drivers/mfd/atmel-smc.c

   1 /*
   2  * Atmel SMC (Static Memory Controller) helper functions.
   3  *
   4  * Copyright (C) 2017 Atmel
   5  * Copyright (C) 2017 Free Electrons
   6  *
   7  * Author: Boris Brezillon <boris.brezillon@free-electrons.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include <linux/mfd/syscon/atmel-smc.h>
  15
  16 /**
  17  * atmel_smc_cs_conf_init - initialize a SMC CS conf
  18  * @conf: the SMC CS conf to initialize
  19  *
  20  * Set all fields to 0 so that one can start defining a new config.
  21  */
  22 void atmel_smc_cs_conf_init(struct atmel_smc_cs_conf *conf)
  23 {
  24         memset(conf, 0, sizeof(*conf));
  25 }
  26 EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_init);
  27
  28 /**
  29  * atmel_smc_cs_encode_ncycles - encode a number of MCK clk cycles in the
  30  *                               format expected by the SMC engine
  31  * @ncycles: number of MCK clk cycles
  32  * @msbpos: position of the MSB part of the timing field
  33  * @msbwidth: width of the MSB part of the timing field
  34  * @msbfactor: factor applied to the MSB
  35  * @encodedval: param used to store the encoding result
  36  *
  37  * This function encodes the @ncycles value as described in the datasheet
  38  * (section "SMC Setup/Pulse/Cycle/Timings Register"). This is a generic
  39  * helper which called with different parameter depending on the encoding
  40  * scheme.
  41  *
  42  * If the @ncycles value is too big to be encoded, -ERANGE is returned and
  43  * the encodedval is contains the maximum val. Otherwise, 0 is returned.
  44  */
  45 static int atmel_smc_cs_encode_ncycles(unsigned int ncycles,
  46                                        unsigned int msbpos,
  47                                        unsigned int msbwidth,
  48                                        unsigned int msbfactor,
  49                                        unsigned int *encodedval)
  50 {
  51         unsigned int lsbmask = GENMASK(msbpos - 1, 0);
  52         unsigned int msbmask = GENMASK(msbwidth - 1, 0);
  53         unsigned int msb, lsb;
  54         int ret = 0;
  55
  56         msb = ncycles / msbfactor;
  57         lsb = ncycles % msbfactor;
  58
  59         if (lsb > lsbmask) {
  60                 lsb = 0;
  61                 msb++;
  62         }
  63
  64         /*
  65          * Let's just put the maximum we can if the requested setting does
  66          * not fit in the register field.
  67          * We still return -ERANGE in case the caller cares.
  68          */
  69         if (msb > msbmask) {
  70                 msb = msbmask;
  71                 lsb = lsbmask;
  72                 ret = -ERANGE;
  73         }
  74
  75         *encodedval = (msb << msbpos) | lsb;
  76
  77         return ret;
  78 }
  79
  80 /**
  81  * atmel_smc_cs_conf_set_timing - set the SMC CS conf Txx parameter to a
  82  *                                specific value
  83  * @conf: SMC CS conf descriptor
  84  * @shift: the position of the Txx field in the TIMINGS register
  85  * @ncycles: value (expressed in MCK clk cycles) to assign to this Txx
  86  *           parameter
  87  *
  88  * This function encodes the @ncycles value as described in the datasheet
  89  * (section "SMC Timings Register"), and then stores the result in the
  90  * @conf->timings field at @shift position.
  91  *
  92  * Returns -EINVAL if shift is invalid, -ERANGE if ncycles does not fit in
  93  * the field, and 0 otherwise.
  94  */
  95 int atmel_smc_cs_conf_set_timing(struct atmel_smc_cs_conf *conf,
  96                                  unsigned int shift, unsigned int ncycles)
  97 {
  98         unsigned int val;
  99         int ret;
 100
 101         if (shift != ATMEL_HSMC_TIMINGS_TCLR_SHIFT &&
 102             shift != ATMEL_HSMC_TIMINGS_TADL_SHIFT &&
 103             shift != ATMEL_HSMC_TIMINGS_TAR_SHIFT &&
 104             shift != ATMEL_HSMC_TIMINGS_TRR_SHIFT &&
 105             shift != ATMEL_HSMC_TIMINGS_TWB_SHIFT)
 106                 return -EINVAL;
 107
 108         /*
 109          * The formula described in atmel datasheets (section "HSMC Timings
 110          * Register"):
 111          *
 112          * ncycles = (Txx[3] * 64) + Txx[2:0]
 113          */
 114         ret = atmel_smc_cs_encode_ncycles(ncycles, 3, 1, 64, &val);
 115         conf->timings &= ~GENMASK(shift + 3, shift);
 116         conf->timings |= val << shift;
 117
 118         return ret;
 119 }
 120 EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_set_timing);
 121
 122 /**
 123  * atmel_smc_cs_conf_set_setup - set the SMC CS conf xx_SETUP parameter to a
 124  *                               specific value
 125  * @conf: SMC CS conf descriptor
 126  * @shift: the position of the xx_SETUP field in the SETUP register
 127  * @ncycles: value (expressed in MCK clk cycles) to assign to this xx_SETUP
 128  *           parameter
 129  *
 130  * This function encodes the @ncycles value as described in the datasheet
 131  * (section "SMC Setup Register"), and then stores the result in the
 132  * @conf->setup field at @shift position.
 133  *
 134  * Returns -EINVAL if @shift is invalid, -ERANGE if @ncycles does not fit in
 135  * the field, and 0 otherwise.
 136  */
 137 int atmel_smc_cs_conf_set_setup(struct atmel_smc_cs_conf *conf,
 138                                 unsigned int shift, unsigned int ncycles)
 139 {
 140         unsigned int val;
 141         int ret;
 142
 143         if (shift != ATMEL_SMC_NWE_SHIFT && shift != ATMEL_SMC_NCS_WR_SHIFT &&
 144             shift != ATMEL_SMC_NRD_SHIFT && shift != ATMEL_SMC_NCS_RD_SHIFT)
 145                 return -EINVAL;
 146
 147         /*
 148          * The formula described in atmel datasheets (section "SMC Setup
 149          * Register"):
 150          *
 151          * ncycles = (128 * xx_SETUP[5]) + xx_SETUP[4:0]
 152          */
 153         ret = atmel_smc_cs_encode_ncycles(ncycles, 5, 1, 128, &val);
 154         conf->setup &= ~GENMASK(shift + 7, shift);
 155         conf->setup |= val << shift;
 156
 157         return ret;
 158 }
 159 EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_set_setup);
 160
 161 /**
 162  * atmel_smc_cs_conf_set_pulse - set the SMC CS conf xx_PULSE parameter to a
 163  *                               specific value
 164  * @conf: SMC CS conf descriptor
 165  * @shift: the position of the xx_PULSE field in the PULSE register
 166  * @ncycles: value (expressed in MCK clk cycles) to assign to this xx_PULSE
 167  *           parameter
 168  *
 169  * This function encodes the @ncycles value as described in the datasheet
 170  * (section "SMC Pulse Register"), and then stores the result in the
 171  * @conf->setup field at @shift position.
 172  *
 173  * Returns -EINVAL if @shift is invalid, -ERANGE if @ncycles does not fit in
 174  * the field, and 0 otherwise.
 175  */
 176 int atmel_smc_cs_conf_set_pulse(struct atmel_smc_cs_conf *conf,
 177                                 unsigned int shift, unsigned int ncycles)
 178 {
 179         unsigned int val;
 180         int ret;
 181
 182         if (shift != ATMEL_SMC_NWE_SHIFT && shift != ATMEL_SMC_NCS_WR_SHIFT &&
 183             shift != ATMEL_SMC_NRD_SHIFT && shift != ATMEL_SMC_NCS_RD_SHIFT)
 184                 return -EINVAL;
 185
 186         /*
 187          * The formula described in atmel datasheets (section "SMC Pulse
 188          * Register"):
 189          *
 190          * ncycles = (256 * xx_PULSE[6]) + xx_PULSE[5:0]
 191          */
 192         ret = atmel_smc_cs_encode_ncycles(ncycles, 6, 1, 256, &val);
 193         conf->pulse &= ~GENMASK(shift + 7, shift);
 194         conf->pulse |= val << shift;
 195
 196         return ret;
 197 }
 198 EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_set_pulse);
 199
 200 /**
 201  * atmel_smc_cs_conf_set_cycle - set the SMC CS conf xx_CYCLE parameter to a
 202  *                               specific value
 203  * @conf: SMC CS conf descriptor
 204  * @shift: the position of the xx_CYCLE field in the CYCLE register
 205  * @ncycles: value (expressed in MCK clk cycles) to assign to this xx_CYCLE
 206  *           parameter
 207  *
 208  * This function encodes the @ncycles value as described in the datasheet
 209  * (section "SMC Pulse Register"), and then stores the result in the
 210  * @conf->setup field at @shift position.
 211  *
 212  * Returns -EINVAL if @shift is invalid, -ERANGE if @ncycles does not fit in
 213  * the field, and 0 otherwise.
 214  */
 215 int atmel_smc_cs_conf_set_cycle(struct atmel_smc_cs_conf *conf,
 216                                 unsigned int shift, unsigned int ncycles)
 217 {
 218         unsigned int val;
 219         int ret;
 220
 221         if (shift != ATMEL_SMC_NWE_SHIFT && shift != ATMEL_SMC_NRD_SHIFT)
 222                 return -EINVAL;
 223
 224         /*
 225          * The formula described in atmel datasheets (section "SMC Cycle
 226          * Register"):
 227          *
 228          * ncycles = (xx_CYCLE[8:7] * 256) + xx_CYCLE[6:0]
 229          */
 230         ret = atmel_smc_cs_encode_ncycles(ncycles, 7, 2, 256, &val);
 231         conf->cycle &= ~GENMASK(shift + 15, shift);
 232         conf->cycle |= val << shift;
 233
 234         return ret;
 235 }
 236 EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_set_cycle);
 237
 238 /**
 239  * atmel_smc_cs_conf_apply - apply an SMC CS conf
 240  * @regmap: the SMC regmap
 241  * @cs: the CS id
 242  * @conf the SMC CS conf to apply
 243  *
 244  * Applies an SMC CS configuration.
 245  * Only valid on at91sam9/avr32 SoCs.
 246  */
 247 void atmel_smc_cs_conf_apply(struct regmap *regmap, int cs,
 248                              const struct atmel_smc_cs_conf *conf)
 249 {
 250         regmap_write(regmap, ATMEL_SMC_SETUP(cs), conf->setup);
 251         regmap_write(regmap, ATMEL_SMC_PULSE(cs), conf->pulse);
 252         regmap_write(regmap, ATMEL_SMC_CYCLE(cs), conf->cycle);
 253         regmap_write(regmap, ATMEL_SMC_MODE(cs), conf->mode);
 254 }
 255 EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_apply);
 256
 257 /**
 258  * atmel_hsmc_cs_conf_apply - apply an SMC CS conf
 259  * @regmap: the HSMC regmap
 260  * @cs: the CS id
 261  * @conf the SMC CS conf to apply
 262  *
 263  * Applies an SMC CS configuration.
 264  * Only valid on post-sama5 SoCs.
 265  */
 266 void atmel_hsmc_cs_conf_apply(struct regmap *regmap, int cs,
 267                               const struct atmel_smc_cs_conf *conf)
 268 {
 269         regmap_write(regmap, ATMEL_HSMC_SETUP(cs), conf->setup);
 270         regmap_write(regmap, ATMEL_HSMC_PULSE(cs), conf->pulse);
 271         regmap_write(regmap, ATMEL_HSMC_CYCLE(cs), conf->cycle);
 272         regmap_write(regmap, ATMEL_HSMC_TIMINGS(cs), conf->timings);
 273         regmap_write(regmap, ATMEL_HSMC_MODE(cs), conf->mode);
 274 }
 275 EXPORT_SYMBOL_GPL(atmel_hsmc_cs_conf_apply);
 276
 277 /**
 278  * atmel_smc_cs_conf_get - retrieve the current SMC CS conf
 279  * @regmap: the SMC regmap
 280  * @cs: the CS id
 281  * @conf: the SMC CS conf object to store the current conf
 282  *
 283  * Retrieve the SMC CS configuration.
 284  * Only valid on at91sam9/avr32 SoCs.
 285  */
 286 void atmel_smc_cs_conf_get(struct regmap *regmap, int cs,
 287                            struct atmel_smc_cs_conf *conf)
 288 {
 289         regmap_read(regmap, ATMEL_SMC_SETUP(cs), &conf->setup);
 290         regmap_read(regmap, ATMEL_SMC_PULSE(cs), &conf->pulse);
 291         regmap_read(regmap, ATMEL_SMC_CYCLE(cs), &conf->cycle);
 292         regmap_read(regmap, ATMEL_SMC_MODE(cs), &conf->mode);
 293 }
 294 EXPORT_SYMBOL_GPL(atmel_smc_cs_conf_get);
 295
 296 /**
 297  * atmel_hsmc_cs_conf_get - retrieve the current SMC CS conf
 298  * @regmap: the HSMC regmap
 299  * @cs: the CS id
 300  * @conf: the SMC CS conf object to store the current conf
 301  *
 302  * Retrieve the SMC CS configuration.
 303  * Only valid on post-sama5 SoCs.
 304  */
 305 void atmel_hsmc_cs_conf_get(struct regmap *regmap, int cs,
 306                             struct atmel_smc_cs_conf *conf)
 307 {
 308         regmap_read(regmap, ATMEL_HSMC_SETUP(cs), &conf->setup);
 309         regmap_read(regmap, ATMEL_HSMC_PULSE(cs), &conf->pulse);
 310         regmap_read(regmap, ATMEL_HSMC_CYCLE(cs), &conf->cycle);
 311         regmap_read(regmap, ATMEL_HSMC_TIMINGS(cs), &conf->timings);
 312         regmap_read(regmap, ATMEL_HSMC_MODE(cs), &conf->mode);
 313 }
 314 EXPORT_SYMBOL_GPL(atmel_hsmc_cs_conf_get);