diff options
Diffstat (limited to 'drivers/clk/clk-plldig.c')
| -rw-r--r-- | drivers/clk/clk-plldig.c | 286 |
1 files changed, 286 insertions, 0 deletions
diff --git a/drivers/clk/clk-plldig.c b/drivers/clk/clk-plldig.c new file mode 100644 index 000000000000..312b8312d503 --- /dev/null +++ b/drivers/clk/clk-plldig.c @@ -0,0 +1,286 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2019 NXP + * + * Clock driver for LS1028A Display output interfaces(LCD, DPHY). + */ + +#include <linux/clk-provider.h> +#include <linux/device.h> +#include <linux/module.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/iopoll.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/bitfield.h> + +/* PLLDIG register offsets and bit masks */ +#define PLLDIG_REG_PLLSR 0x24 +#define PLLDIG_LOCK_MASK BIT(2) +#define PLLDIG_REG_PLLDV 0x28 +#define PLLDIG_MFD_MASK GENMASK(7, 0) +#define PLLDIG_RFDPHI1_MASK GENMASK(30, 25) +#define PLLDIG_REG_PLLFM 0x2c +#define PLLDIG_SSCGBYP_ENABLE BIT(30) +#define PLLDIG_REG_PLLFD 0x30 +#define PLLDIG_FDEN BIT(30) +#define PLLDIG_FRAC_MASK GENMASK(15, 0) +#define PLLDIG_REG_PLLCAL1 0x38 +#define PLLDIG_REG_PLLCAL2 0x3c + +/* Range of the VCO frequencies, in Hz */ +#define PLLDIG_MIN_VCO_FREQ 650000000 +#define PLLDIG_MAX_VCO_FREQ 1300000000 + +/* Range of the output frequencies, in Hz */ +#define PHI1_MIN_FREQ 27000000UL +#define PHI1_MAX_FREQ 600000000UL + +/* Maximum value of the reduced frequency divider */ +#define MAX_RFDPHI1 63UL + +/* Best value of multiplication factor divider */ +#define PLLDIG_DEFAULT_MFD 44 + +/* + * Denominator part of the fractional part of the + * loop multiplication factor. + */ +#define MFDEN 20480 + +static const struct clk_parent_data parent_data[] = { + { .index = 0 }, +}; + +struct clk_plldig { + struct clk_hw hw; + void __iomem *regs; + unsigned int vco_freq; +}; + +#define to_clk_plldig(_hw) container_of(_hw, struct clk_plldig, hw) + +static int plldig_enable(struct clk_hw *hw) +{ + struct clk_plldig *data = to_clk_plldig(hw); + u32 val; + + val = readl(data->regs + PLLDIG_REG_PLLFM); + /* + * Use Bypass mode with PLL off by default, the frequency overshoot + * detector output was disable. SSCG Bypass mode should be enable. + */ + val |= PLLDIG_SSCGBYP_ENABLE; + writel(val, data->regs + PLLDIG_REG_PLLFM); + + return 0; +} + +static void plldig_disable(struct clk_hw *hw) +{ + struct clk_plldig *data = to_clk_plldig(hw); + u32 val; + + val = readl(data->regs + PLLDIG_REG_PLLFM); + + val &= ~PLLDIG_SSCGBYP_ENABLE; + val |= FIELD_PREP(PLLDIG_SSCGBYP_ENABLE, 0x0); + + writel(val, data->regs + PLLDIG_REG_PLLFM); +} + +static int plldig_is_enabled(struct clk_hw *hw) +{ + struct clk_plldig *data = to_clk_plldig(hw); + + return readl(data->regs + PLLDIG_REG_PLLFM) & + PLLDIG_SSCGBYP_ENABLE; +} + +static unsigned long plldig_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + struct clk_plldig *data = to_clk_plldig(hw); + u32 val, rfdphi1; + + val = readl(data->regs + PLLDIG_REG_PLLDV); + + /* Check if PLL is bypassed */ + if (val & PLLDIG_SSCGBYP_ENABLE) + return parent_rate; + + rfdphi1 = FIELD_GET(PLLDIG_RFDPHI1_MASK, val); + + /* + * If RFDPHI1 has a value of 1 the VCO frequency is also divided by + * one. + */ + if (!rfdphi1) + rfdphi1 = 1; + + return DIV_ROUND_UP(data->vco_freq, rfdphi1); +} + +static unsigned long plldig_calc_target_div(unsigned long vco_freq, + unsigned long target_rate) +{ + unsigned long div; + + div = DIV_ROUND_CLOSEST(vco_freq, target_rate); + div = clamp(div, 1UL, MAX_RFDPHI1); + + return div; +} + +static int plldig_determine_rate(struct clk_hw *hw, + struct clk_rate_request *req) +{ + struct clk_plldig *data = to_clk_plldig(hw); + unsigned int div; + + req->rate = clamp(req->rate, PHI1_MIN_FREQ, PHI1_MAX_FREQ); + div = plldig_calc_target_div(data->vco_freq, req->rate); + req->rate = DIV_ROUND_UP(data->vco_freq, div); + + return 0; +} + +static int plldig_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_plldig *data = to_clk_plldig(hw); + unsigned int val, cond; + unsigned int rfdphi1; + + rate = clamp(rate, PHI1_MIN_FREQ, PHI1_MAX_FREQ); + rfdphi1 = plldig_calc_target_div(data->vco_freq, rate); + + /* update the divider value */ + val = readl(data->regs + PLLDIG_REG_PLLDV); + val &= ~PLLDIG_RFDPHI1_MASK; + val |= FIELD_PREP(PLLDIG_RFDPHI1_MASK, rfdphi1); + writel(val, data->regs + PLLDIG_REG_PLLDV); + + /* waiting for old lock state to clear */ + udelay(200); + + /* Wait until PLL is locked or timeout */ + return readl_poll_timeout_atomic(data->regs + PLLDIG_REG_PLLSR, cond, + cond & PLLDIG_LOCK_MASK, 0, + USEC_PER_MSEC); +} + +static const struct clk_ops plldig_clk_ops = { + .enable = plldig_enable, + .disable = plldig_disable, + .is_enabled = plldig_is_enabled, + .recalc_rate = plldig_recalc_rate, + .determine_rate = plldig_determine_rate, + .set_rate = plldig_set_rate, +}; + +static int plldig_init(struct clk_hw *hw) +{ + struct clk_plldig *data = to_clk_plldig(hw); + struct clk_hw *parent = clk_hw_get_parent(hw); + unsigned long parent_rate = clk_hw_get_rate(parent); + unsigned long val; + unsigned long long lltmp; + unsigned int mfd, fracdiv = 0; + + if (!parent) + return -EINVAL; + + if (data->vco_freq) { + mfd = data->vco_freq / parent_rate; + lltmp = data->vco_freq % parent_rate; + lltmp *= MFDEN; + do_div(lltmp, parent_rate); + fracdiv = lltmp; + } else { + mfd = PLLDIG_DEFAULT_MFD; + data->vco_freq = parent_rate * mfd; + } + + val = FIELD_PREP(PLLDIG_MFD_MASK, mfd); + writel(val, data->regs + PLLDIG_REG_PLLDV); + + /* Enable fractional divider */ + if (fracdiv) { + val = FIELD_PREP(PLLDIG_FRAC_MASK, fracdiv); + val |= PLLDIG_FDEN; + writel(val, data->regs + PLLDIG_REG_PLLFD); + } + + return 0; +} + +static int plldig_clk_probe(struct platform_device *pdev) +{ + struct clk_plldig *data; + struct device *dev = &pdev->dev; + int ret; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(data->regs)) + return PTR_ERR(data->regs); + + data->hw.init = CLK_HW_INIT_PARENTS_DATA("dpclk", + parent_data, + &plldig_clk_ops, + 0); + + ret = devm_clk_hw_register(dev, &data->hw); + if (ret) { + dev_err(dev, "failed to register %s clock\n", + dev->of_node->name); + return ret; + } + + ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, + &data->hw); + if (ret) { + dev_err(dev, "unable to add clk provider\n"); + return ret; + } + + /* + * The frequency of the VCO cannot be changed during runtime. + * Therefore, let the user specify a desired frequency. + */ + if (!of_property_read_u32(dev->of_node, "fsl,vco-hz", + &data->vco_freq)) { + if (data->vco_freq < PLLDIG_MIN_VCO_FREQ || + data->vco_freq > PLLDIG_MAX_VCO_FREQ) + return -EINVAL; + } + + return plldig_init(&data->hw); +} + +static const struct of_device_id plldig_clk_id[] = { + { .compatible = "fsl,ls1028a-plldig" }, + { } +}; +MODULE_DEVICE_TABLE(of, plldig_clk_id); + +static struct platform_driver plldig_clk_driver = { + .driver = { + .name = "plldig-clock", + .of_match_table = plldig_clk_id, + }, + .probe = plldig_clk_probe, +}; +module_platform_driver(plldig_clk_driver); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Wen He <wen.he_1@nxp.com>"); +MODULE_DESCRIPTION("LS1028A Display output interface pixel clock driver"); 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