target/linux/layerscape/patches-5.4/808-i2c-0011-i2c-imx-support-slave-mode-for-imx-I2C-driver.patch

   1 From 865433df5d11aef7cfe5d51b362b6276bddb7a15 Mon Sep 17 00:00:00 2001
   2 From: Biwen Li <biwen.li@nxp.com>
   3 Date: Fri, 2 Aug 2019 17:45:56 +0800
   4 Subject: [PATCH] i2c: imx: support slave mode for imx I2C driver
   5
   6 The patch supports slave mode for imx I2C driver
   7
   8 Reviewed-by: Clark Wang <xiaoning.wang@nxp.com>
   9 Signed-off-by: Biwen Li <biwen.li@nxp.com>
  10 ---
  11  drivers/i2c/busses/i2c-imx.c | 219 +++++++++++++++++++++++++++++++++++++++----
  12  1 file changed, 201 insertions(+), 18 deletions(-)
  13
  14 --- a/drivers/i2c/busses/i2c-imx.c
  15 +++ b/drivers/i2c/busses/i2c-imx.c
  16 @@ -265,6 +265,9 @@ struct imx_i2c_struct {
  17         int                     pmuxcr_set;
  18         int                     pmuxcr_endian;
  19         void __iomem            *pmuxcr_addr;
  20 +#if IS_ENABLED(CONFIG_I2C_SLAVE)
  21 +       struct i2c_client       *slave;
  22 +#endif
  23  };
  24
  25  static const struct imx_i2c_hwdata imx1_i2c_hwdata = {
  26 @@ -357,6 +360,14 @@ static inline unsigned char imx_i2c_read
  27         return readb(i2c_imx->base + (reg << i2c_imx->hwdata->regshift));
  28  }
  29
  30 +/* Set up i2c controller register and i2c status register to default value. */
  31 +static void i2c_imx_reset_regs(struct imx_i2c_struct *i2c_imx)
  32 +{
  33 +       imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
  34 +                       i2c_imx, IMX_I2C_I2CR);
  35 +       imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
  36 +}
  37 +
  38  /* Functions for DMA support */
  39  static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
  40                                                 dma_addr_t phy_addr)
  41 @@ -681,23 +692,33 @@ static void i2c_imx_stop(struct imx_i2c_
  42         imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
  43  }
  44
  45 -static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
  46 +/* Clear interrupt flag bit */
  47 +static void i2c_imx_clr_if_bit(unsigned int status, struct imx_i2c_struct *i2c_imx)
  48  {
  49 -       struct imx_i2c_struct *i2c_imx = dev_id;
  50 -       unsigned int temp;
  51 +       status &= ~I2SR_IIF;
  52 +       status |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF);
  53 +       imx_i2c_write_reg(status, i2c_imx, IMX_I2C_I2SR);
  54 +}
  55
  56 -       temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
  57 -       if (temp & I2SR_IIF) {
  58 -               /* save status register */
  59 -               i2c_imx->i2csr = temp;
  60 -               temp &= ~I2SR_IIF;
  61 -               temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF);
  62 -               imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
  63 -               wake_up(&i2c_imx->queue);
  64 -               return IRQ_HANDLED;
  65 -       }
  66 +/* Clear arbitration lost bit */
  67 +static void i2c_imx_clr_al_bit(unsigned int status, struct imx_i2c_struct *i2c_imx)
  68 +{
  69 +       status &= ~I2SR_IAL;
  70 +       status |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IAL);
  71 +       imx_i2c_write_reg(status, i2c_imx, IMX_I2C_I2SR);
  72 +}
  73
  74 -       return IRQ_NONE;
  75 +static irqreturn_t i2c_imx_master_isr(struct imx_i2c_struct *i2c_imx)
  76 +{
  77 +       unsigned int status;
  78 +
  79 +       /* Save status register */
  80 +       status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
  81 +       i2c_imx->i2csr = status | I2SR_IIF;
  82 +
  83 +       wake_up(&i2c_imx->queue);
  84 +
  85 +       return IRQ_HANDLED;
  86  }
  87
  88  static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx,
  89 @@ -1066,6 +1087,13 @@ static int i2c_imx_xfer(struct i2c_adapt
  90
  91         dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
  92
  93 +#if IS_ENABLED(CONFIG_I2C_SLAVE)
  94 +       if (i2c_imx->slave) {
  95 +               dev_err(&i2c_imx->adapter.dev, "Please not do operations of master mode in slave mode");
  96 +               return -EBUSY;
  97 +       }
  98 +#endif
  99 +
 100         if (!pm_runtime_enabled(i2c_imx->adapter.dev.parent)) {
 101                 pm_runtime_enable(i2c_imx->adapter.dev.parent);
 102                 enable_runtime_pm = true;
 103 @@ -1279,11 +1307,169 @@ static u32 i2c_imx_func(struct i2c_adapt
 104                 | I2C_FUNC_SMBUS_READ_BLOCK_DATA;
 105  }
 106
 107 +#if IS_ENABLED(CONFIG_I2C_SLAVE)
 108 +static int i2c_imx_slave_init(struct imx_i2c_struct *i2c_imx)
 109 +{
 110 +       int temp;
 111 +
 112 +       /* Resume */
 113 +       temp = pm_runtime_get_sync(i2c_imx->adapter.dev.parent);
 114 +       if (temp < 0) {
 115 +               dev_err(&i2c_imx->adapter.dev, "failed to resume i2c controller");
 116 +               return temp;
 117 +       }
 118 +
 119 +       /* Set slave addr. */
 120 +       imx_i2c_write_reg((i2c_imx->slave->addr << 1), i2c_imx, IMX_I2C_IADR);
 121 +
 122 +       i2c_imx_reset_regs(i2c_imx);
 123 +
 124 +       /* Enable module */
 125 +       temp = i2c_imx->hwdata->i2cr_ien_opcode;
 126 +       imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
 127 +
 128 +       /* Enable interrupt from i2c module */
 129 +       temp |= I2CR_IIEN;
 130 +       imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
 131 +
 132 +       /* Wait controller to be stable */
 133 +       usleep_range(50, 150);
 134 +       return 0;
 135 +}
 136 +
 137 +static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx)
 138 +{
 139 +       unsigned int status, ctl;
 140 +       u8 value;
 141 +
 142 +       if (!i2c_imx->slave) {
 143 +               dev_err(&i2c_imx->adapter.dev, "cannot deal with slave irq,i2c_imx->slave is null");
 144 +               return IRQ_NONE;
 145 +       }
 146 +
 147 +       status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
 148 +       ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
 149 +       if (status & I2SR_IAL) { /* Arbitration lost */
 150 +               i2c_imx_clr_al_bit(status, i2c_imx);
 151 +       } else if (status & I2SR_IAAS) { /* Addressed as a slave */
 152 +               if (status & I2SR_SRW) { /* Master wants to read from us*/
 153 +                       dev_dbg(&i2c_imx->adapter.dev, "read requested");
 154 +                       i2c_slave_event(i2c_imx->slave, I2C_SLAVE_READ_REQUESTED, &value);
 155 +
 156 +                       /* Slave transmit */
 157 +                       ctl |= I2CR_MTX;
 158 +                       imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
 159 +
 160 +                       /* Send data */
 161 +                       imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR);
 162 +               } else { /* Master wants to write to us */
 163 +                       dev_dbg(&i2c_imx->adapter.dev, "write requested");
 164 +                       i2c_slave_event(i2c_imx->slave, I2C_SLAVE_WRITE_REQUESTED, &value);
 165 +
 166 +                       /* Slave receive */
 167 +                       ctl &= ~I2CR_MTX;
 168 +                       imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
 169 +                       /* Dummy read */
 170 +                       imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
 171 +               }
 172 +       } else if (!(ctl & I2CR_MTX)) { /* Receive mode */
 173 +                       if (status & I2SR_IBB) { /* No STOP signal detected */
 174 +                               ctl &= ~I2CR_MTX;
 175 +                               imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
 176 +
 177 +                               value = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
 178 +                               i2c_slave_event(i2c_imx->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
 179 +                       } else { /* STOP signal is detected */
 180 +                               dev_dbg(&i2c_imx->adapter.dev,
 181 +                                       "STOP signal detected");
 182 +                               i2c_slave_event(i2c_imx->slave, I2C_SLAVE_STOP, &value);
 183 +                       }
 184 +       } else if (!(status & I2SR_RXAK)) {     /* Transmit mode received ACK */
 185 +               ctl |= I2CR_MTX;
 186 +               imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
 187 +
 188 +               i2c_slave_event(i2c_imx->slave, I2C_SLAVE_READ_PROCESSED, &value);
 189 +
 190 +               imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR);
 191 +       } else { /* Transmit mode received NAK */
 192 +               ctl &= ~I2CR_MTX;
 193 +               imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
 194 +               imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
 195 +       }
 196 +       return IRQ_HANDLED;
 197 +}
 198 +
 199 +static int i2c_imx_reg_slave(struct i2c_client *client)
 200 +{
 201 +       struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter);
 202 +       int ret;
 203 +       if (i2c_imx->slave)
 204 +               return -EBUSY;
 205 +
 206 +       i2c_imx->slave = client;
 207 +
 208 +       ret = i2c_imx_slave_init(i2c_imx);
 209 +       if (ret < 0)
 210 +               dev_err(&i2c_imx->adapter.dev, "failed to switch to slave mode");
 211 +
 212 +       return ret;
 213 +}
 214 +
 215 +static int i2c_imx_unreg_slave(struct i2c_client *client)
 216 +{
 217 +       struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter);
 218 +       int ret;
 219 +
 220 +       if (!i2c_imx->slave)
 221 +               return -EINVAL;
 222 +
 223 +       /* Reset slave address. */
 224 +       imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IADR);
 225 +
 226 +       i2c_imx_reset_regs(i2c_imx);
 227 +
 228 +       i2c_imx->slave = NULL;
 229 +
 230 +       /* Suspend */
 231 +       ret = pm_runtime_put_sync(i2c_imx->adapter.dev.parent);
 232 +       if (ret < 0)
 233 +               dev_err(&i2c_imx->adapter.dev, "failed to suspend i2c controller");
 234 +
 235 +       return ret;
 236 +}
 237 +#endif
 238 +
 239  static const struct i2c_algorithm i2c_imx_algo = {
 240         .master_xfer    = i2c_imx_xfer,
 241         .functionality  = i2c_imx_func,
 242 +#if IS_ENABLED(CONFIG_I2C_SLAVE)
 243 +       .reg_slave      = i2c_imx_reg_slave,
 244 +       .unreg_slave    = i2c_imx_unreg_slave,
 245 +#endif
 246  };
 247
 248 +static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
 249 +{
 250 +       struct imx_i2c_struct *i2c_imx = dev_id;
 251 +       unsigned int status, ctl;
 252 +       irqreturn_t irq_status = IRQ_NONE;
 253 +
 254 +       status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
 255 +       ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
 256 +
 257 +       if (status & I2SR_IIF) {
 258 +               i2c_imx_clr_if_bit(status, i2c_imx);
 259 +               if (ctl & I2CR_MSTA)
 260 +                       irq_status = i2c_imx_master_isr(i2c_imx);
 261 +#if IS_ENABLED(CONFIG_I2C_SLAVE)
 262 +               else
 263 +                       irq_status = i2c_imx_slave_isr(i2c_imx);
 264 +#endif
 265 +       }
 266 +
 267 +       return irq_status;
 268 +}
 269 +
 270  static int i2c_imx_probe(struct platform_device *pdev)
 271  {
 272         struct imx_i2c_struct *i2c_imx;
 273 @@ -1392,10 +1578,7 @@ static int i2c_imx_probe(struct platform
 274         if (is_imx7d_i2c(i2c_imx) && i2c_imx->bitrate > IMX_I2C_MAX_E_BIT_RATE)
 275                 i2c_imx->bitrate = IMX_I2C_MAX_E_BIT_RATE;
 276
 277 -       /* Set up chip registers to defaults */
 278 -       imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
 279 -                       i2c_imx, IMX_I2C_I2CR);
 280 -       imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
 281 +       i2c_imx_reset_regs(i2c_imx);
 282
 283         /* Init optional bus recovery */
 284         if (of_match_node(pinmux_of_match, pdev->dev.of_node))