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Diffstat (limited to '')
| -rw-r--r-- | drivers/mfd/atmel-smc.c | 351 |
1 files changed, 351 insertions, 0 deletions
diff --git a/drivers/mfd/atmel-smc.c b/drivers/mfd/atmel-smc.c new file mode 100644 index 000000000..f3bad2b52 --- /dev/null +++ b/drivers/mfd/atmel-smc.c @@ -0,0 +1,351 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Atmel SMC (Static Memory Controller) helper functions. + * + * Copyright (C) 2017 Atmel + * Copyright (C) 2017 Free Electrons + * + * Author: Boris Brezillon <boris.brezillon@free-electrons.com> + */ + +#include <linux/mfd/syscon/atmel-smc.h> +#include <linux/string.h> + +/** + * atmel_smc_cs_conf_init - initialize a SMC CS conf + * @conf: the SMC CS conf to initialize + * + * Set all fields to 0 so that one can start defining a new config. + */ +void atmel_smc_cs_conf_init(struct atmel_smc_cs_conf *conf) +{ + memset(conf, 0, sizeof(*conf)); +} +EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_init); + +/** + * atmel_smc_cs_encode_ncycles - encode a number of MCK clk cycles in the + * format expected by the SMC engine + * @ncycles: number of MCK clk cycles + * @msbpos: position of the MSB part of the timing field + * @msbwidth: width of the MSB part of the timing field + * @msbfactor: factor applied to the MSB + * @encodedval: param used to store the encoding result + * + * This function encodes the @ncycles value as described in the datasheet + * (section "SMC Setup/Pulse/Cycle/Timings Register"). This is a generic + * helper which called with different parameter depending on the encoding + * scheme. + * + * If the @ncycles value is too big to be encoded, -ERANGE is returned and + * the encodedval is contains the maximum val. Otherwise, 0 is returned. + */ +static int atmel_smc_cs_encode_ncycles(unsigned int ncycles, + unsigned int msbpos, + unsigned int msbwidth, + unsigned int msbfactor, + unsigned int *encodedval) +{ + unsigned int lsbmask = GENMASK(msbpos - 1, 0); + unsigned int msbmask = GENMASK(msbwidth - 1, 0); + unsigned int msb, lsb; + int ret = 0; + + msb = ncycles / msbfactor; + lsb = ncycles % msbfactor; + + if (lsb > lsbmask) { + lsb = 0; + msb++; + } + + /* + * Let's just put the maximum we can if the requested setting does + * not fit in the register field. + * We still return -ERANGE in case the caller cares. + */ + if (msb > msbmask) { + msb = msbmask; + lsb = lsbmask; + ret = -ERANGE; + } + + *encodedval = (msb << msbpos) | lsb; + + return ret; +} + +/** + * atmel_smc_cs_conf_set_timing - set the SMC CS conf Txx parameter to a + * specific value + * @conf: SMC CS conf descriptor + * @shift: the position of the Txx field in the TIMINGS register + * @ncycles: value (expressed in MCK clk cycles) to assign to this Txx + * parameter + * + * This function encodes the @ncycles value as described in the datasheet + * (section "SMC Timings Register"), and then stores the result in the + * @conf->timings field at @shift position. + * + * Returns -EINVAL if shift is invalid, -ERANGE if ncycles does not fit in + * the field, and 0 otherwise. + */ +int atmel_smc_cs_conf_set_timing(struct atmel_smc_cs_conf *conf, + unsigned int shift, unsigned int ncycles) +{ + unsigned int val; + int ret; + + if (shift != ATMEL_HSMC_TIMINGS_TCLR_SHIFT && + shift != ATMEL_HSMC_TIMINGS_TADL_SHIFT && + shift != ATMEL_HSMC_TIMINGS_TAR_SHIFT && + shift != ATMEL_HSMC_TIMINGS_TRR_SHIFT && + shift != ATMEL_HSMC_TIMINGS_TWB_SHIFT) + return -EINVAL; + + /* + * The formula described in atmel datasheets (section "HSMC Timings + * Register"): + * + * ncycles = (Txx[3] * 64) + Txx[2:0] + */ + ret = atmel_smc_cs_encode_ncycles(ncycles, 3, 1, 64, &val); + conf->timings &= ~GENMASK(shift + 3, shift); + conf->timings |= val << shift; + + return ret; +} +EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_set_timing); + +/** + * atmel_smc_cs_conf_set_setup - set the SMC CS conf xx_SETUP parameter to a + * specific value + * @conf: SMC CS conf descriptor + * @shift: the position of the xx_SETUP field in the SETUP register + * @ncycles: value (expressed in MCK clk cycles) to assign to this xx_SETUP + * parameter + * + * This function encodes the @ncycles value as described in the datasheet + * (section "SMC Setup Register"), and then stores the result in the + * @conf->setup field at @shift position. + * + * Returns -EINVAL if @shift is invalid, -ERANGE if @ncycles does not fit in + * the field, and 0 otherwise. + */ +int atmel_smc_cs_conf_set_setup(struct atmel_smc_cs_conf *conf, + unsigned int shift, unsigned int ncycles) +{ + unsigned int val; + int ret; + + if (shift != ATMEL_SMC_NWE_SHIFT && shift != ATMEL_SMC_NCS_WR_SHIFT && + shift != ATMEL_SMC_NRD_SHIFT && shift != ATMEL_SMC_NCS_RD_SHIFT) + return -EINVAL; + + /* + * The formula described in atmel datasheets (section "SMC Setup + * Register"): + * + * ncycles = (128 * xx_SETUP[5]) + xx_SETUP[4:0] + */ + ret = atmel_smc_cs_encode_ncycles(ncycles, 5, 1, 128, &val); + conf->setup &= ~GENMASK(shift + 7, shift); + conf->setup |= val << shift; + + return ret; +} +EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_set_setup); + +/** + * atmel_smc_cs_conf_set_pulse - set the SMC CS conf xx_PULSE parameter to a + * specific value + * @conf: SMC CS conf descriptor + * @shift: the position of the xx_PULSE field in the PULSE register + * @ncycles: value (expressed in MCK clk cycles) to assign to this xx_PULSE + * parameter + * + * This function encodes the @ncycles value as described in the datasheet + * (section "SMC Pulse Register"), and then stores the result in the + * @conf->setup field at @shift position. + * + * Returns -EINVAL if @shift is invalid, -ERANGE if @ncycles does not fit in + * the field, and 0 otherwise. + */ +int atmel_smc_cs_conf_set_pulse(struct atmel_smc_cs_conf *conf, + unsigned int shift, unsigned int ncycles) +{ + unsigned int val; + int ret; + + if (shift != ATMEL_SMC_NWE_SHIFT && shift != ATMEL_SMC_NCS_WR_SHIFT && + shift != ATMEL_SMC_NRD_SHIFT && shift != ATMEL_SMC_NCS_RD_SHIFT) + return -EINVAL; + + /* + * The formula described in atmel datasheets (section "SMC Pulse + * Register"): + * + * ncycles = (256 * xx_PULSE[6]) + xx_PULSE[5:0] + */ + ret = atmel_smc_cs_encode_ncycles(ncycles, 6, 1, 256, &val); + conf->pulse &= ~GENMASK(shift + 7, shift); + conf->pulse |= val << shift; + + return ret; +} +EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_set_pulse); + +/** + * atmel_smc_cs_conf_set_cycle - set the SMC CS conf xx_CYCLE parameter to a + * specific value + * @conf: SMC CS conf descriptor + * @shift: the position of the xx_CYCLE field in the CYCLE register + * @ncycles: value (expressed in MCK clk cycles) to assign to this xx_CYCLE + * parameter + * + * This function encodes the @ncycles value as described in the datasheet + * (section "SMC Cycle Register"), and then stores the result in the + * @conf->setup field at @shift position. + * + * Returns -EINVAL if @shift is invalid, -ERANGE if @ncycles does not fit in + * the field, and 0 otherwise. + */ +int atmel_smc_cs_conf_set_cycle(struct atmel_smc_cs_conf *conf, + unsigned int shift, unsigned int ncycles) +{ + unsigned int val; + int ret; + + if (shift != ATMEL_SMC_NWE_SHIFT && shift != ATMEL_SMC_NRD_SHIFT) + return -EINVAL; + + /* + * The formula described in atmel datasheets (section "SMC Cycle + * Register"): + * + * ncycles = (xx_CYCLE[8:7] * 256) + xx_CYCLE[6:0] + */ + ret = atmel_smc_cs_encode_ncycles(ncycles, 7, 2, 256, &val); + conf->cycle &= ~GENMASK(shift + 15, shift); + conf->cycle |= val << shift; + + return ret; +} +EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_set_cycle); + +/** + * atmel_smc_cs_conf_apply - apply an SMC CS conf + * @regmap: the SMC regmap + * @cs: the CS id + * @conf: the SMC CS conf to apply + * + * Applies an SMC CS configuration. + * Only valid on at91sam9 SoCs. + */ +void atmel_smc_cs_conf_apply(struct regmap *regmap, int cs, + const struct atmel_smc_cs_conf *conf) +{ + regmap_write(regmap, ATMEL_SMC_SETUP(cs), conf->setup); + regmap_write(regmap, ATMEL_SMC_PULSE(cs), conf->pulse); + regmap_write(regmap, ATMEL_SMC_CYCLE(cs), conf->cycle); + regmap_write(regmap, ATMEL_SMC_MODE(cs), conf->mode); +} +EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_apply); + +/** + * atmel_hsmc_cs_conf_apply - apply an SMC CS conf + * @regmap: the HSMC regmap + * @cs: the CS id + * @layout: the layout of registers + * @conf: the SMC CS conf to apply + * + * Applies an SMC CS configuration. + * Only valid on post-sama5 SoCs. + */ +void atmel_hsmc_cs_conf_apply(struct regmap *regmap, + const struct atmel_hsmc_reg_layout *layout, + int cs, const struct atmel_smc_cs_conf *conf) +{ + regmap_write(regmap, ATMEL_HSMC_SETUP(layout, cs), conf->setup); + regmap_write(regmap, ATMEL_HSMC_PULSE(layout, cs), conf->pulse); + regmap_write(regmap, ATMEL_HSMC_CYCLE(layout, cs), conf->cycle); + regmap_write(regmap, ATMEL_HSMC_TIMINGS(layout, cs), conf->timings); + regmap_write(regmap, ATMEL_HSMC_MODE(layout, cs), conf->mode); +} +EXPORT_SYMBOL_GPL(atmel_hsmc_cs_conf_apply); + +/** + * atmel_smc_cs_conf_get - retrieve the current SMC CS conf + * @regmap: the SMC regmap + * @cs: the CS id + * @conf: the SMC CS conf object to store the current conf + * + * Retrieve the SMC CS configuration. + * Only valid on at91sam9 SoCs. + */ +void atmel_smc_cs_conf_get(struct regmap *regmap, int cs, + struct atmel_smc_cs_conf *conf) +{ + regmap_read(regmap, ATMEL_SMC_SETUP(cs), &conf->setup); + regmap_read(regmap, ATMEL_SMC_PULSE(cs), &conf->pulse); + regmap_read(regmap, ATMEL_SMC_CYCLE(cs), &conf->cycle); + regmap_read(regmap, ATMEL_SMC_MODE(cs), &conf->mode); +} +EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_get); + +/** + * atmel_hsmc_cs_conf_get - retrieve the current SMC CS conf + * @regmap: the HSMC regmap + * @cs: the CS id + * @layout: the layout of registers + * @conf: the SMC CS conf object to store the current conf + * + * Retrieve the SMC CS configuration. + * Only valid on post-sama5 SoCs. + */ +void atmel_hsmc_cs_conf_get(struct regmap *regmap, + const struct atmel_hsmc_reg_layout *layout, + int cs, struct atmel_smc_cs_conf *conf) +{ + regmap_read(regmap, ATMEL_HSMC_SETUP(layout, cs), &conf->setup); + regmap_read(regmap, ATMEL_HSMC_PULSE(layout, cs), &conf->pulse); + regmap_read(regmap, ATMEL_HSMC_CYCLE(layout, cs), &conf->cycle); + regmap_read(regmap, ATMEL_HSMC_TIMINGS(layout, cs), &conf->timings); + regmap_read(regmap, ATMEL_HSMC_MODE(layout, cs), &conf->mode); +} +EXPORT_SYMBOL_GPL(atmel_hsmc_cs_conf_get); + +static const struct atmel_hsmc_reg_layout sama5d3_reg_layout = { + .timing_regs_offset = 0x600, +}; + +static const struct atmel_hsmc_reg_layout sama5d2_reg_layout = { + .timing_regs_offset = 0x700, +}; + +static const struct of_device_id atmel_smc_ids[] = { + { .compatible = "atmel,at91sam9260-smc", .data = NULL }, + { .compatible = "atmel,sama5d3-smc", .data = &sama5d3_reg_layout }, + { .compatible = "atmel,sama5d2-smc", .data = &sama5d2_reg_layout }, + { /* sentinel */ }, +}; + +/** + * atmel_hsmc_get_reg_layout - retrieve the layout of HSMC registers + * @np: the HSMC regmap + * + * Retrieve the layout of HSMC registers. + * + * Returns NULL in case of SMC, a struct atmel_hsmc_reg_layout pointer + * in HSMC case, otherwise ERR_PTR(-EINVAL). + */ +const struct atmel_hsmc_reg_layout * +atmel_hsmc_get_reg_layout(struct device_node *np) +{ + const struct of_device_id *match; + + match = of_match_node(atmel_smc_ids, np); + + return match ? match->data : ERR_PTR(-EINVAL); +} +EXPORT_SYMBOL_GPL(atmel_hsmc_get_reg_layout); 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