[RESEND,v5,1/1] clk: mstar: msc313 cpupll clk driver

Message ID	20220603190509.45986-2-romain.perier@gmail.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org> From: Romain Perier <romain.perier@gmail.com> To: Michael Turquette <mturquette@baylibre.com>, Stephen Boyd <sboyd@kernel.org>, linux-clk@vger.kernel.org, Daniel Palmer <daniel@0x0f.com>, Romain Perier <romain.perier@gmail.com> Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Willy Tarreau <w@1wt.eu> Subject: [PATCH RESEND v5 1/1] clk: mstar: msc313 cpupll clk driver Date: Fri, 3 Jun 2022 21:05:09 +0200 Message-Id: <20220603190509.45986-2-romain.perier@gmail.com> In-Reply-To: <20220603190509.45986-1-romain.perier@gmail.com> References: <20220603190509.45986-1-romain.perier@gmail.com> MIME-Version: 1.0 Precedence: list Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org
Series	ARM: mstar: cpupll \| expand [RESEND,v5,0/1] ARM: mstar: cpupll [RESEND,v5,1/1] clk: mstar: msc313 cpupll clk driver

diff --git a/drivers/clk/mstar/Kconfig b/drivers/clk/mstar/Kconfig index de37e1bce2d2..146eeb637318 100644 --- a/drivers/clk/mstar/Kconfig +++ b/drivers/clk/mstar/Kconfig @@ -1,4 +1,11 @@ # SPDX-License-Identifier: GPL-2.0-only +config MSTAR_MSC313_CPUPLL + bool "MStar CPUPLL driver" + depends on ARCH_MSTARV7 || COMPILE_TEST + default ARCH_MSTARV7 + help + Support for the CPU PLL present on MStar/Sigmastar SoCs. + config MSTAR_MSC313_MPLL bool "MStar MPLL driver" depends on ARCH_MSTARV7 || COMPILE_TEST @@ -7,3 +14,4 @@ config MSTAR_MSC313_MPLL help Support for the MPLL PLL and dividers block present on MStar/Sigmastar SoCs. + diff --git a/drivers/clk/mstar/Makefile b/drivers/clk/mstar/Makefile index f8dcd25ede1d..21296a04e65a 100644 --- a/drivers/clk/mstar/Makefile +++ b/drivers/clk/mstar/Makefile @@ -2,5 +2,5 @@ # # Makefile for mstar specific clk # - +obj-$(CONFIG_MSTAR_MSC313_CPUPLL) += clk-msc313-cpupll.o obj-$(CONFIG_MSTAR_MSC313_MPLL) += clk-msc313-mpll.o diff --git a/drivers/clk/mstar/clk-msc313-cpupll.c b/drivers/clk/mstar/clk-msc313-cpupll.c new file mode 100644 index 000000000000..c57b509e8c20 --- /dev/null +++ b/drivers/clk/mstar/clk-msc313-cpupll.c @@ -0,0 +1,221 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 Daniel Palmer <daniel@thingy.jp> + */ + +#include <linux/clk-provider.h> +#include <linux/of_address.h> +#include <linux/platform_device.h> + +/* + * This IP is not documented outside of the messy vendor driver. + * Below is what we think the registers look like based on looking at + * the vendor code and poking at the hardware: + * + * 0x140 -- LPF low. Seems to store one half of the clock transition + * 0x144 / + * 0x148 -- LPF high. Seems to store one half of the clock transition + * 0x14c / + * 0x150 -- vendor code says "toggle lpf enable" + * 0x154 -- mu? + * 0x15c -- lpf_update_count? + * 0x160 -- vendor code says "switch to LPF". Clock source config? Register bank? + * 0x164 -- vendor code says "from low to high" which seems to mean transition from LPF low to + * LPF high. + * 0x174 -- Seems to be the PLL lock status bit + * 0x180 -- Seems to be the current frequency, this might need to be populated by software? + * 0x184 / The vendor driver uses these to set the initial value of LPF low + * + * Frequency seems to be calculated like this: + * (parent clock (432mhz) / register_magic_value) * 16 * 524288 + * Only the lower 24 bits of the resulting value will be used. In addition, the + * PLL doesn't seem to be able to lock on frequencies lower than 220 MHz, as + * divisor 0xfb586f (220 MHz) works but 0xfb7fff locks up. + * + * Vendor values: + * frequency - register value + * + * 400000000 - 0x0067AE14 + * 600000000 - 0x00451EB8, + * 800000000 - 0x0033D70A, + * 1000000000 - 0x002978d4, + */ + +#define REG_LPF_LOW_L 0x140 +#define REG_LPF_LOW_H 0x144 +#define REG_LPF_HIGH_BOTTOM 0x148 +#define REG_LPF_HIGH_TOP 0x14c +#define REG_LPF_TOGGLE 0x150 +#define REG_LPF_MYSTERYTWO 0x154 +#define REG_LPF_UPDATE_COUNT 0x15c +#define REG_LPF_MYSTERYONE 0x160 +#define REG_LPF_TRANSITIONCTRL 0x164 +#define REG_LPF_LOCK 0x174 +#define REG_CURRENT 0x180 + +#define LPF_LOCK_TIMEOUT 100000000 + +#define MULTIPLIER_1 16 +#define MULTIPLIER_2 524288 +#define MULTIPLIER (MULTIPLIER_1 * MULTIPLIER_2) + +struct msc313_cpupll { + void __iomem *base; + struct clk_hw clk_hw; +}; + +#define to_cpupll(_hw) container_of(_hw, struct msc313_cpupll, clk_hw) + +static u32 msc313_cpupll_reg_read32(struct msc313_cpupll *cpupll, unsigned int reg) +{ + u32 value; + + value = ioread16(cpupll->base + reg + 4) << 16; + value |= ioread16(cpupll->base + reg); + + return value; +} + +static void msc313_cpupll_reg_write32(struct msc313_cpupll *cpupll, unsigned int reg, u32 value) +{ + u16 l = value & 0xffff, h = (value >> 16) & 0xffff; + + iowrite16(l, cpupll->base + reg); + iowrite16(h, cpupll->base + reg + 4); +} + +static void msc313_cpupll_setfreq(struct msc313_cpupll *cpupll, u32 regvalue) +{ + ktime_t timeout; + + msc313_cpupll_reg_write32(cpupll, REG_LPF_HIGH_BOTTOM, regvalue); + + iowrite16(0x1, cpupll->base + REG_LPF_MYSTERYONE); + iowrite16(0x6, cpupll->base + REG_LPF_MYSTERYTWO); + iowrite16(0x8, cpupll->base + REG_LPF_UPDATE_COUNT); + iowrite16(BIT(12), cpupll->base + REG_LPF_TRANSITIONCTRL); + + iowrite16(0, cpupll->base + REG_LPF_TOGGLE); + iowrite16(1, cpupll->base + REG_LPF_TOGGLE); + + timeout = ktime_add_ns(ktime_get(), LPF_LOCK_TIMEOUT); + while (!(ioread16(cpupll->base + REG_LPF_LOCK))) { + if (ktime_after(ktime_get(), timeout)) { + pr_err("timeout waiting for LPF_LOCK\n"); + return; + } + cpu_relax(); + } + + iowrite16(0, cpupll->base + REG_LPF_TOGGLE); + + msc313_cpupll_reg_write32(cpupll, REG_LPF_LOW_L, regvalue); +} + +static unsigned long msc313_cpupll_frequencyforreg(u32 reg, unsigned long parent_rate) +{ + unsigned long long prescaled = ((unsigned long long)parent_rate) * MULTIPLIER; + + if (prescaled == 0 || reg == 0) + return 0; + return DIV_ROUND_DOWN_ULL(prescaled, reg); +} + +static u32 msc313_cpupll_regforfrequecy(unsigned long rate, unsigned long parent_rate) +{ + unsigned long long prescaled = ((unsigned long long)parent_rate) * MULTIPLIER; + + if (prescaled == 0 || rate == 0) + return 0; + return DIV_ROUND_UP_ULL(prescaled, rate); +} + +static unsigned long msc313_cpupll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate) +{ + struct msc313_cpupll *cpupll = to_cpupll(hw); + + return msc313_cpupll_frequencyforreg(msc313_cpupll_reg_read32(cpupll, REG_LPF_LOW_L), + parent_rate); +} + +static long msc313_cpupll_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + u32 reg = msc313_cpupll_regforfrequecy(rate, *parent_rate); + long rounded = msc313_cpupll_frequencyforreg(reg, *parent_rate); + + /* + * This is my poor attempt at making sure the resulting + * rate doesn't overshoot the requested rate. + */ + for (; rounded >= rate && reg > 0; reg--) + rounded = msc313_cpupll_frequencyforreg(reg, *parent_rate); + + return rounded; +} + +static int msc313_cpupll_set_rate(struct clk_hw *hw, unsigned long rate, unsigned long parent_rate) +{ + struct msc313_cpupll *cpupll = to_cpupll(hw); + u32 reg = msc313_cpupll_regforfrequecy(rate, parent_rate); + + msc313_cpupll_setfreq(cpupll, reg); + + return 0; +} + +static const struct clk_ops msc313_cpupll_ops = { + .recalc_rate = msc313_cpupll_recalc_rate, + .round_rate = msc313_cpupll_round_rate, + .set_rate = msc313_cpupll_set_rate, +}; + +static const struct of_device_id msc313_cpupll_of_match[] = { + { .compatible = "mstar,msc313-cpupll" }, + {} +}; + +static const struct clk_parent_data cpupll_parent = { + .index = 0, +}; + +static int msc313_cpupll_probe(struct platform_device *pdev) +{ + struct clk_init_data clk_init = {}; + struct device *dev = &pdev->dev; + struct msc313_cpupll *cpupll; + int ret; + + cpupll = devm_kzalloc(&pdev->dev, sizeof(*cpupll), GFP_KERNEL); + if (!cpupll) + return -ENOMEM; + + cpupll->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(cpupll->base)) + return PTR_ERR(cpupll->base); + + /* LPF might not contain the current frequency so fix that up */ + msc313_cpupll_reg_write32(cpupll, REG_LPF_LOW_L, + msc313_cpupll_reg_read32(cpupll, REG_CURRENT)); + + clk_init.name = dev_name(dev); + clk_init.ops = &msc313_cpupll_ops; + clk_init.parent_data = &cpupll_parent; + clk_init.num_parents = 1; + cpupll->clk_hw.init = &clk_init; + + ret = devm_clk_hw_register(dev, &cpupll->clk_hw); + if (ret) + return ret; + + return of_clk_add_hw_provider(pdev->dev.of_node, of_clk_hw_simple_get, &cpupll->clk_hw); +} + +static struct platform_driver msc313_cpupll_driver = { + .driver = { + .name = "mstar-msc313-cpupll", + .of_match_table = msc313_cpupll_of_match, + }, + .probe = msc313_cpupll_probe, +}; +builtin_platform_driver(msc313_cpupll_driver);

[RESEND,v5,1/1] clk: mstar: msc313 cpupll clk driver

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