mvebu_a3700_spi.c 6.9 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Copyright (C) 2015 Marvell International Ltd.
  4. *
  5. * Copyright (C) 2016 Stefan Roese <sr@denx.de>
  6. */
  7. #include <common.h>
  8. #include <dm.h>
  9. #include <malloc.h>
  10. #include <spi.h>
  11. #include <clk.h>
  12. #include <wait_bit.h>
  13. #include <asm/io.h>
  14. #include <dm/device_compat.h>
  15. DECLARE_GLOBAL_DATA_PTR;
  16. #define MVEBU_SPI_A3700_XFER_RDY BIT(1)
  17. #define MVEBU_SPI_A3700_FIFO_FLUSH BIT(9)
  18. #define MVEBU_SPI_A3700_BYTE_LEN BIT(5)
  19. #define MVEBU_SPI_A3700_CLK_PHA BIT(6)
  20. #define MVEBU_SPI_A3700_CLK_POL BIT(7)
  21. #define MVEBU_SPI_A3700_FIFO_EN BIT(17)
  22. #define MVEBU_SPI_A3700_SPI_EN_0 BIT(16)
  23. #define MVEBU_SPI_A3700_CLK_PRESCALE_MASK 0x1f
  24. /* SPI registers */
  25. struct spi_reg {
  26. u32 ctrl; /* 0x10600 */
  27. u32 cfg; /* 0x10604 */
  28. u32 dout; /* 0x10608 */
  29. u32 din; /* 0x1060c */
  30. };
  31. struct mvebu_spi_platdata {
  32. struct spi_reg *spireg;
  33. struct clk clk;
  34. };
  35. static void spi_cs_activate(struct spi_reg *reg, int cs)
  36. {
  37. setbits_le32(&reg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
  38. }
  39. static void spi_cs_deactivate(struct spi_reg *reg, int cs)
  40. {
  41. clrbits_le32(&reg->ctrl, MVEBU_SPI_A3700_SPI_EN_0 << cs);
  42. }
  43. /**
  44. * spi_legacy_shift_byte() - triggers the real SPI transfer
  45. * @bytelen: Indicate how many bytes to transfer.
  46. * @dout: Buffer address of what to send.
  47. * @din: Buffer address of where to receive.
  48. *
  49. * This function triggers the real SPI transfer in legacy mode. It
  50. * will shift out char buffer from @dout, and shift in char buffer to
  51. * @din, if necessary.
  52. *
  53. * This function assumes that only one byte is shifted at one time.
  54. * However, it is not its responisbility to set the transfer type to
  55. * one-byte. Also, it does not guarantee that it will work if transfer
  56. * type becomes two-byte. See spi_set_legacy() for details.
  57. *
  58. * In legacy mode, simply write to the SPI_DOUT register will trigger
  59. * the transfer.
  60. *
  61. * If @dout == NULL, which means no actual data needs to be sent out,
  62. * then the function will shift out 0x00 in order to shift in data.
  63. * The XFER_RDY flag is checked every time before accessing SPI_DOUT
  64. * and SPI_DIN register.
  65. *
  66. * The number of transfers to be triggerred is decided by @bytelen.
  67. *
  68. * Return: 0 - cool
  69. * -ETIMEDOUT - XFER_RDY flag timeout
  70. */
  71. static int spi_legacy_shift_byte(struct spi_reg *reg, unsigned int bytelen,
  72. const void *dout, void *din)
  73. {
  74. const u8 *dout_8;
  75. u8 *din_8;
  76. int ret;
  77. /* Use 0x00 as dummy dout */
  78. const u8 dummy_dout = 0x0;
  79. u32 pending_dout = 0x0;
  80. /* dout_8: pointer of current dout */
  81. dout_8 = dout;
  82. /* din_8: pointer of current din */
  83. din_8 = din;
  84. while (bytelen) {
  85. ret = wait_for_bit_le32(&reg->ctrl,
  86. MVEBU_SPI_A3700_XFER_RDY,
  87. true,100, false);
  88. if (ret)
  89. return ret;
  90. if (dout)
  91. pending_dout = (u32)*dout_8;
  92. else
  93. pending_dout = (u32)dummy_dout;
  94. /* Trigger the xfer */
  95. writel(pending_dout, &reg->dout);
  96. if (din) {
  97. ret = wait_for_bit_le32(&reg->ctrl,
  98. MVEBU_SPI_A3700_XFER_RDY,
  99. true, 100, false);
  100. if (ret)
  101. return ret;
  102. /* Read what is transferred in */
  103. *din_8 = (u8)readl(&reg->din);
  104. }
  105. /* Don't increment the current pointer if NULL */
  106. if (dout)
  107. dout_8++;
  108. if (din)
  109. din_8++;
  110. bytelen--;
  111. }
  112. return 0;
  113. }
  114. static int mvebu_spi_xfer(struct udevice *dev, unsigned int bitlen,
  115. const void *dout, void *din, unsigned long flags)
  116. {
  117. struct udevice *bus = dev->parent;
  118. struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
  119. struct spi_reg *reg = plat->spireg;
  120. unsigned int bytelen;
  121. int ret;
  122. bytelen = bitlen / 8;
  123. if (dout && din)
  124. debug("This is a duplex transfer.\n");
  125. /* Activate CS */
  126. if (flags & SPI_XFER_BEGIN) {
  127. debug("SPI: activate cs.\n");
  128. spi_cs_activate(reg, spi_chip_select(dev));
  129. }
  130. /* Send and/or receive */
  131. if (dout || din) {
  132. ret = spi_legacy_shift_byte(reg, bytelen, dout, din);
  133. if (ret)
  134. return ret;
  135. }
  136. /* Deactivate CS */
  137. if (flags & SPI_XFER_END) {
  138. ret = wait_for_bit_le32(&reg->ctrl,
  139. MVEBU_SPI_A3700_XFER_RDY,
  140. true, 100, false);
  141. if (ret)
  142. return ret;
  143. debug("SPI: deactivate cs.\n");
  144. spi_cs_deactivate(reg, spi_chip_select(dev));
  145. }
  146. return 0;
  147. }
  148. static int mvebu_spi_set_speed(struct udevice *bus, uint hz)
  149. {
  150. struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
  151. struct spi_reg *reg = plat->spireg;
  152. u32 data, prescale;
  153. data = readl(&reg->cfg);
  154. prescale = DIV_ROUND_UP(clk_get_rate(&plat->clk), hz);
  155. if (prescale > 0xf)
  156. prescale = 0x10 + (prescale + 1) / 2;
  157. prescale = min(prescale, 0x1fu);
  158. data &= ~MVEBU_SPI_A3700_CLK_PRESCALE_MASK;
  159. data |= prescale & MVEBU_SPI_A3700_CLK_PRESCALE_MASK;
  160. writel(data, &reg->cfg);
  161. return 0;
  162. }
  163. static int mvebu_spi_set_mode(struct udevice *bus, uint mode)
  164. {
  165. struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
  166. struct spi_reg *reg = plat->spireg;
  167. /*
  168. * Set SPI polarity
  169. * 0: Serial interface clock is low when inactive
  170. * 1: Serial interface clock is high when inactive
  171. */
  172. if (mode & SPI_CPOL)
  173. setbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_POL);
  174. else
  175. clrbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_POL);
  176. if (mode & SPI_CPHA)
  177. setbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_PHA);
  178. else
  179. clrbits_le32(&reg->cfg, MVEBU_SPI_A3700_CLK_PHA);
  180. return 0;
  181. }
  182. static int mvebu_spi_probe(struct udevice *bus)
  183. {
  184. struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
  185. struct spi_reg *reg = plat->spireg;
  186. u32 data;
  187. int ret;
  188. /*
  189. * Settings SPI controller to be working in legacy mode, which
  190. * means use only DO pin (I/O 1) for Data Out, and DI pin (I/O 0)
  191. * for Data In.
  192. */
  193. /* Flush read/write FIFO */
  194. data = readl(&reg->cfg);
  195. writel(data | MVEBU_SPI_A3700_FIFO_FLUSH, &reg->cfg);
  196. ret = wait_for_bit_le32(&reg->cfg, MVEBU_SPI_A3700_FIFO_FLUSH,
  197. false, 1000, false);
  198. if (ret)
  199. return ret;
  200. /* Disable FIFO mode */
  201. data &= ~MVEBU_SPI_A3700_FIFO_EN;
  202. /* Always shift 1 byte at a time */
  203. data &= ~MVEBU_SPI_A3700_BYTE_LEN;
  204. writel(data, &reg->cfg);
  205. return 0;
  206. }
  207. static int mvebu_spi_ofdata_to_platdata(struct udevice *bus)
  208. {
  209. struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
  210. int ret;
  211. plat->spireg = (struct spi_reg *)devfdt_get_addr(bus);
  212. ret = clk_get_by_index(bus, 0, &plat->clk);
  213. if (ret) {
  214. dev_err(bus, "cannot get clock\n");
  215. return ret;
  216. }
  217. return 0;
  218. }
  219. static int mvebu_spi_remove(struct udevice *bus)
  220. {
  221. struct mvebu_spi_platdata *plat = dev_get_platdata(bus);
  222. clk_free(&plat->clk);
  223. return 0;
  224. }
  225. static const struct dm_spi_ops mvebu_spi_ops = {
  226. .xfer = mvebu_spi_xfer,
  227. .set_speed = mvebu_spi_set_speed,
  228. .set_mode = mvebu_spi_set_mode,
  229. /*
  230. * cs_info is not needed, since we require all chip selects to be
  231. * in the device tree explicitly
  232. */
  233. };
  234. static const struct udevice_id mvebu_spi_ids[] = {
  235. { .compatible = "marvell,armada-3700-spi" },
  236. { }
  237. };
  238. U_BOOT_DRIVER(mvebu_spi) = {
  239. .name = "mvebu_spi",
  240. .id = UCLASS_SPI,
  241. .of_match = mvebu_spi_ids,
  242. .ops = &mvebu_spi_ops,
  243. .ofdata_to_platdata = mvebu_spi_ofdata_to_platdata,
  244. .platdata_auto_alloc_size = sizeof(struct mvebu_spi_platdata),
  245. .probe = mvebu_spi_probe,
  246. .remove = mvebu_spi_remove,
  247. };