[RFC v1 1/2] PCI: tegra: Simplify clock handling by using clk_bulk*() functions

[Anand Moon <linux.amoon@gmail.com>]

Currently, the driver acquires clocks and prepare/enable/disable/unprepare
the clocks individually thereby making the driver complex to read.

The driver can be simplified by using the clk_bulk*() APIs.

Use:
  - devm_clk_bulk_get_all() API to acquire all the clocks
  - clk_bulk_prepare_enable() to prepare/enable clocks
  - clk_bulk_disable_unprepare() APIs to disable/unprepare them in bulk

As part of this cleanup, the legacy has_cml_clk flag and explicit handling
of individual clocks (pex, afi, pll_e, cml) are removed. Clock sequencing
is now implicitly determined by the order defined in the device tree,
eliminating hardcoded logic and improving maintainability.

Cc: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Anand Moon <linux.amoon@gmail.com>
---
 drivers/pci/controller/pci-tegra.c | 71 +++++-------------------------
 1 file changed, 12 insertions(+), 59 deletions(-)

diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
index 467ddc701adce..3841489198b64 100644
--- a/drivers/pci/controller/pci-tegra.c
+++ b/drivers/pci/controller/pci-tegra.c
@@ -297,7 +297,6 @@ struct tegra_pcie_soc {
 	bool has_pex_clkreq_en;
 	bool has_pex_bias_ctrl;
 	bool has_intr_prsnt_sense;
-	bool has_cml_clk;
 	bool has_gen2;
 	bool force_pca_enable;
 	bool program_uphy;
@@ -330,10 +329,8 @@ struct tegra_pcie {
 
 	struct resource cs;
 
-	struct clk *pex_clk;
-	struct clk *afi_clk;
-	struct clk *pll_e;
-	struct clk *cml_clk;
+	struct clk_bulk_data *clks;
+	int    num_clks;
 
 	struct reset_control *pex_rst;
 	struct reset_control *afi_rst;
@@ -1153,15 +1150,11 @@ static void tegra_pcie_enable_controller(struct tegra_pcie *pcie)
 static void tegra_pcie_power_off(struct tegra_pcie *pcie)
 {
 	struct device *dev = pcie->dev;
-	const struct tegra_pcie_soc *soc = pcie->soc;
 	int err;
 
 	reset_control_assert(pcie->afi_rst);
 
-	clk_disable_unprepare(pcie->pll_e);
-	if (soc->has_cml_clk)
-		clk_disable_unprepare(pcie->cml_clk);
-	clk_disable_unprepare(pcie->afi_clk);
+	clk_bulk_disable_unprepare(pcie->num_clks, pcie->clks);
 
 	if (!dev->pm_domain)
 		tegra_powergate_power_off(TEGRA_POWERGATE_PCIE);
@@ -1174,7 +1167,6 @@ static void tegra_pcie_power_off(struct tegra_pcie *pcie)
 static int tegra_pcie_power_on(struct tegra_pcie *pcie)
 {
 	struct device *dev = pcie->dev;
-	const struct tegra_pcie_soc *soc = pcie->soc;
 	int err;
 
 	reset_control_assert(pcie->pcie_xrst);
@@ -1202,35 +1194,16 @@ static int tegra_pcie_power_on(struct tegra_pcie *pcie)
 		}
 	}
 
-	err = clk_prepare_enable(pcie->afi_clk);
+	err = clk_bulk_prepare_enable(pcie->num_clks, pcie->clks);
 	if (err < 0) {
-		dev_err(dev, "failed to enable AFI clock: %d\n", err);
+		dev_err(dev, "filed to enable clocks: %d\n", err);
 		goto powergate;
 	}
 
-	if (soc->has_cml_clk) {
-		err = clk_prepare_enable(pcie->cml_clk);
-		if (err < 0) {
-			dev_err(dev, "failed to enable CML clock: %d\n", err);
-			goto disable_afi_clk;
-		}
-	}
-
-	err = clk_prepare_enable(pcie->pll_e);
-	if (err < 0) {
-		dev_err(dev, "failed to enable PLLE clock: %d\n", err);
-		goto disable_cml_clk;
-	}
-
 	reset_control_deassert(pcie->afi_rst);
 
 	return 0;
 
-disable_cml_clk:
-	if (soc->has_cml_clk)
-		clk_disable_unprepare(pcie->cml_clk);
-disable_afi_clk:
-	clk_disable_unprepare(pcie->afi_clk);
 powergate:
 	if (!dev->pm_domain)
 		tegra_powergate_power_off(TEGRA_POWERGATE_PCIE);
@@ -1254,25 +1227,11 @@ static void tegra_pcie_apply_pad_settings(struct tegra_pcie *pcie)
 static int tegra_pcie_clocks_get(struct tegra_pcie *pcie)
 {
 	struct device *dev = pcie->dev;
-	const struct tegra_pcie_soc *soc = pcie->soc;
-
-	pcie->pex_clk = devm_clk_get(dev, "pex");
-	if (IS_ERR(pcie->pex_clk))
-		return PTR_ERR(pcie->pex_clk);
 
-	pcie->afi_clk = devm_clk_get(dev, "afi");
-	if (IS_ERR(pcie->afi_clk))
-		return PTR_ERR(pcie->afi_clk);
-
-	pcie->pll_e = devm_clk_get(dev, "pll_e");
-	if (IS_ERR(pcie->pll_e))
-		return PTR_ERR(pcie->pll_e);
-
-	if (soc->has_cml_clk) {
-		pcie->cml_clk = devm_clk_get(dev, "cml");
-		if (IS_ERR(pcie->cml_clk))
-			return PTR_ERR(pcie->cml_clk);
-	}
+	pcie->num_clks = devm_clk_bulk_get_all(dev, &pcie->clks);
+	if (pcie->num_clks < 0)
+		return dev_err_probe(dev, pcie->num_clks,
+				     "failed to get clocks\n");
 
 	return 0;
 }
@@ -2345,7 +2304,6 @@ static const struct tegra_pcie_soc tegra20_pcie = {
 	.has_pex_clkreq_en = false,
 	.has_pex_bias_ctrl = false,
 	.has_intr_prsnt_sense = false,
-	.has_cml_clk = false,
 	.has_gen2 = false,
 	.force_pca_enable = false,
 	.program_uphy = true,
@@ -2374,7 +2332,6 @@ static const struct tegra_pcie_soc tegra30_pcie = {
 	.has_pex_clkreq_en = true,
 	.has_pex_bias_ctrl = true,
 	.has_intr_prsnt_sense = true,
-	.has_cml_clk = true,
 	.has_gen2 = false,
 	.force_pca_enable = false,
 	.program_uphy = true,
@@ -2395,7 +2352,6 @@ static const struct tegra_pcie_soc tegra124_pcie = {
 	.has_pex_clkreq_en = true,
 	.has_pex_bias_ctrl = true,
 	.has_intr_prsnt_sense = true,
-	.has_cml_clk = true,
 	.has_gen2 = true,
 	.force_pca_enable = false,
 	.program_uphy = true,
@@ -2418,7 +2374,6 @@ static const struct tegra_pcie_soc tegra210_pcie = {
 	.has_pex_clkreq_en = true,
 	.has_pex_bias_ctrl = true,
 	.has_intr_prsnt_sense = true,
-	.has_cml_clk = true,
 	.has_gen2 = true,
 	.force_pca_enable = true,
 	.program_uphy = true,
@@ -2459,7 +2414,6 @@ static const struct tegra_pcie_soc tegra186_pcie = {
 	.has_pex_clkreq_en = true,
 	.has_pex_bias_ctrl = true,
 	.has_intr_prsnt_sense = true,
-	.has_cml_clk = false,
 	.has_gen2 = true,
 	.force_pca_enable = false,
 	.program_uphy = false,
@@ -2672,7 +2626,7 @@ static int tegra_pcie_pm_suspend(struct device *dev)
 	}
 
 	reset_control_assert(pcie->pex_rst);
-	clk_disable_unprepare(pcie->pex_clk);
+	clk_bulk_disable_unprepare(pcie->num_clks, pcie->clks);
 
 	if (IS_ENABLED(CONFIG_PCI_MSI))
 		tegra_pcie_disable_msi(pcie);
@@ -2706,9 +2660,9 @@ static int tegra_pcie_pm_resume(struct device *dev)
 	if (IS_ENABLED(CONFIG_PCI_MSI))
 		tegra_pcie_enable_msi(pcie);
 
-	err = clk_prepare_enable(pcie->pex_clk);
+	err = clk_bulk_prepare_enable(pcie->num_clks, pcie->clks);
 	if (err) {
-		dev_err(dev, "failed to enable PEX clock: %d\n", err);
+		dev_err(dev, "failed to enable clock: %d\n", err);
 		goto pex_dpd_enable;
 	}
 
@@ -2729,7 +2683,6 @@ static int tegra_pcie_pm_resume(struct device *dev)
 
 disable_pex_clk:
 	reset_control_assert(pcie->pex_rst);
-	clk_disable_unprepare(pcie->pex_clk);
 pex_dpd_enable:
 	pinctrl_pm_select_idle_state(dev);
 poweroff:
-- 
2.50.1