Re: [PATCH 1/4] i2c: busses: i2c-st: Add ST I2C controller

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On 18/09/2013 12:01, Maxime COQUELIN wrote:
> This patch adds support to SSC (Synchronous Serial Controller)
> I2C driver. This IP also supports SPI protocol, but this is not
> the aim of this driver.
>
> This IP is embedded in all ST SoCs for Set-top box platorms, and
> supports I2C Standard and Fast modes.
>
> Cc: Srinivas Kandagatla <srinivas.kandagatla@xxxxxx>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@xxxxxx>
> ---
>   Documentation/devicetree/bindings/i2c/i2c-st.txt |   35 ++
>   drivers/i2c/busses/Kconfig                       |   10 +
>   drivers/i2c/busses/Makefile                      |    1 +
>   drivers/i2c/busses/i2c-st.c                      |  713 ++++++++++++++++++++++
>   drivers/i2c/busses/i2c-st.h                      |  216 +++++++
>   5 files changed, 975 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/i2c/i2c-st.txt
>   create mode 100644 drivers/i2c/busses/i2c-st.c
>   create mode 100644 drivers/i2c/busses/i2c-st.h
>
> diff --git a/Documentation/devicetree/bindings/i2c/i2c-st.txt b/Documentation/devicetree/bindings/i2c/i2c-st.txt
> new file mode 100644
> index 0000000..a7d6381
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/i2c/i2c-st.txt
> @@ -0,0 +1,35 @@
> +I2C for ST platforms
> +
> +Required properties :
> +- compatible : Must be "st,comms-i2c"
> +- reg : Offset and length of the register set for the device
> +- interrupts : the interrupt number
> +- clocks : phandle to the I2C clock source
> +
> +Recommended (non-standard) properties :
> +- clock-frequency : Desired I2C bus clock frequency in Hz. Otherwise
> +  the default 100 kHz frequency will be used. As only Normal and Fast modes
> +  are supported, possible values are 100000 and 400000.
> +
> +Optional (non-standard) properties:
> +- st,glitches : Enable timing glitch suppression support.
> +- st,glitch-clk : SCL line timinig glitch suppression value in ns.
> +- st,glitch-dat : SDA line timinig glitch suppression value in ns.
> +- st,hw-glitches : Enable filter glitch suppression support.
> +- st,hw-glitch-clk : SCL line filter glitch suppression value in us.
> +- st,hw-glitch-dat : SDA line filter glitch suppression value in us.
> +
> +Examples :
> +
> +i2c0: i2c@fed40000{

Space before the '{'

> +       compatible      = "st,comms-i2c";
> +       reg             = <0xfed40000 0x110>;
> +       interrupts      =  <GIC_SPI 187 IRQ_TYPE_EDGE_RISING>;
> +       clocks          = <&CLK_S_ICN_REG_0>;
> +       clock-frequency = <400000>;
> +       pinctrl-names   = "default";
> +       pinctrl-0       = <&pinctrl_i2c0_default>;
> +       st,glitches;
> +       st,glitch-clk   = 500;
> +       st,glitch-dat   = 500;
> +};
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index cdcbd83..18ff129 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -776,6 +776,16 @@ config I2C_RCAR
>            This driver can also be built as a module.  If so, the module
>            will be called i2c-rcar.
>
> +config I2C_ST
> +       tristate "STMicroelectronics SSC I2C support"
> +       depends on ARCH_STI
> +       help
> +         Enable this option to add support for STMicroelectronics SoCs
> +         hardware SSC (Synchronous Serial Controller) as an I2C controller.
> +
> +         This driver can also be built as module. If so, the module
> +         will be called i2c-st.
> +
>   comment "External I2C/SMBus adapter drivers"
>
>   config I2C_DIOLAN_U2C
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index d00997f..9ea5d422 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -92,5 +92,6 @@ obj-$(CONFIG_I2C_PCA_ISA)     += i2c-pca-isa.o
>   obj-$(CONFIG_I2C_SIBYTE)       += i2c-sibyte.o
>   obj-$(CONFIG_SCx200_ACB)       += scx200_acb.o
>   obj-$(CONFIG_SCx200_I2C)       += scx200_i2c.o
> +obj-$(CONFIG_I2C_ST)           += i2c-st.o
>
>   ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
> diff --git a/drivers/i2c/busses/i2c-st.c b/drivers/i2c/busses/i2c-st.c
> new file mode 100644
> index 0000000..fa4451f
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-st.c
> @@ -0,0 +1,713 @@
> +/*
> + * Copyright (C) 2013 STMicroelectronics
> + *
> + * I2C master mode controller driver, used in STMicroelectronics devices.
> + *
> + * Author: Maxime Coquelin <maxime.coquelin@xxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2, as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/i2c.h>
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/delay.h>
> +#include <linux/interrupt.h>
> +#include <linux/err.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include "i2c-st.h"
> +
> +#define DRIVER_NAME "st-i2c"
> +
> +static struct st_i2c_timings i2c_timings[] = {
> +       [I2C_MODE_STANDARD] = {
> +               .rate                   = 100000,
> +               .rep_start_hold         = 4000,
> +               .rep_start_setup        = 4700,
> +               .start_hold             = 4000,
> +               .data_setup_time        = 250,
> +               .stop_setup_time        = 4000,
> +               .bus_free_time          = 4700,
> +               .glitch_dat_max         = 1200,
> +       },
> +       [I2C_MODE_FAST] = {
> +               .rate                   = 400000,
> +               .rep_start_hold         = 600,
> +               .rep_start_setup        = 600,
> +               .start_hold             = 1000,
> +               .data_setup_time        = 500,
> +               .stop_setup_time        = 900,
> +               .bus_free_time          = 1300,
> +               .glitch_dat_max         = 200,
> +       },
> +};
> +
> +static void st_i2c_flush_rx_fifo(struct st_i2c_dev *i2c_dev)
> +{
> +       int count, i;
> +
> +       /*
> +        * Counter only counts up to 7 but fifo size is 8...
> +        * When fifo is full, counter is 0 and RIR bit of status register is
> +        * set
> +        */
> +       if (readl(i2c_dev->base + SSC_STA) & SSC_STA_RIR)
> +               count = SSC_RXFIFO_SIZE;
> +       else
> +               count = readl(i2c_dev->base + SSC_RX_FSTAT) &
> +                       SSC_RX_FSTAT_STATUS;
> +
> +       for (i = 0; i < count; i++)
> +               readl(i2c_dev->base + SSC_RBUF);
> +}
> +
> +static void st_i2c_soft_reset(struct st_i2c_dev *i2c_dev)
> +{
> +       /*
> +        * FIFO needs to be emptied before reseting the IP,
> +        * else the controller raises a BUSY error.
> +        */
> +       st_i2c_flush_rx_fifo(i2c_dev);
> +
> +       st_i2c_set_bits(i2c_dev->base + SSC_CTL, SSC_CTL_SR);
> +       st_i2c_clr_bits(i2c_dev->base + SSC_CTL, SSC_CTL_SR);
> +}
> +
> +/**
> + * st_i2c_hw_config() - Prepare SSC block, calculate and apply tuning timings
> + * @i2c_dev: Controller's private data
> + */
> +static void st_i2c_hw_config(struct st_i2c_dev *i2c_dev)
> +{
> +       unsigned long rate;
> +       u32 val, ns_per_clk;
> +       struct st_i2c_timings *t = &i2c_timings[i2c_dev->mode];
> +       struct st_i2c_glitches *g = &i2c_dev->glitches;
> +
> +       st_i2c_soft_reset(i2c_dev);
> +
> +       val = SSC_CLR_REPSTRT | SSC_CLR_NACK | SSC_CLR_SSCARBL |
> +               SSC_CLR_SSCAAS | SSC_CLR_SSCSTOP;
> +       writel(val, i2c_dev->base + SSC_CLR);
> +
> +       /* SSC Control register setup */
> +       val = SSC_CTL_PO | SSC_CTL_PH | SSC_CTL_HB | SSC_CTL_DATA_WIDTH_9;
> +       writel(val, i2c_dev->base + SSC_CTL);
> +
> +       rate = clk_get_rate(i2c_dev->clk);
> +       ns_per_clk = 1000000000 / rate;
> +
> +       /* Baudrate */
> +       val = rate / (2 * t->rate);
> +       writel(val, i2c_dev->base + SSC_BRG);
> +
> +       /* Pre-scaler baudrate */
> +       writel(1, i2c_dev->base + SSC_PRE_SCALER_BRG);
> +
> +       /* Enable I2C mode */
> +       writel(SSC_I2C_I2CM, i2c_dev->base + SSC_I2C);
> +
> +       /* Repeated start hold time */
> +       val = (t->rep_start_hold + g->glitch_dat) / ns_per_clk;
> +       writel(val, i2c_dev->base + SSC_REP_START_HOLD);
> +
> +       /* Repeated start set up time */
> +       val = (t->rep_start_setup + g->glitch_clk) / ns_per_clk;
> +       writel(val, i2c_dev->base + SSC_REP_START_SETUP);
> +
> +       /* Start hold time */
> +       if (g->glitch_dat < t->glitch_dat_max)
> +               val = (t->start_hold + g->glitch_dat) / ns_per_clk;
> +       else
> +               val = (t->start_hold + t->glitch_dat_max) / ns_per_clk;
> +       writel(val, i2c_dev->base + SSC_START_HOLD);
> +
> +       /* Data set up time */
> +       val = (t->data_setup_time + g->glitch_dat) / ns_per_clk;
> +       writel(val, i2c_dev->base + SSC_DATA_SETUP);
> +
> +       /* Stop set up time */
> +       val = (t->stop_setup_time + g->glitch_clk) / ns_per_clk;
> +       writel(val, i2c_dev->base + SSC_STOP_SETUP);
> +
> +       /* Bus free time */
> +       val = (t->bus_free_time + g->glitch_dat) / ns_per_clk;
> +       writel(val, i2c_dev->base + SSC_BUS_FREE);
> +
> +       if (!g->hw_glitches) {
> +               writel(0, i2c_dev->base + SSC_NOISE_SUPP_WIDTH);
> +               return;
> +       }
> +
> +       /* Prescalers set up */
> +       val = rate / 10000000;
> +       writel(val, i2c_dev->base + SSC_PRSCALER);
> +       writel(val, i2c_dev->base + SSC_PRSCALER_DATAOUT);
> +
> +       /* Noise suppression witdh */
> +       val = g->hw_glitch_clk * rate / 100000000;
> +       writel(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH);
> +
> +       /* Noise suppression max output data delay width */
> +       val = g->hw_glitch_dat * rate / 100000000;
> +       writel(val, i2c_dev->base + SSC_NOISE_SUPP_WIDTH_DATAOUT);
> +
> +       return;
> +}
> +
> +static int st_i2c_wait_free_bus(struct st_i2c_dev *i2c_dev)
> +{
> +       u32 sta;
> +       int i;
> +
> +       for (i = 0; i < 10; i++) {
> +               sta = readl(i2c_dev->base + SSC_STA);
> +               if (!(sta & SSC_STA_BUSY))
> +                       return 0;
> +
> +               usleep_range(2000, 4000);
> +       }
> +
> +       dev_err(i2c_dev->dev, "bus not free (status = 0x%08x)\n", sta);
> +
> +       return -EBUSY;
> +}
> +
> +/**
> + * st_i2c_write_tx_fifo() - Write a byte in the Tx FIFO
> + * @i2c_dev: Controller's private data
> + * @byte: Data to write in the Tx FIFO
> + */
> +static inline void st_i2c_write_tx_fifo(struct st_i2c_dev *i2c_dev, u8 byte)
> +{
> +       u16 tbuf = byte << 1;
> +
> +       writel(tbuf | 1, i2c_dev->base + SSC_TBUF);
> +}
> +
> +/**
> + * st_i2c_wr_fill_tx_fifo() - Fill the Tx FIFO in write mode
> + * @i2c_dev: Controller's private data
> + *
> + * This functions fills the Tx FIFO with I2C transfert buffer when
> + * in write mode.
> + */
> +static void st_i2c_wr_fill_tx_fifo(struct st_i2c_dev *i2c_dev)
> +{
> +       struct st_i2c_client *c = &i2c_dev->client;
> +       u32 tx_fstat, sta;
> +       int i;
> +
> +       sta = readl(i2c_dev->base + SSC_STA);
> +       if (sta & SSC_STA_TX_FIFO_FULL)
> +               return;
> +
> +       tx_fstat = readl(i2c_dev->base + SSC_TX_FSTAT) & SSC_TX_FSTAT_STATUS;
> +
> +       if (c->count < (SSC_TXFIFO_SIZE - tx_fstat))
> +               i = c->count;
> +       else
> +               i = SSC_TXFIFO_SIZE - tx_fstat;
> +
> +       for (; i > 0; i--, c->count--, c->buf++)
> +               st_i2c_write_tx_fifo(i2c_dev, *c->buf);
> +}
> +
> +/**
> + * st_i2c_rd_fill_tx_fifo() - Fill the Tx FIFO in read mode
> + * @i2c_dev: Controller's private data
> + *
> + * This functions fills the Tx FIFO with fixed pattern when
> + * in read mode to trigger clock.
> + */
> +static void st_i2c_rd_fill_tx_fifo(struct st_i2c_dev *i2c_dev, int max)
> +{
> +       struct st_i2c_client *c = &i2c_dev->client;
> +       u32 tx_fstat, sta;
> +       int i;
> +
> +       sta = readl(i2c_dev->base + SSC_STA);
> +       if (sta & SSC_STA_TX_FIFO_FULL)
> +               return;
> +
> +       tx_fstat = readl(i2c_dev->base + SSC_TX_FSTAT) & SSC_TX_FSTAT_STATUS;
> +
> +       if (max < (SSC_TXFIFO_SIZE - tx_fstat))
> +               i = max;
> +       else
> +               i = SSC_TXFIFO_SIZE - tx_fstat;
> +
> +       for (; i > 0; i--, c->xfered++)
> +               st_i2c_write_tx_fifo(i2c_dev, 0xff);
> +}
> +
> +static void st_i2c_read_rx_fifo(struct st_i2c_dev *i2c_dev)
> +{
> +       struct st_i2c_client *c = &i2c_dev->client;
> +       u32 i, sta;
> +       u16 rbuf;
> +
> +       sta = readl(i2c_dev->base + SSC_STA);
> +       if (sta & SSC_STA_RIR) {
> +               i = SSC_RXFIFO_SIZE;
> +       } else {
> +               i = readl(i2c_dev->base + SSC_RX_FSTAT);
> +               i &= SSC_RX_FSTAT_STATUS;
> +       }
> +
> +       for (; (i > 0) && (c->count > 0); i--, c->count--) {
> +               rbuf = readl(i2c_dev->base + SSC_RBUF) >> 1;
> +               *c->buf++ = (u8)rbuf & 0xff;
> +       }
> +
> +       if (i) {
> +               dev_err(i2c_dev->dev, "Unexpected %d bytes in rx fifo\n", i);
> +               st_i2c_flush_rx_fifo(i2c_dev);
> +       }
> +}
> +
> +/**
> + * st_i2c_terminate_xfer() - Send either STOP or REPSTART condition
> + * @i2c_dev: Controller's private data
> + */
> +static void st_i2c_terminate_xfer(struct st_i2c_dev *i2c_dev)
> +{
> +       struct st_i2c_client *c = &i2c_dev->client;
> +
> +       st_i2c_clr_bits(i2c_dev->base + SSC_IEN, SSC_IEN_TEEN);
> +       st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STRTG);
> +
> +       if (c->stop) {
> +               st_i2c_set_bits(i2c_dev->base + SSC_IEN, SSC_IEN_STOPEN);
> +               st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG);
> +       } else {
> +               st_i2c_set_bits(i2c_dev->base + SSC_IEN, SSC_IEN_REPSTRTEN);
> +               st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_REPSTRTG);
> +       }
> +}
> +
> +/**
> + * st_i2c_handle_write() - Handle FIFO empty interrupt in case of write
> + * @i2c_dev: Controller's private data
> + */
> +static void st_i2c_handle_write(struct st_i2c_dev *i2c_dev)
> +{
> +       struct st_i2c_client *c = &i2c_dev->client;
> +
> +       st_i2c_flush_rx_fifo(i2c_dev);
> +
> +       if (!c->count)
> +               /* End of xfer, send stop or repstart */
> +               st_i2c_terminate_xfer(i2c_dev);
> +       else
> +               st_i2c_wr_fill_tx_fifo(i2c_dev);
> +}
> +
> +/**
> + * st_i2c_handle_write() - Handle FIFO enmpty interrupt in case of read
> + * @i2c_dev: Controller's private data
> + */
> +static void st_i2c_handle_read(struct st_i2c_dev *i2c_dev)
> +{
> +       struct st_i2c_client *c = &i2c_dev->client;
> +       u32 ien;
> +
> +       /* Trash the address read back */
> +       if (!c->xfered) {
> +               readl(i2c_dev->base + SSC_RBUF);
> +               st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_TXENB);
> +       } else
> +               st_i2c_read_rx_fifo(i2c_dev);
> +
> +       if (!c->count) {
> +               /* End of xfer, send stop or repstart */
> +               st_i2c_terminate_xfer(i2c_dev);
> +       } else if (c->count == 1) {
> +               /* Penultimate byte to xfer, disable ACK gen. */
> +               st_i2c_clr_bits(i2c_dev->base + SSC_I2C, SSC_I2C_ACKG);
> +
> +               /* Last received byte is to be handled by NACK interrupt */
> +               ien = SSC_IEN_NACKEN | SSC_IEN_ARBLEN;
> +               writel(ien, i2c_dev->base + SSC_IEN);
> +
> +               st_i2c_rd_fill_tx_fifo(i2c_dev, c->count);
> +       } else
> +               st_i2c_rd_fill_tx_fifo(i2c_dev, c->count - 1);
> +}
> +
> +/**
> + * st_i2c_isr() - Interrupt routine
> + * @irq: interrupt number
> + * @data: Controller's private data
> + */
> +static irqreturn_t st_i2c_isr(int irq, void *data)
> +{
> +       struct st_i2c_dev *i2c_dev = data;
> +       struct st_i2c_client *c = &i2c_dev->client;
> +       u32 sta, ien, it;
> +
> +       ien = readl(i2c_dev->base + SSC_IEN);
> +       sta = readl(i2c_dev->base + SSC_STA);
> +
> +       /* Use __fls() to check error bits first */
> +       it = __fls(sta & ien);
> +
> +       switch (1 << it) {
> +       case SSC_STA_TE:
> +               if (c->addr & I2C_M_RD)
> +                       st_i2c_handle_read(i2c_dev);
> +               else
> +                       st_i2c_handle_write(i2c_dev);
> +               break;
> +
> +       case SSC_STA_STOP:
> +       case SSC_STA_REPSTRT:
> +               writel(0, i2c_dev->base + SSC_IEN);
> +               complete(&i2c_dev->complete);
> +               break;
> +
> +       case SSC_STA_NACK:
> +               writel(SSC_CLR_NACK, i2c_dev->base + SSC_CLR);
> +
> +               /* Last received byte handled by NACK interrupt */
> +               if ((c->addr & I2C_M_RD) && (c->count == 1) && (c->xfered)) {
> +                       st_i2c_handle_read(i2c_dev);
> +                       break;
> +               }
> +
> +               it = SSC_IEN_STOPEN | SSC_IEN_ARBLEN;
> +               writel(it, i2c_dev->base + SSC_IEN);
> +
> +               st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG);
> +               c->result = -EIO;
> +               break;
> +
> +       case SSC_STA_ARBL:
> +               writel(SSC_CLR_SSCARBL, i2c_dev->base + SSC_CLR);
> +
> +               it = SSC_IEN_STOPEN | SSC_IEN_ARBLEN;
> +               writel(it, i2c_dev->base + SSC_IEN);
> +
> +               st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STOPG);
> +               c->result = -EIO;
> +               break;
> +
> +       default:
> +               dev_err(i2c_dev->dev, "%s: it %d unhandled (status=0x%08x)\n",
> +                               __func__, it, readl(i2c_dev->base + SSC_STA));
> +       }
> +
> +       return IRQ_HANDLED;
> +}
> +
> +/**
> + * st_i2c_xfer_msg() - Transfer a single I2C message
> + * @i2c_dev: Controller's private data
> + * @msg: I2C message to transfer
> + * @is_first: first message of the sequence
> + * @is_last: last message of the sequence
> + */
> +static int st_i2c_xfer_msg(struct st_i2c_dev *i2c_dev, struct i2c_msg *msg,
> +                           bool is_first, bool is_last)
> +{
> +       struct st_i2c_client *c = &i2c_dev->client;
> +       u32 ctl, i2c, it;
> +       unsigned long timeout;
> +       int ret;
> +
> +       c->addr         = (u8)(msg->addr << 1);
> +       c->addr         |= (msg->flags & I2C_M_RD);
> +       c->buf          = msg->buf;
> +       c->count        = msg->len;
> +       c->xfered       = 0;
> +       c->result       = 0;
> +       c->stop         = is_last;
> +
> +       init_completion(&i2c_dev->complete);
> +
> +       ctl = SSC_CTL_EN | SSC_CTL_MS | SSC_CTL_EN_RX_FIFO | SSC_CTL_EN_TX_FIFO;
> +       st_i2c_set_bits(i2c_dev->base + SSC_CTL, ctl);
> +
> +       i2c = SSC_I2C_TXENB;
> +       if (c->addr & I2C_M_RD)
> +               i2c |= SSC_I2C_ACKG;
> +       st_i2c_set_bits(i2c_dev->base + SSC_I2C, i2c);
> +
> +       /* Write slave address */
> +       st_i2c_write_tx_fifo(i2c_dev, c->addr);
> +
> +       /* Pre-fill Tx fifo with data in case of write */
> +       if (!(c->addr & I2C_M_RD))
> +               st_i2c_wr_fill_tx_fifo(i2c_dev);
> +
> +       it = SSC_IEN_NACKEN | SSC_IEN_TEEN | SSC_IEN_ARBLEN;
> +       writel(it, i2c_dev->base + SSC_IEN);
> +
> +       if (is_first) {
> +               ret = st_i2c_wait_free_bus(i2c_dev);
> +               if (ret)
> +                       return ret;
> +
> +               st_i2c_set_bits(i2c_dev->base + SSC_I2C, SSC_I2C_STRTG);
> +       }
> +
> +       timeout = wait_for_completion_timeout(&i2c_dev->complete,
> +                       i2c_dev->adap.timeout);
> +       ret = c->result;
> +
> +       if (!timeout) {
> +               dev_err(i2c_dev->dev, "Write to slave 0x%x timed out\n",
> +                               c->addr);
> +               ret = -ETIMEDOUT;
> +       }
> +
> +       i2c = SSC_I2C_STOPG | SSC_I2C_REPSTRTG;
> +       st_i2c_clr_bits(i2c_dev->base + SSC_I2C, i2c);
> +
> +       writel(SSC_CLR_SSCSTOP | SSC_CLR_REPSTRT, i2c_dev->base + SSC_CLR);
> +
> +       return ret;
> +}
> +
> +/**
> + * st_i2c_xfer() - Transfer a single I2C message
> + * @i2c_adap: Adapter pointer to the controller
> + * @msgs: Pointer to data to be written.
> + * @num: Number of messages to be executed
> + */
> +static int st_i2c_xfer(struct i2c_adapter *i2c_adap,
> +                       struct i2c_msg msgs[], int num)
> +{
> +       struct st_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap);
> +       bool last, first;
> +       int ret, i;
> +
> +       i2c_dev->busy = true;
> +
> +       ret = clk_prepare_enable(i2c_dev->clk);
> +       if (ret) {
> +               dev_err(i2c_dev->dev, "Failed to prepare_enable clock\n");
> +               return ret;
> +       }
> +
> +       pinctrl_pm_select_default_state(i2c_dev->dev);
> +
> +       st_i2c_hw_config(i2c_dev);
> +
> +       first = true;
> +
> +       for (i = 0; i < num; i++) {
> +               last = (i < num - 1) ? false : true;
> +
> +               ret = st_i2c_xfer_msg(i2c_dev, &msgs[i], first, last);
> +               if (ret)
> +                       break;
> +
> +               first = false;
> +       }
> +
> +       pinctrl_pm_select_idle_state(i2c_dev->dev);
> +
> +       clk_disable_unprepare(i2c_dev->clk);
> +
> +       i2c_dev->busy = false;
> +
> +       return (ret < 0) ? ret : i;
> +}
> +
> +#ifdef CONFIG_PM
> +static int st_i2c_suspend(struct device *dev)
> +{
> +       struct platform_device *pdev =
> +               container_of(dev, struct platform_device, dev);
> +       struct st_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
> +
> +       if (i2c_dev->busy)
> +               return -EBUSY;
> +
> +       pinctrl_pm_select_sleep_state(dev);
> +
> +       return 0;
> +}
> +
> +static int st_i2c_resume(struct device *dev)
> +{
> +       pinctrl_pm_select_default_state(dev);
> +       /* Go in idle state if available */
> +       pinctrl_pm_select_idle_state(dev);
> +
> +       return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(st_i2c_pm, st_i2c_suspend, st_i2c_resume);
> +#define ST_I2C_PM      (&st_i2c_pm)
> +#else
> +#define ST_I2C_PM      NULL
> +#endif
> +
> +static u32 st_i2c_func(struct i2c_adapter *adap)
> +{
> +       return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> +}
> +
> +static struct i2c_algorithm st_i2c_algo = {
> +       .master_xfer = st_i2c_xfer,
> +       .functionality = st_i2c_func,
> +};
> +
> +static int st_i2c_of_get_glitches(struct device_node *np,
> +               struct st_i2c_dev *i2c_dev)
> +{
> +       struct st_i2c_glitches *g = &i2c_dev->glitches;
> +       int ret;
> +
> +       g->glitches = of_property_read_bool(np, "st,glitches");
> +       if (g->glitches) {
> +               ret = of_property_read_u32(np, "st,glitch-clk",
> +                               &g->glitch_clk);
> +               if (ret) {
> +                       dev_err(i2c_dev->dev, "st,glitch-clk not found\n");
> +                       return ret;
> +               }
> +
> +               ret = of_property_read_u32(np, "st,glitch-dat",
> +                               &g->glitch_dat);
> +               if (ret) {
> +                       dev_err(i2c_dev->dev, "st,glitch-dat not found\n");
> +                       return ret;
> +               }
> +       }
> +
> +       g->hw_glitches = of_property_read_bool(np, "st,hw-glitches");
> +       if (g->hw_glitches) {
> +               ret = of_property_read_u32(np, "st,hw-glitch-clk",
> +                               &g->hw_glitch_clk);
> +               if (ret) {
> +                       dev_err(i2c_dev->dev, "st,hw-glitch-clk not found\n");
> +                       return ret;
> +               }
> +
> +               ret = of_property_read_u32(np, "st,hw-glitch-dat",
> +                               &g->hw_glitch_dat);
> +               if (ret) {
> +                       dev_err(i2c_dev->dev, "st,hw-glitch-dat not found\n");
> +                       return ret;
> +               }
> +       }
> +
> +       return 0;
> +}
> +
> +static int st_i2c_probe(struct platform_device *pdev)
> +{
> +       struct device_node *np = pdev->dev.of_node;
> +       struct st_i2c_dev *i2c_dev;
> +       struct resource *res;
> +       u32 clk_rate;
> +       struct i2c_adapter *adap;
> +       int ret;
> +
> +       i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
> +       if (!i2c_dev)
> +               return -ENOMEM;
> +
> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       i2c_dev->base = devm_ioremap_resource(&pdev->dev, res);
> +       if (IS_ERR(i2c_dev->base))
> +               return PTR_ERR(i2c_dev->base);
> +
> +       i2c_dev->irq = irq_of_parse_and_map(np, 0);
> +       if (!i2c_dev->irq) {
> +               dev_err(&pdev->dev, "IRQ missing or invalid\n");
> +               return -EINVAL;
> +       }
> +
> +       i2c_dev->clk = of_clk_get(np, 0);
> +       if (IS_ERR(i2c_dev->clk)) {
> +               dev_err(&pdev->dev, "Unable to request clock\n");
> +               return PTR_ERR(i2c_dev->clk);
> +       }
> +
> +       i2c_dev->mode = I2C_MODE_STANDARD;
> +       ret = of_property_read_u32(np, "clock-frequency", &clk_rate);
> +       if ((!ret) && (clk_rate == 400000))
> +               i2c_dev->mode = I2C_MODE_FAST;
> +
> +       i2c_dev->dev = &pdev->dev;
> +
> +       ret = devm_request_irq(&pdev->dev, i2c_dev->irq, st_i2c_isr, 0,
> +                       pdev->name, i2c_dev);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq);
> +               return ret;
> +       }
> +
> +       pinctrl_pm_select_default_state(i2c_dev->dev);
> +       /* In case idle state available, select it */
> +       pinctrl_pm_select_idle_state(i2c_dev->dev);
> +
> +       ret = st_i2c_of_get_glitches(np, i2c_dev);
> +       if (ret)
> +               return ret;
> +
> +       adap = &i2c_dev->adap;
> +       i2c_set_adapdata(adap, i2c_dev);
> +       snprintf(adap->name, sizeof(adap->name), "ST I2C(0x%08x)", res->start);
> +       adap->owner = THIS_MODULE;
> +       adap->timeout = 2 * HZ;
> +       adap->retries = 0;
> +       adap->class = I2C_CLASS_HWMON | I2C_CLASS_DDC | I2C_CLASS_SPD;
> +       adap->algo = &st_i2c_algo;
> +       adap->dev.parent = &pdev->dev;
> +       adap->dev.of_node = pdev->dev.of_node;
> +
> +       ret = i2c_add_adapter(adap);
> +       if (ret) {
> +               dev_err(&pdev->dev, "Failed to add adapter\n");
> +               return ret;
> +       }
> +
> +       platform_set_drvdata(pdev, i2c_dev);
> +
> +       dev_info(i2c_dev->dev, "%s initialized\n", adap->name);
> +
> +       return 0;
> +}
> +
> +static int st_i2c_remove(struct platform_device *pdev)
> +{
> +       struct st_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
> +
> +       i2c_del_adapter(&i2c_dev->adap);
> +
> +       return 0;
> +}
> +
> +static struct of_device_id st_i2c_match[] = {
> +       { .compatible = "st,comms-i2c", },
> +       {},
> +};
> +MODULE_DEVICE_TABLE(of, st_i2c_match);
> +
> +static struct platform_driver st_i2c_driver = {
> +       .driver = {
> +               .name = DRIVER_NAME,
> +               .owner = THIS_MODULE,
> +               .of_match_table = st_i2c_match,
> +               .pm = &st_i2c_pm,
> +       },
> +       .probe = st_i2c_probe,
> +       .remove = st_i2c_remove,
> +};
> +
> +module_platform_driver(st_i2c_driver);
> +
> +MODULE_AUTHOR("STMicroelectronics");
> +MODULE_DESCRIPTION("STMicroelectronics I2C driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/i2c/busses/i2c-st.h b/drivers/i2c/busses/i2c-st.h
> new file mode 100644
> index 0000000..7bce6c0
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-st.h
> @@ -0,0 +1,216 @@
> +/*
> + * Copyright (C) 2013 STMicroelectronics
> + *
> + * I2C master mode controller driver, used in STMicroelectronics devices.
> + *
> + * Author: Maxime Coquelin <maxime.coquelin@xxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2, as
> + * published by the Free Software Foundation.
> + */
> +
> +#ifndef __I2C_ST_H_
> +#define __I2C_ST_H_
> +
> +/* SSC registers */
> +#define SSC_BRG                                0x000
> +#define SSC_TBUF                       0x004
> +#define SSC_RBUF                       0x008
> +#define SSC_CTL                                0x00C
> +#define SSC_IEN                                0x010
> +#define SSC_STA                                0x014
> +#define SSC_I2C                                0x018
> +#define SSC_SLAD                       0x01C
> +#define SSC_REP_START_HOLD             0x020
> +#define SSC_START_HOLD                 0x024
> +#define SSC_REP_START_SETUP            0x028
> +#define SSC_DATA_SETUP                 0x02C
> +#define SSC_STOP_SETUP                 0x030
> +#define SSC_BUS_FREE                   0x034
> +#define SSC_TX_FSTAT                   0x038
> +#define SSC_RX_FSTAT                   0x03C
> +#define SSC_PRE_SCALER_BRG             0x040
> +#define SSC_CLR                                0x080
> +#define SSC_NOISE_SUPP_WIDTH           0x100
> +#define SSC_PRSCALER                   0x104
> +#define SSC_NOISE_SUPP_WIDTH_DATAOUT   0x108
> +#define SSC_PRSCALER_DATAOUT           0x10c
> +
> +/* SSC Control */
> +#define SSC_CTL_DATA_WIDTH_9           0x8
> +#define SSC_CTL_DATA_WIDTH_MSK         0xf
> +#define SSC_CTL_BM                     0xf
> +#define SSC_CTL_HB                     BIT(4)
> +#define SSC_CTL_PH                     BIT(5)
> +#define SSC_CTL_PO                     BIT(6)
> +#define SSC_CTL_SR                     BIT(7)
> +#define SSC_CTL_MS                     BIT(8)
> +#define SSC_CTL_EN                     BIT(9)
> +#define SSC_CTL_LPB                    BIT(10)
> +#define SSC_CTL_EN_TX_FIFO             BIT(11)
> +#define SSC_CTL_EN_RX_FIFO             BIT(12)
> +#define SSC_CTL_EN_CLST_RX             BIT(13)
> +
> +/* SSC Interrupt Enable */
> +#define SSC_IEN_RIEN                   BIT(0)
> +#define SSC_IEN_TIEN                   BIT(1)
> +#define SSC_IEN_TEEN                   BIT(2)
> +#define SSC_IEN_REEN                   BIT(3)
> +#define SSC_IEN_PEEN                   BIT(4)
> +#define SSC_IEN_AASEN                  BIT(6)
> +#define SSC_IEN_STOPEN                 BIT(7)
> +#define SSC_IEN_ARBLEN                 BIT(8)
> +#define SSC_IEN_NACKEN                 BIT(10)
> +#define SSC_IEN_REPSTRTEN              BIT(11)
> +#define SSC_IEN_TX_FIFO_HALF           BIT(12)
> +#define SSC_IEN_RX_FIFO_HALF_FULL      BIT(14)
> +
> +/* SSC Status */
> +#define SSC_STA_RIR                    BIT(0)
> +#define SSC_STA_TIR                    BIT(1)
> +#define SSC_STA_TE                     BIT(2)
> +#define SSC_STA_RE                     BIT(3)
> +#define SSC_STA_PE                     BIT(4)
> +#define SSC_STA_CLST                   BIT(5)
> +#define SSC_STA_AAS                    BIT(6)
> +#define SSC_STA_STOP                   BIT(7)
> +#define SSC_STA_ARBL                   BIT(8)
> +#define SSC_STA_BUSY                   BIT(9)
> +#define SSC_STA_NACK                   BIT(10)
> +#define SSC_STA_REPSTRT                        BIT(11)
> +#define SSC_STA_TX_FIFO_HALF           BIT(12)
> +#define SSC_STA_TX_FIFO_FULL           BIT(13)
> +#define SSC_STA_RX_FIFO_HALF           BIT(14)
> +
> +/* SSC I2C Control */
> +#define SSC_I2C_I2CM                   BIT(0)
> +#define SSC_I2C_STRTG                  BIT(1)
> +#define SSC_I2C_STOPG                  BIT(2)
> +#define SSC_I2C_ACKG                   BIT(3)
> +#define SSC_I2C_AD10                   BIT(4)
> +#define SSC_I2C_TXENB                  BIT(5)
> +#define SSC_I2C_REPSTRTG               BIT(11)
> +#define SSC_I2C_SLAVE_DISABLE          BIT(12)
> +
> +/* SSC Tx FIFO Status */
> +#define SSC_TX_FSTAT_STATUS            0x07
> +
> +/* SSC Rx FIFO Status */
> +#define SSC_RX_FSTAT_STATUS            0x07
> +
> +/* SSC Clear bit operation */
> +#define SSC_CLR_SSCAAS                 BIT(6)
> +#define SSC_CLR_SSCSTOP                        BIT(7)
> +#define SSC_CLR_SSCARBL                        BIT(8)
> +#define SSC_CLR_NACK                   BIT(10)
> +#define SSC_CLR_REPSTRT                        BIT(11)
> +
> +/* SSC Clock Prescaler */
> +#define SSC_PRSC_VALUE                 0x0f
> +
> +
> +#define SSC_TXFIFO_SIZE                        0x8
> +#define SSC_RXFIFO_SIZE                        0x8
> +
> +enum st_i2c_mode {
> +       I2C_MODE_STANDARD,
> +       I2C_MODE_FAST,
> +       I2C_MODE_END,
> +};
> +
> +/**
> + * struct st_i2c_timings - per-Mode tuning parameters
> + * @rate: I2C bus rate
> + * @rep_start_hold: I2C repeated start hold time requirement
> + * @rep_start_setup: I2C repeated start set up time requirement
> + * @start_hold: I2C start hold time requirement
> + * @data_setup_time: I2C data set up time requirement
> + * @stop_setup_time: I2C stop set up time requirement
> + * @bus_free_time: I2C bus free time requirement
> + * @glitch_dat_max: I2C data glitch max time
> + */
> +struct st_i2c_timings {
> +       u32 rate;
> +       u32 rep_start_hold;
> +       u32 rep_start_setup;
> +       u32 start_hold;
> +       u32 data_setup_time;
> +       u32 stop_setup_time;
> +       u32 bus_free_time;
> +       u32 glitch_dat_max;
> +};
> +
> +/**
> + * struct st_i2c_glitches - per-SoC tuning parameters
> + * @glitches: Glitches are defined for this SoC
> + * @glitch_clk: Clk line glitch tuning value
> + * @glitch_dat: Data line glitch tuning value
> + * @hw_glitches: HW glitches are defined for this SoC
> + * @hw_glitch_clk: Clk line hw glitch value
> + * @hw_glitch_dat: Data line hw glitch value
> + */
> +struct st_i2c_glitches {
> +       bool    glitches;
> +       u32     glitch_clk;
> +       u32     glitch_dat;
> +       bool    hw_glitches;
> +       u32     hw_glitch_clk;
> +       u32     hw_glitch_dat;
> +};
> +
> +/**
> + * struct st_i2c_client - client specific data
> + * @addr: 8-bit slave addr, including r/w bit
> + * @count: number of bytes to be transfered
> + * @xfered: number of bytes already transferred
> + * @buf: data buffer
> + * @result: result of the transfer
> + * @stop: last I2C msg to be sent, i.e. STOP to be generated
> + */
> +struct st_i2c_client {
> +       u8      addr;
> +       u32     count;
> +       u32     xfered;
> +       u8      *buf;
> +       int     result;
> +       bool    stop;
> +};
> +
> +/**
> + * struct st_i2c_dev - private data of the controller
> + * @adap: I2C adapter for this controller
> + * @dev: device for this controller
> + * @base: virtual memory area
> + * @complete: completion of I2C message
> + * @irq: interrupt line for th controller
> + * @clk: hw ssc block clock
> + * @mode: I2C mode of the controller. Standard or Fast only supported
> + * @glitches: Glitch filters tuning parameters
> + * @client: I2C transfert information
> + * @busy: I2C transfer on-going
> + */
> +struct st_i2c_dev {
> +       struct i2c_adapter      adap;
> +       struct device           *dev;
> +       void __iomem            *base;
> +       struct completion       complete;
> +       int                     irq;
> +       struct clk              *clk;
> +       int                     mode;
> +       struct st_i2c_glitches glitches;
> +       struct st_i2c_client    client;
> +       bool                    busy;
> +};
> +
> +static inline void st_i2c_set_bits(void __iomem *reg, u32 mask)
> +{
> +       writel(readl(reg) | mask, reg);
> +}
> +
> +static inline void st_i2c_clr_bits(void __iomem *reg, u32 mask)
> +{
> +       writel(readl(reg) & ~mask, reg);
> +}
> +
> +#endif /* __I2C_ST_H_ */
> --
> 1.7.9.5
>
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