mfd: Add support for STMPE SPI interface

Few STMPE controller can have register interface over SPI or I2C. Current
implementation only supports I2C.

This patch adds support for SPI interface for accessing STMPE's address space.

Signed-off-by: Viresh Kumar <viresh.kumar@st.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 7bc5581..06766ec 100644 (file)
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -258,7 +258,7 @@ config TWL6040_CORE
 
 config MFD_STMPE
        bool "Support STMicroelectronics STMPE"
-       depends on I2C=y && GENERIC_HARDIRQS
+       depends on (I2C=y || SPI_MASTER=y) && GENERIC_HARDIRQS
        select MFD_CORE
        help
          Support for the STMPE family of I/O Expanders from
@@ -288,6 +288,12 @@ config STMPE_I2C
        default y
        help
          This is used to enable I2C interface of STMPE
+
+config STMPE_SPI
+       bool "STMPE SPI Inteface"
+       depends on SPI_MASTER
+       help
+         This is used to enable SPI interface of STMPE
 endmenu
 
 config MFD_TC3589X

diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 5eb90a7..7f389a8 100644 (file)
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_MFD_TI_SSP)      += ti-ssp.o
 
 obj-$(CONFIG_MFD_STMPE)                += stmpe.o
 obj-$(CONFIG_STMPE_I2C)                += stmpe-i2c.o
+obj-$(CONFIG_STMPE_SPI)                += stmpe-spi.o
 obj-$(CONFIG_MFD_TC3589X)      += tc3589x.o
 obj-$(CONFIG_MFD_T7L66XB)      += t7l66xb.o tmio_core.o
 obj-$(CONFIG_MFD_TC6387XB)     += tc6387xb.o tmio_core.o

diff --git a/drivers/mfd/stmpe-spi.c b/drivers/mfd/stmpe-spi.c
new file mode 100644 (file)
index 0000000..53efce4
--- /dev/null
+++ b/drivers/mfd/stmpe-spi.c
@@ -0,0 +1,148 @@
+/*
+ * ST Microelectronics MFD: stmpe's spi client specific driver
+ *
+ * Copyright (C) ST Microelectronics SA 2011
+ *
+ * License Terms: GNU General Public License, version 2
+ * Author: Viresh Kumar <viresh.kumar@st.com> for ST Microelectronics
+ */
+
+#include <linux/spi/spi.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include "stmpe.h"
+
+#define READ_CMD       (1 << 7)
+
+static int spi_reg_read(struct stmpe *stmpe, u8 reg)
+{
+       struct spi_device *spi = stmpe->client;
+       int status = spi_w8r16(spi, reg | READ_CMD);
+
+       return (status < 0) ? status : status >> 8;
+}
+
+static int spi_reg_write(struct stmpe *stmpe, u8 reg, u8 val)
+{
+       struct spi_device *spi = stmpe->client;
+       u16 cmd = (val << 8) | reg;
+
+       return spi_write(spi, (const u8 *)&cmd, 2);
+}
+
+static int spi_block_read(struct stmpe *stmpe, u8 reg, u8 length, u8 *values)
+{
+       int ret, i;
+
+       for (i = 0; i < length; i++) {
+               ret = spi_reg_read(stmpe, reg + i);
+               if (ret < 0)
+                       return ret;
+               *(values + i) = ret;
+       }
+
+       return 0;
+}
+
+static int spi_block_write(struct stmpe *stmpe, u8 reg, u8 length,
+               const u8 *values)
+{
+       int ret = 0, i;
+
+       for (i = length; i > 0; i--, reg++) {
+               ret = spi_reg_write(stmpe, reg, *(values + i - 1));
+               if (ret < 0)
+                       return ret;
+       }
+
+       return ret;
+}
+
+static void spi_init(struct stmpe *stmpe)
+{
+       struct spi_device *spi = stmpe->client;
+
+       spi->bits_per_word = 8;
+
+       /* This register is only present for stmpe811 */
+       if (stmpe->variant->id_val == 0x0811)
+               spi_reg_write(stmpe, STMPE811_REG_SPI_CFG, spi->mode);
+
+       if (spi_setup(spi) < 0)
+               dev_dbg(&spi->dev, "spi_setup failed\n");
+}
+
+static struct stmpe_client_info spi_ci = {
+       .read_byte = spi_reg_read,
+       .write_byte = spi_reg_write,
+       .read_block = spi_block_read,
+       .write_block = spi_block_write,
+       .init = spi_init,
+};
+
+static int __devinit
+stmpe_spi_probe(struct spi_device *spi)
+{
+       const struct spi_device_id *id = spi_get_device_id(spi);
+
+       /* don't exceed max specified rate - 1MHz - Limitation of STMPE */
+       if (spi->max_speed_hz > 1000000) {
+               dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
+                               (spi->max_speed_hz/1000));
+               return -EINVAL;
+       }
+
+       spi_ci.irq = spi->irq;
+       spi_ci.client = spi;
+       spi_ci.dev = &spi->dev;
+
+       return stmpe_probe(&spi_ci, id->driver_data);
+}
+
+static int __devexit stmpe_spi_remove(struct spi_device *spi)
+{
+       struct stmpe *stmpe = dev_get_drvdata(&spi->dev);
+
+       return stmpe_remove(stmpe);
+}
+
+static const struct spi_device_id stmpe_spi_id[] = {
+       { "stmpe811", STMPE811 },
+       { "stmpe1601", STMPE1601 },
+       { "stmpe2401", STMPE2401 },
+       { "stmpe2403", STMPE2403 },
+       { }
+};
+MODULE_DEVICE_TABLE(spi, stmpe_id);
+
+static struct spi_driver stmpe_spi_driver = {
+       .driver = {
+               .name   = "stmpe-spi",
+               .bus    = &spi_bus_type,
+               .owner  = THIS_MODULE,
+#ifdef CONFIG_PM
+               .pm     = &stmpe_dev_pm_ops,
+#endif
+       },
+       .probe          = stmpe_spi_probe,
+       .remove         = __devexit_p(stmpe_spi_remove),
+       .id_table       = stmpe_spi_id,
+};
+
+static int __init stmpe_init(void)
+{
+       return spi_register_driver(&stmpe_spi_driver);
+}
+subsys_initcall(stmpe_init);
+
+static void __exit stmpe_exit(void)
+{
+       spi_unregister_driver(&stmpe_spi_driver);
+}
+module_exit(stmpe_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("STMPE MFD SPI Interface Driver");
+MODULE_AUTHOR("Viresh Kumar <viresh.kumar@st.com>");

diff --git a/drivers/mfd/stmpe.h b/drivers/mfd/stmpe.h
index 18d89a6..a73f4c1 100644 (file)
--- a/drivers/mfd/stmpe.h
+++ b/drivers/mfd/stmpe.h
@@ -120,6 +120,7 @@ int stmpe_remove(struct stmpe *stmpe);
 
 #define STMPE811_REG_CHIP_ID           0x00
 #define STMPE811_REG_SYS_CTRL2         0x04
+#define STMPE811_REG_SPI_CFG           0x08
 #define STMPE811_REG_INT_CTRL          0x09
 #define STMPE811_REG_INT_EN            0x0A
 #define STMPE811_REG_INT_STA           0x0B