diff options
Diffstat (limited to 'drivers/clk/clk-si521xx.c')
| -rw-r--r-- | drivers/clk/clk-si521xx.c | 395 |
1 files changed, 395 insertions, 0 deletions
diff --git a/drivers/clk/clk-si521xx.c b/drivers/clk/clk-si521xx.c new file mode 100644 index 000000000000..ac8d4c59cd3d --- /dev/null +++ b/drivers/clk/clk-si521xx.c @@ -0,0 +1,395 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Driver for Skyworks Si521xx PCIe clock generator driver + * + * The following series can be supported: + * - Si52144 - 4x DIFF + * - Si52146 - 6x DIFF + * - Si52147 - 9x DIFF + * Currently tested: + * - Si52144 + * + * Copyright (C) 2022 Marek Vasut <marex@denx.de> + */ + +#include <linux/bitfield.h> +#include <linux/bitrev.h> +#include <linux/clk-provider.h> +#include <linux/i2c.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/regmap.h> + +/* OE1 and OE2 register */ +#define SI521XX_REG_OE(n) (((n) & 0x1) + 1) +#define SI521XX_REG_ID 0x3 +#define SI521XX_REG_ID_PROG GENMASK(7, 4) +#define SI521XX_REG_ID_VENDOR GENMASK(3, 0) +#define SI521XX_REG_BC 0x4 +#define SI521XX_REG_DA 0x5 +#define SI521XX_REG_DA_AMP_SEL BIT(7) +#define SI521XX_REG_DA_AMP_MASK GENMASK(6, 4) +#define SI521XX_REG_DA_AMP_MIN 300000 +#define SI521XX_REG_DA_AMP_DEFAULT 800000 +#define SI521XX_REG_DA_AMP_MAX 1000000 +#define SI521XX_REG_DA_AMP_STEP 100000 +#define SI521XX_REG_DA_AMP(UV) \ + FIELD_PREP(SI521XX_REG_DA_AMP_MASK, \ + ((UV) - SI521XX_REG_DA_AMP_MIN) / SI521XX_REG_DA_AMP_STEP) +#define SI521XX_REG_DA_UNKNOWN BIT(3) /* Always set */ + +/* Count of populated OE bits in control register ref, 1 and 2 */ +#define SI521XX_OE_MAP(cr1, cr2) (((cr2) << 8) | (cr1)) +#define SI521XX_OE_MAP_GET_OE(oe, map) (((map) >> (((oe) - 1) * 8)) & 0xff) + +#define SI521XX_DIFF_MULT 4 +#define SI521XX_DIFF_DIV 1 + +/* Supported Skyworks Si521xx models. */ +enum si521xx_model { + SI52144 = 0x44, + SI52146 = 0x46, + SI52147 = 0x47, +}; + +struct si521xx; + +struct si_clk { + struct clk_hw hw; + struct si521xx *si; + u8 reg; + u8 bit; +}; + +struct si521xx { + struct i2c_client *client; + struct regmap *regmap; + struct si_clk clk_dif[9]; + u16 chip_info; + u8 pll_amplitude; +}; + +/* + * Si521xx i2c regmap + */ +static const struct regmap_range si521xx_readable_ranges[] = { + regmap_reg_range(SI521XX_REG_OE(0), SI521XX_REG_DA), +}; + +static const struct regmap_access_table si521xx_readable_table = { + .yes_ranges = si521xx_readable_ranges, + .n_yes_ranges = ARRAY_SIZE(si521xx_readable_ranges), +}; + +static const struct regmap_range si521xx_writeable_ranges[] = { + regmap_reg_range(SI521XX_REG_OE(0), SI521XX_REG_OE(1)), + regmap_reg_range(SI521XX_REG_BC, SI521XX_REG_DA), +}; + +static const struct regmap_access_table si521xx_writeable_table = { + .yes_ranges = si521xx_writeable_ranges, + .n_yes_ranges = ARRAY_SIZE(si521xx_writeable_ranges), +}; + +static int si521xx_regmap_i2c_write(void *context, unsigned int reg, + unsigned int val) +{ + struct i2c_client *i2c = context; + const u8 data[3] = { reg, 1, val }; + const int count = ARRAY_SIZE(data); + int ret; + + ret = i2c_master_send(i2c, data, count); + if (ret == count) + return 0; + else if (ret < 0) + return ret; + else + return -EIO; +} + +static int si521xx_regmap_i2c_read(void *context, unsigned int reg, + unsigned int *val) +{ + struct i2c_client *i2c = context; + struct i2c_msg xfer[2]; + u8 txdata = reg; + u8 rxdata[2]; + int ret; + + xfer[0].addr = i2c->addr; + xfer[0].flags = 0; + xfer[0].len = 1; + xfer[0].buf = (void *)&txdata; + + xfer[1].addr = i2c->addr; + xfer[1].flags = I2C_M_RD; + xfer[1].len = 2; + xfer[1].buf = (void *)rxdata; + + ret = i2c_transfer(i2c->adapter, xfer, 2); + if (ret < 0) + return ret; + if (ret != 2) + return -EIO; + + /* + * Byte 0 is transfer length, which is always 1 due + * to BCP register programming to 1 in si521xx_probe(), + * ignore it and use data from Byte 1. + */ + *val = rxdata[1]; + return 0; +} + +static const struct regmap_config si521xx_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .cache_type = REGCACHE_NONE, + .max_register = SI521XX_REG_DA, + .rd_table = &si521xx_readable_table, + .wr_table = &si521xx_writeable_table, + .reg_write = si521xx_regmap_i2c_write, + .reg_read = si521xx_regmap_i2c_read, +}; + +static unsigned long si521xx_diff_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + unsigned long long rate; + + rate = (unsigned long long)parent_rate * SI521XX_DIFF_MULT; + do_div(rate, SI521XX_DIFF_DIV); + return (unsigned long)rate; +} + +static long si521xx_diff_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *prate) +{ + unsigned long best_parent; + + best_parent = (rate / SI521XX_DIFF_MULT) * SI521XX_DIFF_DIV; + *prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent); + + return (*prate / SI521XX_DIFF_DIV) * SI521XX_DIFF_MULT; +} + +static int si521xx_diff_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + /* + * We must report success but we can do so unconditionally because + * si521xx_diff_round_rate returns values that ensure this call is a + * nop. + */ + + return 0; +} + +#define to_si521xx_clk(_hw) container_of(_hw, struct si_clk, hw) + +static int si521xx_diff_prepare(struct clk_hw *hw) +{ + struct si_clk *si_clk = to_si521xx_clk(hw); + struct si521xx *si = si_clk->si; + + regmap_set_bits(si->regmap, SI521XX_REG_OE(si_clk->reg), si_clk->bit); + + return 0; +} + +static void si521xx_diff_unprepare(struct clk_hw *hw) +{ + struct si_clk *si_clk = to_si521xx_clk(hw); + struct si521xx *si = si_clk->si; + + regmap_clear_bits(si->regmap, SI521XX_REG_OE(si_clk->reg), si_clk->bit); +} + +static const struct clk_ops si521xx_diff_clk_ops = { + .round_rate = si521xx_diff_round_rate, + .set_rate = si521xx_diff_set_rate, + .recalc_rate = si521xx_diff_recalc_rate, + .prepare = si521xx_diff_prepare, + .unprepare = si521xx_diff_unprepare, +}; + +static int si521xx_get_common_config(struct si521xx *si) +{ + struct i2c_client *client = si->client; + struct device_node *np = client->dev.of_node; + unsigned int amp; + int ret; + + /* Set defaults */ + si->pll_amplitude = SI521XX_REG_DA_AMP(SI521XX_REG_DA_AMP_DEFAULT); + + /* Output clock amplitude */ + ret = of_property_read_u32(np, "skyworks,out-amplitude-microvolt", + &); + if (!ret) { + if (amp < SI521XX_REG_DA_AMP_MIN || amp > SI521XX_REG_DA_AMP_MAX || + amp % SI521XX_REG_DA_AMP_STEP) { + return dev_err_probe(&client->dev, -EINVAL, + "Invalid skyworks,out-amplitude-microvolt value\n"); + } + si->pll_amplitude = SI521XX_REG_DA_AMP(amp); + } + + return 0; +} + +static void si521xx_update_config(struct si521xx *si) +{ + /* If amplitude is non-default, update it. */ + if (si->pll_amplitude == SI521XX_REG_DA_AMP(SI521XX_REG_DA_AMP_DEFAULT)) + return; + + regmap_update_bits(si->regmap, SI521XX_REG_DA, + SI521XX_REG_DA_AMP_MASK, si->pll_amplitude); +} + +static void si521xx_diff_idx_to_reg_bit(const u16 chip_info, const int idx, + struct si_clk *clk) +{ + unsigned long mask; + int oe, b, ctr = 0; + + for (oe = 1; oe <= 2; oe++) { + mask = bitrev8(SI521XX_OE_MAP_GET_OE(oe, chip_info)); + for_each_set_bit(b, &mask, 8) { + if (ctr++ != idx) + continue; + clk->reg = SI521XX_REG_OE(oe); + clk->bit = 7 - b; + return; + } + } +} + +static struct clk_hw * +si521xx_of_clk_get(struct of_phandle_args *clkspec, void *data) +{ + struct si521xx *si = data; + unsigned int idx = clkspec->args[0]; + + return &si->clk_dif[idx].hw; +} + +static int si521xx_probe(struct i2c_client *client) +{ + const u16 chip_info = (u16)(uintptr_t)device_get_match_data(&client->dev); + const struct clk_parent_data clk_parent_data = { .index = 0 }; + struct si521xx *si; + unsigned char name[6] = "DIFF0"; + struct clk_init_data init = {}; + int i, ret; + + if (!chip_info) + return -EINVAL; + + si = devm_kzalloc(&client->dev, sizeof(*si), GFP_KERNEL); + if (!si) + return -ENOMEM; + + i2c_set_clientdata(client, si); + si->client = client; + + /* Fetch common configuration from DT (if specified) */ + ret = si521xx_get_common_config(si); + if (ret) + return ret; + + si->regmap = devm_regmap_init(&client->dev, NULL, client, + &si521xx_regmap_config); + if (IS_ERR(si->regmap)) + return dev_err_probe(&client->dev, PTR_ERR(si->regmap), + "Failed to allocate register map\n"); + + /* Always read back 1 Byte via I2C */ + ret = regmap_write(si->regmap, SI521XX_REG_BC, 1); + if (ret < 0) + return ret; + + /* Register clock */ + for (i = 0; i < hweight16(chip_info); i++) { + memset(&init, 0, sizeof(init)); + snprintf(name, 6, "DIFF%d", i); + init.name = name; + init.ops = &si521xx_diff_clk_ops; + init.parent_data = &clk_parent_data; + init.num_parents = 1; + init.flags = CLK_SET_RATE_PARENT; + + si->clk_dif[i].hw.init = &init; + si->clk_dif[i].si = si; + + si521xx_diff_idx_to_reg_bit(chip_info, i, &si->clk_dif[i]); + + ret = devm_clk_hw_register(&client->dev, &si->clk_dif[i].hw); + if (ret) + return ret; + } + + ret = devm_of_clk_add_hw_provider(&client->dev, si521xx_of_clk_get, si); + if (!ret) + si521xx_update_config(si); + + return ret; +} + +static int __maybe_unused si521xx_suspend(struct device *dev) +{ + struct si521xx *si = dev_get_drvdata(dev); + + regcache_cache_only(si->regmap, true); + regcache_mark_dirty(si->regmap); + + return 0; +} + +static int __maybe_unused si521xx_resume(struct device *dev) +{ + struct si521xx *si = dev_get_drvdata(dev); + int ret; + + regcache_cache_only(si->regmap, false); + ret = regcache_sync(si->regmap); + if (ret) + dev_err(dev, "Failed to restore register map: %d\n", ret); + return ret; +} + +static const struct i2c_device_id si521xx_id[] = { + { "si52144", .driver_data = SI521XX_OE_MAP(0x5, 0xc0) }, + { "si52146", .driver_data = SI521XX_OE_MAP(0x15, 0xe0) }, + { "si52147", .driver_data = SI521XX_OE_MAP(0x17, 0xf8) }, + { } +}; +MODULE_DEVICE_TABLE(i2c, si521xx_id); + +static const struct of_device_id clk_si521xx_of_match[] = { + { .compatible = "skyworks,si52144", .data = (void *)SI521XX_OE_MAP(0x5, 0xc0) }, + { .compatible = "skyworks,si52146", .data = (void *)SI521XX_OE_MAP(0x15, 0xe0) }, + { .compatible = "skyworks,si52147", .data = (void *)SI521XX_OE_MAP(0x15, 0xf8) }, + { } +}; +MODULE_DEVICE_TABLE(of, clk_si521xx_of_match); + +static SIMPLE_DEV_PM_OPS(si521xx_pm_ops, si521xx_suspend, si521xx_resume); + +static struct i2c_driver si521xx_driver = { + .driver = { + .name = "clk-si521xx", + .pm = &si521xx_pm_ops, + .of_match_table = clk_si521xx_of_match, + }, + .probe_new = si521xx_probe, + .id_table = si521xx_id, +}; +module_i2c_driver(si521xx_driver); + +MODULE_AUTHOR("Marek Vasut <marex@denx.de>"); +MODULE_DESCRIPTION("Skyworks Si521xx PCIe clock generator driver"); +MODULE_LICENSE("GPL"); |