Re: [PATCH v16 1/1] clk: npcm8xx: add clock controller

From: Christophe JAILLET
Date: Sun May 21 2023 - 13:58:08 EST

Le 21/05/2023 à 16:32, Tomer Maimon a écrit :
Nuvoton Arbel BMC NPCM8XX contains an integrated clock controller which
generates and supplies clocks to all modules within the BMC.

Signed-off-by: Tomer Maimon <tmaimon77@xxxxxxxxx>

Hi,

should there be a v17, below a few nits and questions.

Jusrt my 2c,

---
drivers/clk/Kconfig | 8 +
drivers/clk/Makefile | 1 +
drivers/clk/clk-npcm8xx.c | 566 ++++++++++++++++++++++++++++++++++++++
3 files changed, 575 insertions(+)
create mode 100644 drivers/clk/clk-npcm8xx.c

diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 016814e15536..2249de28a46a 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -325,6 +325,14 @@ config COMMON_CLK_LOCHNAGAR
This driver supports the clocking features of the Cirrus Logic
Lochnagar audio development board.
+config COMMON_CLK_NPCM8XX
+ tristate "Clock driver for the NPCM8XX SoC Family"
+ depends on ARCH_NPCM || COMPILE_TEST
+ help
+ This driver supports the clocks on the Nuvoton BMC NPCM8XX SoC Family,
+ all the clocks are initialized by the bootloader, so this driver
+ allows only reading of current settings directly from the hardware.
+
config COMMON_CLK_LOONGSON2
bool "Clock driver for Loongson-2 SoC"
depends on LOONGARCH || COMPILE_TEST
diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index 0aebef17edc6..88713cbfbab5 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_ARCH_MILBEAUT_M10V) += clk-milbeaut.o
obj-$(CONFIG_ARCH_MOXART) += clk-moxart.o
obj-$(CONFIG_ARCH_NOMADIK) += clk-nomadik.o
obj-$(CONFIG_ARCH_NPCM7XX) += clk-npcm7xx.o
+obj-$(CONFIG_COMMON_CLK_NPCM8XX) += clk-npcm8xx.o
obj-$(CONFIG_ARCH_NSPIRE) += clk-nspire.o
obj-$(CONFIG_COMMON_CLK_OXNAS) += clk-oxnas.o
obj-$(CONFIG_COMMON_CLK_PALMAS) += clk-palmas.o
diff --git a/drivers/clk/clk-npcm8xx.c b/drivers/clk/clk-npcm8xx.c
new file mode 100644
index 000000000000..9e6ed073d124
--- /dev/null
+++ b/drivers/clk/clk-npcm8xx.c
@@ -0,0 +1,566 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Nuvoton NPCM8xx Clock Generator
+ * All the clocks are initialized by the bootloader, so this driver allow only

nit: allows (as in Kconfig)

[...]

+/* npcm8xx clock registers*/
+#define NPCM8XX_CLKSEL (0x04)
+#define NPCM8XX_CLKDIV1 (0x08)
+#define NPCM8XX_CLKDIV2 (0x2C)
+#define NPCM8XX_CLKDIV3 (0x58)
+#define NPCM8XX_CLKDIV4 (0x7C)
+#define NPCM8XX_PLLCON0 (0x0C)
+#define NPCM8XX_PLLCON1 (0x10)
+#define NPCM8XX_PLLCON2 (0x54)
+#define NPCM8XX_PLLCONG (0x60)
+#define NPCM8XX_THRTL_CNT (0xC0)

nit: () around this values looks superfluous.

+
+#define PLLCON_LOKI BIT(31)
+#define PLLCON_LOKS BIT(30)

[...]

+static struct clk_hw *
+npcm8xx_clk_register_pll(struct device *dev, void __iomem *pllcon,
+ const char *name, const struct clk_parent_data *parent,
+ unsigned long flags)
+{
+ struct npcm8xx_clk_pll *pll;
+ struct clk_init_data init = {};
+ int ret;
+
+ pll = kzalloc(sizeof(*pll), GFP_KERNEL);

Everything looks devm_()'ed in this driver, except this kzalloc.
Except the one below, there is no kfree to free this memory, and no .remove() function.

Is it on purpose?

+ if (!pll)
+ return ERR_PTR(-ENOMEM);
+
+ init.name = name;
+ init.ops = &npcm8xx_clk_pll_ops;
+ init.parent_data = parent;
+ init.num_parents = 1;
+ init.flags = flags;
+
+ pll->pllcon = pllcon;
+ pll->hw.init = &init;
+
+ ret = devm_clk_hw_register(dev, &pll->hw);
+ if (ret) {
+ kfree(pll);
+ return ERR_PTR(ret);
+ }
+
+ return &pll->hw;
+}
+
+static DEFINE_SPINLOCK(npcm8xx_clk_lock);
+
+static int npcm8xx_clk_probe(struct platform_device *pdev)
+{
+ struct clk_hw_onecell_data *npcm8xx_clk_data;
+ struct device *dev = &pdev->dev;
+ void __iomem *clk_base;
+ struct resource *res;
+ struct clk_hw *hw;
+ unsigned int i;
+ int err;
+
+ npcm8xx_clk_data = devm_kzalloc(dev, struct_size(npcm8xx_clk_data, hws,
+ NPCM8XX_NUM_CLOCKS),
+ GFP_KERNEL);
+ if (!npcm8xx_clk_data)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ clk_base = devm_ioremap(dev, res->start, resource_size(res));
+ if (!clk_base) {
+ dev_err(&pdev->dev, "Failed to remap I/O memory\n");

Here and below: mostly a matter of taste, but usually return dev_err_probe() saves a few LoC and keep the error code in the error message.

+ return -ENOMEM;
+ }
+
+ npcm8xx_clk_data->num = NPCM8XX_NUM_CLOCKS;
+
+ for (i = 0; i < NPCM8XX_NUM_CLOCKS; i++)
+ npcm8xx_clk_data->hws[i] = ERR_PTR(-EPROBE_DEFER);
+
+ /* Register plls */
+ for (i = 0; i < ARRAY_SIZE(npcm8xx_pll_clks); i++) {
+ struct npcm8xx_pll_data *pll_clk = &npcm8xx_pll_clks[i];
+
+ hw = npcm8xx_clk_register_pll(dev, clk_base + pll_clk->reg,
+ pll_clk->name, &pll_clk->parent,
+ pll_clk->flags);
+ if (IS_ERR(hw)) {
+ dev_err(dev, "npcm8xx_clk: Can't register pll\n");
+ return PTR_ERR(hw);
+ }
+ pll_clk->hw = *hw;
+ }
+
+ /* Register fixed dividers */
+ hw = devm_clk_hw_register_fixed_factor(dev, NPCM8XX_CLK_S_PLL1_DIV2,
+ NPCM8XX_CLK_S_PLL1, 0, 1, 2);
+ if (IS_ERR(hw)) {
+ dev_err(dev, "npcm8xx_clk: Can't register fixed div\n");
+ return PTR_ERR(hw);
+ }
+ hw_pll1_div2 = *hw;
+
+ hw = devm_clk_hw_register_fixed_factor(dev, NPCM8XX_CLK_S_PLL2_DIV2,
+ NPCM8XX_CLK_S_PLL2, 0, 1, 2);
+ if (IS_ERR(hw)) {
+ dev_err(dev, "npcm8xx_clk: Can't register pll2 div2\n");
+ return PTR_ERR(hw);
+ }
+ hw_pll2_div2 = *hw;
+
+ hw = devm_clk_hw_register_fixed_factor(dev, NPCM8XX_CLK_S_PLL_GFX_DIV2,
+ NPCM8XX_CLK_S_PLL_GFX, 0, 1, 2);
+ if (IS_ERR(hw)) {
+ dev_err(dev, "npcm8xx_clk: Can't register gfx div2\n");
+ return PTR_ERR(hw);
+ }
+ hw_gfx_div2 = *hw;
+
+ /* Register muxes */
+ for (i = 0; i < ARRAY_SIZE(npcm8xx_muxes); i++) {
+ struct npcm8xx_clk_mux_data *mux_data = &npcm8xx_muxes[i];
+
+ hw = devm_clk_hw_register_mux_parent_data_table(dev,
+ mux_data->name,
+ mux_data->parent_data,
+ mux_data->num_parents,
+ mux_data->flags,
+ clk_base + NPCM8XX_CLKSEL,
+ mux_data->shift,
+ mux_data->mask,
+ 0,
+ mux_data->table,
+ &npcm8xx_clk_lock);
+ if (IS_ERR(hw)) {
+ dev_err(dev, "npcm8xx_clk: Can't register mux\n");
+ return PTR_ERR(hw);
+ }
+ mux_data->hw = *hw;
+ }
+
+ hw = devm_clk_hw_register_fixed_factor(dev, NPCM8XX_CLK_S_PRE_CLK,
+ NPCM8XX_CLK_S_CPU_MUX, 0, 1, 2);
+ if (IS_ERR(hw)) {
+ dev_err(dev, "npcm8xx_clk: Can't register ckclk div2\n");

ckclk or just clk?

Based on naming only, this div2 (here and below) looks strange.
Is it on purpose, on just a cut'n'paste from the previous message?

+ return PTR_ERR(hw);
+ }
+ hw_pre_clk = *hw;
+
+ hw = devm_clk_hw_register_fixed_factor(dev, NPCM8XX_CLK_S_AXI,
+ NPCM8XX_CLK_S_TH, 0, 1, 2);
+ if (IS_ERR(hw)) {
+ dev_err(dev, "npcm8xx_clk: Can't register axi div2\n");
+ return PTR_ERR(hw);
+ }
+ npcm8xx_clk_data->hws[NPCM8XX_CLK_AXI] = hw;
+
+ hw = devm_clk_hw_register_fixed_factor(dev, NPCM8XX_CLK_S_ATB,
+ NPCM8XX_CLK_S_AXI, 0, 1, 2);
+ if (IS_ERR(hw)) {
+ dev_err(dev, "npcm8xx_clk: Can't register atb div2\n");
+ return PTR_ERR(hw);
+ }
+ npcm8xx_clk_data->hws[NPCM8XX_CLK_ATB] = hw;
+
+ /* Register clock dividers specified in npcm8xx_divs */
+ for (i = 0; i < ARRAY_SIZE(npcm8xx_divs); i++) {
+ const struct npcm8xx_clk_div_data *div_data = &npcm8xx_divs[i];
+
+ hw = clk_hw_register_divider_parent_data(dev, div_data->name,
+ &div_data->parent_data,
+ div_data->flags,
+ clk_base + div_data->reg,
+ div_data->shift,
+ div_data->width,
+ div_data->clk_divider_flags,
+ &npcm8xx_clk_lock);
+ if (IS_ERR(hw)) {
+ dev_err(dev, "npcm8xx_clk: Can't register div table\n");
+ goto err_div_clk;
+ }
+
+ if (div_data->onecell_idx >= 0)
+ npcm8xx_clk_data->hws[div_data->onecell_idx] = hw;
+ }
+
+ err = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
+ npcm8xx_clk_data);
+ if (err) {
+ dev_err(dev, "unable to add clk provider\n");
+ hw = ERR_PTR(err);
+ goto err_div_clk;
+ }
+
+ return err;
+
+err_div_clk:
+ while (i--) {
+ if (npcm8xx_divs[i].onecell_idx >= 0)
+ clk_hw_unregister_divider(npcm8xx_clk_data->hws[npcm8xx_divs[i].onecell_idx]);
+ }

There is an error handling path in the probe, but no .remove() function.
Should there be one?

CJ

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