[PATCH 2/2 v4] clk: Add Gemini SoC clock controller
Stephen Boyd
sboyd at codeaurora.org
Thu Jun 1 00:02:08 PDT 2017
On 05/24, Linus Walleij wrote:
> diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
> index 36cfea38135f..69178fd58ac8 100644
> --- a/drivers/clk/Kconfig
> +++ b/drivers/clk/Kconfig
> @@ -126,6 +126,13 @@ config COMMON_CLK_CS2000_CP
> help
> If you say yes here you get support for the CS2000 clock multiplier.
>
> +config COMMON_CLK_GEMINI
> + bool "Clock driver for Cortina Systems Gemini SoC"
> + select MFD_SYSCON
Is there an appropriate depends on ARCH_FOO || COMPILE_TEST we
can put here? Just so that this isn't exposed to people who dont'
like seeing options they don't care about but we still get
compile testing coverage.
> + ---help---
> + This driver supports the SoC clocks on the Cortina Systems Gemini
> + platform, also known as SL3516 or CS3516.
> +
> config COMMON_CLK_S2MPS11
> tristate "Clock driver for S2MPS1X/S5M8767 MFD"
> depends on MFD_SEC_CORE || COMPILE_TEST
> diff --git a/drivers/clk/clk-gemini.c b/drivers/clk/clk-gemini.c
> new file mode 100644
> index 000000000000..5a0de8415f91
> --- /dev/null
> +++ b/drivers/clk/clk-gemini.c
> @@ -0,0 +1,357 @@
> +/*
> + * Cortina Gemini Clock Controller driver
> + * Copyright (c) 2017 Linus Walleij <linus.walleij at linaro.org>
> + */
> +
> +#define pr_fmt(fmt) "clk-gemini: " fmt
> +
> +#include <linux/clkdev.h>
Used?
> +#include <linux/slab.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/clk-provider.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
> +#include <dt-bindings/clock/cortina,gemini-clock.h>
> +
> +/* Globally visible clocks */
> +static DEFINE_SPINLOCK(gemini_clk_lock);
Include spinlock.h?
> +static struct clk *gemini_clks[GEMINI_NUM_CLKS];
> +static struct clk_onecell_data gemini_clk_data;
> +
> +#define GEMINI_GLOBAL_STATUS 0x04
> +#define PLL_OSC_SEL BIT(30)
> +#define AHBSPEED_SHIFT (15)
> +#define AHBSPEED_MASK 0x07
> +#define CPU_AHB_RATIO_SHIFT (18)
> +#define CPU_AHB_RATIO_MASK 0x03
> +
> +#define GEMINI_GLOBAL_PLL_CONTROL 0x08
> +
> +#define GEMINI_GLOBAL_MISC_CONTROL 0x30
> +#define PCI_CLK_66MHZ BIT(18)
> +#define PCI_CLK_OE BIT(17)
> +
> +#define GEMINI_GLOBAL_CLOCK_CONTROL 0x34
> +#define PCI_CLKRUN_EN BIT(16)
> +#define TVC_HALFDIV_SHIFT (24)
> +#define TVC_HALFDIV_MASK 0x1f
> +#define SECURITY_CLK_SEL BIT(29)
> +
> +#define GEMINI_GLOBAL_PCI_DLL_CONTROL 0x44
> +#define PCI_DLL_BYPASS BIT(31)
> +#define PCI_DLL_TAP_SEL_MASK 0x1f
Can these get some tabs to align up the numbers in each line? My
eyes can't easily read the values from the defines.
> +
> +struct gemini_gate_data {
This one doesn't get kernel doc? :(
> + u8 bit_idx;
> + const char *name;
> + const char *parent_name;
> + unsigned long flags;
> +};
> +
> +/**
> + * struct clk_gemini_pci - Gemini PCI clock
> + * @hw: corresponding clock hardware entry
> + * @map: regmap to access the registers
> + * @rate: current rate
> + */
> +struct clk_gemini_pci {
> + struct clk_hw hw;
> + struct regmap *map;
> + unsigned long rate;
> +};
> +
> +/*
> + * FIXME: some clocks are marked as CLK_IGNORE_UNUSED: this is
> + * because their kernel drivers lack proper clock handling so we
> + * need to avoid them being gated off by default. Remove this as
> + * the drivers get fixed to handle clocks properly.
> + *
> + * The DDR controller may never have a driver, but certainly must
> + * not be gated off.
You can use CLK_IS_CRITICAL for that then.
> + */
> +static const struct gemini_gate_data gemini_gates[] __initconst = {
> + { 1, "security-gate", "secdiv", 0 },
> + { 2, "gmac0-gate", "ahb", 0 },
> + { 3, "gmac1-gate", "ahb", 0 },
> + { 4, "sata0-gate", "ahb", 0 },
> + { 5, "sata1-gate", "ahb", 0 },
> + { 6, "usb0-gate", "ahb", 0 },
> + { 7, "usb1-gate", "ahb", 0 },
> + { 8, "ide-gate", "ahb", 0 },
> + { 9, "pci-gate", "ahb", 0 },
> + { 10, "ddr-gate", "ahb", CLK_IGNORE_UNUSED },
> + { 11, "flash-gate", "ahb", CLK_IGNORE_UNUSED },
> + { 12, "tvc-gate", "ahb", 0 },
> + { 13, "boot-gate", "apb", 0 },
> +};
> +
[..]
> +
> +static void gemini_pci_disable(struct clk_hw *hw)
> +{
> + struct clk_gemini_pci *pciclk = to_pciclk(hw);
> +
> + regmap_update_bits(pciclk->map,
The regmap is atomic right? Just checking to make sure we aren't
taking a mutex instead of a spinlock inside these ops.
> + GEMINI_GLOBAL_MISC_CONTROL,
> + PCI_CLK_OE, 0);
> + regmap_update_bits(pciclk->map, GEMINI_GLOBAL_CLOCK_CONTROL,
> + PCI_CLKRUN_EN, 0);
And regmap writes can't fail right?
> +}
> +
[..]
> +
> +static struct clk *gemini_pci_clk_setup(const char *name,
Would need to be marked __init if this doesn't become a platform
driver.
> + const char *parent_name,
> + struct regmap *map)
> +{
> + struct clk_gemini_pci *pciclk;
> + struct clk_init_data init;
> + struct clk *clk;
> +
> + pciclk = kzalloc(sizeof(*pciclk), GFP_KERNEL);
> + if (!pciclk)
> + return ERR_PTR(-ENOMEM);
> +
> + init.name = name;
> + init.ops = &gemini_pci_clk_ops;
> + init.flags = 0;
> + init.parent_names = (parent_name ? &parent_name : NULL);
> + init.num_parents = (parent_name ? 1 : 0);
There's always a parent name though?
> + pciclk->map = map;
> + pciclk->hw.init = &init;
> +
> + clk = clk_register(NULL, &pciclk->hw);
> + if (IS_ERR(clk))
> + kfree(pciclk);
> +
> + return clk;
> +}
> +
> +static void __init gemini_cc_init(struct device_node *np)
> +{
> + void __iomem *base;
> + struct regmap *map;
> + struct clk *clk;
> + unsigned int mult, div;
> + unsigned long freq;
> + u32 val;
> + int ret;
> + int i;
> +
> + /* Remap the system controller for the exclusive register */
> + base = of_iomap(np, 0);
> + if (!base) {
> + pr_err("no memory base\n");
> + return;
> + }
> + map = syscon_node_to_regmap(np);
> + if (IS_ERR(map)) {
> + pr_err("no syscon regmap\n");
> + return;
> + }
> +
> + /* RTC clock 32768 Hz */
> + clk = clk_register_fixed_rate(NULL, "rtc", NULL, CLK_IGNORE_UNUSED,
> + 32768);
> + gemini_clks[GEMINI_CLK_RTC] = clk;
> +
> + ret = regmap_read(map, GEMINI_GLOBAL_STATUS, &val);
> + if (ret) {
> + pr_err("failed to read global status register\n");
> + return;
> + }
> +
> + /*
> + * XTAL is the crystal oscillator, 60 or 30 MHz selected from
> + * strap pin E6
> + */
> + if (val & PLL_OSC_SEL)
> + freq = 30000000;
> + else
> + freq = 60000000;
> + clk = clk_register_fixed_rate(NULL, "xtal", NULL, CLK_IGNORE_UNUSED,
The CLK_IGNORE_UNUSED is not really meaningful because fixed rate
clks don't have enable/disable ops. Please remove the flag from
all fixed rate clk registrations.
> + freq);
> + pr_info("main crystal @%lu MHz\n", (freq/1000000));
Please add space around that freq / 1000000.
> +
> + /* VCO clock derived from the crystal */
> + mult = 13 + ((val >> AHBSPEED_SHIFT) & AHBSPEED_MASK);
> + div = 2;
> + /* If we run on 30 Mhz crystal we have to multiply with two */
s/Mhz/MHz/
> + if (val & PLL_OSC_SEL)
> + mult *= 2;
> + clk = clk_register_fixed_factor(NULL, "vco", "xtal", CLK_IGNORE_UNUSED,
> + mult, div);
Drop ignore unused flag.
> +
> + /* The AHB clock is always 1/3 of the VCO */
> + clk = clk_register_fixed_factor(NULL, "ahb", "vco",
> + CLK_IGNORE_UNUSED, 1, 3);
Drop ignore unused flag.
Also, please move to using clk_hw_register*() APIs so that clk
pointers aren't used in this provider driver.
> + gemini_clks[GEMINI_CLK_AHB] = clk;
> +
> + /* The APB clock is always 1/6 of the AHB */
> + clk = clk_register_fixed_factor(NULL, "apb", "ahb",
> + CLK_IGNORE_UNUSED, 1, 6);
> + gemini_clks[GEMINI_CLK_APB] = clk;
> +
> + /* CPU clock derived as a fixed ratio from the AHB clock */
> + switch ((val >> CPU_AHB_RATIO_SHIFT) & CPU_AHB_RATIO_MASK) {
> + case 0x0:
> + /* 1x */
> + mult = 1;
> + div = 1;
> + break;
> + case 0x1:
> + /* 1.5x */
> + mult = 3;
> + div = 2;
> + break;
> + case 0x2:
> + /* 1.85x */
> + mult = 24;
> + div = 13;
> + break;
> + case 0x3:
> + /* 2x */
> + mult = 2;
> + div = 1;
> + break;
Could this be an array of mult/div pairs that we index directly?
Would save some lines and save lives! Well maybe not that last
part.
> + }
> + clk = clk_register_fixed_factor(NULL, "cpu", "ahb",
> + CLK_IGNORE_UNUSED, mult, div);
> + gemini_clks[GEMINI_CLK_CPU] = clk;
> +
> + /* Security clock is 1:1 or 0.75 of APB */
> + ret = regmap_read(map, GEMINI_GLOBAL_CLOCK_CONTROL, &val);
> + if (ret) {
> + pr_err("failed to read global clock control register\n");
> + return;
> + }
> + if (val & SECURITY_CLK_SEL) {
> + mult = 1;
> + div = 1;
> + } else {
> + mult = 3;
> + div = 4;
> + }
> + clk = clk_register_fixed_factor(NULL, "secdiv", "ahb",
> + 0, mult, div);
> +
> + /*
> + * These are the leaf gates, at boot no clocks are gated.
> + */
> + for (i = 0; i < ARRAY_SIZE(gemini_gates); i++) {
> + const struct gemini_gate_data *gd;
> +
> + gd = &gemini_gates[i];
> + gemini_clks[GEMINI_CLK_GATES + i] =
> + clk_register_gate(NULL, gd->name,
clk_hw_register_gate().
> + gd->parent_name,
> + gd->flags,
> + base + GEMINI_GLOBAL_CLOCK_CONTROL,
> + gd->bit_idx,
> + CLK_GATE_SET_TO_DISABLE,
> + &gemini_clk_lock);
> + }
> +
> + /*
> + * The TV Interface Controller has a 5-bit half divider register.
> + * This clock is supposed to be 27MHz as this is an exact multiple
> + * of PAL and NTSC frequencies. The register is undocumented :(
> + * FIXME: figure out the parent and how the divider works.
> + */
> + mult = 1;
> + div = ((val >> TVC_HALFDIV_SHIFT) & TVC_HALFDIV_MASK);
> + pr_debug("TVC half divider value = %d\n", div);
> + div += 1;
> + clk = clk_register_fixed_rate(NULL, "tvcdiv", "xtal", 0, 27000000);
> + gemini_clks[GEMINI_CLK_TVC] = clk;
> +
> + /* FIXME: very unclear what the parent is */
> + clk = gemini_pci_clk_setup("PCI", "xtal", map);
> + gemini_clks[GEMINI_CLK_PCI] = clk;
> +
> + /* FIXME: very unclear what the parent is */
> + clk = clk_register_fixed_rate(NULL, "uart", "xtal", CLK_IGNORE_UNUSED,
> + 48000000);
> + gemini_clks[GEMINI_CLK_UART] = clk;
> +
> + /* Register the clocks to be accessed by the device tree */
> + gemini_clk_data.clks = gemini_clks;
> + gemini_clk_data.clk_num = ARRAY_SIZE(gemini_clks);
> + of_clk_add_provider(np, of_clk_src_onecell_get, &gemini_clk_data);
And of_clk_add_hw_provider().
> +}
> +CLK_OF_DECLARE_DRIVER(gemini_cc, "cortina,gemini-syscon", gemini_cc_init);
Is there a reason why this isn't a platform driver?
--
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