Add a driver for SILabs 570, 571, 598, 599 programmable oscillators. The devices generate low-jitter clock signals and are reprogrammable via an I2C interface. Cc: Guenter Roeck <linux@xxxxxxxxxxxx> Signed-off-by: Soren Brinkmann <soren.brinkmann@xxxxxxxxxx> --- v5: - fix typo in bindings documentation - mention the unit for the 'temperature-stability' property - remove calls to clk_unregister() (the device managed code takes care of it) v4: - actually check and handle error on clk_set_rate() call v3: - add delay in the path for small frequency changes, which can take up to 100us according to the data sheet - use real range for usleep_range() argument - use dev_err() over dev_warn() in set_rate() - add list of applicable devices for 7ppm DT prop - remove comments regarding platform data - ignore 7ppm DT prop for incompatible devices - replace raw numbers with #defines - convert DT prop 'temperature-stability' from boolean to u32 - make 'temperature-stability' DT prop required (actually not fully true, for 59x it is ignored and the driver does not require its presence) v2: - document clock-output-names in bindings documentation - don't use wildcards in compatibility string - change Kconfig entry to "... 570 and compatible devices" - change some indentation flaws - use 10000 as MIN and MAX value in usleep_range - fail probe() if 'factory-fout' is not provided in DT - default factory fout #defines removed - use i2c driver_data instead of OF data - remove some related structs and data - rename DT property 'initial-fout' => 'clock-frequency' (like si5351 driver) - add some more details regarding the 'factory-fout' DT property --- .../devicetree/bindings/clock/silabs,si570.txt | 39 ++ drivers/clk/Kconfig | 10 + drivers/clk/Makefile | 1 + drivers/clk/clk-si570.c | 531 +++++++++++++++++++++ 4 files changed, 581 insertions(+) create mode 100644 Documentation/devicetree/bindings/clock/silabs,si570.txt create mode 100644 drivers/clk/clk-si570.c diff --git a/Documentation/devicetree/bindings/clock/silabs,si570.txt b/Documentation/devicetree/bindings/clock/silabs,si570.txt new file mode 100644 index 0000000..c09f21e --- /dev/null +++ b/Documentation/devicetree/bindings/clock/silabs,si570.txt @@ -0,0 +1,39 @@ +Binding for Silicon Labs 570, 571, 598 and 599 programmable +I2C clock generators. + +Reference +This binding uses the common clock binding[1]. Details about the devices can be +found in the data sheets[2][3]. + +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt +[2] Si570/571 Data Sheet + http://www.silabs.com/Support%20Documents/TechnicalDocs/si570.pdf +[3] Si598/599 Data Sheet + http://www.silabs.com/Support%20Documents/TechnicalDocs/si598-99.pdf + +Required properties: + - compatible: Shall be one of "silabs,si570", "silabs,si571", + "silabs,si598", "silabs,si599" + - reg: I2C device address. + - #clock-cells: From common clock bindings: Shall be 0. + - factory-fout: Factory set default frequency. This frequency is part specific. + The correct frequency for the part used has to be provided in + order to generate the correct output frequencies. For more + details, please refer to the data sheet. + - temperature-stability: Temperature stability of the device in PPM. Should be + one of: 7, 20, 50 or 100. + +Optional properties: + - clock-output-names: From common clock bindings. Recommended to be "si570". + - clock-frequency: Output frequency to generate. This defines the output + frequency set during boot. It can be reprogrammed during + runtime through the common clock framework. + +Example: + si570: clock-generator@5d { + #clock-cells = <0>; + compatible = "silabs,si570"; + temperature-stability = <50>; + reg = <0x5d>; + factory-fout = <156250000>; + }; diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig index 279407a..349b88a 100644 --- a/drivers/clk/Kconfig +++ b/drivers/clk/Kconfig @@ -64,6 +64,16 @@ config COMMON_CLK_SI5351 This driver supports Silicon Labs 5351A/B/C programmable clock generators. +config COMMON_CLK_SI570 + tristate "Clock driver for SiLabs 570 and compatible devices" + depends on I2C + depends on OF + select REGMAP_I2C + help + ---help--- + This driver supports Silicon Labs 570/571/598/599 programmable + clock generators. + config COMMON_CLK_S2MPS11 tristate "Clock driver for S2MPS11 MFD" depends on MFD_SEC_CORE diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile index 7b11106..c0e94b3 100644 --- a/drivers/clk/Makefile +++ b/drivers/clk/Makefile @@ -40,6 +40,7 @@ obj-$(CONFIG_COMMON_CLK_AXI_CLKGEN) += clk-axi-clkgen.o obj-$(CONFIG_COMMON_CLK_WM831X) += clk-wm831x.o obj-$(CONFIG_COMMON_CLK_MAX77686) += clk-max77686.o obj-$(CONFIG_COMMON_CLK_SI5351) += clk-si5351.o +obj-$(CONFIG_COMMON_CLK_SI570) += clk-si570.o obj-$(CONFIG_COMMON_CLK_S2MPS11) += clk-s2mps11.o obj-$(CONFIG_CLK_TWL6040) += clk-twl6040.o obj-$(CONFIG_CLK_PPC_CORENET) += clk-ppc-corenet.o diff --git a/drivers/clk/clk-si570.c b/drivers/clk/clk-si570.c new file mode 100644 index 0000000..5d0ac9f --- /dev/null +++ b/drivers/clk/clk-si570.c @@ -0,0 +1,531 @@ +/* + * Driver for Silicon Labs Si570/Si571 Programmable XO/VCXO + * + * Copyright (C) 2010, 2011 Ericsson AB. + * Copyright (C) 2011 Guenter Roeck. + * Copyright (C) 2011 - 2013 Xilinx Inc. + * + * Author: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx> + * Sören Brinkmann <soren.brinkmann@xxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/clk-provider.h> +#include <linux/delay.h> +#include <linux/module.h> +#include <linux/i2c.h> +#include <linux/regmap.h> +#include <linux/slab.h> + +/* Si570 registers */ +#define SI570_REG_HS_N1 7 +#define SI570_REG_N1_RFREQ0 8 +#define SI570_REG_RFREQ1 9 +#define SI570_REG_RFREQ2 10 +#define SI570_REG_RFREQ3 11 +#define SI570_REG_RFREQ4 12 +#define SI570_REG_CONTROL 135 +#define SI570_REG_FREEZE_DCO 137 +#define SI570_DIV_OFFSET_7PPM 6 + +#define HS_DIV_SHIFT 5 +#define HS_DIV_MASK 0xe0 +#define HS_DIV_OFFSET 4 +#define N1_6_2_MASK 0x1f +#define N1_1_0_MASK 0xc0 +#define RFREQ_37_32_MASK 0x3f + +#define SI570_MIN_FREQ 10000000L +#define SI570_MAX_FREQ 1417500000L +#define SI598_MAX_FREQ 525000000L + +#define FDCO_MIN 4850000000LL +#define FDCO_MAX 5670000000LL + +#define SI570_CNTRL_RECALL (1 << 0) +#define SI570_CNTRL_FREEZE_M (1 << 5) +#define SI570_CNTRL_NEWFREQ (1 << 6) + +#define SI570_FREEZE_DCO (1 << 4) + +/** + * struct clk_si570: + * @hw: Clock hw struct + * @regmap: Device's regmap + * @div_offset: Rgister offset for dividers + * @max_freq: Maximum frequency for this device + * @fxtal: Factory xtal frequency + * @n1: Clock divider N1 + * @hs_div: Clock divider HSDIV + * @rfreq: Clock multiplier RFREQ + * @frequency: Current output frequency + * @i2c_client: I2C client pointer + */ +struct clk_si570 { + struct clk_hw hw; + struct regmap *regmap; + unsigned int div_offset; + u64 max_freq; + u64 fxtal; + unsigned int n1; + unsigned int hs_div; + u64 rfreq; + u64 frequency; + struct i2c_client *i2c_client; +}; +#define to_clk_si570(_hw) container_of(_hw, struct clk_si570, hw) + +enum clk_si570_variant { + si57x, + si59x +}; + +/** + * si570_get_divs() - Read clock dividers from HW + * @data: Pointer to struct clk_si570 + * @rfreq: Fractional multiplier (output) + * @n1: Divider N1 (output) + * @hs_div: Divider HSDIV (output) + * Returns 0 on success, negative errno otherwise. + * + * Retrieve clock dividers and multipliers from the HW. + */ +static int si570_get_divs(struct clk_si570 *data, u64 *rfreq, + unsigned int *n1, unsigned int *hs_div) +{ + int err; + u8 reg[6]; + u64 tmp; + + err = regmap_bulk_read(data->regmap, SI570_REG_HS_N1 + data->div_offset, + reg, ARRAY_SIZE(reg)); + if (err) + return err; + + *hs_div = ((reg[0] & HS_DIV_MASK) >> HS_DIV_SHIFT) + HS_DIV_OFFSET; + *n1 = ((reg[0] & N1_6_2_MASK) << 2) + ((reg[1] & N1_1_0_MASK) >> 6) + 1; + /* Handle invalid cases */ + if (*n1 > 1) + *n1 &= ~1; + + tmp = reg[1] & RFREQ_37_32_MASK; + tmp = (tmp << 8) + reg[2]; + tmp = (tmp << 8) + reg[3]; + tmp = (tmp << 8) + reg[4]; + tmp = (tmp << 8) + reg[5]; + *rfreq = tmp; + + return 0; +} + +/** + * si570_get_defaults() - Get default values + * @data: Driver data structure + * @fout: Factory frequency output + * Returns 0 on success, negative errno otherwise. + */ +static int si570_get_defaults(struct clk_si570 *data, u64 fout) +{ + int err; + u64 fdco; + + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_RECALL); + + err = si570_get_divs(data, &data->rfreq, &data->n1, &data->hs_div); + if (err) + return err; + + /* + * Accept optional precision loss to avoid arithmetic overflows. + * Acceptable per Silicon Labs Application Note AN334. + */ + fdco = fout * data->n1 * data->hs_div; + if (fdco >= (1LL << 36)) + data->fxtal = div64_u64(fdco << 24, data->rfreq >> 4); + else + data->fxtal = div64_u64(fdco << 28, data->rfreq); + + data->frequency = fout; + + return 0; +} + +/** + * si570_update_rfreq() - Update clock multiplier + * @data: Driver data structure + * Passes on regmap_bulk_write() return value. + */ +static int si570_update_rfreq(struct clk_si570 *data) +{ + u8 reg[5]; + + reg[0] = ((data->n1 - 1) << 6) | + ((data->rfreq >> 32) & RFREQ_37_32_MASK); + reg[1] = (data->rfreq >> 24) & 0xff; + reg[2] = (data->rfreq >> 16) & 0xff; + reg[3] = (data->rfreq >> 8) & 0xff; + reg[4] = data->rfreq & 0xff; + + return regmap_bulk_write(data->regmap, SI570_REG_N1_RFREQ0 + + data->div_offset, reg, ARRAY_SIZE(reg)); +} + +/** + * si570_calc_divs() - Caluclate clock dividers + * @frequency: Target frequency + * @data: Driver data structure + * @out_rfreq: RFREG fractional multiplier (output) + * @out_n1: Clock divider N1 (output) + * @out_hs_div: Clock divider HSDIV (output) + * Returns 0 on success, negative errno otherwise. + * + * Calculate the clock dividers (@out_hs_div, @out_n1) and clock multiplier + * (@out_rfreq) for a given target @frequency. + */ +static int si570_calc_divs(unsigned long frequency, struct clk_si570 *data, + u64 *out_rfreq, unsigned int *out_n1, unsigned int *out_hs_div) +{ + int i; + unsigned int n1, hs_div; + u64 fdco, best_fdco = ULLONG_MAX; + static const uint8_t si570_hs_div_values[] = { 11, 9, 7, 6, 5, 4 }; + + for (i = 0; i < ARRAY_SIZE(si570_hs_div_values); i++) { + hs_div = si570_hs_div_values[i]; + /* Calculate lowest possible value for n1 */ + n1 = div_u64(div_u64(FDCO_MIN, hs_div), frequency); + if (!n1 || (n1 & 1)) + n1++; + while (n1 <= 128) { + fdco = (u64)frequency * (u64)hs_div * (u64)n1; + if (fdco > FDCO_MAX) + break; + if (fdco >= FDCO_MIN && fdco < best_fdco) { + *out_n1 = n1; + *out_hs_div = hs_div; + *out_rfreq = div64_u64(fdco << 28, data->fxtal); + best_fdco = fdco; + } + n1 += (n1 == 1 ? 1 : 2); + } + } + + if (best_fdco == ULLONG_MAX) + return -EINVAL; + + return 0; +} + +static unsigned long si570_recalc_rate(struct clk_hw *hw, + unsigned long parent_rate) +{ + int err; + u64 rfreq, rate; + unsigned int n1, hs_div; + struct clk_si570 *data = to_clk_si570(hw); + + err = si570_get_divs(data, &rfreq, &n1, &hs_div); + if (err) { + dev_err(&data->i2c_client->dev, "unable to recalc rate\n"); + return data->frequency; + } + + rfreq = div_u64(rfreq, hs_div * n1); + rate = (data->fxtal * rfreq) >> 28; + + return rate; +} + +static long si570_round_rate(struct clk_hw *hw, unsigned long rate, + unsigned long *parent_rate) +{ + int err; + u64 rfreq; + unsigned int n1, hs_div; + struct clk_si570 *data = to_clk_si570(hw); + + if (!rate) + return 0; + + if (div64_u64(abs(rate - data->frequency) * 10000LL, + data->frequency) < 35) { + rfreq = div64_u64((data->rfreq * rate) + + div64_u64(data->frequency, 2), data->frequency); + n1 = data->n1; + hs_div = data->hs_div; + + } else { + err = si570_calc_divs(rate, data, &rfreq, &n1, &hs_div); + if (err) { + dev_err(&data->i2c_client->dev, + "unable to round rate\n"); + return 0; + } + } + + return rate; +} + +/** + * si570_set_frequency() - Adjust output frequency + * @data: Driver data structure + * @frequency: Target frequency + * Returns 0 on success. + * + * Update output frequency for big frequency changes (> 3,500 ppm). + */ +static int si570_set_frequency(struct clk_si570 *data, unsigned long frequency) +{ + int err; + + err = si570_calc_divs(frequency, data, &data->rfreq, &data->n1, + &data->hs_div); + if (err) + return err; + + /* + * The DCO reg should be accessed with a read-modify-write operation + * per AN334 + */ + regmap_write(data->regmap, SI570_REG_FREEZE_DCO, SI570_FREEZE_DCO); + regmap_write(data->regmap, SI570_REG_HS_N1 + data->div_offset, + ((data->hs_div - HS_DIV_OFFSET) << HS_DIV_SHIFT) | + (((data->n1 - 1) >> 2) & N1_6_2_MASK)); + si570_update_rfreq(data); + regmap_write(data->regmap, SI570_REG_FREEZE_DCO, 0); + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_NEWFREQ); + + /* Applying a new frequency can take up to 10ms */ + usleep_range(10000, 12000); + + return 0; +} + +/** + * si570_set_frequency_small() - Adjust output frequency + * @data: Driver data structure + * @frequency: Target frequency + * Returns 0 on success. + * + * Update output frequency for small frequency changes (< 3,500 ppm). + */ +static int si570_set_frequency_small(struct clk_si570 *data, + unsigned long frequency) +{ + /* + * This is a re-implementation of DIV_ROUND_CLOSEST + * using the div64_u64 function lieu of letting the compiler + * insert EABI calls + */ + data->rfreq = div64_u64((data->rfreq * frequency) + + div_u64(data->frequency, 2), data->frequency); + regmap_write(data->regmap, SI570_REG_CONTROL, SI570_CNTRL_FREEZE_M); + si570_update_rfreq(data); + regmap_write(data->regmap, SI570_REG_CONTROL, 0); + + /* Applying a new frequency (small change) can take up to 100us */ + usleep_range(100, 200); + + return 0; +} + +static int si570_set_rate(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate) +{ + struct clk_si570 *data = to_clk_si570(hw); + struct i2c_client *client = data->i2c_client; + int err; + + if (rate < SI570_MIN_FREQ || rate > data->max_freq) { + dev_err(&client->dev, + "requested frequency %lu Hz is out of range\n", rate); + return -EINVAL; + } + + if (div64_u64(abs(rate - data->frequency) * 10000LL, + data->frequency) < 35) + err = si570_set_frequency_small(data, rate); + else + err = si570_set_frequency(data, rate); + + if (err) + return err; + + data->frequency = rate; + + return 0; +} + +static const struct clk_ops si570_clk_ops = { + .recalc_rate = si570_recalc_rate, + .round_rate = si570_round_rate, + .set_rate = si570_set_rate, +}; + +static bool si570_regmap_is_volatile(struct device *dev, unsigned int reg) +{ + switch (reg) { + case SI570_REG_CONTROL: + return true; + default: + return false; + } +} + +static bool si570_regmap_is_writeable(struct device *dev, unsigned int reg) +{ + switch (reg) { + case SI570_REG_HS_N1 ... (SI570_REG_RFREQ4 + SI570_DIV_OFFSET_7PPM): + case SI570_REG_CONTROL: + case SI570_REG_FREEZE_DCO: + return true; + default: + return false; + } +} + +static struct regmap_config si570_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .cache_type = REGCACHE_RBTREE, + .max_register = 137, + .writeable_reg = si570_regmap_is_writeable, + .volatile_reg = si570_regmap_is_volatile, +}; + +static int si570_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct clk_si570 *data; + struct clk_init_data init; + struct clk *clk; + u32 initial_fout, factory_fout, stability; + int err; + enum clk_si570_variant variant = id->driver_data; + + data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + init.ops = &si570_clk_ops; + init.flags = CLK_IS_ROOT; + init.num_parents = 0; + data->hw.init = &init; + data->i2c_client = client; + + if (variant == si57x) { + err = of_property_read_u32(client->dev.of_node, + "temperature-stability", &stability); + if (err) { + dev_err(&client->dev, + "'temperature-stability' property missing\n"); + return err; + } + /* adjust register offsets for 7ppm devices */ + if (stability == 7) + data->div_offset = SI570_DIV_OFFSET_7PPM; + + data->max_freq = SI570_MAX_FREQ; + } else { + data->max_freq = SI598_MAX_FREQ; + } + + if (of_property_read_string(client->dev.of_node, "clock-output-names", + &init.name)) + init.name = client->dev.of_node->name; + + err = of_property_read_u32(client->dev.of_node, "factory-fout", + &factory_fout); + if (err) { + dev_err(&client->dev, "'factory-fout' property missing\n"); + return err; + } + + data->regmap = devm_regmap_init_i2c(client, &si570_regmap_config); + if (IS_ERR(data->regmap)) { + dev_err(&client->dev, "failed to allocate register map\n"); + return PTR_ERR(data->regmap); + } + + i2c_set_clientdata(client, data); + err = si570_get_defaults(data, factory_fout); + if (err) + return err; + + clk = devm_clk_register(&client->dev, &data->hw); + if (IS_ERR(clk)) { + dev_err(&client->dev, "clock registration failed\n"); + return PTR_ERR(clk); + } + err = of_clk_add_provider(client->dev.of_node, of_clk_src_simple_get, + clk); + if (err) { + dev_err(&client->dev, "unable to add clk provider\n"); + return err; + } + + /* Read the requested initial output frequency from device tree */ + if (!of_property_read_u32(client->dev.of_node, "clock-frequency", + &initial_fout)) { + err = clk_set_rate(clk, initial_fout); + if (err) { + of_clk_del_provider(client->dev.of_node); + return err; + } + } + + /* Display a message indicating that we've successfully registered */ + dev_info(&client->dev, "registered, current frequency %llu Hz\n", + data->frequency); + + return 0; +} + +static int si570_remove(struct i2c_client *client) +{ + of_clk_del_provider(client->dev.of_node); + return 0; +} + +static const struct i2c_device_id si570_id[] = { + { "si570", si57x }, + { "si571", si57x }, + { "si598", si59x }, + { "si599", si59x }, + { } +}; +MODULE_DEVICE_TABLE(i2c, si570_id); + +static const struct of_device_id clk_si570_of_match[] = { + { .compatible = "silabs,si570" }, + { .compatible = "silabs,si571" }, + { .compatible = "silabs,si598" }, + { .compatible = "silabs,si599" }, + { }, +}; +MODULE_DEVICE_TABLE(of, clk_si570_of_match); + +static struct i2c_driver si570_driver = { + .driver = { + .name = "si570", + .of_match_table = of_match_ptr(clk_si570_of_match), + }, + .probe = si570_probe, + .remove = si570_remove, + .id_table = si570_id, +}; +module_i2c_driver(si570_driver); + +MODULE_AUTHOR("Guenter Roeck <guenter.roeck@xxxxxxxxxxxx>"); +MODULE_AUTHOR("Soeren Brinkmann <soren.brinkmann@xxxxxxxxxx"); +MODULE_DESCRIPTION("Si570 driver"); +MODULE_LICENSE("GPL"); -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
