[PATCH v4 10/18] spi: add locomo SPI driver

Dmitry Eremin-Solenikov
2015-05-25T11:41:45Z

LoCoMo chip has a built-in simple SPI controller. On Sharp SL-5500 PDDAs
it is connected to external MMC slot.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
---
drivers/spi/Kconfig | 10 ++
drivers/spi/Makefile | 1 +
drivers/spi/spi-locomo.c | 332 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 343 insertions(+)
create mode 100644 drivers/spi/spi-locomo.c

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 198f96b..c9e3176 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -258,6 +258,16 @@ config SPI_LM70_LLP
which interfaces to an LM70 temperature sensor using
a parallel port.

+config SPI_LOCOMO
+ tristate "Locomo SPI master"
+ depends on MFD_LOCOMO
+ help
+ This enables using the SPI controller as present in the LoCoMo
+ chips. It is probably only useful on the Sharp SL-5x00 PDA family.
+
+ On SL-5500 and SL-5000 devices this controller is used for
+ MMC/SD cards.
+
config SPI_MPC52xx
tristate "Freescale MPC52xx SPI (non-PSC) controller support"
depends on PPC_MPC52xx
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index d8cbf65..623c463 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -44,6 +44,7 @@ obj-$(CONFIG_SPI_GPIO) += spi-gpio.o
obj-$(CONFIG_SPI_IMG_SPFI) += spi-img-spfi.o
obj-$(CONFIG_SPI_IMX) += spi-imx.o
obj-$(CONFIG_SPI_LM70_LLP) += spi-lm70llp.o
+obj-$(CONFIG_SPI_LOCOMO) += spi-locomo.o
obj-$(CONFIG_SPI_MESON_SPIFC) += spi-meson-spifc.o
obj-$(CONFIG_SPI_MPC512x_PSC) += spi-mpc512x-psc.o
obj-$(CONFIG_SPI_MPC52xx_PSC) += spi-mpc52xx-psc.o
diff --git a/drivers/spi/spi-locomo.c b/drivers/spi/spi-locomo.c
new file mode 100644
index 0000000..bef0354
--- /dev/null
+++ b/drivers/spi/spi-locomo.c
@@ -0,0 +1,332 @@
+/*
+ * 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; version 2 of the License.
+ *
+ * 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/delay.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+#include <linux/mfd/locomo.h>
+
+struct locomospi_dev {
+ struct regmap *regmap;
+
+ int clock_base;
+ int clock_div;
+ unsigned nsecs;
+
+ unsigned int save_ct;
+ unsigned int save_md;
+};
+
+static void locomospi_chipselect(struct spi_device *spi, bool enable)
+{
+ struct locomospi_dev *spidev;
+
+ dev_dbg(&spi->dev, "SPI cs: %s\n", enable ? "enable" : "disable");
+
+ spidev = spi_master_get_devdata(spi->master);
+
+ regmap_update_bits(spidev->regmap, LOCOMO_SPICT, LOCOMO_SPICT_CS,
+ enable ? LOCOMO_SPICT_CS : 0);
+}
+
+static u32 locomospi_txrx_word(struct spi_device *spi,
+ unsigned nsecs,
+ u32 word)
+{
+ struct locomospi_dev *spidev;
+ int wait;
+ int j;
+ unsigned int rx;
+ unsigned int r;
+
+ spidev = spi_master_get_devdata(spi->master);
+
+ if (spidev->clock_div == DIV_64)
+ wait = 0x10000;
+ else
+ wait = 8;
+
+ for (j = 0; j < wait; j++) {
+ regmap_read(spidev->regmap, LOCOMO_SPIST, &r);
+ if (r & LOCOMO_SPI_RFW)
+ break;
+ }
+ if (j == wait)
+ dev_err_ratelimited(&spi->dev, "rfw timeout\n");
+
+ regmap_write(spidev->regmap, LOCOMO_SPITD, word);
+ ndelay(nsecs);
+
+ for (j = 0; j < wait; j++) {
+ regmap_read(spidev->regmap, LOCOMO_SPIST, &r);
+ if (r & LOCOMO_SPI_RFR)
+ break;
+ }
+ if (j == wait)
+ dev_err_ratelimited(&spi->dev, "rfr timeout\n");
+
+ regmap_read(spidev->regmap, LOCOMO_SPIRD, &rx);
+ ndelay(nsecs);
+
+ dev_dbg(&spi->dev, "SPI txrx: %02x/%02x\n", word, rx);
+
+ return rx;
+}
+
+static void locomo_spi_set_speed(struct locomospi_dev *spidev, u32 hz)
+{
+ spidev->nsecs = (1000000000/2) / hz;
+
+ if (hz >= 24576000) {
+ spidev->clock_base = CLOCK_25MHZ;
+ spidev->clock_div = DIV_1;
+ } else if (hz >= 22579200) {
+ spidev->clock_base = CLOCK_22MHZ;
+ spidev->clock_div = DIV_1;
+ } else if (hz >= 18432000) {
+ spidev->clock_base = CLOCK_18MHZ;
+ spidev->clock_div = DIV_1;
+ } else if (hz >= 12288000) {
+ spidev->clock_base = CLOCK_25MHZ;
+ spidev->clock_div = DIV_2;
+ } else if (hz >= 11289600) {
+ spidev->clock_base = CLOCK_22MHZ;
+ spidev->clock_div = DIV_2;
+ } else if (hz >= 9216000) {
+ spidev->clock_base = CLOCK_18MHZ;
+ spidev->clock_div = DIV_2;
+ } else if (hz >= 6144000) {
+ spidev->clock_base = CLOCK_25MHZ;
+ spidev->clock_div = DIV_4;
+ } else if (hz >= 5644800) {
+ spidev->clock_base = CLOCK_22MHZ;
+ spidev->clock_div = DIV_4;
+ } else if (hz >= 4608000) {
+ spidev->clock_base = CLOCK_18MHZ;
+ spidev->clock_div = DIV_4;
+ } else if (hz >= 3072000) {
+ spidev->clock_base = CLOCK_25MHZ;
+ spidev->clock_div = DIV_8;
+ } else if (hz >= 2822400) {
+ spidev->clock_base = CLOCK_22MHZ;
+ spidev->clock_div = DIV_8;
+ } else if (hz >= 2304000) {
+ spidev->clock_base = CLOCK_18MHZ;
+ spidev->clock_div = DIV_8;
+ } else if (hz >= 384000) {
+ spidev->clock_base = CLOCK_25MHZ;
+ spidev->clock_div = DIV_64;
+ } else if (hz >= 352800) {
+ spidev->clock_base = CLOCK_22MHZ;
+ spidev->clock_div = DIV_64;
+ } else { /* set to 288 Khz */
+ spidev->clock_base = CLOCK_18MHZ;
+ spidev->clock_div = DIV_64;
+ }
+
+ regmap_update_bits(spidev->regmap, LOCOMO_SPIMD,
+ LOCOMO_SPIMD_XSEL | LOCOMO_SPIMD_CLKSEL |
+ LOCOMO_SPIMD_XEN,
+ 0);
+ regmap_update_bits(spidev->regmap, LOCOMO_SPIMD,
+ LOCOMO_SPIMD_XSEL | LOCOMO_SPIMD_CLKSEL |
+ LOCOMO_SPIMD_XEN,
+ spidev->clock_div | (spidev->clock_base << 3) |
+ LOCOMO_SPIMD_XEN);
+
+ usleep_range(300, 400);
+}
+
+static int locomo_spi_setup_transfer(struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct locomospi_dev *spidev;
+
+ spidev = spi_master_get_devdata(spi->master);
+
+ regmap_update_bits(spidev->regmap, LOCOMO_SPIMD,
+ LOCOMO_SPIMD_XON,
+ LOCOMO_SPIMD_XON);
+
+ locomo_spi_set_speed(spidev, t->speed_hz);
+
+ return 0;
+}
+
+static int locomospi_transfer_one(struct spi_master *master,
+ struct spi_device *spi,
+ struct spi_transfer *t)
+{
+ struct locomospi_dev *spidev = spi_master_get_devdata(spi->master);
+ int rc;
+ unsigned count;
+ const u8 *tx = t->tx_buf;
+ u8 *rx = t->rx_buf;
+
+ rc = locomo_spi_setup_transfer(spi, t);
+ if (rc < 0)
+ return rc;
+
+ if (!t->len)
+ return 0;
+
+ for (count = t->len; likely(count > 0); count--) {
+ u8 word = 0;
+
+ if (tx)
+ word = *tx++;
+ word = locomospi_txrx_word(spi, spidev->nsecs, word);
+
+ if (rx)
+ *rx++ = word;
+ }
+
+ return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int locomo_spi_suspend(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct locomospi_dev *spidev = spi_master_get_devdata(master);
+ int ret;
+
+ /* Stop the queue running */
+ ret = spi_master_suspend(master);
+ if (ret) {
+ dev_warn(dev, "cannot suspend master\n");
+ return ret;
+ }
+
+ regmap_read(spidev->regmap, LOCOMO_SPICT, &spidev->save_ct);
+ regmap_write(spidev->regmap, LOCOMO_SPICT, LOCOMO_SPICT_CS);
+ regmap_read(spidev->regmap, LOCOMO_SPIMD, &spidev->save_md);
+ regmap_write(spidev->regmap, LOCOMO_SPIMD,
+ LOCOMO_SPIMD_MSB1ST | LOCOMO_SPIMD_DOSTAT |
+ LOCOMO_SPIMD_RCPOL | LOCOMO_SPIMD_TCPOL |
+ (CLOCK_25MHZ << 3) | DIV_64);
+
+ return 0;
+}
+
+static int locomo_spi_resume(struct device *dev)
+{
+ struct spi_master *master = dev_get_drvdata(dev);
+ struct locomospi_dev *spidev = spi_master_get_devdata(master);
+ int ret;
+
+ regmap_write(spidev->regmap, LOCOMO_SPIMD, spidev->save_md);
+ regmap_write(spidev->regmap, LOCOMO_SPICT, spidev->save_ct);
+
+ /* Start the queue running */
+ ret = spi_master_resume(master);
+ if (ret)
+ dev_err(dev, "problem starting queue (%d)\n", ret);
+
+ return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(locomo_spi_pm_ops,
+ locomo_spi_suspend, locomo_spi_resume);
+
+#define LOCOMO_SPI_PM_OPS (&locomo_spi_pm_ops)
+#else
+#define LOCOMO_SPI_PM_OPS NULL
+#endif
+
+static int locomo_spi_probe(struct platform_device *pdev)
+{
+ struct spi_master *master;
+ struct locomospi_dev *spidev;
+ int ret = -ENODEV;
+
+ master = spi_alloc_master(&pdev->dev, sizeof(struct locomospi_dev));
+ if (!master)
+ return -ENOMEM;
+
+ master->bus_num = 0;
+ master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
+ master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 8);
+ master->max_speed_hz = 24576000;
+ master->num_chipselect = 1;
+ master->set_cs = locomospi_chipselect;
+ master->transfer_one = locomospi_transfer_one;
+
+ spidev = spi_master_get_devdata(master);
+
+ spidev->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+ if (!spidev->regmap)
+ goto out_put;
+
+ spidev->clock_div = DIV_1;
+ spidev->clock_base = CLOCK_25MHZ;
+
+ platform_set_drvdata(pdev, master);
+
+ regmap_write(spidev->regmap, LOCOMO_SPIMD,
+ LOCOMO_SPIMD_MSB1ST | LOCOMO_SPIMD_DOSTAT |
+ LOCOMO_SPIMD_RCPOL | LOCOMO_SPIMD_TCPOL |
+ LOCOMO_SPIMD_XON);
+
+ regmap_write(spidev->regmap, LOCOMO_SPIMD,
+ LOCOMO_SPIMD_MSB1ST | LOCOMO_SPIMD_DOSTAT |
+ LOCOMO_SPIMD_RCPOL | LOCOMO_SPIMD_TCPOL |
+ LOCOMO_SPIMD_XON | LOCOMO_SPIMD_XEN |
+ (spidev->clock_base << 3) | spidev->clock_div);
+
+ regmap_write(spidev->regmap, LOCOMO_SPICT, LOCOMO_SPICT_CS |
+ LOCOMO_SPICT_CEN | LOCOMO_SPICT_RXUEN |
+ LOCOMO_SPICT_ALIGNEN);
+
+ ret = devm_spi_register_master(&pdev->dev, master);
+ if (ret) {
+ dev_err(&pdev->dev, "bitbang start failed with %d\n", ret);
+ goto out_put;
+ }
+
+ return 0;
+
+out_put:
+ spi_master_put(master);
+ return ret;
+}
+
+static int locomo_spi_remove(struct platform_device *pdev)
+{
+ struct spi_master *master = platform_get_drvdata(pdev);
+ struct locomospi_dev *spidev = spi_master_get_devdata(master);
+
+ regmap_update_bits(spidev->regmap, LOCOMO_SPICT, LOCOMO_SPICT_CEN, 0);
+ regmap_update_bits(spidev->regmap, LOCOMO_SPIMD, LOCOMO_SPIMD_XEN, 0);
+ regmap_update_bits(spidev->regmap, LOCOMO_SPIMD, LOCOMO_SPIMD_XON, 0);
+ regmap_update_bits(spidev->regmap, LOCOMO_SPICT,
+ LOCOMO_SPICT_CS,
+ LOCOMO_SPICT_CS);
+
+ return 0;
+}
+
+static struct platform_driver locomo_spi_driver = {
+ .probe = locomo_spi_probe,
+ .remove = locomo_spi_remove,
+ .driver = {
+ .name = "locomo-spi",
+ .pm = LOCOMO_SPI_PM_OPS,
+ },
+};
+module_platform_driver(locomo_spi_driver);
+
+MODULE_AUTHOR("Thomas Kunze thommy at tabao.de");
+MODULE_DESCRIPTION("LoCoMo SPI driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:locomo-spi");
--
2.1.4