diff options
Diffstat (limited to 'drivers/clk/nxp/clk-lpc18xx-creg.c')
| -rw-r--r-- | drivers/clk/nxp/clk-lpc18xx-creg.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/drivers/clk/nxp/clk-lpc18xx-creg.c b/drivers/clk/nxp/clk-lpc18xx-creg.c new file mode 100644 index 000000000000..d44b61afa2dc --- /dev/null +++ b/drivers/clk/nxp/clk-lpc18xx-creg.c @@ -0,0 +1,226 @@ +/* + * Clk driver for NXP LPC18xx/43xx Configuration Registers (CREG) + * + * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include <linux/clk-provider.h> +#include <linux/delay.h> +#include <linux/kernel.h> +#include <linux/mfd/syscon.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/regmap.h> + +#define LPC18XX_CREG_CREG0 0x004 +#define LPC18XX_CREG_CREG0_EN1KHZ BIT(0) +#define LPC18XX_CREG_CREG0_EN32KHZ BIT(1) +#define LPC18XX_CREG_CREG0_RESET32KHZ BIT(2) +#define LPC18XX_CREG_CREG0_PD32KHZ BIT(3) + +#define to_clk_creg(_hw) container_of(_hw, struct clk_creg_data, hw) + +enum { + CREG_CLK_1KHZ, + CREG_CLK_32KHZ, + CREG_CLK_MAX, +}; + +struct clk_creg_data { + struct clk_hw hw; + const char *name; + struct regmap *reg; + unsigned int en_mask; + const struct clk_ops *ops; +}; + +#define CREG_CLK(_name, _emask, _ops) \ +{ \ + .name = _name, \ + .en_mask = LPC18XX_CREG_CREG0_##_emask, \ + .ops = &_ops, \ +} + +static int clk_creg_32k_prepare(struct clk_hw *hw) +{ + struct clk_creg_data *creg = to_clk_creg(hw); + int ret; + + ret = regmap_update_bits(creg->reg, LPC18XX_CREG_CREG0, + LPC18XX_CREG_CREG0_PD32KHZ | + LPC18XX_CREG_CREG0_RESET32KHZ, 0); + + /* + * Powering up the 32k oscillator takes a long while + * and sadly there aren't any status bit to poll. + */ + msleep(2500); + + return ret; +} + +static void clk_creg_32k_unprepare(struct clk_hw *hw) +{ + struct clk_creg_data *creg = to_clk_creg(hw); + + regmap_update_bits(creg->reg, LPC18XX_CREG_CREG0, + LPC18XX_CREG_CREG0_PD32KHZ, + LPC18XX_CREG_CREG0_PD32KHZ); +} + +static int clk_creg_32k_is_prepared(struct clk_hw *hw) +{ + struct clk_creg_data *creg = to_clk_creg(hw); + u32 reg; + + regmap_read(creg->reg, LPC18XX_CREG_CREG0, ®); + + return !(reg & LPC18XX_CREG_CREG0_PD32KHZ) && + !(reg & LPC18XX_CREG_CREG0_RESET32KHZ); +} + +static unsigned long clk_creg_1k_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + return parent_rate / 32; +} + +static int clk_creg_enable(struct clk_hw *hw) +{ + struct clk_creg_data *creg = to_clk_creg(hw); + + return regmap_update_bits(creg->reg, LPC18XX_CREG_CREG0, + creg->en_mask, creg->en_mask); +} + +static void clk_creg_disable(struct clk_hw *hw) +{ + struct clk_creg_data *creg = to_clk_creg(hw); + + regmap_update_bits(creg->reg, LPC18XX_CREG_CREG0, + creg->en_mask, 0); +} + +static int clk_creg_is_enabled(struct clk_hw *hw) +{ + struct clk_creg_data *creg = to_clk_creg(hw); + u32 reg; + + regmap_read(creg->reg, LPC18XX_CREG_CREG0, ®); + + return !!(reg & creg->en_mask); +} + +static const struct clk_ops clk_creg_32k = { + .enable = clk_creg_enable, + .disable = clk_creg_disable, + .is_enabled = clk_creg_is_enabled, + .prepare = clk_creg_32k_prepare, + .unprepare = clk_creg_32k_unprepare, + .is_prepared = clk_creg_32k_is_prepared, +}; + +static const struct clk_ops clk_creg_1k = { + .enable = clk_creg_enable, + .disable = clk_creg_disable, + .is_enabled = clk_creg_is_enabled, + .recalc_rate = clk_creg_1k_recalc_rate, +}; + +static struct clk_creg_data clk_creg_clocks[] = { + [CREG_CLK_1KHZ] = CREG_CLK("1khz_clk", EN1KHZ, clk_creg_1k), + [CREG_CLK_32KHZ] = CREG_CLK("32khz_clk", EN32KHZ, clk_creg_32k), +}; + +static struct clk *clk_register_creg_clk(struct device *dev, + struct clk_creg_data *creg_clk, + const char **parent_name, + struct regmap *syscon) +{ + struct clk_init_data init; + + init.ops = creg_clk->ops; + init.name = creg_clk->name; + init.parent_names = parent_name; + init.num_parents = 1; + + creg_clk->reg = syscon; + creg_clk->hw.init = &init; + + if (dev) + return devm_clk_register(dev, &creg_clk->hw); + + return clk_register(NULL, &creg_clk->hw); +} + +static struct clk *clk_creg_early[CREG_CLK_MAX]; +static struct clk_onecell_data clk_creg_early_data = { + .clks = clk_creg_early, + .clk_num = CREG_CLK_MAX, +}; + +static void __init lpc18xx_creg_clk_init(struct device_node *np) +{ + const char *clk_32khz_parent; + struct regmap *syscon; + + syscon = syscon_node_to_regmap(np->parent); + if (IS_ERR(syscon)) { + pr_err("%s: syscon lookup failed\n", __func__); + return; + } + + clk_32khz_parent = of_clk_get_parent_name(np, 0); + + clk_creg_early[CREG_CLK_32KHZ] = + clk_register_creg_clk(NULL, &clk_creg_clocks[CREG_CLK_32KHZ], + &clk_32khz_parent, syscon); + clk_creg_early[CREG_CLK_1KHZ] = ERR_PTR(-EPROBE_DEFER); + + of_clk_add_provider(np, of_clk_src_onecell_get, &clk_creg_early_data); +} +CLK_OF_DECLARE(lpc18xx_creg_clk, "nxp,lpc1850-creg-clk", lpc18xx_creg_clk_init); + +static struct clk *clk_creg[CREG_CLK_MAX]; +static struct clk_onecell_data clk_creg_data = { + .clks = clk_creg, + .clk_num = CREG_CLK_MAX, +}; + +static int lpc18xx_creg_clk_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct regmap *syscon; + + syscon = syscon_node_to_regmap(np->parent); + if (IS_ERR(syscon)) { + dev_err(&pdev->dev, "syscon lookup failed\n"); + return PTR_ERR(syscon); + } + + clk_creg[CREG_CLK_32KHZ] = clk_creg_early[CREG_CLK_32KHZ]; + clk_creg[CREG_CLK_1KHZ] = + clk_register_creg_clk(NULL, &clk_creg_clocks[CREG_CLK_1KHZ], + &clk_creg_clocks[CREG_CLK_32KHZ].name, + syscon); + + return of_clk_add_provider(np, of_clk_src_onecell_get, &clk_creg_data); +} + +static const struct of_device_id lpc18xx_creg_clk_of_match[] = { + { .compatible = "nxp,lpc1850-creg-clk" }, + {}, +}; + +static struct platform_driver lpc18xx_creg_clk_driver = { + .probe = lpc18xx_creg_clk_probe, + .driver = { + .name = "lpc18xx-creg-clk", + .of_match_table = lpc18xx_creg_clk_of_match, + }, +}; +builtin_platform_driver(lpc18xx_creg_clk_driver); |