. 2) Updated macro and comments to indicate that the BITS correspond to disabling ACSPCIE output, due to which clearing them enables the reference clock output. 3) Replaced "PAD" with "refclk" both in the function name and in the error prints. 4) Wrapped lines to be within the 80 character limit to match the rest of the driver. drivers/pci/controller/cadence/pci-j721e.c | 38 ++++++++++++++++++++++ 1 file changed, 38 insertions(+)